We are using some PBD from polymer source. The have plenty of molecular weights, low PDI. Tg should be close the lower bound you mention thought, -60C.

PVAc, Tg is 40C

PPMA, Tg is 40C

PBMA, Tg is 25C

Poly(DL-lactic acid) (PDLLA), Tg is 55C. (PLLA is semi-crystalline but PDLLA is not)

Atactic polylactide (PDLLA) - synthesized from racemic mixture of D- and L-lactides by a ring-opening polymerization. The monomer and "catalyst" (tin octoate) are commercially available and the synthesis of PDDLA (in bulk) is very simple. The resulting polymer is amorphous, has a Tg = 35-40 deg C, low PDI (

Depending on instrument. We have TA AR2000, testing polymer is Liten offered by TA.

Thank you, among those listed above, which one do you think is the best choice for "click chemistry"?

A low dispersion, moderately High molecular weight amporphous polymer you can synthesize yourself? An epoxy maybe? My synthesis skills are not that strong so getting a good monodisperse sample, or close to it, was always tough for me. I ended up buying viscosity standards from VWR with known molecular weights and working with nylons in theta solvents, but nylon is semi-crystalline. How important is it that these be well characterised systems that have a good data base to compare to in the literature? There are some siloxanes and silicon-based polymers that might do the trick, but they are not the easiest thing to synthesize and a lot of the data came out of Russia about two decades ago. They are hard to get good data on because most of them did not have attractive properties for commercial applications. So there is not a lot of common data. But for rheological studies and maters of acedemic interest, they might work. You will have to do some literature work on POSS Polyhedral Oligomeric Silsequioxane 20 -30 yrs ago out of UC Irvine. I don't think POSS itself is what you need, but one of the siloxane comparison polymers.

Yanfei, by the click chemistry approach you can obtain a myriad of acrylic and vinyl polymers, and many of them could meet your requirements.

Dear to study rheologycal properties viscosity limit of the polymer plays important role u just see what are extream values given in manual to go with your instrument

Great, thanks for the help!

Synthesising copolymer with caprolactone -60 C Tg may help djusting the Tg and you need to optimise the ratio. Longer reaction time and high temp reaction conditions in the presence of specific catalyst is generally required to get High MW.

Or you can try synthesize Polyurethanes using their low molecular weight diols

Li,

For rheology study you may first to know the level of coefficient of viscosity and then try to measure viscosity with variable parameter of temperature to know about your query.

PLA or its derivatives such as PDLLA is sensitive to wet and thermal history. When you use this kind of polymers to study rheologica properties, it will generate problems in repeating tests.Please read some articles on the PLA degradation/decomposition.

Use PEG-PPG-PEG poloxamers they can be obtained in different MW and PDI ratios not sure about their crystallinity but if you have good enough PPG fragment its crystallinity should become low due to diminished packing interactions. They also can be obtained from various providers and good reference data can be easily obtained. Hope this helps.

PEG-PPG-PEG series are very interesting for rheology tests, but not for all kind of test. Due to it architecture these poloxamers overdo thermal transition, mostly LCST. Very cool for temperature demonstration in rheology. e.g. A 20%w/v water solution of Pluronic F127 overdo a LCST gelification near body temperature.

Random copolymers of LLA, TMC, CL, GA are all amorphous and Tg may be set in almost all the desired range. By using proper initiators, you may make them suitable for click chemistry.

Indeed, as Prof. Bergamo indicated, these kind of block copolymers are able to develop gel transitions nearby 36-37ºC, but not for all of them, and thereby (as well as many other biological already passed tests) they have been used as drug carriers, gene therapy, enzyme or protein stabilizers, surfactants, among others. As I stated please also refer to the "cloudy point" for each kind of copolymer, if you see in a table of the phase transitions present for the series, this molecular "turbulence" can be modified depending on chemical structure, and the amount of PPG is very important to modulate this property. Again, hope this helps.

can atactic polypropylene (PP) and polyvinyl acetate (PVAc) be used in "click chemistry"? Thank you

What about poly-acrylic acid and/or starch grafted with that copolymer

the glass transition temperature Tg of poly acrylic acid is too high ~ 100 C. Now we are mainly looking at atactic amorphous polypropylene.

atactic amorphous PP is very inert in chemistry and I doubt how to use click chemistry for this polymer? It would be better to synthesize a copolymer with functional groups and soft main chains. PEG-PPG-PEG series as copolymers have C-O-C links and they are in most cases are soft at rt. Among them, F-127 in aqueous has a phase transition at around 36-37 degree C. I have published a paper (doi: 10.1002/macp.200800040) on oxidization of the end groups of the chains for your reference. However, click chemistry needs simple, clear and stable routes to realize a production of designed compound.

You can see Poly Ethylene Oxide (PEO)

you should give a couple of more details of what you want to do.

There are several options:

- aPP (commercially hard to get but rather stable)

- 1,2 PBd (not 1,4 PBd)

- several acrylates

- LLDPEs with very high comonomer contents

- PIB (Tg could be a little bit too low)

You can use PVA or PEO

Chandan, both are semicrystalline, so not what the OP wants

You can use Polybutadiene (low cis) which I think meets all the requirements you mentioned.

Polymers with sole amorphous character is difficult to get unless one controls critically the synthesis of it.

poly(isobutylmethacrylate) has a Tg of ~45C and can be made by a standard free radical polymerization process.