Synthesis and functionalities of poly(N-vinylalkylamide). V. Control of a lower critical solution temperature of poly(N-vinylalkylamide)

Synthesis and functionalities of poly(N-vinylalkylamide). XII. Synthesis and thermosensitive property of poly(vinylamine) copolymer prepared from poly(N-vinylformamide-co-N-vinylisobutyramide)

“…The experimental data gave linear plots. This phenomenon is similar to that observed in the poly(NVIBA‐ co ‐NVA) and poly(NIPAAm‐ co ‐NVA) 3. However, in the case of the latter, the change in transmittance was not sharper than that of poly(NVF‐ co ‐NVIBA) aqueous solutions, but rather exhibited gentle tailing accompanied by a temperature increase.…”

“…These results suggest that NVF and NVIBA are classified as nonconjugated‐type vinyl monomers. These values are comparable to the values r 1 = 0.94 and r 2 = 0.99 ( M 1 = NVIBA, M 2 = NVA) 3. Therefore the comonomers definitely were converted to random copolymers.…”

Effect of alkyl substituents structures and added ions on the phase transition of polymers and gels prepared from methyl 2‐alkylamidoacrylates

“…Note that only small difference of chemical structures of the alkyl substituents ( i Pr and n Pr) led large difference in their transition temperatures (> 19 °C). Although the lower transition temperature of n Pr‐substituted polymer than i Pr‐substituted one was also reported for poly( N ‐alkylacrylamide)1–3 and poly( N ‐vinyl alkylamide) series,6 the differences of the transition temperatures between n Pr‐ and i Pr‐substituted ones of these series are not so large (9 and 7 °C for the former and the later series, respectively). The differences of solubility and cloud points of the four polymers in Scheme 1 should reflect the stability of hydration structure around the hydrophobic groups; the hydrophobic hydration became more unfavorable entropically with increasing size of the hydrophobic groups54 so that the polymer became insoluble or its cloud point decreased.…”

Control of Temperature-Sensitive Properties of Poly(amidoamine) Dendrimers Using Peripheral Modification with Various Alkylamide Groups

“…In contrast, poly(N-vinyl-n-valeramide) is insoluble in water, even in cold water, because of its hydrophobic side groups. 9 Therefore, it is likely that PAM groups are too hydrophilic to provide thermosensitive properties to the PAMAM G5 dendrimer, whereas NBAM and VAM groups might have appropriate hydrophobicity to yield dendrimer with temperature sensitivity.…”

“…In general, the LCST of thermosensitive polymers is known to decrease with increasing hydrophobicity of the polymer chains. ,, Regarding poly( N -vinylalkylamide)s, which are polymers with a linear structure that shares common structural units with these alkylamide-terminated dendrimers, the LCST of poly( N -vinyl- n -butyramide) is reported as 32 °C. In contrast, poly( N -vinyl- n -valeramide) is insoluble in water, even in cold water, because of its hydrophobic side groups …”