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I am new to polymer field and willing to prepare polymer (conducting) during synthesis (calculation) with pyrrole and some oxidization reagent we have to choose 1:2 ratio. I am not getting why we are choosing 1:2 ratio any one plz suggest me any information regarding this or else any book regarding these calculation of polymer synthesis.
Thank you
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It will depend upon the degree of unsaturation in the monomeric units, concentration of it and strength of oxidizing agent.
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Hi, everyone!
I am doing polymer synthesis, but the amount of polymer I can get from one synthesis is very small, about tens of microgram. I am using GPC to characterize it, but the information I can get is very limited.
Could anyone suggest any characterization method to get the polymer structural information that only use very small amount of samples? Better recyclable.
Thank you very much!
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Except the analyses that have been mentioned, you can performe ATR-FTIR analysis to determine its chemical stucture.
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Hello everyone!
Our group is trying to synthesize PIM-1 and bought some TFTPN from different companies. However, the TFTPN from different companies showed different colors-from white to yellow. The companies told us that they are the same good and provided us with the NMR spectrum. I am confused about how could the same compound has two colors. Did you encounter the same issue before or have any idea?
Thanks!
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Dear Yuewen Jia, whatever the color is, it should be purified by sublimation prior to its use. My Regards
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I am currently attempting to synthesize Methacrylate-headed PEO macromonomer using Methacryloyl Chloride (MAC) and PEO in Toluene containing Pyridine. I am unsure of the ratios needed for the synthesis. After evaluating some of the structures and possible by-products I was going to start with [2:1] ratio of MAC and PEO, [1:1] of MAC and Toluene, and [3:1] Pyridine and Toluene. If anyone with polymer synthesis experience could shed some light on figuring out the ratios better or if this sounds like a good place to start would be great. Thanks!
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Dear Cole Carpenter, I would like to put the following remarks. The amount of MAC is to be taken in slight excess with the equivalent number of OH end groups and not with respect to the PEO MW. The same thing to pyridine, with respect to the presumed evolved amount of HCl. There are many reviews dealing with the end functionalization of PEGs and PEOs end groups, an example is in the following RG thread I posted years ago. My Regards
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Dear all
What are the best books in chemistry that can be used for curriculum design "i.e. for Materials Chemistry"?
Please write the name of the best books that you read/know in the field of "chemistry"? General Chemistry, Organic, Physical Chemistry, Inorganic, Biochemistry, Polymer synthesis, Polymer Chemistry, Computational Chemistry, Solvents and Solvation theories, Analytical Chemistry, Electrochemistry, etc [...] and Chemistry Laboratory Design.
Thank you very much
- - -
* Additional comment:
You can, also, send to me links (or the books' front page photo) or E books (PDF or any) here or in private message. Thank you!
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Top 3 Chemistry Books | Personal Statement Reading
  • 1) Periodic Tales: The curious lives of the elements - Hugh Aldersey-Williams.
  • 2) Obsessive Genius: The Inner World of Marie Curie - Barbara Goldsmith.
  • 3) H2O: A biography of water - Phillip Ball.
  • Bonus: Periodic Videos.
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I did some reaction of polymer synthesis in which triethylamine was used. I have NMR of the resultant polymer in which I am expecting that triethylamine is converted into diethylamine. Is it possible? Please share some references. Thanks in advance.
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Hello,
I am a synthetic polymer chemist. I would like to explore the simulation counterpart of my experimental work. Can anyone suggest a good software able to simulate polymerization reactions, and possibly some properties of the obtained polymer?
Please, notice that I am not looking for a chemical engineering simulation software.
Thank you.
Alberto Mariani
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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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hello
  My thesis is defined base on acrylated Polyurethan. I used HEMA (hydroxy ethylmethacrylate) as a reactive diluent and benzophenone (BP) as a UV initiator with methyl diethanolamine as an accelator. But my system is so viscous and needs heating for adding photo initiator and proper mixing. I use 45º c for adding photo initiator and mixing. but most of the time it stat to crosslinking from the bottom of the sample container. I mean before curing with UV lamp it start crosslinking.
I thought that its because of BP . Its a thermal initiator too. so I need a UV initiator can be used in higher temperature. Could you please introduce appropriate one?
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Irgacure-2959
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Dear Collegues,
I am currently looking for PhD candidates or PostDocs with a strong background in monomer and polymer synthesis for my lab at the University of Freiburg, Germany. If you know of any suitable candidates, could you please direct their attention to my lab? Thank you!
Best,
Karen
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Respected Professor,
I am Dr. Chiragkumar M. Patel, presently working as a research associate supervised by Dr. KVSN Raju, at Division of Polymers & Functional Materials, Indian Institute of Chemical Technology Hyderabad. It’s my ardent interest to enhance my research aptitude by further exploring the challenges in the field of polymer science coupled with sustainable chemistry.
My current research work is schemed involving the methodology of non isocyanate polyurethane coatings for high performance functional materials.
My doctoral thesis was headed as - “Synthesis and characterization of polyol from agriculture waste and its applications”. My work during the tenure of Ph.D. included systematic preparation, characterization and applications of prepared bio-based polymeric precursor. My research was just not confined to the above work but has a wider extension, leading to application of rigid polyurethane, adhesives as well as in the field of smart two-pack coating system whose outcome will be reflected in my upcoming publications.
My laboratory virtues are:
Maturity, honesty, trouble shooting and the ability to deal with challenges as great opportunities. An enthusiast and hardworking researcher in a highly interdisciplinary and collaborative environment. Volunteer responsibility with a cheerful countenance and pursues task diligently. Ability to work in group and lead a team. My research interests include sustainable chemistry by synthesizing bio-based polymeric precursor and characterization, looking into their application towards polyurethane based coating, adhesives and rigid foam and finally study of their mechanical and chemical properties. My C.V., is attached to this mail for your kind consideration.
Thank you and looking forward to hearing from you soon.
With best regards,
Sincerely yours,
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I used EBiB as an initiator to polymerize acrylic monomer. However there are always some dead chains shown in GPC and the PDI is 1.3~1.4. Does this mean my initiator is too active for this monomer and the radical may not go back to dormant species before they terminate? Should I use less active initiators like MBrP? Or is there any other variables I need to adjust like the amount of AIBN or Sn(EH)2? Thank you!
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I have to end a reaction in process due to sone emergency. I was synthesizing poly glycerol sebacate. I reacted them at 170 under nitrogen for an hr and then stopped. Normal duration is 4 hr. Should I continue it from ther or to go for new??
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Dear Ramish Riaz, if kinetics consistency is important then you have to repeat the synthesis with respect to the reference procedure. You did not said any thing about evolved water elimination! Reversibility of the reaction by hydrolysis may occurs before restarting. My Regards
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I have prepare polyimide solution.But after electrospinning I cann't see any nano fibers.Its form only beads.How to solve this problem? What is the best purification way to the monomer before synthesis the polymer?
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According to the fact that we couldn't use huge sonicators and run the same lab based experiment for industrial productions because of its acute or chronic health effects, I wonder what is the best replacement for sonication to obtain a homogenous mixture of polymers and nanosheets in industries?
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Dear all, what is the role of sonication in your case? Is it for mixing/dispersion or for reaction assisting. If it is for the later option you can use microwaves. My Regards
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Hi All,
I am doing polymer synthesis research. The project is to synthesize poly-l-lactic acid with polypropylene glycol to get a triblock copolymer. Stannous octoate is the catalyst, solvent is toluene and reaction temperature is 140C, reaction is carried out under nitrogen atmosphere. After reaction is done, toluene will be evaporated by using rotary evaporation, product will be dissolved in dichloromethane and titrated to cold methanol or diethyl-ether. The major problem is the products will be dissolved into methanol or diethyl-ether and I can't successfully collect them. Even the hilderbrand solubility parameter of methanol and diethyl-ether are much larger than polypropylene glycol 's.
I have two main considerations:
1. There are not lots of initiators to initiate the polymerization, maybe I will add some general initiators like AIBN?
2. I successfully synthesized the product, I need to select a correct solvent instead of methanol or diethyl-ether.
Can someone give me some suggestions?
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Dear all, you can not use AIBN or any type of radical initiator. Your monomers are not vinylic or acrylic. If it is a ring oppening polymerization ionic initiation is more suitable, though in some special cases radical initiators may work. My Regards
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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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for polymer synthesis
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Abdelkader BOUAZIZ @ Thanks alot,,
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I'm working in a Polymer synthesis And i need a GPC instrument to characterize it and i cant find it Anywhere in Egypt cairo i need help
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Dear Mariam,
Can you please give me the details of your polymer and the solvent suitable for dissolution? I might be able to perform few experiments for you.
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Hi
I'm trying to react a bis-aminopropyl linear PDMS oligomer with a short PEG acrylate via a Michaels addition to form a triblock copolymer. My read of the literature suggests that this reaction should proceed easily via heating and should not require a solvent but this has been unsuccessful so far. I have tried the reaction both neat and in ethanol, with and without a weak base catalyst (triethylamine) and with and without heating.
Can anyone hazard what I might be doing wrong here? NMRs appear to show some conversion is occurring, but some of these reactions have been left on for a weak or more without achieving quantitative yields of product.
Any thoughts would be greatly appreciated, thanks
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I think you should use stronger bases as catalysts like organic superbases. Often guanidines are good catalysts for aza-Michael addition, like tetramethylguanidine or TBC (triazabicyclo decene). But also P4-tBu, a phosphazene base should work. DBU and DABCO are a little bit worse in such reactions but better than normal trialkylamines. It should work in neat at temperatures below 100°C.
You have an additional problem, the complete incompatiblity of the two reactants. This problem can be overcome by addition of a polyether modified polysilicon. Such products are sold from byk as defoamers or air release additives : https://www.byk.com/en/additives/product-groups/defoamers-air-release-additives.html
Perhaps also a non-ionic emulsifier helps, like tween 80.
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Not really getting much luck in researching this on my own, and I'm also new to the area of latex polymerization so maybe I'm missing something. I'm trying to calculate the interaction parameter of a polymer that I'm synthesizing, but I don't know what the structure actually is since its I'm just using free-radical polymerization to get a polymer from 3 different monomers of changing concentrations. If anyone has any leads or ideas to do this, it would be appreciated. Thanks in advance!
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Hello,
I am synthesizing a material based on a cyclosiloxane compound, where I am attaching functional groups onto the silicon atoms. My worry is that the siloxane ring could open during the reaction, as they are notoriously weak rings, which is something I do not want to happen. The silicon atoms have 5 carbon arms, and I am attaching a compound at the end of each arm. Therefore, it is impossible to tell whether or not the ring has opened by conventional methods (H & C NMR, FTIR, MS...etc.). The only method I can think of is using Si NMR, would that prove whether or not the siloxane ring has opened?
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I think there are a few options for you to try. I'm assuming your compound is symmetric, but if it wasn't and depending on the size, you could use HMBC to confirm covalent bonds (or lack thereof). I'm guessing this isn't an option though.
1H NMR you might be able to see a hydroxyl peak and you might even see new peaks appear (very close to 0) instead of a single peak, as the electronic environment where the ring opened will be slightly different. These shifts are very small so I can't guarantee you'd see clearly resolved peaks. Also note that these shifts may appear below 0 ppm.
IR would also show a broad and diagnostic OH peak if the ring opened, which would be very quick and easy to assess. This would be the first thing I would try.
In theory, you would see a different mass on MS but I don't think these would fly well (likely be destroyed by ionization).
Finally, I would say TLC could potentially be used as you'll see a new spot with a much lower Rf. Ceric Ammonium Molybdate (CAM) should stain very strongly for hydroxyl groups; you could also try stains that give different colors (e.g., vanillin and p-anisaldehyde), as I expect the silanol group would give rise to a very different color. This wouldn't give you a conclusive answer, but it might give you enough of a clue to feel confident.
If exhausting this arsenal of characterization techniques gives you only equivocal results of whether or not your ring opened, then I would suggest going to 29Si NMR. If your institute has easy access to these more exotic NMR nuclei then this should be a good way to get a definitive answer.
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Hi all,
I am struggling to purify a series of polyesters which do not have melting points. That is to say, they do not nicely precipitate in non-solvents and instead form highly viscous gels. I have allowed these gels to form in non-solvent while in freezer, and then have successfully decanted the mixture, leaving a crude gel behind. However HNMR still reveals the presence of unreacted monomer. There are not any literature boiling points on my monomers in this series, but they must be quite high (mw = 400-600). [I have tried vacuum drying at 100 millitorr @ 80C with no luck].
Any suggestions? Thanks!
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Hi;
I suggest you read the following patent: WO2014131747A1 (Novel method for purifying polyesters).
With my best regards
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I want to synthesize PEDOT and de dope this polymer
I will conduct the experiment like below method.
I have a question. which hydrazine can I use?
Hydrazine anhydrous? or Hydrazine monohydrate?
The monomer is easily polymerized due to its low oxidation potential. The polymerization procedure is depicted as follows: 0.591 g EDOT and 2.08 g FeCl3 were mixed under nitrogen with 20 ml freshly distilled CHCl3 in a 50 ml three-necked flask with magnetic stirring. The reaction lasted for 48 h at room temperature. After filtration of CHCl3, the black compound was washed with dilute hydrochloric acid, distilled water, and then was extracted by ethanol in a Soxhlet extractor, dried at 80 ◦C in an oven to constant weight (0.581 g, yield 98.3%). The polymer was stirred in hydrazine for 5 h to de-dope, then was filtered. The black solid was extracted in Soxhlet extractor one more time with ethanol. After drying to constant weight, 0.577 g black powder was obtained
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I would take hydrazine hydrate. But I could imagine more efficient procedures. Iron (III) is extracted form aqueous acidic solutions in chloroform with tributylphophine oxide as ligand. It could be suffient to treat an acidic suspension of PEDOT with tributylphosphineoxide and extract the iron in chloroform. Also dioctylarsinic acid can be used as ligand to achieve extraction in organic media.
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In the first step i am synthesizing hydroxy polyethylene glycol acrylate - 200 (HPEGA - 200). The above step is immediately followed by the addition of acrylic acid, sodium salt of 2-methyl-2-propene-1-sulfonic acid along with sodium persulfate as an initiator. During the second step immediate frothing and rise of the products inside the flask was observed. Frothing and rising even goes beyond the attached refluxing unit of 300 mm length. This results in spilling of the products outside the system which interrupts the reaction and i couldn't get the final product.
I don't understand what is the problem during my synthesis
Could anyone please help me out.
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Hi Ponambala,
It may be due to high foaming or due to improper reaction....
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Most of the literature suggest that primary diols have high potential for the chemical industries. What would be the strength and applicability of polymer obtained from diol containing one primary and a secondary alcoholic group?
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Dear Alam,
this rule particularly concerns the diols used for production of polyesters exploited in the textile industry. Monomeric units derived from linear-alpha,omega-diols namely allow linear supramolecular arragement of macromolecules and thus formation of crystallites giving to fibres high axial tensile strength. However, if one consider applications in the field of coatings, also polyols with branched chains are useful and used.
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I'm synthesizing a PLLA grafted with itaconic anhydride in a rheocord mixer. After the grafting, I would like to determine the concentration of the grafted itaconic anhydride.
I dissolved a grafted PLLA sample in THF and then I carried out an acid–base titration with 0.005 M potassium hydroxide (KOH) in ethanol.
I tried to determine the equivalent point in two different ways at 25°C:
1) by means of phenolphtalein as indicator;
2) by means of a pH-meter (CRISON TitroMatic 1S equipped with an electrode CRISON 52.2) measuring the pH and the conductivity.
In both cases I had problems:
1) I can't appreciate the color changing of the indicator;
2) the system seems to be unstable and both the pH and the conductivity fluctuate.
I guess the problem is related with the solvent (THF) because when I tried to perform a similar titration in a water/ethanol solution the pH-meter gave stable results.
My questions are:
Is there any alternative method to determine the anhydride concentration?
Or is there any solution to let my system be more stable to perform a pH measure?
Best regards,
Francesco Chiacchio
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I agree with you
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I am working on star shape polymer synthesis by ATRP reaction
I used erythritol core activated with 2-bromoisobutyryl bromide. I used HPMA with MMA in different ratio, anisole, CuBr, PMDETA, Nitrogen gas to deoxygenate reaction flask, Temp-90 degree C.
I am getting green sticky material even after I tried to remove Cu by alumina column, when I tried purification by precipitating in diethyl ether, it is not precipitating.
Why this is happening?
Can anybody please suggest me the better way to get my product?
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I agree with Karol, however the solubility will depend on the HPMA/MMA ratio as well as on the final molecular weight of copolymer.
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I am aware that the standard way to remove MEHQ from Methacrylic Acid is to perform reduced pressure distillation. The papers I see suggest using ~ 10 Torr pressure to perform distillation. Unfortunately I do not have access to such a pump. I am very aware of the fact that I can just add a little extra initiator, I was wondering if there was a way of removing MEHQ apart from the reduced pressure technique.
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While flash chromatography is a viable method for small quantities, I have used activated granular carbon to remove the MEHQ. The carbon was 4-8 mesh (large granular for easy handling) that was placed in a vacuum drying oven at 120C for 24 hours. This was then added to the acrylate to adsorb the MEHQ. The slurry was gently mechanically agitated for good mixing. Please use a mechanical agitator, not a magnetic spin bar (as the bar tends to 'grind' the carbon to smaller powder against the bottom of the beaker/pot). You can monitor the MEHQ content, adding additional carbon and agitation time until you reach the desired inhibitor content. Then simply filter the carbon off of the acrylate. If you totally deplete all of the inhibitor, use the monomer as soon as possible. Acrylic acid polymerization is self accelerating (giving off a lot of heat of polymerization) and can result in a violent (read explosive) reaction (conditions).
I recommend removal of inhibitor on only amounts you can use within 24 hours of filtering. So long as the monomer is in contact with the carbon-MEHQ, I have not had any stability problems. Once filtered, the monomer is VERY reactive.
I have used this method with a number of different acrylate and methacrylate monomers, with sizes of 100 grams up to 10 kilos in an industrial setting.
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I want read and understand the complete mechanism of Thermosensitive Hydrogel Synthesis, as well as wanna Major catalysts and the structural and mechanical Role in thermosentive polymer synthesis.
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the catalysts may vary upon choice of materials or precursors we used. you can choose your favorable compunds. there are 1000s of studies reported with different catalysts. its hard to find review on all available catalyst. i have compiled articles which repoted various catalyst. i will mail you the articles.
all the best
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Does anybody know that How could I distille dioxane  and vinylcaprolactam for polymer synthesis? I need to use special reagent, or just under vacuum could be enough?
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Yes, For distilling dioxan I recommended what Anup Kumar mentioned, using chromatographic grade basic Al2O3 to remove impurities including peroxides and reflux it for several hours over sodium wire and distilled under nitrogen or argon and stored in the dark.
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I am trying to make PLGA-PEG nanoparticles. For this, first I make PLGA-NHS from PLGA-COOH bu using PLGA-COOH , NHS and EDC in DCM.
I precipitate it (PLGA-NHS) using Methanol.
Further, I use this PLGA-NHS with PEG-COOH + DIEA in Chloroform.
The reaction is kept on stirring for 24hr. But when I precipitate it, i don't get a proper yield. The maximum I could get is 3% yield, which is unacceptable.
Can anyone tell me which can be the problems, or critical steps .
Thanks. 
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Hi Tanzeel, this is a while after your experiment, but would you be able to give the concentration of PLGA and PEG you used for your synthesis? I'm running into a similar problem myself so it'd be very helpful to hear what ratios/concentrations you used. Thanks!
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I intend to prepare a solution using melamine-formaldehyde powder. Is there any solvent which can highly dissolve it?
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The most important solvents for melamine are: water, DMSO and
polyhydroxyl alcohols in which it has the highest solubility of 2-5.7 g in
diols and of 10.0 g in glycerol in 100 g of solvent, at 140°C
or this ref:
Kucharski M., Głowacz-Czerwonka D.: Solubilization of nitrogen-containing heterocyclic compounds in reactive solvents. J. Appl. Polym. Sci. 2002, 84 (14), 2650.
Głowacz-Czerwonka D., Kucharski M.: New melamine–formaldehyde–ketone polymers. II. Dissolution of melamine in reactive solvents prepared from cyclohexanone. J. Appl. Polym. Sci. 2005, 96 (1), 775.
Głowacz-Czerwonka D., Kucharski M.: New melamine–formaldehyde–
ketone polymers. V. Coatings from melamine and MEK-based reactive solvents.J. Appl. Polym. Sci. 2008, 109 (4), 2156.
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I need articles which include the modification (carboxylation, amination, hydroxilation by using any materials) of pyrrole to avoid pyrrole polymerization.
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Carboxylation is a typical and well-known reaction in the field of pyrroles
Org. Synth. 1971, 51, 100
DOI: 10.15227/orgsyn.051.0100
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Dear all,
I am using EIS to investigate the anticorrosion performance of polymeric based nanocomposite. Recently I have got a comment from one reviewer regarding my Nyquist plots that it must be isotropic.
What does that mean and how to achieve it??
Samples of my Nyquist plots are attached
Thanks 
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In Origin, you can set the axes length of X:Y =1 by going to the layer section of graph in size/speed section
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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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Hello Everyone ,
Greetings!!
I am going to work on polymer nano composites, kindly suggest me and share me the synthesis of nano composites and preventing the agglomeration of nano composites. How to bind with the polymer,
synthesis method with an Eco-friendly approach. Wish to know the basics. It will be very helpful if some one suggests articles and books related to this .Thank you very much.
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Hi,
In-situ photopolymerization is very robust method to obtain polymer nanocomposites. It is eco-friendly (solvent free process) and also facile way for fabricating especially membranes and thin films. Furthermore, it provides a number of advantages, e.g. homogeneity and time, compared to thermal process (either shaping or reaction).
Best regards.
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I have done the reaction at 0 degree. The substituted group affected the polymer yield. Is it possible to increase the yield of the substituted polymer group by oxidative polymerization method?
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yes you can do it, you need another monomer that has an attractor group to synthesize a copolymer to improve performance
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Hi everyone, I have a doubt. Polymer synthesis is new for me. Usually, polycondensation reaction of polymers (synthesis of poly arylene ether) takes place using DMAc as the solvent and 170 degree celcius. Some polycondensation reaction (involving aminated monomer) takes place using NMP as the solvent and the temperature around 150 degree. Please explain why NMP as a solvent and low temperature. Thank you very much for your consideration.
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Thank you everyone. I am using this monomer (3,3'-Dihydroxybenzidine). it contains two primary amine groups. polymerization involves Monomer like this, they used NMP as solvent. what is the advantage using NMP over DMAc.
last time i synthesized aminated polyaryl ether sulfone. But tyhe molecular weight was low.
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Hi,
Does anybody know how to convert RAFT end chain group to ATRP?
Can you recommend an example of paper who has done this?
Thanks
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Thank you very much for sharing these papers
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I am thinking that does the molecular weight of polyol affecting the drying time of polyurethane dispersion coating?
and if there is no longer excess isocyanate content in the dispersion thus, no moisture-curing with oxygen in air, will it still dry? 
My samples (using copolymer polyol) seemed to be tacky and could not dried. 
I am thinking does the type of polyol affecting too? I am using normal polyol and copolymer polyols. The copolymer polyols dispersion cannot dried well despite increasing NCO/OH ratio. 
Thanks in advance.
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Dear Angel,
you shoud try of vacuum shouk method . I think it might help.In addition It would be great rather fast - avoiding long-term swelling .
see can you Publication : Effect of bubble based degradation on the physical properties of Single Wall Carbon Nanotube/Epoxy Resin composite and new approach in bubbles reduction Article Aug 2016 · Composites Part A Applied Science and Manufacturing Seyyed Alireza Hashemi · Seyyed Mojtaba Mousavi
Good luck with your research!
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Hello.
I'm trying to make a film using Polycaprolactone(PCL) by solution casting method
at first, I used PCL (Mw ; 70000) but it crystallized too fast and became really hard film  when i dissolved PCL in the condition of  10% w/v (10g of PCL/ 100ml of Chloroform)
So i bought PCL-diol (Mw : 2000). It was solid and waxy.
I dissolved it in solvent and dried for 24hr. but it didn't became film.
does PCL-diol have a film making property?
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To see if PCL-diol polymer has film-forming properties, there is any easy method:
You need to have a metallic ring "the size of a small hand bracelet" which contains little mercury placed inside a glass dish. Pour the polymer's solution over mercury & let the solvent evaporate without heating in a fume cupboard. After that, try to take the film by means of tweezers. If you cannot pull a circular film & you see that it has crumbled, then the polymer does not have fiber-forming properties. Conversely, a film formed is indicative of success, of course.
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I know this is a long shot but I am trying to microencapsulate a PCM containing a mixture of an alcohol and fatty acid ester and have currently only found in-situ polymerisation using the following surfactants: styrene maleic anhydride copolymer or sodium styrene maleic acid colpolymer as potential ways of doing this (the alcohol group makes microencapsulation a lot more difficult). If anyone has any other possible suggestions of surfactants or microencapsulation methods let me know!
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One source of methods is to consider searching commercial patents especially US ones - have done this for PCM in the past and found them useful if you have some knowledge to start with.
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free radical polymerization using PEG-ABCPA as macroinitiator
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Thanks Amin Shavandi for the papers and suggestion. i will look into that. thanks again.
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When I was injected Vinyl acetate monomer in emulsion polymerization reaction then reaction temperature decreases immediately my actual question is that I want to increase temperature up to 80*C so what will do for it 
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Thank You 
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I want to know the catalyst and solvent to polymerise aromatic diol and aliphatic dichloro. Earlier I tried, but not achieved good molecular weight and also polydispersity index is 2.5.  
Also please send URL of a particular article also.
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Thank you sir, for your kind response to my enquiry. Can you please send any published article related to this.
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hello
with respect
One part of my PhD thesis is synthesis of biodegradable polyurethane based on hydroxylated Polylactic Acid. In this case synthesis of hydroxyl terminated PLA is required. I used polycondensation process with lactic acid (LA 90%)  as monomer and DBTDL as catalyst an butanediol (BD) as a diol function. the period of process was set at 8 hour on the 180 °C  with nitrogen purge and under vacuum . With 1 mole% BD (1 mole percent of LA) the acid number of 84 and hydroxyl numebr of 96 were resulted (by Titrasion method of end groups) , and with 4% of BD the acid number of 15 and hydroxyl numebr of 138 were resulted , also the molecular weight of latter on was lower . But in the articles the acid number of hydroxylated PLA is reported mostly below 2.
So what do think about my test results? Are they reasonable data? do you have any advice for me? I mean higher acid number is reasonable for molecular weight near 3000 of PLA-OH ? what wrong about my procedure? 
Also another question is that does such kind of condensation process need condenser set up or just nitrogen purge and vacuum is enough ?
I need PLA-OH weight with molecular approximately 4000 and OH number near 40.
Thank you all for your time .
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Dear Samaneh salkhi, I advise you that, add an excess of BD as the terminating agent after the molecular weight reached into 4000. The alpha hydroxy group of lactic acid will react slow compared to HO of BD. The unreacted or excess of BD will be removed in hexane solvent.   
Bio-absorbable Polymers in Implantation-An Overview, J Scientific & Industrial Research, 68 (2009) 993-1009.
Fluorescence-detectable, star-shaped polylactic acid construction for implantation. European Polymer Journal. 48 (2012) 1357–1360.
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Hi!
My question concerns the use of isopropanol for the synthesis of carboxymethylpullulan or dextran. I know that it can improve  the obtained substitution degree and also protect the polysaccharide from hydrolysis due to the NaOH. But anyone knows why? Thanks in advance
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Dear Julia,
I haven't worked with pullulan or dextrans but I was working with starch carboxymethylation, where isopropanol is also good solvent for etheryfication.
1. Isopropanol is good precipitating medium for starch (starch granules slightly swells but gelatinization is avoided) and final product of carboxymethylation for the one hand and isopropanol is good solvent for other reagents (like monochloroacetic acid).  This solvent is also good precipitation medium for the other polysaccharides with lower molecular weight.
2. Acctually the best solvents for nucleophilic substitutions SN2 are aprotic media (you can look at here: http://www.sciencedirect.com/science/article/pii/0144861795000836), but starch reguires polar media for alkalization (first step of etherification) St-OH + NaOH  --> St-O- Na+ + H2O. So some extra water affect reaction efficiency.
3. It can be related to screening effect and relative polarity of organic solvent (isop. has lower relative polarity than methanol or ethanol). Properties of the solvent influences on occuring or efficiency of side reactions (sodium glycolates).  
4. Even if reaction is conducted in organic solvent excess of NaOH leads to home decrease in aver. molecular weight of polysaccharide chains.
Meybe attached articles will be helpful anyway.
Best regards
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To prepare a homopolymer by emulsion reaction, what is an efficient way to control the molecular weight and polydispersity? monomer/initiator ratio, chain transfer agent, reaction time?
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Thank you all!
According to use chain transfer agent to control molecular weight, how to decide the amount of CTA should be added? early experience or reference would be appreciated!
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Could anyone suggest a polymer having following properties?
1. It should be easily soluble in water at 20 degree C
2. It should NOT be soluble in ethanol
3. It's melting point must be well above 100 degree C
4. It should NOT have any hydroxy, carboxylic, and amine functional groups in the side chain. 
Thank you.
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Poly(acrylamide-co- diallyldimethylammonium chloride) -see the structure in the file below- will most probably meet your requirements. The copolymer Poly (AAm-co-DADMAC) is definitely water-soluble & my expectation is that it is EtOH-insoluble.
Since the polymer contains ionic bonds plus extra strong secondary bonds, its melting point is expected to be very high.
Needless to say that it doesn't  have any hydroxy, carboxylic, and amine functional groups in the side chain. There are amide & ammonium yes but they differ from the 3 mentioned functional groups.
However, experimentation with a small amount of polymer or copolymer can give better information than anything else.  
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What is the difference of real system and equation by Flory?
For example, polycarbonate condensation polymerization, PDI is usually 2.2~2.4 by GPC.
This is a step-growth polymerization not a chain-transfer or radical polymerization.
BPA + DPC = polycarbonate + phenol
Thank you for answers! You give me many hints!
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 I agree fully with Dr. BOUAZIZ.  Chain transfer reactions cause PDI to get much larger than 2 (as is common especially with many polyolefin materials).
The explanations given in an earlier answer, about stoichiometric imbalance, will get you PDI < 2 (rather  than PDI > 2).  Also, crosslinking is not really relevant for polycarbonates which is a thermoplastic.
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I would like to synthesis materials through soft chemistry method. When I am reading the steps it is mentioned about polymerization process to obtained xerogel. Please kindly anyone could explain about it. Thank you.
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There are no methods of soft chemistry. There are methods for synthesizing a soft mutter. Examples of soft substances: surfactant micelles, proteins, enzymes, supramolecular substances .... Solvents are involved in the organization of the volumetric form of these substances. Their shape, volume affects the temperature, pressure, solvents, inorganic electrolytes. Some of them are prepared by polymerization. They are usually water-soluble high-molecular compounds polyethylene oxide, polyacrylamide. When the conditions change, they form globules in the water. Globules combine and form gels.Therefore, they differ from a solid mutter.
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I see some researcher mentioned this topic and gave some articles for this.
Mushtaq Ahmad · 127.01 · Pakistan Atomic Energy Commission
howerver, this paper cited information about PCL solubility form other papers 
Coulembier O, Degee P, Hedrick JL, Dubois P. From controlled ring-opening polymerization to biodegradable aliphatic polyester: Especially poly(beta-malic acid) derivatives. Progress in Polymer Science. 2006;31:723-47.
I cannot find information from this. I am really confused about this information. Can u help me give more papers five exactly information bout PCL solubility
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Thanks Mrinmay Mandal, i tested the solubility PCL in acetone. DCM, DMF, chlorofrom and THF ( Mw of PCl = 65k-80k). DMF and THF cannot dissolve PCL. 
I mean that when I created the literature review about this, Some papers give incorrect information, maybe not clear. I need some informative and reliable papers which related to this topic
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I am using the phenothiazine (400ppm) to inhibit premature polymerization
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This is a patent for phenothiazine removal
Also, look at previous question, I'm almost certain this has come up in the past.
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Hi.
I am interested in your project room temperature cure two component acrylic glue. can you explain more about the oxidation/ reduction system of it. which initiators and co-initiators you want to use?
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CHPO as the oxidant , and thiourea derivatives & triethyl amine as the reducing agents in the formulation system.
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To synthesize polyurethane prepolymer using TDI it is necessary to remove unreacted excess monomeric TDI to reach low free monomer prepolymer. What is the most simple way and which procedure is industrial?  
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wash in very dilute ammonia will react the excess and crosslink then wash in water = alternatively dilute alkaline material
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I have been using the ones reported by Grubbs and coworkers but my polymeric nano-particles' Mn ever matches their predicted Mn. The procedure calls for adding a solution of the catalyst (Grubbs III) to a solution of the monomer and stirring at room temperature then quenching with ethyl vinyl ether after which the product is collected by precipitation in hexane:ether (1:1). I tried varying the time and/or he concentration of the monomer solution as well as the sequence of addition of reagents but nothing seems to get the polymerization to produce architectures with a measured Mn that is close to the predicted Mn. The GPC machine is calibrated against polystyrene standards and my polymeric nano particles are made of polyethylene glycol. I don't know if calibrating the GPC against polyethylene glycol standards would help but I am going to do that assuming that the way nanoparticles fold in solution is a contributing factor. 
Thank you 
Rana
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As mentioned above, Grubbs  3 is one of the fastest catalyst. It's unlikely you will get the same results as for the Grubbs catalysts of the 1st generation that were used in the paper. My guess is that all monomer is consumed before you have all components properly mixed, resulting in unreacted catalyst and catalyst wit nobornene oligomers attached. You could try to decrease the reaction temeperature or use more equivalents of monomer. We did similar experiments with Grubbs 3 and got a full initiation with 5 equiv. of a modified norbornene. Furthermore, make sure that you really have unreacted catalyst, as the propagating species appears in NMR as two resonances / double peak (cis and trans).See attached figure and links.
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I've seen some work in the literature, but I'm wondering if there's a way to synthesize a polymeric hydroperoxide (i.e. a polymer back bone, with -O-O-H side chains) starting from a poly-ol or a polyolefin.
Thanks,
Tony
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By oxidation with different oxidants. The main problem is the control of the oxidation reaction.
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Dear fellow researchers,
I am currently performing a polymerization process and wish to know the overall percentage conversion in regards to my initial monomer content.
I have seen in some articles the use of H-NMR to investigate the conversion. However, my sample is in aqueous solution, will the presence of water affect the readings obtained through the H-NMR? In case it does affect, should I dry my sample prior to testing? In the event I do so, the effect of drying may have a chance to evaporate my monomer as it is volatile.
Else, do any of you of another possible method to calculate the conversion.
Thank you all for your attention
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Dear all,
chemical titration of the double bond is a simple way. Small aliquots are taken along the course of polymerization and rapidly quenshed in cold hydroquinone solution to stop any further polymerization after sampling. Here I suppose it is a polyaddition polymerization and not a step-growth one. Regards
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I was using Paraformaldehyde in some of my reactions and its Molecular weight was unknown. 
For measuring viscosity average molecular weight different concentrations of paraformaldhyde solution is required. But, paraformaldehyde is insoluble in water at room temperature and dissolves in water at 60 C and we get clear solution after addition of NaOH.  
if paraformaldehyde dissolves in water it forms formaldehyde solution instead of paraformaldehyde!!
can any one suggest,
1. How to prepare different concentrations of Paraformaldehyde solution (or) 2. Mark-Houwink constants for paraformaldehyde solution in water
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Your question falls apart into 2 parts: 1. Making paraformaldehyde (PF) solutions, 2. Measuring molecular weight (MW).
1. Literature suggests that dimethylsulfoxide (DMSO) is suitable as a solvent for PF, provided that temperature is not too high. See attached file (Johnson et al., 1975).
2. Measuring MW by intrinsic viscosity is only feasible if results can be compared with at least 2 standard PF samples with known MW, which may be problematic. Moreover, MW of PF seems to be rather low, with degrees of polymerization ranging from 8-100 according to Wikipedia. Such low values could also make the use of osmotic pressure and light scattering problematic. Perhaps the best way is to use freezing point depression (FPD) in DMSO, because this quantity only depends on the number of molecules in solution and not on solute type. So you can compare FPD of your sample with FPD of e.g. sucrose, preferably at a range of concentrations. If you have sensitive NMR equipment available, you could also try to estimate MW from the amount of terminal H or C. Please note that DMSO is hygroscopic.     
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What is the appropriate concentration for the diol and isocyanate if want to get hight molecular polymer? And DMF, DMSO, NMP, which one is the good solvent for this polymerization? How long will this reaction take and generally whether it should be heat up if DBTDL catalyst has been added? And if I do 0.1mmol scale polymerization reaction, which require only very limited amount like 5uL catalyst, whether adding 1 drop of DBTDL directly will affect the polymerization?
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For aliphatic diisocyanates, like HDI, IPDI (often the best candidate of aliphatic diisocyanates), hydrogenated MDI or TMXDI the best catalyst is DBTL which can be applied in amounts of  200-1000 ppm. Tin dilaurate, Desmorapid SO, is the best catalyst for aromatic diisocyanates like TDI or MDI. Bismuth neodecanoate can be used for all isocyanates in amounts of at least 1000 ppm but has the advantage that it is less sensitive against water, because it catalyses the reaction of isocyanate and alcohol faster than the reaction between isocyanate and water. For better dosage the catalyst can be thinned in THF as already explained by Jatin Sethi. High amounts of catalysts have no negative influence on the polyaddition reaction itself but on the stability of the resulting polyurethane. DMSO and NMP are not optimal in PU formation because they are not "innocent" solvents. They can also react with the diisocyanate. They should only be applied if the diol component is not soluble in other solvents. THF is in most cases the best solvent for PU reaction, but also MEK - and if the solubility of the diol allows it - halogenated hydrocarbons, esters or aromatic solvents are appropriate. The concentration of reactants and polymer can be in the range of 25 %. The stoichiometry should be near 1:1. In several cases a slight isocyanate excess of 1% could be advantageously. Dryness of the diol and the solvent is crucial for a good urethane formation, because water destroys isocyanate under CO2 evolution (Bi catalyst better than Sn in respect to the water reaction but less active). 
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I have been using formulations from the 1920's and 30's from the patent literature to create the resole prepolymer.  There were a couple of cases that addressed this colour issue.  One that I found on my own was the use of a nitrogen purge throughout the prepolymer synthesis, which helped a lot.  It still gets slightly yellow and darkens upon curing.  Other methods have involved the use of neutralizing acid for the sodium hydroxide catalyst; lactic acid was used but this did not give clear resins.  Other concoctions have been suggested to bleach the resin with no help.
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Phenol-formaldehyde resins, which are obtained from phenols and formaldehyde, have the greatest practical importance. Depending on the relative amounts of the reactants and the nature of the catalyst, the reaction produces either novolacs or resols resins. Thus, in the presence of acid catalysts (usually hydrochloric or oxalic acid) and an excess of phenol, novolac resins are obtained; in the presence of basic catalysts, such as NaOH, Ba(OH)2, and NH4OH, and an excess of formaldehyde, resols are formed.
Their color depends on the type of catalyst used in production and ranges from light yellow to reddish. However, do not forget the effect of phenol and phenol type as well. Phenol-formaldehyde resins harden during processing upon heating; with novolac resins, however, a hardener is required (usually hexamethyl-enetetramine). In addition, synthesize, curing, time, temperature can also affect the color.
Hope this will help. 
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Is there any way to avoid polymerization of δ-Valerolactone during reaction with SOCl2?
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Parhalad Sharma
Please, clarify your question !  
Have you added thionyl chloride to the lactone and you ended up with polymer !!!?
Good luck
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I am synthesizing cross-linked and pyrolysised PVDF membrane via the procedures followed by Science 353(6301) 804-807, 2016. I am worrying about byproduct gases during the pyrolysis of PVDF membrane. Fluorous gases might be formed and it would affect the furnace and medical problem. I would like to know and respond this issue safely. Plus, the followed paper used stainless-steel mesh was loaded into the tube, I think that it caused protect the quartz wall of the tube furnace against the byproduct gases. Is it worling well? If it is not, anyone has alternative?
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Our group aims to use the reduced molecular weight polyester in a reactive copolymerization with another to produce a compatibilizer for blends using this two polymers. What are the most efficient way to make this molecular weight reduction?
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I'd recommend recirculating the melted polyester in a single screw or double screw extruder.  The heat (Tm +20) and shearing action of the extruder will gradually break down the molecular weight through beta-scission and autooxidation--if antioxidants are present, they will eventually be consumed. By converting screw torque into viscosity values, you can estimate the rate of molecular weight degradation.  As Florian said above, a little moisture will accelerate MW degradation by ester hydrolysis. You may be able to do your reactive copolymerization directly in the extruder if it will dissolve into the melt.
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I want to synthesize polyaniline from anilne. I have read that aniline needs to be distilled before being used in the polymerization process. How do I get distilled aniline from aniline
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Dear Rahul,
Distil aniline with a water steam - it forms hetero-azeotrop containing 19,2 % of aniline that boils at 98.7 °C. Aniline containing dissolved water is obtained from distillate by decantation since it forms sepaprate phase.     For polymerization, you do not need to dry so obtained aniline, because polymerization is carried out in aqueous environment. You only take into account that, at 25 °C, equilibrium content of water in aniline is 4,76 weight % !
Best regards, J.V.
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I search an accurate method for determiantion hydroxyl value in Hydroxy acrylic resin, saturated polyester resin and alkyd resin.
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many thanks dears Abdelkader BOUAZIZ and Navneet Kumar
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I read some articles about how to synthesise solvent-free acrylic hot melt pressure-sensitive adhesive with UV-curable methods (photopolymerization), but all of them mention that to make a prepolymer or oligomer still use solvent and then evaporated before UV-irradiation process. Is it the only way or we can make prepolymer or oligomer without use solvent? 
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You can try using emulsion polymerization in water medium. It would avoid using solvent, but you have to do experiments if incorporating uv curable additives possible. Good luck!
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4,4'-methylene-diphenylene isocyanate (Pinus Merkusii Jungh Et De Vriese)
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A viscometer (also called viscosimeter) is an instrument used to measure the viscosity of a fluid. For liquids with viscosities which vary with flow conditions, an instrument called a rheometer is used. Thus, a viscometer can be considered as a special type of rheometer. Viscometers only measure under one flow condition.
Standard laboratory viscometers for liquids
-U-tube viscometers
-Falling sphere viscometers
-Falling ball viscometer
-Falling piston viscometer
-Oscillating piston viscometer
-Vibrational viscometers
-Quartz viscometer
-Rotational viscometers
-Electromagnetically spinning sphere viscometer (EMS viscometer)
-Bubble viscometer
-Rectangular-slit viscometer
As you mentioned, your Polyurethane are gel samples and resulted of the reaction of MDI with Lignin isolates. I think the viscosity of your samples are quite high, you might need to use the right equipment and accessories for the measurement. Some rotational viscometers with the right selection can help you to do so.
Good luck!
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What is the most efficient method for protein quaternization (cationization)?
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Dear Dr. Tsanov,
Thank you so much for your answer. Could you send me the method you used?
Beste regards
Petrus
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I want to use alkoxide initiators for the polymerization of styrene. Can i use high vacuum techniques for the sodium alkoxide initiators.
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The reactivity of a simple alkoxide is too low to effectively initiate anionic polymerisation of styrene. Thus, if you obtain a polymer at all, you will loose control on molar mass and on dispersity (due to slow initiation) .
 There might be some Special systems, which might be able to inititate styrene polymerisation. But these are certainly not simple alkoxides but will require additional additives/coinitiators etc.
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Im trying to react C5 and acrylate monomer. As we know, acrylate monomers are esters consists of vinyl group. What kind of reaction takes place between C5 and vinyl group and how is the reaction occur? 
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What exactly is C5?
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I tried to make crosslinked EPDM (DOW EPDM 4570) which dissolved in toluene with 3three wt% BPO (85 C, 24 hr) as an initiator.
But, I couldn't get the crosslinked polymer, and it was all dissolved in toluene. 
I couldn't find the reason why I can't get crosslinked polymer?
Would you let me know what I need to do to get partly crosslinked polymer?
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Normally the peroxide curing of EPDM is done in neat with a peroxide of high decomposition temperature (e.g. dicumylperoxide) at 160-180°C. It is not usual to do it in solution. If you use a solution the chain transfer constant of the solvent is crucial. Toluene exhibit a relative high chain transfer so that most of the radicals are consumed by abstracting hydrogen from the methyl group of the toluene. Benzene is the best solvent in respect to low chain transfer followed by chlorobenzene. With these solvents you will have a better chance. Mostly a co-curing reagent is added to peroxide curing of EPDM like TMP-trimethacrylate, triallylisocyanurate, triallylcyanurate or bismaleinimides from MDA or TDA. These co-curing reagents will further increase the chance to get a gel.
But if you have already a solution of EPDM you can also epoxidize its double bonds (in the easiest cse) with m-chloroperbenzoic acid. The epoxidized EPDM can be easily crosslinked with amines like isophorone diamine (IPDA). This peroxide free procedure will work in every case and is easier in the laboratory than radical vulcanization. 
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I have this polymer with some amino functionality, but I need to know how much functionality it has. I am given an amine number of 2.5-3.3, and a viscosity range of 1000-2500 cts. I wish I had the molecular weight. Do I have to know how much titrant and how much sample they used to get this number in order to do the conversion?
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I am assuming that the number you have is in meq/g (see for instance: http://www.huntsman.com/performance_products/Media%20Library/a_MC348531CFA3EA9A2E040EBCD2B6B7B06/Products_MC348531D0B9FA9A2E040EBCD2B6B7B06/Amines_MC348531D0BECA9A2E040EBCD2B6B7B06/Polyetheramines%20%20%20JE_MC348531D0E07A9A2E040EBCD2B6B7B06/Diamine%20products_MC348531D0EA1A9A2E040EBCD2B6B7B06/files/JEFFAMINE%20D-2000_US.pdf). Then there is ca. 330 g/eq. However, for epoxy reactions, there are two reactive groups so the epoxy based equivalent weight is half that. For curing with isocyanates, you can assume 1 reactive group (the second is usually neglected). Thus the equivalent weight is 330 g/eq or 165 g/eq. From this information alone you cannot determine functionality.
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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 volume 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 would suggest to dissolve the polymer in toluene and wash by shaking in a separating funnel with diluted HCl.
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We would like to verify whether a polymer alternative that we made truly underwent the process of photopolymerization. 
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You can mesure the solid content, by putting the sample of the emulsion in a convection oven at 120°C for 4h. If the monomers are polymerized they contribute to the solid, otherwise they evaporate together with the water. In the case of quantitative conversion you will find all monomers as polymer in the solid content.
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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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Is Reaction between PropylMethyl Acrylate and Ethylene Methyl Acrylate Possible? And if its possible, what are the expected result ? 
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@Thines Raj Kogiladas 
Please rephrase your question so we can help you. If you are talking only about the monomers you can use living free-radical polymerization or even radical polymerization control methods like (RAFT, ATRP etc ...).
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