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Polymeric Materials - Science topic

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Hello and have a good time
We have a viscous polymeric material that is used as a thin coating on the ceramic part of piezoelectric disks in shock sensors.
This material helps to reduce noise and increase the sensitivity of the sensor.
We separated the material using heat and sent it for FTIR testing. Experimental results show that the main chemical composition of the substance is triacontane. Which is used in making wax paraffins. What is the reason for the performance of this material on the sensitivity of the sensor? Also how can I find these materials commercially
You can see it in the attachment
Thank you very much
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The shear strength of foams is a question. All of them currently are made with a uniform density of say 50 or 100 KG/ CU.M. The maximum shear stress is invariably related to their density. So why not have a higher density at the core and a lower density at the surface, there by maintaining a  low over all density, in order to have a high shear strength at the core ? Will this FGM idea work for a manufacturer ?
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hello dear padmanabhan
I'm interested in FGMFoam solver and i wanted to know can you send it to me?
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Consider a small tube made of polymer or ceramic (inner diameter of about 3mm, outer diameter of about 1cm, and 5cm length), inside which a high-gas pressure should be generated in a short time (few microseconds). How can we measure the maximum gas pressure that the tube can withstand before it breaks or deforms, even before starting the actual experiment?
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Dear Mohamed A. Abd Al-Halim, please check the following links. My Regards
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What are alpha and beta relaxation, seen in polymeric materials (observed in dielectric studies)? I wanted to know the physical origin and the way to identify them in dielectric spectra.
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Dear Vipin Cyriac, these are types of local segmental motions each related to a special sequence of repeating units along and by side of the main chain backbone. They are detected in amorphous (co)polymer (and blends) in the range of the glass transition temperature Tg. Please have a look at the following links. My Regards
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Might be a silly question for this forum, but I need round polymer fibers approx 10µm diameter, minimum 50mm length but preferably on reel. Preferably non toxic. Preferably European supplier. Anyone that can point me in the right direction?
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Hi Petter,
You may make an inquiry at Alfa Chemistry, they offer kinds of good-quality materials.
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Dear All,
Is there any standard procedure for torsion test of polymeric materials under static loads at ambient temperatures or an existing standard for other materials should be used?
Best Regards,
Hamed
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Dear Hamed Sadaghian, various set of experiments are possible. Please check the following documents. My Regards
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Dear All,
Is there a unified standard for pure shear testing of polymeric materials?
Best Regards,
Hamed
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Dear Hamed Sadaghian, please check the following chapter. My Regards
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I am studying a thermoplastic polyester elastomer. I want to get a prony series from the data available that can be further used for FEA simulations. Is there any way to obtain the prony series parameters from the available data.
(Data sheet is attached)
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Hello Ashu,
Maybe these papers help you:
Methods of interconversion between linear viscoelastic material functions. Part I—A numerical method based on Prony series
Viscoelastic relaxation modulus characterization using Prony series
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What polymeric material has the most similar properties as nylon 6.6 in terms of the processing and mechanical properties, and it is not from the polyamides family?
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Dear Magdalena Góra, a rough suggestions, may be polyacrylonitrile, poly(metha)acrylates and polyurethane. My Regards
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Hello-I am currently writing a research proposal regarding degradation of certain polymers by bacteria but I am not sure what kinds of assays I should be running to identify particular secreted extracellular enzymes that are involved in breakdown of the polymer. Any suggestions would really be appreciated. 
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Dear Tori,
I recommend you to check:
Handbook of detection of enzymes on electrophoretic gels.
Gennady P. Manchenko 2nd Ed.
CRC Press
ISBN 0-8493-1257-4
You can find a lot of protocols to detect enzymes by zymogram.
Best regards
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Dear Researchers :
Does anyone have experience or knows specific works about the study of Mechanical Properties (i.e. , tensile strength, yield stress, limit of elongation (%), elastic modulus, etc.) of Polymeric Matrices...
These could be:
- Polyethylene/Polypropelene (PP)
- another PP or PE co-polymer, ter-polymer, etc
- EPR
- EPDM
- HDPE, LDPE, LLDPE
or other plastics or elastometers blends
but when Al2O3 particles (or nps) are embedded in the matrix ??
I will appreciate any help, or any direction,
Best Regards !:)
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Dear Franklin Uriel Parás Hernández, literature is really rich with the subject you are studying. Please check the following documents. My Regards
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By considering the fewer number of repeating monomeric units than polymer i.e. Oligomers. How Oligomers are better than polymeric materials in different applications like mechanofluorochromism, gas sensing, or other stimuli-responsive?
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Dear all, these are general information : low solution/melt viscosity, less prone to mechanical degradation, ease of synthesis and processing. My Regards
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in literature we find a lot of studies to check the stability of the polymeric materials by DSC analysis. like PE materials properties were analyzed by measuring the variation in oxidation induction time (OIT). However, no specific studies were performed for the PVC materials (mainly pipes). Can anyone please provide specific reason for that ? or if studies were performed please provide. thanks
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Thanks to Jose Filho and Roland Wilder for kind response,
I will look into it.
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Hi all.
I want to make polymer composite ink for 3d printing(Extrusion method).
so, I need a polymer matrix that has low melting point(~100 C, low is better)
And also it should have low viscosity for easy mixing with other material.
Is there any polymer candidate you could recommend for me?
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Looking for a cheaper alternative to PDMS with similar flexibility and low melting point.
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Flexdym is a great alternative to PDMS, which saves you time and money.
The fabrication protocol is only 2-15 minutes long, depending on your application. And because Flexdym is a thermoplastic, it can be recycled and re-molded.
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I am currently running thermal polymerizations of compounds that form free radicals at elevated temperatures (T>120 degrees C).  I want to attempt to polymerize at discrete temperatures between 120 and 200 degrees C.  
Can I use AIBN radical initiator at these elevated temperatures without risk of explosion (in the literature it seems that AIBN is typically used at temps ranging from 60-80 degrees C)?  
If not, is there another radical initiator I can use at temperatures this high??
Thanks!
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Dear Mohamed Chaala, the best is the one that insures high solvation and low transfer reaction. The solvent is much more choosen with respect to the monomer first. My Regards
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To calculate the cristallite size L We need K the Scherrer Constante
what is mean this parameter and what is its value for the polymers
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Dear Belouadah Abdelhakim, please take a look at the following document. My Regards
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Hi everyone,
May I ask if there any ideas to fix the PET film on the glass substrate for nanoindentation test? Because PET itself is not able to attach to the substrate, if we fix the film only by using tapes adhere on four sides of the square shape glass substrate, the film might dislocate during indentation causing the results to become inaccurate. Your ideas and suggestions will be much appreciated. Thank you
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Ok no problem. Your suggestion is much appreciated. Thank you so much.
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My Industry R&D lab is considering purchase of an MS system to go on our existing Waters UPLC. Currently the only MS capability we have is a single quad GC/MS system. We want to be able to (1) analyze larger MW molecules outside of GC range and (2) be able to deformulate competitive product materials in adhesives, and various polymeric materials of various chemistries as well as low abundance additives, etc.
my main concern is that I am reading that sample cleanliness can cause big issues for qTOF work and we typically are analyzing complex formulations. qTOF seems to be the way to go for qualitative identification but how good is it with quantitation compared to a single quad system? how is sensitivity to low abundance compounds?
Thank you!
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Thanks for your response. I'm familiar with GCMS and with UPLC. I'm mainly refering to the differences between a single quad MS and qTOF systems for a UPLC.
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For my Ph.D. I require polymer membrane (those are irradiated by high energy particle and used in chemical etching). I want to purchase below 80nm pore size membrane. Many companies produce this but they give only packet up to 10000Rs. If anyone can exchange polycarbonate membrane, please contact me.
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Dear Mukesh,
You may make an inquiry at Alfa Chemistry, they offer kinds of high-purity chemicals.
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we specialize in styrene-butadiene emulsion polymerization, we run conversion to 60%, and we recover the unconverted (1.3 butadiene) at a purity of average of 73% and major impurity is (cis-2 butene), how can we minimize this impurity formation
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I agree Jing Jin, You can try to change the solvent of emulsion polymerization because that the content of 1.3 butadiene is controlled by the polarity of the solvent.
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Some residues from ferilizers coatings, and products of hyrogels/agrogels degradation are accumulated in plants tissues. I am looking for literature about this issue, where I can find more details, especially, data related to polymeric contaminations like products of degradation or microplastic. I will be grateful for any help.
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I want to dry the magnetite nanoparticles (Fe3O4) and then coat them with the polymeric material.
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Dear Sedef,
first you have to wash your NPs with the Deionized water and ethanol to remove the impurities, then separate your NPs with the magnet in the plate and upside down the plate to remove solution and keep only the NPs. Now you can put it in to the oven at 40C during the night. Be careful not to increase the Temp since it will affect your magnetization.
I hope my answer was helpful.
Also for more information for preparing NPs and coating you can read this articles which I have done some studies before.
  • 10.1088/1361-6528/aaa2b5
  • 10.1039/C7RA08903A
  • 10.1088/1748-605X/aab8d7
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Is there any reference to explain the polymeric bonding mechanism of epoxy resin polymeric adhesives to carbon fiber reinforced polymer (CFRP) laminates or strips. I am a structural engineer and I would like to understand the chemistry aspect of this bonding process.
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You did not specify the resin used for CFRP. The adhesion mechanism all depends on what resin is used for making the composite. However, both thermoplastic matrix or cross-linked thermosetting polymer all exhausted the chemical reactivity by making the composite laminates. Even for a popular matrix for making a composite, epoxy resin matrix, the chances are that the epoxy does not have chemical functional groups left to form covalent bonds with the epoxy adhesive. This leaves the secondary bonding interactions, such as hydrogen bonding, van der Waals interaction and mechanical interlocking, the only bonding mechanisms. For example, an epoxy used for making CFRP will have residual hydroxyl groups to which the epoxy adhesive can hydrogen bond. In case you can heat treat the bonded system to rather high temperature, these hydroxy group can potentially form ether bond (covalent bond), but this is not a usual situation if you use room temperature or near room temperature curing conditions. In case the composite laminate surface can be roughened, then the epoxy adhesive can form some mechanical interlocking, which will further enhance the adhesion.
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I am currently trying to characterize the behaviour of different plastic polymers, in particular when stretched in an uniaxial direction.
I already conducted the classic tensile test, and got a general idea of the different features that the materials show, but I am having a hard time trying to measure their stretching stiffness; any suggestions on lab tests for this?
I found an equation linking stiffness to the elastic modulus and the resisting cross section, but I`d rather find it in a different way so as to not refer to a single type of test for all of my data.
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Take a look at this article, it can be helpful to you
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I need a few polymeric materials that are not water-soluble and at reasonable prices. Can someone guide you?
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Many polymers are water insoluble in market.Nylons,PP,HDPE LDPE,ABS,PVC,PC,PTFE,PMMA,SAN,Polystyrene etc.But important is your application (purpose) or what out of it you wants to make and how much you require?
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I need to solve a polyurethane binder and the recommended solvent is NMP( N-Methyl-2-pyrrolidone ) but I have to replace it with another solvent due to material  shortage. Is there any alternative ?
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This is also my question. I am working on this topic currently, and my preliminary experiments shows that heat treatment can have a positive effect on leaching. I will publish the results of these experiments in the future.
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the food containers are manufactured from polymeric materials which in direct contact with the food inside it and i would like to improve their buckling strength by addition several nano materials to the polymeric materials.
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Silicate nanosheets such as montmorillonite will be sufficient. You could try with nanocellulose as well or hybrid of montmorillonite and nanocellulose.
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Hello Dears ;
Why we use the Ethanol Alcohol for cleaning the surface of polymeric materials.?
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Besides cheapness, ethanol is usually provided as 92% or 95% which means a water content of 8% or 5%. As such, the mixture ethanol/water will display adequate solvating power to cleaning the surfaces of polymers. We cannot use absolute ethanol (~100%) for cleaning polymers.
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Which failure mechanisms would be triggered by temperature cycling on a polymeric part? (Is it only thermal fatigue?)
I am doing accelerated temperature cycling by simulation, Which criteria can represent latent defects on material? (Creep strain rate, equivalent plastic strain, E-modulus reduction,...)
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And to find hysteresis bending, would be equivalent plastic strain a suitable clue?
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I build a chamber (10ul) in a PDMS for PCR application but when I heat the chamber (after 5-6 cycles), evaporation occurred and vanish the liquid in the chamber.
It seems the inlet and outlet of the chamber have leakage.
Is it possible that the vapor leak from above of the chamber (2mm PDMS)?
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Dear Mohammad reza,
welcome,
So, it seems that the PMDS is permeable to the vapor the material enclosed in it.
May a remedy is to seal the surface of the chamber by coating it with thin film of noble metal like gold.
Best wishes
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I have accessibility to a cheap source of plexiglass scraps. I am thinking to a recycling projects and producing new products based on PMMA recycling. What is your suggestion for PMMA recycling? What can we make from recycled plexiglass which has both economic value and innovation??
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PMMA cannot be easily recycled & it is not usually collected for such a purpose. Recycling a plastic proceeds if it is worthwhile doing in regard of cost & ease of processing and getting reasonable profit after the effort that is done.
It is possible to get the methyl methacrylate monomer from PMMA solid waste by depolymerization but this process is energy-intensive.
It is unfortunate that there is no relevant research on "facile" recycling of PMMA although PMMA is almost non-biodegradable as a waste. In some places, they try to get rid of it by pyrolysis.
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Actually, after adding PDMS (polydimethylsiloxane hydroxyl terminated Mn~600 g/mol) in DMF, it's very hard to distinguish or elucidate whether the polymer got solubilise! But I think the material is getting solubilise.
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DMSO and DMF cannot solubilize hydroxyl-terminated PDMS. IPA and THF can. May I know where I can find a list of LogP of common solvents? I have problem by mixing polyurethane and hydroxyl-terminated PDMS together. Thanks.
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Artificial Membranes, Polymeric Materials, Membrane Technology
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It depends on the membrane you make. There is no specific time for the flux to be stabilized. Some of the ultrafiltration membrane reaches a steady state after 30 minutes, the others take more than 2 hours to be stabilized.
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I fabricate polymer solutions with a high viscosity and degass them under vacuum. But when I want to pump these solutions, air bubbles produce again. What is the suitable pump for moving solutions without getting air bubbles.
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Low RPM gear pump should perform best for your material.
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If I measure Polarized Raman spectrum for graphene sheets, what are the informations I can get from it?
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Thank you so much Mr. Dheeraj Kumar
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I grow adherent cells on polymeric materials and want to stain cells without using fluorescence.
The stain should be
1. water-based (no alcohols or organic solvents) in order to preserve the integrity of the material
2. intense and stain at least the cytoplasmic fraction of the cell
3. resistant to dehydration
4. stable for at least one week without the requirement for mounting
Many thanks!
Valeria
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Please reformulated your question as follows:
- Histological stains are not water based ! Why??
read this link:
The Difference Between Water-Based and Solvent-Based Dyes.
these dyes are used to paint and NOT in the HISTOLOGY.!!!!
Also :
Which water based histological stain stains the cytoplasm of my cells?
(Valeria dixit)
Use soluble instead based
Well, you must read this book:
B. Romeis Mikroskopische Technik
Also:
I grow adherent cells on polymeric materials and want to stain cells without using fluorescence.
(Valeria dixit)
What a kind of cells (HeLa, Fibroblastes, tumor cells...)
IMPORTANT, do you want to stain the cells in VIVO or in VITRO??
For in Vivo staining, some dyes will be transported in the cytoplasma and
will be found in lysosomes.
For in Vitro staining and after fixation, the dyes will stain cytoplasma and nucleolus
What a kind of dyes do you want to use?
- Basic
-Anionic
-Neutral
Also:
Intense and stain at least the cytoplasmic fraction of the cell
(Valeria dixit)
Please read the book :
Molecular Biology of the cell Bruce Alberts et al. 1983 Garland Publishers USA
Also:
resistant to dehydration (Valeria dixit).
Do you mean the use of toluene/ethanol after staining (in order to avoid a shrinking).
As you see your question remains OBSOLETE if you don't reformulate and
give the required infos.
JRG
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I need to wash paper with 1% PVA, but don't have any proper guideline.
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1% could be 1% by volume or 1% by mass. This is not defined.
If we get to 100 mL of final solution then (by volume) 1 mL of PVA needs to be diluted in 99 mL of water (to make 100 mL total - Lewis's final concentration is 1/101 and thus not 1% w/v...). However, if there's volume change then this isn't the most appropriate way - here the comment of Rafik is applicable (dissolve 1 mL or 1 g in 50 mL and make up to 100 mL in a standard flask)
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Hi,
I would like to check the bio-compatibility of a polymeric material. what are the biochemical/toxicological test or any other method that I can perform in order to prove the bio-compatibility.
Any suggestions on cell line culture or any other method will be highly appreciated.
Thanks in advance for your kind help and suggestion.
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Dear Sir. Concerning your issue about how to check the biocompatibility of a polymeric material. An in vivo method is described for screening polymeric materials for biocompatibility. The test is based on grading acute and subacute tissue reactions at 7 and 28 days, respectively, following implantation in rats. The method is reproducible and reliable. It is designed to provide uniform test criteria for biocompatibility assessment in the early phases of the development of surgical implant materials. I think the following below links may help you in your analysis:
Thanks
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What is the difference between FTIR and ATR-FTIR?
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ATR (attenuated total reflectance) is a special accessory unit which can be used with FTIR (Fourier transform infrared) spectrometers. It enables you to measure directly onto a solid state sample surface by pressing the sample towards an ATR crystal (e.g. diamond), including liquid and gas samples, thus avoiding the need to prepare pellets (small concentration of sample in e.g. KBr, mechanically or chemically dissolved) for use in the normal transmittance mode. The ATR FTIR technique makes it possible to study materials which are non-transparent to infrared radiation in a pristine condition. Hence, the extensive, time consuming and often cumbersome sample preparation by pressing thin KBr pellets as in traditional FTIR transmittance spectroscopy is avoided. The traditional technique might even change the sample material in question. The ATR technique is based on a special reflectance setup where the sample is pressed directly onto various crystals with high refractive indices, e.g. diamond. Further details may e.g. be found in the following article (which may be requested through Research Gate): B. P. Jelle, T.-N. Nilsen, P. J. Hovde and A. Gustavsen, ”Accelerated Climate Aging of Building Materials and their Characterization by Fourier Transform Infrared Radiation Analysis”, Journal of Building Physics, 36, 99-112, 2012.
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Does anyone know the good parameters of sonicator (times, temp, and power) for good dispersion of cellulose nanofibers in water and modification of MWCNT?
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Hi Paula,
It works well with low concentration (0.1 - 0.2wt%), so would be 0.1g of CNF need 100 or 50 ml of water.
For bacterial cellulose, once it is formed a membrance, it is hard to disperse even at low concentration.
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Due to their poor electrical and mechanical proprieties, many polymeric materials are not suitable for electric power applications, mainly for electrical insulation. For instance, PVC is widely used in industrial applications, it is intended only for low voltage application though, because of high dielectric constant and high losses.
On the other hand, it has been found that Calcium carbonate, for example, improves the base properties of PVC by adding stiffness to the polymer matrix.
How can improve the mechanical and electrical properties of polymers (PVC, PP, PE,...etc)? and what are the most common (recent) methods used so far?
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As the polymers are now a good alternative to metals in today’s manufacturing world, the above efforts and the current work present in your work aim to give a clear understanding of the ability of PVC to work safely within the designed loads in the applications where PVC is used.you must conducting polymer blend electrolytes complexed with magnetic nano particlewere prepared using a solution casting technique .
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for producing glass fiber reinforced polyamide 6 composites, we used recycled polyamide 6 which viscosity is 3.5, but after compounding its high viscosity and molecular weight caused problems in injection molding process. so we have to reduce molecular weight of polyamide. can anybody help me about this problem?
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Dear Nooshin,
Firstly, I don’t know that you have already solved your problem by finding the adequate answers.
Based on a long experience in the field of PA6, I will say that the grades with relative viscosity between 3 and 5 are mostly designed for the processing by extrusion. Presence of glass fibers will increase contribute to the increase of viscosity in the molten state. Please take a look on BASF’ documentation for PA.
But how to proceed to use these PA-GF for injection molding, process in which a big fluidity is required? I assume that other colleagues will propose the reduction of PA6 molecular weights using undried polymer to promote its hydrolysis, by adding specific additives or products, but I believe that it is a key-point to arrive to a controlled process of PA6 degradation- which could be for discussion, whereas in presence of some oligomers the aspect of injected items is not very nice.
I’m rather for traditional solutions such as the increase of injection molding and mold temperatures, addition of processing lubricants or small amounts of plasticizers…
Good luck and best regards,
Marius
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Consider we are testing soil  and polymeric material as a stress controlled -shear test.
we will plot stress- strain. In this case after getting peak vale, is it possible to get lower values compared to peak value after the peak value is achieved?
Normally in strain controlled test for example in soil, we will get peak value and lower ultimate value.
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YES. There are loading rate dependent components - by applying F you can't control the loading rate v... This is a point I'm defending in my Ph.D. thesis:
Equation of motions has 3 components, K, C and M (stiffness, viscosity and mass)
F=K*u + C*v + M*a
If F is the input, then some set of u, v and a will be the output. Therefore, we cannot "isolate" K by applying F, because all three components are generated: (1) static stiffness K*u, (2) dynamic viscosity C*v and (3) inertia M*a.
This is especially problematic in geotechnics, as all three components (K, C and M) act as nonlinear, state / phase dependent functions.
The C component is especially noticeable in partially undrained sand. Pore water takes time to drain, therefore pore-pressure buildup is loading rate (v) dependent. It can generate reduced strength in contracting (liquefying) phase of loading, and/or additional strength during expanding (dilating) phases of loading.
Therefore, it is crucial to keep both v and a under control, at very low values, to measure quasi static stiffness K. It is crucial to recognize the difference between "F as the input" and "F as the output"... It is NOT OK to "input the output"...
If F is the output: u, v and a are the input (v~0, and a~0 is required, to isolate K*u).
If u is the output: F, C*v and M*a are the inputs. F can't be applied without generating C*v and M*a.
This makes a HUGE difference in loading rate sensitive soils (such as partially undrained sand, at the sea floor, reacting to impact loads).
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I'm going to print a polymerization material by PZT inkjet printer. So, will it accelerate the polymerization. 
And the frequency is 5 kHz.
Thanks.
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Ultrasound is just that - a frequency above that of hearing.  If you have a high vibration rate then you'll induce cavitation as whatever vibrates, moves and creates a vacuum in the space if the fluid can't follow the movement.
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Hello!
What is the best solvent for Polyactivetm polymer (77 wt % of PEO (1500 g/mol) and 23 wt % of PBT)?
I should make at least 3 wt.% solution to cover PSF support. So the solvents shouldn't affect polysulfone. Any suggestions?
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 I might try DMF/EtOH/H2O
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I am doing the UV cross-linking of isoprene in porous polymeric film. I know that the reaction is successful because after cross-linking film is not more soluble in organic solvents. However I need additional analytic method to prove it and desirably to calculate the % of cross-linking. Will be grateful for yours suggestion.
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Dear Luliia:
My advice is to use FT-IR.  If the shape of your sample is such that the measurement is complicated - you can use an FT-IR ATR method.  The proposed way is the easiest and the fastest.
I do not advice you to use Soxlet extraction method - because - the crosslinking reaction will continue in the course of extraction- and the extent of crosslinking  will be over-estimated. 
Good Luck to you with your experiments,
Leonid
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I want no agglomeration of metal particles in the PLA- chlorofrom solvent solution. I am using solvent casting method to make the composite and finding the composite is not electrically conductive. 
I want the composite to be electrically conductive. Any suggestions
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Dear Krish,
In addition to these suggestions, don't forget to consider dispersing polymers created for engine oil additives.  These have to disperse soot particles and metal wear particles.  I suggested one such material (Chevron OLOA 11000) on ResearchGate many months ago.  Perhaps if you search for that answer I posted, or look at the types of chemical functionalities that the internet shows you when you query it about OLOA 11000 then you may get some good ideas about other dispersants to try.
To also echo Dr. Goya, please be certain your system exceeds the percolation conditions for the morphology of particle and volume packing fraction in your application.
Best regards,
Mike Bender
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I am producing polymer porous membranes through non-solvent induced phase separation and I need to extend the length of finger-like structures. It seems like sponge-like structures are always formed on the side that is distant from the coagulant/polymer solution interface (the part of the nascent membrane in direct contact with the support).
What is the main parameter that affect the finger-like morphology and that can be controlled in order to promote the formation of this specific morphology only?
Additionally, which is the best analysis to reach a better understanding about the motivations and dynamics of finger-like formation process?
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Actually ,Shape of pore is depend on the miscibility or exchange rate of solvent and non-solvent during phase inversion,temperature and concentration of polymer. Miscibility of solvent and non-solvent largely depend on solubility parameter at particular temperature.Higher the miscibility between the solvent and non-solvent,faster the phase inversion process,which formed the larger pore on the bottom part.This is due to the  sudden rush of solvent towards the non-solvent which drag the polymer along with towards the non-solvent side and  space vacant by the polymer is converted into the pore.If polymer concentration is low ,means solvent concentration is high,high solvent amount of solvent observed the large drag along with polymer towards the non-solvent during precipitation.Due to that reason polymer solution with lower concentration always leads to the larger pore during phase inversion compare to higher polymer concentration.
           One another parameter is drying time.Drying time of cast solution allowed the solvent to evaporate  from the surface and leads to the formation dense or less porous structure on surface compare to bottom side of the membrane.
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Will blending low concentration PVA to another high concentration, both have the same molecular weight, affect the swelling degree and hydrophilicity??
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Dear Asmaa, 
It may depend on the physico-chemical compatibility of the blend. Also, be very careful which kind of polymer you are adding in the composition. If you are trying to prepare a film which is insoluble in water you may have to chemically modified PVA by cross-linking. 
good luck. 
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if there is any such polymer would that be available commercially? 
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I suggest NYLON 4/6  which is also called POLY(TETRAMETHYLENE ADIPAMIDE).
This polymer has the properties you look for, e.g. it has a melting point of 295 °C so it has heat resistance at the temperature you mentioned.
It is commercially available (see this reference) but ask the supplier to provide all the necessary information. Wishing you success.
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I have been looking for sometime without success on the web and in the literature for a curable polymer with an intermediate Youngs Modulus range:3MPa-500MPa.
Could anyone give me some suggestion on this?
Thanks
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Hi,
I think PVDF should be good..another polymer we looked at is polyurathene..wat do you think?
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Can be better if the exact series of polymer is known.
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PP is one of the most commonly used polymers, and has good mechanical properties, heat resistance, low cost, ease of processing, and full recyclability. Its biggest drawback is low impact strength, which can be improved by a toughening modification. Therefore, a blending method, the most efficient and easy, has been widely used. Polyblends are a product by melt-blending or solvent-blending two or more polymers. The mechanical or physical properties of polyblends depend on the phase morphology, action between continuous and dispersed phase, and the component ratios.
There are some polymers which can be blended well with PP such as PE. The blends of PP with HDPE, LDPE, LLDPE, VLDPE, ULDPE, and PET have been studied etc. For a toughening modification, other thermoplastics or elastomers are used as modifiers to blend with PP in order to increase its toughness.
Hope this will help.
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Hi
I need to make a thin biodegradable film with high tensile strength. 
Any suggestions for a polymer or a mixture that favors hydrogel formation would be appreciated.
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Thanks Ricardo
I have already considered PLA and it is biodegradable. However, I am looking for other alternatives.
If anyone has any in-house polymer and ready to share, then it would be a good venture to explore and re-discover new applications of the polymer.
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I started a project that deals with the diffusion of gold nanoparticles through elastomeric films.
The films will be contacted with an aqueous solution of gold nanoparticles (5 nm in diameter) with a concentration of 50 ppm.
The elastomeric materials should be nitriles or silicone.
Is there a chance that elastomers will swell due to contact with water? Will the free volume created between the chains following the swelling be sufficient to let the 5 nm nanoparticles diffuse through the rubbery structure? If so, what techniques can I use to track / detect these nanoparticles inside the film structure.
I’m new in the field, please provide me your suggestions on the subject and thank you in advance.
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the AU NP are not suitable for this 
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I'm working on a project on drug delivery system. My team is researching on the conjugation of HPMC (a semi-synthesized polymer) and Zein (a protein extracted from corn). If anyone knows any information about how to conjugate those two (maybe make them become a micelle we suppose), please let me know. Thank you so much for your support. You are helping to create a new tool for advanced nanomedicine application in enhancing the dissolution rate of poorly water soluble drugs!
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Hydrophilic-hydrophobic polymer blend for modulation of crystalline changes and molecular interactions in solid dispersion. go through this article 
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I have read in one journal that the blending of PMMA into PVDF will enhance the transparency of the membrane. Does anyone know what else we can do to produce transparent membranes?
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PVDF is a semi-crystalline polymer while PMMA is a amorphous polymer, by blending them we can get a miscible blend of constituent polymers which are transparent. 
Usually we can make transparent films of PVDF using polar solvents such as DMF. It's transparency highly depends upon synthesis conditions such as humidity, ambient temperature etc. Under optimized conditions, we can get nearly 70% transparent films.
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I would like to calculate degree of crystallinity of nanocomposite masterbatch blend based on PLA/PHBV with L-CNC nucleating agent?
There is no bimodal endothermic peak..
PLA is Ingeo 3251D
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Martin, 
I understand that you can have been excited seen your DSC.
What was your personal interpretation and the one of your advisor?
I suppose you are limited by the DSC capability to get the Tg of the PHBV and to get a controlled cooling rate.
Could you share the first heat of your DSCs?
Could you share the cooling curve?
What is the repeatability of your DSCs for that 50/50 mixture utilizing your procedure?
Regards
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I am new to XPS and my background is complete different (Electronic Engineering), so please excuse the naivity of my questions. 
1. Lets say I have some XPS data of a polymeric material and I got C-1s and O-1s specta and I want to obtain the C1s at% relative to O1s. Peak fitting and literature indicate that there are multiple peaks in both related to chemical shifts. In the C1s there are peaks associated with C-O and C=O bonds. Does this mean that there have to be curves for these two also in the O1s spectra? Each of these peaks will be related to an at%, the three peaks from the C-1s (one being the C-c core line) and the two from the O-1s. What should be used to calculate the at% of C relative to O?
2. I want to compare the XPS spectra ontained from surfaces processed differently (temperature) to see how the at% of each element is affected. Should all peaks remain at the same B.E.? should their FWHM remain constant?  
3. What is the best way of displaying survey spectra in a publication with regards to background subtraction? Should I use a linear background or a Shirley for the whole spectrum?
4. For the C-1s peak should I use a symmetric or assymetric curve?
5. How should one decide on the Gaussian/Lorentzian ratio?
I am using the ThermoFisher J-Alpha and the Advantage software.
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Wow! This is the starting point for a section of a course on XPS. Background correction. Peak shifts. Peak fitting. Spectral display. That is a lot!
My first recommendation is one that is made in many forums on software when someone enters who is brand new and basically says ... Tell me everything you know about how to get this specific result (implicit: so that I can do what I need right away without really having to do any background studies on it).
--> Read and do tutorials. Read the manuals. Read subject books on the topic. Read the background literature specific to your system.
My second recommendation at your point is to find a subject expert in the field who can guide you with your studies. I imagine that Imperial College should have someone who can fill such a roll.
Now, specifically ...
1a) The literature you have should provide the answer to your question.
1b) The ratio of C/O is the atomic % of C to the atomic % of O. A reference on XPS will explain how this is determined.
2) Generally, peak positions and widths (and shapes) should remain the same for the same chemistry. The positions and half-widths may change depending on how the chemistry of the material changes. Deciding when to change peak positions and half-widths is actually part of the detective work.
3) Survey scans are displayed without background subtraction. High resolution scans should be displayed with the background included. It should be at least a Shirley and possibly a Tougaard.
4 and 5) This is part of the detective work. The chemistry of the sample dictates the shape, position, and width of the peaks. But, you do not know the chemistry of the sample exactly to start. So, you have to "guess" at what it is, use the corresponding peaks in fitting, and see if you get results that are consistent with what is expected. Otherwise, change the shape, positions, or widths of the peaks and try again. The mystery of proper peak fitting in XPS is that it is NOT a black box where you input specific peak assignments and get out your sample chemistry unambiguously. It is rather an interactive process where you learn what is best for your sample by testing various options. The good news is that you have a wealth of resources to help you find the best starting points for your peak fitting. You only have to go explore them more thoroughly.
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Attached is a graph adopted from an article (ACS Nano, 2012, 6 (2), pp 1427–1437) which shows, increasing the number of layers in an Inverse opal film, leads to a decrease in the fraction of filled pores upon immersing in a liquid. Its based on percolation modeling. 
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seems that with number of layers pores below surface get less and less accessible.
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I have been producing polycaprolactone fibers by means of electrospinning on an aluminium foil onto a metallic collector plate. After the polymer fibers have deposited on the foil, I remove it from the collector plate. How can I store these fibers? Until now I have been folding the aluminum foil and labelling it with the name and suitable parameters used to produce that particular fiber. . But I have realised that this is not the way one is supposed to follow as the fibers are fragile and folding the foil may break the fibers. What is other alternative solution? This would also help me  carry the fibers from one lab to another.
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You can use desiccators so that it will remove moisture from fibers and protect from water vapour in the air. So that your fibers shelf life can be increased without any changes.
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I'm a trainee in a company which supplies space engines and we currently use an encapsulating epoxy resin (Stycast W67) with a low viscosity (200-300 cP) but a very long polymerization time (22 hours). We want to replace it in order to gain time. 
Thanks for your answer. 
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MERECO XL-389 has a viscosity close to water and cures 2hrs. at 60 C
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Polymer scientists
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Hello
I would react on the comment by Gökhan Topçu. Light scattering techniques can give you polymer chains dimensions, but these are NOT equal to the length of the polymer chain! Most common is the evaluation of the hydrodynamic radius Rh, which is the radius of a hypothetical sphere with hydrodynamic properties equal to the polymer coil.  The chain itself can easily be order of magnitude longer than Rh. Therefore, Rh (and other radii from scattering methods) will depend on the solution properties, temperature, etc. Only if you would have the chains in a fully stretched conformation (highly unlikely for most systems), then Rh would get close to the real chain length.
What is possible is to measure the Mw of your polymer and then, supposed that you know the length of the repeating units, Mw and the molar or weight fractions of the two blocks, you can calculate the total length of the polymer chain and the block lengths.
Regards
Josef
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You can see on the curve, the Young Modulus decrease. Is there a problem with our machine or it's due to material plasticization and matrix / fiber decohesion ?
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it'ok. Best regards...
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I'm working on a non-hygroscopic non-swellable matrix..
Can anyone guide me in this regard?
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No Sir, PVP is hygroscopic. There might be some specific grade of it whch would be nonhygroscopic
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How can I significantly increase the viscosity of a low molecular weight polyisobutylene binder (treacle consistency to soft solid consistency), in-situ, at room temperature but over several weeks?  Slow cross-linking, but how?  Any other ideas?  
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I don't know if this will help you...but. The industrial means to crosslink polyisobutylene is to add around 1% isoprene during the polymerisation of the poly isobutylene. The resulting coploymer can then be crosslinked using sulphur as you would for a natural rubber. The rate of crosslinking will be slow at room temperature.
If you are stuck with the pure polyiosbutylene binder I would try leaving under a UV light and see if that promotes more polymerisation (probabaly wont croslink) and an increase in viscosity over several weeks.
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what is the best method could use to get a well-defined network to appear in SEM as I have prepared before and actually gave a good application in swelling and absorbance butt with low characterization confirmation.
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thank you for your interest and reply
My Goal is preparing a full interpenetrating network and FTIR studies already confirm formation bond between C-O and N-H but unfortunately network does not appear in SEM.However, I got very good swelling  once applying 
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Hey everyone, I am working on the project about to synthesize thermoplastic polyurethane as hot melt adhesive by using MDI and butane diol as hard segment and polycarbonate diol as macrodiol.
After first phase of research, I chose some formula to synthesize again. I did exactly the same procedure that I used to synthesize my previous samples. But it turns out with different properties, including thermal properties, crystalline structure and of course mechanical properties.
I know that maybe because of moisture impurity in MDI and other chemicals. I did even resynthesized over and over by using freshly open bottle of MDI and DMF (solvent), but the results still the same.
I also reviewed synthesis papers and handbook again and again to find out what I missed about synthesis method. However, I could not find anything.
Could anyone tell me about the factors that affect properties of TPU, please?
Thank you so much in advance.
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Did you check the MDI for dimer (uretdione) content, is it a clear melt at 46°C? If not, either filter or decant it or distill it. Further, did you check the polycarbonate diol for water (it has to be less than 0.02 %) and traces of decomposition due to added amine catalyst? By using DMF with only very low amine content (< 1 ppm) the amine will damage the chains of the polycarbonate, the same is with tertiary amine catalysts. Is the time of preparation of all the batches always identical? With polycarbonates, minute changes may have a great effect on your PUR properties.
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Can be any product but the result must be a soft polymer, like a market bag
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Dear Marcelo, give a look to epoxidized vegetable oils. Probably you can find some not expensive. Regards
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Nylon 6 polymer is producing some high molecular weight polymer not suitable for Yarn spinning.The yarn breakages are observed .
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Dear Rajesh,
Your question is a little general because the good spinning of PA 6 is determined by numerous factors & constraints that must be satisfied to obtain fibers of good quality. Please consider as essentially the selection of adequate grade of polyamide (e.g., molecular characteristics for spinning, usually the industrial producer is giving some additional information regarding the relative viscosity in sulfuric acid solutions (e.g., 2,4 – 3.2). Then, it is important to dry carefully your polymer and to use the adequate processing parameters for spinning.
On the other hand, where the grade of PA 6 has high molecular weight (e.g., relative viscosity between 4-6), due to the high viscosity in the molten state, the polymer is mostly indicated for the extrusion of monofilaments, rods, tubes, plates, etc.
I will recommend to use for more information the web site of BASF regarding the various grades of PA 6…
Good luck in your R&D works,
Marius
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From the project it seems that the recycled polymeric materials can be used for fabrication of tiles. when we used it as a tiles material it becomes close in contact with the human body. so how can we made this material eco-friendly.
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Waste material recycler are available but we have confined ourselves to safe waste plastic. But later on we will be working on PET and PVC recycling also.,
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Is percolation or percolation threshold phenomenon applicable only in conducting filler-nonconducting polymer matrix system (e.g CNT-Polycabonate) ? or it can also be applicable for conducting filler-conducting polymer matrix (e.g CNT-polyaniline)? Please open the discussion. 
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Anil, Gyorgy and all - percolation ptheory  for threshold phenomena can only be applied for systems, where the dispersed / distributed phase (particles, holes or else) are statistically randomly distributed (as Gyorgy mentioned about the holes in dams).
As soon as the dispersed phase (particles, holes, droplets) size is less than 1 micrometer in diameter, interfacial interactions are playing the dominant role and it is impossible to statistically randomly distribute the particles - instead, they are forming "dissipative structures" which have very fine complex forms and deliver the connectivity which end up in a threshold, see review or my original publications here:
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Hi.
In my team, I'm now responsible for synthesizing a strong anionic-exchange material, which involves the task of attaching tertiary amine functional group on a poly(vinylbenzylcholride-co-divinylbenzene) base, using triethylamine (TEA) in varied volumes of toluene.
I'm having trouble with the washing step, which would remove the residual TEA. I tried using HCl 2% (v/v) in acetone, but I could not control the formation of the resulting ammonium salt, which would precipitate and deposit on my synthesized material.
Please suggest me any other appropriate cleaning method. Furthermore, I'd like to ask a detection method for residual TEA, since I don't know whether scanning for its absorption peak in the 210-220 nm region is the correct way or not.
Many thanks in advance.
I can make it clearer if the descriptions are not detailed enough, so please don't hesitate to pop in your questions.
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I dont know it can help you or not as my case is different. I have to use TEA for functionalization of PEO with p-Toluenesulfonyl chloride. In that case I do an work-up of my product with ammonium chloride in water-DCM followed by drying in MgSO4 and precipitation in ether. That procedure gives me a complete removal of TEA and you may find some interest.
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  1. Materials
  2. Packaging innovation
  3. Morphic, malleable 
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Please refer to recently synthesiized structurally dynamic polymers. There is large variety of these polymers. They may be molded under specific condition such as temperature, light, or other conditions.
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We have a certain quantity of HDPE pellets recovered from waste. We are considering the possibility to cross link the polymer pellets in extruder.
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 Good idea. Your raw material stream maybe fairly degraded, check brittleness of the X -linked jackets, to find balance of peroxide with acceptable brittleness control
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 Percentages  of chemicals(Sodium Hydro oxide and sodium silicate) to be used and what concentration we need to maintain to attain the optimum Results.. 
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yes I agree, you can take into account extra modification with fibers of different ypes: natural like Rami and synthetic.
Janik
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I have to fabricate a "convex-shaped" strip That must resist to mechanical deformation (the convex will be straightened) many times, possibly, in a wide range of temperatures and That recover the same dimensions without deformation. I have think to polyimide or silicone rubbers.
Can anyone suggest me a suitable grade of the above Mentioned materials, or other materials suitable for this purpose?
Thank you in advance.
Fabio
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 There is an excellent Polyimide for that Vespel of DuPont
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material i have-methaacrylic acid + methaacrylamide (1:3) ( monomers)
DMSO/methanol (solvent)
AMA ( initiator)
EDGA (cross-linker)
i have been following thermal method but polymerization is not happening. please guide. thank you 
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AMA is the abbreviation for allyl methacrylate. This is not an initiator but a branching and cross linking monomer. You should add a real initiator like AIBN, benzoyl peroxide or another peroxide. Peroxides can be further activated by adding a tertiary amine, e.g. ethyl-4-dimethylamino benzoate, dimethylamino toluidine or N,N-bishydroxyethyl aniline. Without activation the polymerization runs at 60-90°C, with activation at 20-60°C.