Thermorheological and glass transition properties of PNIPA/PVP and PNIPA/Carbopol blends

Cross-Linked Poly(acrylic acid) Microgels from Precipitation Polymerization

“…It is known that several factors can influence T g of cross-linked polymers; crosslinking density, secondary bonding (specially hydrogen bonding), the side chains and the free volume. T g is increased by increasing the cross-linking density [14,15,28] and hydrogen bonding [28,29] , which is due to rising polymer rigidity and restriction of the segment motions. The side chain [20] and then the free volume (the volume through which polymer can move) [20] decrease T g because of increasing rotation of chains segments.…”

Sustained Release Pellets Based on Poly(N-Isopropyl Acrylamide): Matrix and In Situ Photopolymerization-Coated Systems

“…This is explained by the null elasticity of PNIPA dispersions and by its compatibility with PVP in aqueous solution, without interacting each other. 8 Moreover, PNIPA behaved as a binder making the obtaining of pellets even without PVP possible.…”

“…Most temperature-sensitive polymeric excipients have a LCST too high to be useful for this purpose (e.g., cellulose ethers above 418C). 7 By contrast, poly(Nisopropyl acrylamide), PNIPA, exhibits the LCST at around 338C, 8 which is not significantly altered by saliva components or gastrointestinal fluids. 9 Owing to its LCST, PNIPA cross-linked hydrogels undergo intense volume phase-transitions.…”

Greater insight into the MTDSC technique involving fundamental sinusoidal heat flow equations

“…This provides the user with a greater understanding of the sample properties being tested, hence making MTDSC an invaluable technique for polymer analysis. Some examples of research conducted using MTDSC include studies on the kinetics of polymer crystallisation [7,16], the analysis of polymer melting [9,17,18] and various studies examining the glass transition [1,19].…”