Hi Kate,Your reply was very useful. Your professionalism is greatly appreciated. Thank You very much.Kind regards,Saravan

New generation epoxy systems that combine unprecedented durability and easy processing improve the reliability and longevity of energy generation and distribution equipment including wind blades, high-voltage insulators and composite-reinforced conductor cables: To withstand extreme conditions, new methods for toughening the epoxy adhesive used in assembling blades are yielding impressive improvements in bonding quality to reduce skin/adhesive delamination and adhesive joint failure. Specifically, by utilizing nanoparticles during polymerization, Huntsman chemists are dramatically increasing

Dear Saravan,1) If water reaches the saturation point in the CO2, water will condense on the pipeline surface. The liquid water - carbon dioxide mixture will drive the corrosion by the significant concentration of the species. If water stays in the gas phase - hence below the saturation point - the concentration is a 1000 fold lower (density difference between gas and liquid). This fact can be traced back in the corrosion rates found(!)I believe that for H2O in CO2 the minimum saturation point is 1000 ppm at 30 degrees Celsius at a pressure 50 bar (see other thread on this subject).I don't

Hi Kate,The information you have given about corrosion of X-Steels was amazing. I have some questions about it.1) When it is said dry CO2 is non-corrosive .....what % of water content is required to make it corrosive.2) I am dealing with a fluid 99% CO2 and 0.8-1.4ppm of H2S. What do you think the corrosion rate of a X-52 steel would be for this fluid???3) My partial pressure range is 44 bar and temperature is 44 deg celsius according to thermodynamics of CO2 the fluid remains as gas in this state. So what kind of corrosion can I expect in this case????Your reply would be greatly appreciated.

Hi Kate,the information you have given about corrosion of X-Steels was amazing. I have some questions about it.1) When it is said dry CO2 is non-corrosive .....what % of water content is required to make it corrosive.2) I am dealing with a fluid 99% CO2 and 0.8-1.4ppm of H2S. What do you think the corrosion rate of a X-52 steel would be for this fluid???3) My partial pressure range is 44 bar and temperature is 44 deg celsius according to thermodynamics of CO2 the fluid remains as gas in this state. So what kind of corrosion can I expect in this case????Your reply would be greatly appreciated.

hi Kate,the information you have given about corrosion of X-Steels was amazing. I have some questions about it.1) When it is said dry CO2 is non-corrosive .....what % of water content is required to make it corrosive.2) I am dealing with a fluid 99% CO2 and 0.8-1.4ppm of H2S. What do you think the corrosion rate of a X-52 steel would be for this fluid???3) My partial pressure range is 44 bar and temperature is 44 deg celsius according to thermodynamics of CO2 the fluid remains as gas in this state. So what kind of corrosion can I expect in this case????Your reply would be greatly appreciated.

hi Kate,the information you have given about corrosion of X-Steels was amazing. I have some questions about it.1) When it is said dry CO2 is non-corrosive .....what % of water content is required to make it corrosive.2) I am dealing with a fluid 99% CO2 and 0.8-1.4ppm of H2S. What do you think the corrosion rate of a X-52 steel would be for this fluid???3) My partial pressure range is 44 bar and temperature is 44 deg celsius according to thermodynamics of CO2 the fluid remains as gas in this state. So what kind of corrosion can I expect in this case????Your reply would be greatly appreciated.

You might decide on your budget and then pick one of these in descending order of preference:1. Catia / Abaqus package2. Abaqus Computer Aided Engineering3. Patran / Nastran4. Femap / Nastran5. Ansys Workbencj6. Nisa, Algor, Cosmos, etc.Rgearding Chefem:CHEFEM adds - like it says - CHEmical interactions to FEM based engineering analysis. Specifically when dealing with chemicals and/or high temperature and pressure conditions Chefem is very useful. Why? One of the most important reasons is that the multiphysics packages listed above are not good in the solubility / diffusion / interfacial

Hello,I am a mechanical engineer in charge to assess a new equipment made from plastic based materials. Now, in order to select the appropriate materials and analyze the expected service life of the structure, we are orienting ourselves on existing FEM software, like Abaqus / Catia, Ansys, Nastran or SolidWorks Premium. According to the brochures, these programs not only utilize static, but also dynamic loads on composite structures, such as impact, torsional, flexural loads, and subsequent damage and failure analyis.Now, my questions are:- What FEM simulation program should I use?- Is the CLS

The course will provide the participants with a knowledge of fundamental principles of statistical mechanicsand thermodynamics, of how to link microscopic phenomena with macroscopic properties and of how to model complex chemical systems.The course is of relevance to researchers involved in molecular modeling, molecular thermodynamics, polymer physics and physical chemistry of fluids. People involved in process and / or advanced material design will benefit from it.Source: Technical University of DenmarkOrganizer: Technical University of DenmarkPlace / Date: Denmark, Lyngby, 28 June – 9 July

These sorts of chemical resistance inquiries look simple, but they are rather complex due to their reliance on solubility thermodynamics, diffusion processes and fracture mechanics (such as ultimate tensile strength). Unfilled high performance epoxy and vinyl ester resins being exposed to continuous exposure of Glycerol (Antifreeze) can be safely used in the temperature range till around 30 degrees Celsius. In the range from 30 to 50 degrees Celsius an appriate fibre reinforcement (woven roving / csm) can theoretically extend the application to this range. Above 50 degrees Celsius the material

Vikas Mittal from the BASF Polymer Research Laboratories has edited a one-stop resource for researchers and developers alike covering a plethora of nanocomposite properties and their enhancement mechanisms. With contributors from industry as well as academia, each chapter elucidates in detail the mechanisms to achieve a certain functionality of the polymer nanocomposite, such as improved biodegradability, increased chemical resistance and tribological performance. Special emphasis is laid on the interdependence of the factors that affect the nanocomposite properties such that readers obtain

Nima,Thanks for your posting. Could you explain you question a little more in detail. Are you interested in FEM related modelling of bio composite materials, specifically the long term physical - chemical behaviour of Truss Elements? What sort of FEM simulation program are you using, e.g. Abaqus, SolidWorks Professional, Ansys, MSC Marc

Hi,If it possible for you can you help me about Performance of Biocomposite materials As The Truss Element, tnx...Nima

Vikas Mittal from the BASF Polymer Research Laboratories has edited a one-stop resource for researchers and developers alike covering a plethora of nanocomposite properties and their enhancement mechanisms. With contributors from industry as well as academia, each chapter elucidates in detail the mechanisms to achieve a certain functionality of the polymer nanocomposite, such as improved biodegradability, increased chemical resistance and tribological performance. Special emphasis is laid on the interdependence of the factors that affect the nanocomposite properties such that readers obtain

Today Composite Agency releases the following press release in the framework of JEC 2010 (13 Apr 2010 / 15 Apr 2010 - Paris France):We have brought chemical interactions into FEM based composite analysis!No doubt that current FEM based multiphysics programs are state-of-the-art. The colourful Von Mises, displacement graphs, etc. are very useful and - also very important - look great!But there is one drawback. Usually they ignore effects of chemical/uv interactions with the composite matrix and reinforcements. Species solubility thermodynamics, subsequent diffusion, swelling, plasticizing,

Today I read in the Dutch Newspaper that the Canadian pipeline (which has just become operational) requires a Carbon Dioxide purity of 95% to transport the stuff economically. Do not have the slightest idea on the composition of the remainder 5% (perhaps methane and a few heavier products?). The pipeline is indeed made from X65 steel. According to the newspaper, they are pretty satisfied with the project and are looking for other projects which may include longer pipelines (this one is 204 miles, at the current oil price longer pipelines are becoming economically attractive also).

Thanks. So the depicted swelling isotherms for CO2 in Epoxy (picture in news section) changes over time? For proper design of oil and gas equipment (also think of applications containing PVDF) I can imagine that the swelling / expansion isotherms over time are of major importance. If the coating or structural material swelling beyond the specifications, the proof of the lifetime pudding is in the eating! Marc

Could you include the composite material behaviour during rapid gas decompression (RGD)? Rodney

Is the Composite Lifetime Simulation device capable of predicting material fracture, crack fatigue growth and surface degradation in a variety of circumstances? How does the presence of chemicals (say salt water, oxygen, nitrogen) influence the composite fracture in cycling loading conditions (think of a wind turbine blade)?Thanks,John

Swelling restraint is the restraint of mass and temperature driven due to adhesional / cohesional restraint by crystalline areas, chains of high molecular weight, and filler particles, like fibres. For aged materials, the swelling restraint usually decreases because the material relaxes, the adhesive degrades slowly etc. Hence, expansion increases over time. At the same time, the free volume of the polymer decreases as a result of physical ageing, this will result in lower diffusivities. For swollen polymers, the net effect will be an increase in permeation rate over time. Kind Regards,

Thanks.I have two additional questions on the Composite Lifetime Simulation program:- What does Mechanical / Swelling Restraint mean?- What is the effect of physical ageing on predicted behaviour: for example how is diffusion and swelling influenced by ageing?Regards,Marc

Many claims have been made by researchers and suppliers about the role of nano clays in plastics. When properly dispersed and bonded to matrix, most studies suggest nanoclay to impart improved strength, stiffness, creep resistance, low HRR, barrier properties at 1-5% w/w level. However, dispersing higher level nanoclay does not always produce consistent outcome. QC and QA procedures are time consuming and expensive. High level of surface treatement agents (>20%) and need for additional compatibilizers used causes higher level of discoloration, need for increased amount of heat stabilizers (

Jim,Unfortunately I don't have access to the article, could you attach it? Secondly, there is few work on X steels in CO2 environment that really contains hard and rigorous figure. The most rigorous statements I found so far are as follows:Corrosion of pipelines is an important issue. Dry CO2 does not corrode the carbon-manganese steels generally used for pipelines, as long as the relative humidity is less than 60 per cent; this conclusion continues to apply in the presence of O2, N2, NOx and SOx contaminants, which would probably be components of any CO2 produced by a CCS process. CO2 that

Composite Agency wishes you a Merry Christmas and a Happy New Year

Thanks for this post (we will definitely place this one in FAQ's for the software!).Multicomponent solubility and diffusion can be evaluated with IDC-SAC. The species data that is required for the lattice based thermodynamical and diffusion routines, are free volume, chemical interaction parameters (Hildebrand* solubility parameters) and density. For all species and polymers this data is available within existing literature and within the IDC-SAC simulation device. Regarding chemical reactions: these have partly been programmed but can also be backed-up with existing library information. For

Composite Agency completed the 4th and final module of the IDC-SAC simulation program: the Mechanical Restraint Module (a.k.a. Swelling Restraint Module). Short term as well as long term service life of composites is greatly influenced by the interfacial behavior.This new IDC-SAC module is based on a combination of Thermodynamic (Gibbs Free Energy analysis) and Mechanical analysis of interfaces between different materials. The applied concept allows - contrary to other commonly used concepts like Interlaminar Shear Strength (ILSS) - integrated analysis of interfacial behavior of composite

Hi does anyone have sorption isotherms(water) of the following products(at atmosferic pressure);abs 23-85°CPA6/PA66 23-90°C(or 80°C if 90°C is not available)PC 23-120°CPES 23-160°CPBT 23-130°C(120°C if 130°C not available)PPA 23-140°CThanks

Can multicomponent solvent interactions (think of carbon dioxide, hydrogen sulfide, water, hydrogen cyanide and nitrogen dioxide) be evaluated using IDC-SAC simulation? I am interested in solubility and swelling phenomena, diffusion and (simultaneous or subsequent) corrosion? Thanks, Marc

Jim,Unfortunately I don't have access to the article, could you attach it? Secondly, there is few work on X steels in CO2 environment that really contains hard and rigorous figure. The most rigorous statements I found so far are as follows:Corrosion of pipelines is an important issue. Dry CO2 does not corrode the carbon-manganese steels generally used for pipelines, as long as the relative humidity is less than 60 per cent; this conclusion continues to apply in the presence of O2, N2, NOx and SOx contaminants, which would probably be components of any CO2 produced by a CCS process. CO2 that

Are you familiar with an article called CO2 erosion–corrosion of pipeline steel (API X65) in oil and gas conditions - A systematic approach by Xinming Hu and Anne Nevillea (source: WearVolume 267, Issue 11, 29 October 2009, Pages 2027-2032 ICAP 2008) Could you please comment?AbstractA systematic study of pipeline steel (API X65) degradation due to erosion–corrosion containing sand in a CO2 saturated environment has been carried out. This work focuses on the total API X 65 material loss, corrosion, erosion and their interactions (synergy) as a function of environmental parameters (

Composite Agency has completed the 4th and final module of the IDC-SAC simulation program: the Mechanical Restraint module.This module is based on a novel Gibbs Free Energy - Mechanical Fracture analysis of interfaces between different materials. The applied concept allows - contrary to other commonly used concepts like Interlaminar Shear Strength (ILSS) - integrated analysis of interfacial behaviour of composite materials exposed to hydrostatic pressure and swelling driven by mass uptake and temperature gradients. The interfaces under consideration can be macroscopic interfaces, such as Epoxy

Thanks so far. Need to check some other internal issues with regard to Fusion Bonded Epoxy coating solution, I will get back to this soon.Michael

Recently Composite Agency has completed the 4th and final module of the IDC-SAC simulation program: the Mechanical Restraint module.This module is based on a novel Gibbs Free Energy / FEM analysis of interfaces between different materials. The applied concept allows - contrary to other commonly used concepts like Interlaminar Shear Strength (ILSS) - integrated analysis of interfacial behaviour of composite materials exposed to hydrostatic pressure and swelling driven by mass uptake and temperature gradients. The interfaces under consideration can be macroscopic interfaces, such as Epoxy and

Michael, Thanks for your enthausiasm. Probably the key advantage of Nano Clay based Epoxy say Fusion Bonded Epoxy materials in Oil, Gas and Chemical operation, will be their capability of restraining dimensional change due to temperature and mass swelling phenomena in the direction of the Nano Clay x and y, z properties will not alter very substantially. Especially for larger diameter pipelines say 5 inch and larger this could be a promising property much more dimensional stability of the composite coating which is of vital importance for prevention of delamination, blister formation and

Squeezing polymers into extremely thin nano layers can make them a whole lot less gas-permeable, US scientists have shown. The constrained polymer films are forced to grow as ordered crystallites, forming an effective barrier against diffusing gases.Anne Hiltner and Eric Baer from Case Western Reserve University in Cleveland, Ohio, were actually trying to develop a selectively permeable polymer when they made their discovery. The team found that sandwiching nano layers of polyethylene oxide (PEO) between layers of poly(ethylene-co-acrylic acid) (EAA) forces the PEO to form large, crystalline

Interesting subject! The following I just found on the internetIn general, Nano Clay's carbon-network composition makes it highly conductive and its two-dimensional geometry gives it a high surface area (between 700 and 1700 m2/g for Vor-x™ compared to 200 to 500 m2/g for CNTs, for example). In composites, this high surface area allows Nano Clay to improve properties like conductivity, barrier, and strength and to reduce a polymer's coefficient of thermal expansion (CTE) at low weight loadings, explains Mr. Crain. Nano Clay's greatest benefit in composite applications is found where a

Interesting subject! Here is a related quote I found from the internetIn general, Nano Clay's carbon-network composition makes it highly conductive and its two-dimensional geometry gives it a high surface area (between 700 and 1700 m2/g for Vor-x™ compared to 200 to 500 m2/g for CNTs, for example). In composites, this high surface area allows Nano Clay to improve properties like conductivity, barrier, and strength and to reduce a polymer's coefficient of thermal expansion (CTE) at low weight loadings, explains Mr. Crain. Nano Clay's greatest benefit in composite applications is found where a

Dear all,Thanks for the case with the simulation of nano Nano Clay (a one-atom-thick planar sheet of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice) in Fusion Bonded Epoxy (FBE). It really seems that the suggested system is capable of dealing with interfacial strains and pressures resulting from hydrostatic, temperature and swelling. This might certainly change the game for Hydrogen and Carbon Dioxide transport in large diameter pipelines (larger than 6-8 inch diameter). At this point, I am getting curious to possible drawbacks of this solution (mainly from the

DNV has developed a unified approach to help ensure that CO2 is transmitted in offshore and onshore pipelines in a reliable, safe and cost-effective manner. Det Norske Veritas (DNV) initiated the joint industry project, CO2PIPETRANS, to develop the standard one year ago. Existing pipeline standards had to be extended to incorporate specific guidelines for the transmission of CO2.The partners are ArcelorMittal, BP, Chevron, Dong Energy, Gassco, Gassnova, ILF, Petrobras, Shell, StatoilHydro and Vattenfall. Special acknowledgement is also given to representatives of the Health and Safety

Squeezing polymers into extremely thin layers can make them a whole lot less gas-permeable, US scientists have shown. The constrained polymer films are forced to grow as ordered crystallites, forming an effective barrier against diffusing gases.Anne Hiltner and Eric Baer from Case Western Reserve University in Cleveland, Ohio, were actually trying to develop a selectively permeable polymer when they made their discovery. The team found that sandwiching very thin layers of polyethylene oxide (PEO) between layers of poly(ethylene-co-acrylic acid) (EAA) forces the PEO to form large, crystalline

The design and fabrication of ultrathin polymer layers are of increasing importance because of the rapid development of nanoscience and nanotechnology. Confined, two-dimensional crystallization of polymers presents challenges and opportunities due to the long-chain, covalently bonded nature of the macromolecule. Using an innovative layer-multiplying coextrusion process to obtain assemblies with thousands of polymer nanolayers, we discovered a morphology that emerges as confined polyethylene oxide (PEO) layers are made progressively thinner. When the thickness is confined to 20 nanometers, the

Composite Agency,Thank you very much for your prompt reply.See attached paper on CFRP pipeline faiure behaviour at 150 bar for additional information to my posting pdf publication CFRP composite cylinders damaged by internal pressure. Their findings are in line with Composite Agency's statements on the IDC-SAC capability, but the publication lacks

Dear Donald Green,Yes, buckling modes of multilayer structures e.g. Polyethylene to Aluminum, Reinforced Epoxy plies, PU isolation on X65 high-strength steel, etc. are included in IDC-SAC.In case of internal pressure, temperature variations and swelling strains, I assume that at this point you are - above all - interested in circumferential buckling phenomena. The determination and prediction of this buckling behaviour in multilayer is an important core capability of IDC-SAC because this failure mode is a result of the combined action of internal pressure, temperature and swelling strains.

Hi Platform,I have been skimming the literature and internet for a rigorous but self-explanatory solution of the buckling modes of a multilayer pipeline, consisting of different materials say metal and - reinforced polymer, glued to each other with adhesive or with an annular space. The pipeline is exposed to 1 internal pressure, 2 temperature gradient and 3 a mass swelling gradient as a result of diffusion through polymers. Solutions should include as well as thin wall pipe in which membrane theory should apply as thick walled multi layer cylinder pipeline. I want to apply the

So what Who cares

Thank you for the answer.It helps

Jan, OK point taken. You are interested in a worst case gas flux of Methane through HDPE (note that if the Methane accumulates in a non ventilated environment or a ventilated environment with a slower resulting removal rate than the diffusive flux, Methane pressure will build-up in the annulus, which will reduce the flux as a function of time - then the interfacial space and removal rate is of importance). The bootstrap calculation for the worst case flux of Methane through HDPE at 6 bar is as follows:-Permeation of Methane in HDPE in ambient conditions is (IDC-SAC database figure):9E-13 [

Thank you for the explanation.Still I'm interested in the calculation:I just dont understand why is important to know space between HDPE and STEEL, when there is atmospheric pressure and space is ventilated, to prevent cumulation of methane. For me is important volume of diffused methane.Here are the conditions.What is the volume of diffused methane in one year, per meter of pipe, whenHDPE pipe has outside diameter 110mm, inside diameter 97,4mm, and methane has temperature 20°C, pressure inside of pipe is 600kPa ? HDPE pipe is inside steel pipe which has outside diameter 133mm and inside

Pressure inside is 6 Bar? Collapse resistance pressure for unaged thin HDPE cylinders is approximated by:Pcollapse = 0.365 * E * (t^2/r^2) with r >> tWith E is the Young Moduls of HDPE (08. Gpa, unaged), t is the thickness of the wall (6.3 mm), r is the radius (48.7mm) gives:48 Bar.Now since the maximum gas pressure in the interface between HDPE and Steel will never exceed the maximum system pressure (6 Bar), the interfacial pressure differential will always stays much smaller then the collapse pressure (48 Bar). After a certain time of loading the HDPE modulus will decrease, hence the

Thank you for the reply.Let say that Steel pipe is still tight, and gas due to the permeation through HDPE will accumulate and will create pressure outside of HDPE pipe. After depressurization of HDPE pipe pressure of permeationed methane between HDPE pipe and steel pipe may be so high that HDPE pipe will collapse?Did I understad this correctly?If yes, I will propose to create openings on steel pipe, and these openings will be connected to open surface, so methane could excape, and pressure level between HDPE pipe and stell pipe will be atmosheric pressure. Is this solution ok?Still I'm

Jan,Thanks for the posting.Yes, methane gas will accumulate - due to the permeation through HDPE - in the annular space between HDPE and the old steel pipe (at least when the old steel pipe is tight - then the secondary diffusion due to steel layer will be much slower - this should be checked because the story that follows assumes old but still tight steel).You will need a continuous flow in the annular space, to remove the Methane, and hereby preventing the HDPE inner pipe from collapsing in case of a sudden depressurization (of course this will also depend on the hoop/buckling stress

Relining is when you put new HDPE pipe in old Steel pipe.Outside diameter of new HDPE pipe is smaller than inside diameter of old steel pipe.There is a gap between pipes.Question is:Is there a possibility of accumulation of methane which flows in HDPE pipe and will diffuse in the gap between pipes? What is the volume of diffused methane in one year, per meter of pipe, when HDPE pipe has outside diameter 110mm, inside diameter 97,4mm, and methane has temperature 20°C, pressure inside of pipe is 600kPa ?Thank you

Many thhanks for your assistance. Ed

Dear Kurt:Good to hear! Good luck with the project!;-)Sijmon

Dear Sijmon,Thank you very much for your reply - and the remarks on the importance of thermodynamics with regard to pollution of potable water pipelines.Now I'm on track again!Kind RegardsKurt

Dear Kurt,The diffusivity of Xylenes and Ethyl Benzene into LDPE and HDPE can be extracted from available reference data. Temperature dependency can be estimated using Arrhenius Law. Below we list some of the diffusvities. However, note that with regard to pollution of potable water pipelines, the thermodynamics (resulting in a certain solubility of the chemicals in the polymer, giving rise to an actual drive force for diffusion, swellling or stress cracks) is just as - or even more - important than the actual diffusion coefficient.Diffusion coefficients (theoretical minimum figures while

i need diffusion coeficients of Mg , Ba and Ta. please let me know

Dear Platform,I'm looking for diffusion coefficients in order to determine diffusion of monoaromate gases - xylenes and ethylbenzene - into water pipes made of LDPE and HDPE.How do I calculate the effect of temperature and permeant concentration?May somebody assist me?Thanks in advanceRegardsKurt Overgaard

Hey Rodney,I know that glycerol solvents are mostly used to dry this stream. How big it is and what the costs are I do not directly know. But I think if you google glycerol, drying, CO2 you will find some things. It of course also depends on the capacity required to dry. A lot of current CO2 pipelines in operation have such drying equipment. I suppose they have looked if it is economical....Good luck!Tim

Hey Rodney,I know that glycerol solvents are mostly used to dry this stream. How big it is and what the costs are I do not directly know. But I think if you google glycerol, drying, CO2 you will find some things. It of course also depends on the capacity required to dry. A lot of current CO2 pipelines in operation have such drying equipment. I suppose they have looked if it is economical....Good luck!Tim

Hey Rodney,I know that glycerol solvents are mostly used to dry this stream. How big it is and what the costs are I do not directly know. But I think if you google glycerol, drying, CO2 you will find some things. It of course also depends on the capacity required to dry. A lot of current CO2 pipelines in operation have such drying equipment. I suppose they have looked if it is economical....Good luck!Tim

Dear Ed,Thanks for your interesting posting.SHIN-ETSU Sifel® is a rather specific sealant which stays flexible below - 50 degrees Celsius and is chemically resistant to Amine based oil additives. As a consequence of this low temperature applicability, the glass transition temperature is low - lower than -50 degrees Celsius - and therefore the free volume in the sealant will be considerable - at room temperature, and of course at higher temperatures. The Tg is -65 degrees Celsius. The available free volume determines the diffusion rate of water in the sealant.As such, the diffusion rate of

I have subjected a sealed silicone oil filled pressure sensor to 300 hrs of 95% RH humidity testing. The temperature varies between 15C and 60C.It appears based on sensor output at high temperatures (>100C) that moisture is entering into the sensor oil cavity.iSeveral type of Shin-Etsu Sifel sealants are used within this sensors.Sifel is a combination of perfluoropolyether backbone with a terminal silicone cross linking group.This materail has a reported moisture permeability of 5 gm /m**2* 24 hrHow does this permeability compare to silicone adhesives?I have no experiences with permeability

Structural weakness forces Boeing to retrofit the 787 Dreamliner.Boeing states that the issue with composites isn't that they aren't strong; it's that they are so internally complex. They consist of layers oriented in different directions; those layers, in turn, are made of individual fibers that may vary somewhat in composition. This makes it difficult for engineers to accurately mimic their performance in computer models for premanufacture testing.

Tim,Thanks for your message. Personally - also taking my example into account - I should not bother about the 50 ppm range - at least if you are able to remove the water also. Secondly, since I am not very familiar with chemical processing equipment, could you give an example of this state of the art drying technology which could dry below 4000 ppm in the conditions stated? Is it large sized drying bed equipment or what so ever? Thanks again.Regards,Rodney

Hey Rodney,Always interested in CO2 :D. I think from an economical point of view drying towards very low ppm levels is doing the trick (state of the art technology is already much applied with relatively low costs) and then just carbon steel (cheaper meter/ mile price) pipeline for long distance dense phase CO2 transport.The only thing where I am interested in, is what the exact effect of SOx, NOx, H2S, Ar, O2, H2,etc as a contaminent (like max 5% in the stream) in my CO2 stream is on corrosion (chemical and physical) of my carbon steel pipeline. The stream assumed to be dry to like 50 ppm as

Thanks Tim for rejuvenating this actual topic! Concerning the Water content in high pressure CO2: my impression is that an increasing CO2 pressure reduces the saturation fraction for Water. With a minimum around the critical point. Subsequently there is indeed an increase, but this is minor. At 30 degrees Celsius and pressures of 100 bar and larger, the saturation fraction stabilizes in the order of 4000 ppm. This saturation fraction is roughly ten times less than atmospheric air at 30 degrees Celsius, and hence equals a relative humidity of 10% in these conditions. Any amount above this

Rodney,If you look at the solubility of water in CO2, solubility is increasing after a certain point. An example from Sintef energy: pure CO2, 25C, from 65 bar the solubility of water in CO2 increasing when pressure increases, 1100 ppm-3300 ppm water in CO2 stream. If you dry your CO2 stream between each compression step and afterwards to for example 50 ppm, I would not expect free water in my pipeline (not by condensation), or do I miss something. I think some pipeline system will not be there for 100 years, this totally depends on the needed lifetime of the assets (CO2 source, transport line

Since heat shrink tubing is often cross-linked through the use of electron beams, peroxides or moisture - the cross-linking helps to make the tubing maintain its shape, both before and after shrinking - the permeation characteristics will be less than virgin material. However permeation in itself is in most tubing application not of major concern, usually the degree of swelling and/or stress cracking causes mechanical problems on the relative short term. With this regard, a PTFE based solution remains a good option. At least as long as the material is not strained for long times and exposed

thanks!Is there flexible PTFE tubing ? flexible enough to create a seal for gas over a glass pipette ? Do PTFE shrink tubes preserve the permeation charactaristics of ordinary PTFE tubing ?thanks again

thanks!Is there flexible PTFE tubing ? flexible enough to create a seal for gas over a glass pipette ? Do PTFE shrink tubes preserve the permeation charactaristics of ordinary PTFE tubing ?thanks again

Dear Shalom:Probably Polytetrafluoroethylene (PTFE) or Polyvinylidene fluoride (PVDF) based flexible is suitable. Also Polyamide (PA, Nylon 11 and Nylon 12) based flexible could be used. The permeability of 100% Acetone vapour in PVDF, PTFE, PA in ambient condtions is in the order of 1E-8 gram/m x s. Divide this figure by the wall thickness and multiply this figure with the total wall square to obtain the total mass flux per second.Polyethylenes could also be used but they have short life time expectation due to potential for stress cracks (the grades with higher crystallinity). Moreover,

Hilooking for tubing with at least fair resistance to Acetone vapor.need tubing with ID ~ 1/32 should be as soft as possible (must be able to slip over a glass pipette and seal to gas at low pressure)thanks

Hilooking for figures on permeability of PTFE tubing- specifically PTFE shrink tubing (no info by manufacturer)thanks

A new way of printing organic electronics is more reliable and yields higher performance. The interface behaviour (which is also important for diffusive transport and permeation properties) is improved to a substantial extent. Read the introduction by Katherine Bourzac.It is possible to print large, flexible arrays of cheap, plastic transistors to drive displays. But the performance of these organic electronics is still not consistent enough for commercial devices. A new method for printing a wide variety of semiconducting organic compounds such as polymers is much more reliable - and on top

Dear Platform on Ingrated Materials Simulation and Analysis, From a report on Breakdown Risks in Wind Energy Turbines, I rephrase the following on Rotor Blade Damage: Fibreglass rotor blades represent the most vulnerable component of a wind turbine. Lightning, Vibrations or contact with the tower can result in major damage to the blades. Design errors and manufacturing defects can also cause problems in the rotor blades during its operation. For example, blades can develop cracks at the edges, near the hub or at the tips. The possibility of the bolts breaking due to overload cannot be rules

Thanks, this is very helpful to obtain a ball park idea (which I need at this moment). Get back to this more thoroughly shortly.Keep up the good work,Nick

Currently this issue is of major interest since the diffusion rates of all commonly used chemicals in almost all commonly used polymers (including Polyethylene, PPS, PEEK, PVDF, Polyamide etc.) are usually higher than the metal. Hence after a relative short time, the liner or coating becomes saturated with chemical. Then a combination of swelling and possibly temperature stress at the interface comes to play. The interface stress as a result of mass swelling can be calculated with formula like (for a long thin walled cylinder):Scirc = [1 x (mass swelling of unrestrained sample in x direction

Nick, maybe the following is helpful:Titre du document / Document title:Horizontal cylinder-in-cylinder buckling under compression and torsion : Review and application to composite drill pipeAuteur(s) / Author(s):WICKS Nathan ; WARDLE Brian L. ; PAFITIS Demos ; Résumé / Abstract:Available analytical results and experiments on the structural behavior of constrained horizontal cylinders subjected to axial compression, torsion, and gravitational loads are reviewed. Such configurations are of interest to the oil-drilling field and provide static design expressions for steel tubulars. The

Nick, maybe the following can be helpful:Titre du document / Document title:Horizontal cylinder-in-cylinder buckling under compression and torsion : Review and application to composite drill pipeAuteur(s) / Author(s):WICKS Nathan ; WARDLE Brian L. ; PAFITIS Demos ; Résumé / Abstract:Available laboratory results and experiments on structural behavior of constrained horizontal cylinders subjected to axial compression, torsion, and gravitational loads are reviewed. Such configurations are of interest to the oil-drilling field and provide static design expressions for steel tubulars. The

Hello Diffusion Platform:I have a question on polymer based thin film solar cells, and specifically on an article Protecting OLEDs and Solar Cells from Moisture Using Nanotechnology and a Nanoengineered Barrier on www.azonano.com. I am not an expert in the field of Water Vapour Transmssion in Nano layers or Solar Cell / Photovoltaics, but several key statements in this article seem at least utterly

Dear All:Is glass fibre reinforced (Vinyl Ester) Epoxy and/or Polyester resin chemical resistant to Glycerol (Glycerol being conveyed in a pipe at ambient conditions: slight overpressure, temperature in the range of +5 to +60 degrees Celsius). Further to the information on this forum and website, I have some serious doubts on the use of comonly used FRP for Glycerol due to diffusion and swelling phenomena. Can the pipe collapse due to extensive swelling? What are other expected (corrosion / chemical resistance) failure modes or defects of such a piping system?Thanks,Hein

In March 2009 Pamela Waterman published an interesting article Composite Analyis Making New Choices, An engineering design guide to choosing software for working with today's Composite Materials on Desktop Engineering Online. Click here to read the overview article, please note the various links at the footer of the aticle

Water vapour condensation on - and diffusive transport in - thin polymer based flexible solar cell films can give rise to several physical-chemical failure modes, such as swelling stresses on interfaces, reduced impact resistance (Tg depression), blister formation driven by osmotic pressure or chemical degradation of another laminate component. In this in-house project, properties of transparent Polyimide substrates are researched, with the objective to enhance lifetime and to increase solar cell efficiency. Among others, the high glass transition temperature, low free volume and excellent UV

During June 24-26 the Fifth Internatial Conference on Diffusion in Solids and Liquids, Diffusion in Nano and Nanostructured Materials, Mass and Heat Transfer will be held in Rome. With regard to Mass Transfer the following topics are discussed: Basics of diffusion, Carburisation and Nitridation, Internal precipitation, Alloy heat treatment, Particle growth and coarsening, Microstructural and crystallographic texture evolution, Reactive diffusion,Phase transformations, Multiphase diffusion systems, Microelectronic and nanoscale systems, Interfaces, Diffusion in crystalline and amorphous materials, etc. Read more.

Can anyone suggest an appropriate model or calculation method for supercritical carbon dioxide and water, solubility and diffusivity as a function of the species temperature and pressure. If we would assume Sanchez-Lacombe (SL) equation of state, how would this influence the swelling behaviour of GRP and subsequent CO2 and H2O time lag, permeation rates and decrease in mechanical properties (assuming one sided exposure in atmospheric outside conditions). I am experiencing a fundamental lack regarding the previous, so please help!Thanks,Horst

Note that the initial thermal resistance of PUR foam (Polyurethane Micro Foam, 2003) is 0.0255 W / m K

Dear All:Current pipe in pipe or multilayer pipe solutions for heat transport consist (from inside to outside) of metal inner pipe, Polyurethane isolation foam and a PE (Polyethylene) outer pipe. My questions concern the following:- Does diffusion of water and other molecules in ground water through Polyethylene influence the service life of these hot water pipelines, more specifically: does the metal inner pipe corrode by diffused water?- What is the influence of joints and muffs on the water diffusion characteristics of these buried pipe in pipe solutions? How do welds influence the ageing

Dear All:Current pipe in pipe or multilayer pipe solutions for heat transport consist (from inside to outside) of metal inner pipe, Polyurethane isolation foam and a PE (polyethylene) outer pipe. My questions concern the following:- Does diffusion of water and other molecules in ground water through Polyethylene influence the service life of these hot water pipelines?- Does diffusion occur more probably via PE joints / muffs or comparable materials?- How is the water transport in the PU foam and how does this degrade / corrode the inner steel pipe (or 2 pipes)?- How does this influence

Dear Sheridelle,In case of this specific example, being EPDM rubber with Air as permeant this is very well possible. You may want to contact us for more information and / or similar calculations.With kind regards,Composite Agency

Hi everyone,Being a newbie on permeation, I´d need some help to understand some theorical subtilities about it.For my project, which is concerning an EPDM hose filled with air under a temperature that can reach 70°C, I would like to know how many volum of air i´m loosing every day.I would like first to determinate this volum in theory. But the facts are, that I don´t know how to proceed ! In the different books that i read on the subject, I can find a permeations´s rate for EPDM rubber under 65,6°C of : 3299 cm3.mm / (m2.day.atm)But all the equations (Fick´s equation) that i found are

Rodney,Could we get in contact with each other via mail?I still have some questions remaining about the transport of impure CO2 transport.You can reply and put send me email notifications on replies..... and still hide it for public. The moderator can then share emails, still safe way to get i ntouch.Thanks Tim

Hi ther..i just would like to know in more detail about the application of arrhenius model.Maybe I'll be very gratefull if you could explain or give example of the application of arrhenius model in power system component (ie:cable).How the load effect the temperature in a cable and how we can use the arrhenius model to determine the probability of failure of a cable when the temperature rise due to oveload

Two scientists from the University of Southern Mississippi have developed a polyurethane based polymer that can utilize UV rays to heal scratches:At the core of their design is polyurethane, which is an elastic polymer that already has decent scratch resistance. To enhance its ability to withstand mechanical damage, Ghosh and Urban added two more components, OXE and CHI. OXE has an unstable chemical structure (a four-membered ring containing three carbons and one oxygen) that makes it prone to being split open. CHI is UV sensitive. The idea is that, if the polyurethane gets damaged by a

Tim,HDPE is corrosion resistant to supercritical saturated CO2 (for examples 100 bar 25 degrees Celsius and almost saturated with water), since the pH of carbonic acid is in the range of 3 to 4. Carbonic acid is even in these circumstances a weak acid.Sulphuric acid is a nasty one. For a given concentration sulphuric acid is 500.000 times stronger than Carbonic Acid. For long term operation at very low pH, fluoro polymers (PVDF, ETFE) maybe better.Note that in high pressure applications the above materials are used in combination with stronger structural materials, such as metals. In that case

Do you have to perform a quick permeability or another physical - chemical oriented calculation? Are you on a congress and wondering why the presenter is so enthusiastic about the results, while you and your colleague are unable to quickly interpret the units he / she is showing to you?No problem from now on, use our brand new online unit converter.

Hello everyone,From the information that I gathered here and elsewhere I know that the corrosiveness and permibility of a pure CO2 stream through a HDPE is low and HDPE is resistent to pure CO2.What I want to know is what the corrosiveness is of CO2 in the presence of water > forming carbonic acids and what the reaction with HDPE is.Further, what if the CO2 stream contains small % of H2S, SOx, NOx,O2, H2, CH4, etc (with H2O), what will happen with the HDPE then (corrosiveness, permibility,chemical reactions between each other and HDPE, etc).I am keen on learning more about this!Thanks!Tim

Hi Akshay, furher to your questions:1. Diffusion coefficient according to the free volume theory Probably still the best theory for calculation of an unknown diffusion coefficient of a liquid or gas in a polymer, is the free volume theory for diffusion. The theory is developed by Cohen and Turnbull (1959) who considered transport in a liquid of hard spheres. Molecules reside, most of the time, in cages bound by their neighbours. Occasionaly a fluctuation in density opens up a hole within a cage large enough to permit considerable displacement of the molecule contained by it. Succesful

I have an interest in getting diffusion rates for metal ions through cation exchange membranes or other cationic media (such as ion exchange resins) in an aqueous environment. Example: diffusion rate for K+ ions across a 1 cm barrier of sulfonated poly styrene particles, where [K+] High=1M, and [K+] Lo is 0.0.01M (all components are in water, and the resin is in the K+ form). For the sake of experimental design, what is the best reputable calculation method to acquire insight in the multicomponent diffusion coefficients of ions and water in polymers and multilayer laminate materials? I read on

From the viewpoint of the CO2 pipeline material decision, supercritical CO2 transport is indeed the challenge of the current moment. Among others, the phenomenon of condensation of acid on the pipeline wall (indeed the solubility of water at the 100 bar is very low, hence in no circumstance carbonic acid formation will be prevented) will require at least an epoxy / vinyl ester based - or similar material - as structural material or coating. This is mainly due to the required lifetimes (at least more than a hundred years) of a carbon dioxide piping system. With regard to current developments:

We are orienting ourselves on pipeline solutions for CO2 (99.84% pure carbon dioxide) transport from, among others, coal plants to empty natural gas reservoirs. The fact that the water content in the CO2 is close to saturation (under the ball park assumption that the saturation water fraction in supercritical 17N carbon dioxide is 4E-3 from Spycher and Pruess, 2005) combined with the chemical reaction of - among other species - Carbon dioxide with Water under formation of Carbonic Acid leads to a requirement for long term corrosion resistant pipeline solutions. Two conceptual solutions have

Many thanks so far. Could you produce the water or vapour diffusion / permeation concentration profile and mass transfer for the flax - epoxy bio composite for a laminate consisting of 3 different plies? I remember this was once done for the water vapour transmission rate (WVTR) determination of GRP consisting of glass veil, chopped strand mat and a woven roving layer, after they had performed ASTM E96 and ASTM D570 laboratory tests for each layer seperately. The appplication is a cubic composite container for an electronic device. Brooke

I am interested in the long term chemical resistance of phenolic epoxy to chemicals like sulfuric acid (40%), nitric acid (30%), chromic acid (40%) and hydrofluoric acid (10%). Is there any source or reference for long term chemical resistance laboratory tests and/or simulation?Thanks,Frank

I am looking for water diffusion and permeation properties of photo acid generators (PAG’s) in a thin polymer film. This is for a semiconductor lithography application.Currently I use an experimental technique that enables us to get a ball park diffusion coefficient of a photo acid generator diffusing through a polymer into water flowing over the polymer surface (room temperature). In first odere, the experimental technique seems to give use reasonable results. However, we are interested in getting the temperature dependence (.Arrhenius relationship – activation energy) for photo acid

Thanks Brooke and Mark:Natural fibres, like flax and hemp, have a relative high strength and stiffness to weight ratio, relative high toughness, good thermal properties and are biodegradable. However there are some challenges in the practical use, which is an intrinsic poor compatibality between the fibre and several matrices, including pe, pp, vinyl ester, epoxy and polyurethane resin materials and inherent high moisture uptake and subsequent swelling of the flax (or hemp which is also used). At 23 degrees Celsius, the 100% moisture absorption of most low or medium hydrophobic polymers -

Interesting question.Currently in The Netherlands there are some green biocomposites projects going on. One involves the projected future replacement of steel by a biocomposite nose and real panels of the Dutch InterCity trains. The bio composite contains natural fibres, probably flax fibres, and ordinary high fire resistant resin. The suggested bio solution has lower weight and is more environmental friendly since it does not contain glass fibres. The overall long term physical properties - very probably also including the water permeation diffusion resistance of the flax - resin

Hi all,I am still interested in the chemical and long term mechanical properties of biocomposites, especially in a long term humid environment (80%, 90%, 100% of moisture). Specific interest are the following biocomposite formulations: - Polylactide based resin with 20 wt% natural flax fibre;- Furan based resin with 20 wt% natural flax fibre. Some basic information like water diffusion coefficient, water solubility, resin - flax interface behaviour and retention of Young modulus is already worthful, since I can not find a lot of chemical-physical property information on the bio composites

Dear All:Probably the best option is an epoxy (phenolic) based liner, with the structural strength of a tank in tank solution, and sufficient cast epoxy on the inside and outside of the tank (the glass fibres must be protected well from the water, otherwise capillary uptake and subsequent fibre-epoxy degradation may come into play, for exact laminate definition also the outside environment of the tank is of importance; atmospheric or moisture dry circumstances). Reason is that PP will not adhere to concrete and has insufficient structural strength, PU will have a better adhesion but swells

I am facing the same problem. We are supposed to store DM water at 60 Deg. > C in a RCC Tank. Two of supplier has proposed (1) PU coating (2) > Polypropelene Coating. I will be thankful to u if u can guide me which > suits best for application in Concrete tank

Alex,Demineralised water is much aggressive and will permeate coatings compared with potable or sea water. Blistering will be rapid if the epoxy or polyurethane coating is not designed for immersion service. From past experience this type of situation will call for a composite coating system consisting of sealer/primer, glass fabric reinforcement and a temperature/permeation resistant top coat. The exact details can be specified once the following questions are answered: Is there impurities in the water?Does the temperature remain constant or vary in each tank?What was the condition of the

Michael, thanks for the helpful website reference. I am mainly interested in epoxy tank coating / liner. Water temperature varies from 25 to 100 degrees Celsius. Is the adhesion between the epoxy coating and the concrete tank normally an issue?Regards,Micheal

Charles,Thanks for your joint interest in this issue. Please mind that my main interest is a resin or thermoplastic polymer on top of a substrate (coating / lining), and not corrosion of GRP, used as a construction material for tanks, pipes and several other chemical and civil engineering applications. Concerning GRP based on CSM and Woven Roving, the matrix material and sizings are of importance. Best,Alex

Jasper,This is not a silly question at all. To formulate the answer in the appropriate chemical - physical terminology takes some time and paper, hence I will try to keep it practical:Henry behaviour occurs in dilute solutions.If the solubility of the chemical stays below 0.1 vol%, the variation of the water vapour diffusion coefficient in a polymer is so small, that in most applications one may assume that the diffusivity is a constant (however for advanced electronics and medical controlled release applications care must be taken).Although the isotherm for several species in polymers looks

Dear,Again I have a very basic and possibly silly question: If a sorption isotherm for a certain material is Henrian (linear relationship between partial vapour pressure and vapour concentration), does this automatically mean that the diffusion coefficient of the vapour inside this material is not a function of concentration?Thanks again!Jasper

Could you include the corrosion of FRP composites by atmospheric moisture, more specifically do fibre sizings chemically degrade by water or is there some other mechanism trigger corrosion of FRP materials?Dan Harding

Many thanks for your assistance!Best,Rahul

Dear Alex:Further to the remark of Michael, I am curious whether - at an ambient temperature - a plastic, say epoxy, is required with or without glass fibres? I read that frp with glass flakes - although that the glass flakes add to the mechanical properties - are no good for the water, acid, alkaline (as is probably the case in the nuclear tank) FRP diffusion and chemical resistance. And what about FRP containing Chopped Strand Mat (CSM) or FRP with Woven Roving?What is the best FRP material avialable for these sorts of applications from the viewpoint of mechanical, corrosion resistance and

Alex,What is the temperature of the water inside the tank?Regards,Michael

Dear Drew:For the diffusion coefficient of moisture in Polyamide (Nylon) you may assume an exponential dependence on concentration. Note that this factor is only included to account for plasticization of the matrix due to presence of Water.Only for a ball park estimation the above described diffusivity is sufficient. To obtain an exact diffusion rate as function of humidity, one must include:- The swelling of the matrix (which makes the matrix move in the opposite water diffusion direction),- The chemical activity of water in the matrix (chemical activities drive diffusion process instead of

I go to school at the University of Minnesota Twin Cities and am currently working with a group on a design project to age a plastic part made from Nylon 6.66. In my research, I have found that this plastic absorbs moisture which leads to a decrease in the strength properties of the part. I have used the Arrhenius equation to determine the moisture uptake in the part as a function of the diffusivity coefficient and time but it is only for 100% relative humidity. I fail to draw the conclusion to moisture uptake and relative humidity. I believe the diffusion coefficient is affected by

Hi Jasper,Yes, correct. The ratio S1 / S2 is in diffusion literature often denoted as K, the distribution coefficient. K is dependent on temperature and pressure. The concentration is indeed discontinuous. The rate at which the discontinuous equilibrium is obtained, depends on the layer thickness and diffusion coefficients in each layer. However, if one material swells at the interface of two materials, the swelling stress usually exceeds - if no adhesive, surface roughening etc. is present - the interfacial strength (interfacial surface energies). Hence, holes appear, and the interface is not

Boron carbide (chemical formula B4C) is an extremely hard ceramic material used in tank armor, bulletproof vests, and numerous industrial applications. Check Wikipedia on Boron Carbide for more information

HelloI 'm looking for high temperature material(1200 degrees Celsius)which can applied to a roller surface. Surface should have durometer hardness 70-90 shore Thanks,Lev Shugol

Dear Sijmon,Thanks for your reply. Your reference on multilayer diffusion is helpful. I'd like to check whether I understand things by posing a little case:If you put two layers of different materials together (Henrian interface), each with their own solubility coefficient S and both layers contain the same initial diffusant concentration, will there then be a spontaneous redistribution of the diffusant over the two layers until C1 = S1/S2 * C2 (with a concentration discontinuity at the interface)? This means that there is transport of material despite the absence of an (initial) concentration

First of all thank you for this integrated forum on composite materials. Your intrinsic objective to combine mechanical, chemical and permeation knowledge in order to predict service life of plastic based materials is probably the one and only proper approach for long term analysis and quantification of composite ageing and fatigue phenomena in industrial applications. My question is not so difficult. However, since I have not found the answer so far, it probably requires some sort of integrated frp material approach.I have a glass fibre and/or carbon fibre epoxy composite which is exposed to

boron carbide ceramic powder is one of the hardest materials known, ranking third behind diamond and cubic boron nitride. It is the hardest material produced in tonnage quantities. It has the following properties and features: high purity, small particle diameters with an uniform distribution, low loose loading density, excellent mechanic, thermal, electrical and chemical properties, high abrasion resistance, high surface activity, corrosion resistance, high temperature resistance, low thermal conductivity, high modulus of elasticity. It is ideal for a wide variety of applications.

Hello,I 'm looking for high temperature material( 1200C)which can applyed to a roller surface. Surface should have durometer hardness 70-90 shore ThanksLev Shugol

What is the lifetime of a Glass Reinforced Plastic laminate exposed to an alkaline solution with pH 14? Although the GFRP product under our consideration exists more than 50 years, lack of computing expertise, still makes the above - perhaps trivial - question actual. Currently we are simulating the diffusion of Sodium Hydroxide through a GFRP laminate. The laminate consists of a boundary layer of 100% resin, with a subsequent layer of glass fibres (73 wt%) and resin (27 wt%). Unfortunately, the sized glass fibre have a poor corrosion resistance against Sodium Hydroxide (corrosion front rate

It is widely recognized that for the service life of polymer based electronic applications, UV resistance and chemical barrier properties are an important design parameters. Especially shelf and service life of polymer based laminate solutions, such as light and video displays, photo cells, etc., often depend on a combination of the before mentioned properties. Nevertheless, diffusion analysis is usually done using the layman's equations: Fick's Laws. In addition and paradoxally, current use of FEA simulation software leads to an increasing use of Fick's laws in all kinds of - in itself state-

We conducted a research on the effect of stress on diffusion of water in cast epoxy cylinders and found that the diffusion coefficient, using the free volume concept, is related to the stress as follows:Ds = D0 e ^[a * (S / G)]with:Ds = diffusion coefficient in stressed situation [m2/s]D0 = diffusion coefficient in initial unstressed situation [m2/s]a = ranges from 6 to 10 in our experiments [-]S = compressive / tensile stress [N/m2]G = SHEAR modulus [N/m2]In case of a bend bar, the alpha factor for the compression side (a is near to 6) is lower than for the tension side (a is near to 10).

Hi Gianfranco,I think that for your problem state-of-the-art simulation programmes are available, so programming by yourselves would probably be reinventing the wheel (unless you like programming and/or finding things out yourselves - please also bear in mind that it will take an awful lot of time...).

Thanks this is very helpful. We will be in touch shortly.Jon

Dear All:Our plastic hydrogen battery design requires the containment of hydrogen as well as water. I really would appreciate a brief summary of how Plastic A can be a better Hydrogen barrier than plastic B, but plastic B is a better water barrier than Plastic A. Furthermore, I am interested in long term mechanical retention due to the influence of - I suppose in this case - water in the polymer combined with temperature en compressive stress effects.Thank you in advance for any help you may be able to provide.Richard

Could you please help me with this confusing problem?Suppose, there is a PET bottle, which is evacuated and then filled with Neon gas at a sub atmospheric pressure...like 200 torr. Is it possible that due to higher permeability of Neon compared to air components, the pressure inside the bottle starts to decline in room condition, despite the higher pressure of outside? This is the result I obtain when I use the steady state permeation equation:Permeability=F*L/(Pout-Pin)Does this equation stand for this condition

DOT Offshore Symposium - The Netherlands Date: 3 October 2008 Location: Aula Congress Centre - Delft University of Technology. Presentations include topics by reputable experts on Deep Sea Installations, Offshore Production of Stranded a Natural Gas resources that are currently not used for economic/technical reasons Gas, Wind Turbines Installation Offshore, Carbon Dioxide Storage Opportunities, etc.

I just wanted to add that the coating thicknesses commonly used for the subject Fusion Bonded Epoxy (FBE) coatings and the Abrasion Resistant coatings, which I mentioned previously are as follows:FBE - we use coating thicknesses of between 14 - 22 mils, which give good corrosion resistance in seawater applications when considering about 5% coating failure for the life of the system (20 - 40 years)when using a cathodic protection system such as aluminum alloy anodes. This would apply to products produced by 3M and others such as Napco.Abrasion Resistant Coatings - we commonly use around 150

Many many thanks Neal for this valuable follow-up on the use of Fusion Bonded Epoxy coatings for cryogenic LNG pipelines. Specials thanks for the background information on the industrial application of FBE coatings! This post really keeps up the good work.Regards,Sijmon van der walComposite Agency

Further to my posting yesterday, hereby the method for moisture or oxygen time lag calculation for a multilayer laminate. The time lag (or breakthrough time ) follows from: (1) The stationary chemicals concentration profile in the laminate. The concentration graph enables calculation of the mean square displacement. Note that in case of anomalous moisture permeation steady state concentration profiles are curved (inward for dual model sorption, outward for Flory Huggins, etc.)(2) The mean overall diffusivity. Again in case of anomalous diffusion, the diffusion coefficient isn't often constant

Dear Jon,Thanks for the follow-up. My apologies for the fact that I haven't got much time to study your post or for putting the library figures in the IDC – SAC simulation program. Time lag is a practical measure for breakthrough time of chemicals diffusing through a layer. But realize that time lag isn't the time that the first molecules appear. They appear much faster on the other side than the lag time, and the first molecule will be on the other side within one second...(read more on this in Einstein's article on Brownian Motion). If the first molecules are already causing problems in

Hi Paula,Good suggestions.The 50-100 bars pressure was for accelerated ageing weathering conditions for diffusion, permeation and chemical corrosion, but is obviously wrong. Nevertheless, I am curious to accelerated exposure conditions concerning water, oxygen and carbon dioxide. Hence, let us increase temperature from ambient to say 80 degrees Celsius. I am sure IDC-SAC is able to transpose these figures back to more ambient environmental conditions using some sort of William - Landel - Ferry (WLF) equation (the WLF formula should be adjusted for the glassy polymers) and something more...

Hi Jon,I really appreciate your questions on this nice forum... Can you explain what the high pressure has to do with moisture and gas diffusion in solar cell substrates / polymer based photovoltaics ;-)? Secondly, I want to add something. If we would really go green, why not suggest a bio plastic for solar cell substrate material? What do you think of a multilayer laminate composed of polylactide or furan based coating resins (i.e. SiOx plasma coated)? Can you perform time lag and mass flux calculation, especially with regard to water, for these composite plastics also?Keep up the good work!

Dear All:Thanks Composite Agency for the valuable feedback. I have some additional rather fundamental questions / remarks on diffusion, time lag and water /oxygen / carbon dioxide / nitrogen transmission rates through mutilayer laminate structures under exterme high pressure (50 to 100 bar). The materials we are interested in:- Aluminum oxide (transparant Al2O3) on top of Polyethylene Naphthalate (PEN)- SiOx (Quartz) - Polyethylene Terephthalate (plasma coated PET)- Aluminum oxide - Polyimide - Aluminum Oxide- HDPE - Ethylene Vinyl Alcohol Polymer (EVOH) - HDPEThe question are as follows:-

Dear Jasper,Many thanks for your post.I think the following case: hydrogen diffusion in polyamide on steel is of your interest. Specifically the part on diffusion, and probably the analytical multilayer solution presented in the appendix.One comment to this concept paper (originally produced for JEC Composites in April 2008): if the interface between two layers is tight, you may assume that the solubility coefficients are

I need to get some rough calculations done on the permeability of HFC-134a across various polymers (polyamide, polyethylene terephthalate, polyethyelene naphtathalate, polyether etherketone, etc.) at different pressures and different wall thicknesses of 0.25mm - 0.75mm. Ideally I would like an Excel spreadsheet created -or the diffusion multilayer simulation programme described on the website (IDC-SAC software) - that I could plug in different values. I am trying to determine if I can make a small injected molded part containing HFC-134a (Chemical Name 1,1,1,2-tetrafluoroethane, Molecular

Hi,I'm interested in a theoretical description of transient diffusion of a vapour through material interfaces of multilaminates of different materials, that each have a different solubility coefficient towards this vapour. e.g. How does the vapour accumulate at the interface? What does the surface concentration discontinuity look like as a function of time? etc.Does anyone know any relevant literature on this?All best,Jasper Michels

Hi,I am a research scientist involved in the development of medical electronic packaging solutions. Recently, I read an article on water and oxygen scavengers in polymers and resins for reducing water vapour and oxygen transmission rates (the actual example was on Oxygen in Polyethylene Terephthalate). I am not sure about the principle, does it work like silica gel or some sort of nano polymer getter? Thanks,Ron

Hi Max,The issue you raise is rather interesting. Here follows a short and very global calculation of the Amperes in a plastic based Solar Cell:-100% Sun Light ~ 1 kW/m2, -Polymer Based Solar Cell Efficiency ~3% = 30 W/m2-Voltage ~3 VoltAs Power = V x I, then it follows that I=10 A/m2.I think most the conductivity of the polymer can be neglected, compared to 10 Amperes per square meter. Moreover, as a transparent substrate, more hydrophobic polymers are used. Water diffusion rate [m2/s] and total water vapour transmission rate [WVTR gram/m2 day] of candidate materials, such as polyesters:

3M Corporation have developed a FBE coating that can take down to -300 deg F and up to +300 deg F, so it can be used in cryogenic LNG pipeline applications for an offshore environment. Recent tests by 3M have proven that it will work in cryogenic applications. We are using it on the product pipe in a subsea LNG pipe-in-pipe application where the product pipe is protected from corrosion during transit from the mill and during on-site fabrication. The FBE coating actually will then spend its life within the annular space, which is filled with nitrogen and an aerogen high efficiency insulation

Hi Albert, According to the book of Springer, Environmental Effects on Composite Materials, change in strength and in modulus depends upon a) the material, b) the temperature and c) the envirionment (relative humidity of air or type of liquid chemical involved). It states that the weight uptake and change in strength and modulus are related, whereas saturated salt water, antifreeze and indolene have the most influence. After drying of the exposed samples it appeared that the losses in strength and Young modulus did recover - but not to their original values. Unfortunately this was not modelled

Rahul,Many many thanks for your reply! My primary interest is the electric conductivity of the plastic - or polymer based - substrate in real-life conditions, i.e. moisture from the atmosphere (as a result of rain or high humidity) which is capable to diffuse into any plastic material. With glass this is indeed not a potential problem. On the other hand, plastic substrates are lightweight and mechanically flexible...Polyamide is quite hydrophilic, so the electric conducitivity will definitely change during water exposure. How much Voltage and Electric Current (Amperes) did you obtain per

p.s. the electrical conductivity of Polyamide without moisture equals 10 E-12 S/m [A/ V m

Dear Rahul,For my thesis, I am currently working on an evaluation of different substrate materials for solar cells. Do you know whether electric current loss through plastic of polymer based substrate materials is a significant issue (probably with and without the presence of diffused moisture - i.e. some sorts of Polyamide have an equilibrium moisture uptake of 20 wt% - does this cause electric current loss)?I have some idea of the electric conductiivity of polymers, so in essence I want to know the electric current in a polymer based solar cell of 3 to 5 Volts (at the Tin Oxide anode side)?

Dear Neil,Thank you very much for your suggestion on the Fusion Bonded Epoxy Coating (FBE) solution. Are you familiar with any recent case or case history of the application of FBE (type of material and coating thickness) coating in environmental conditions that resemble the environmental conditions stated as close as possible?Thanks Again,Joe Lee

Hi Jay,You can assume that the comparative permeation figures by Du Pont definitely have the correct order of magnitude. However realize that a factor that is very very important with PTFE and TFM in case of diffusion, solubility and permeation calculations is the degree of crystallinity. If you could provide us with the figures you have, we may be able to assist you in a detailed manner. Note that in case of PTFE and TFM, Helium permeation is a good measure for worst case mass transfer through the material.Regards,Composite Agency

I have seen comparative numbers by DuPont. Can anyone help me with this, may be helium volume/area/time for a 1 and 2 mm thick PTFE and TFM material? Thank you in adavance. JA

Thanks for your replies!I recently fabricated my first Organic Solar cell using glass substrate and nano layers of organic polymer blends. Now working on reducing the environmental effect on the cell and increasing its efficiency!Thanks,Rahul Gaba

We have a problem with liners/coating on the concrete tanks filled with demineralized water in a nuclear power plant. Liners are:- epoxy based and/or - polyurethane based (both 1-2 mm thick) Liner is separating ('blistering') from the concrete substrate. Do you have any experience or explanation? Can your chemical - physical simulation programme (the IDC-SAC tool) for coating assessment deal with this sort of industrial application in a proper manner?

Dear All:I want to programme a simulation programme for heat transfer in a metal pipeline with an organic coating on the inside. With this regard I have two questions: - what programming language can I choose best? and - do I solve best with finite element analysis or finite difference methodology? What are the advantages/disadvantages of these mathematical simulation / estimation methods for temperature gradient and flux calculations.Thank you all in advance.BestGianfranco

Joe, According to our experts there are about 30 years' track record for the use of FBE as an external pipeline coating. An ISO standard (ISO21809-2) has been published this year. However, this standard does notrefer to cryogenic conditions (which do not normally apply forpipelines). For the coating to be qualified for cryogenic conditions, itneeds to be based on a known code/standard. What code/ standard would a qualification (testing) that you refer to be based on?If you can provide me this information for a FBE coating, I can supply you with the name of a product that will fit your

Many thanks Hendrik for your interesting reference! Indeed X-60 is the preferable material for transport of gases like Hydrogen. With regard to CO2, especially if some water is present, I would really think that polymers or plastic based composites have the potential to show a better overall technical and economic performance.Thanks again,Holger

Hello Holger, In the United States there are a few big CO2 pipelines at this moment. The material that they use for the pipeline is carbon steel (X - 60).I dont't have any info on corrosion etc. at this moment present but there are many scientific articles writen about this subject. A big US company that build/own CO2 pipelines is "Kinder Morgan" You could try to contact them. (my excuses for my english i need to refresh it) Greetings Hendrik

I'm looking for a novel polymer based coating material to be used in organic photovoltaics for a solar cell. Reason is that combined exposure to moisture and UV light reduce photovoltaics ability to convert sunlight in electricity. Therefore most polymer, or thin film, based solar cells have a service life of about 25-30 years. Currently some technologies are being developed, such as a Photon Conversion Material (PCM) coating which converts UV light in visible light (using blue Polyfluorene). This solar cell technology is perhaps promising, but seemingly adds (only) 5 years to the lifetime. I am looking forward to you comments!