Thermoresponsive poly(2-oxazoline) homopolymers and copolymers in aqueous solutions studied by NMR spectroscopy and dynamic light scattering
作者： Rafał Konefał , Jiří Spěváček , Peter Černoch , None
DOI: 10.1016/J.EURPOLYMJ.2018.01.019
关键词:
摘要: Abstract Structural changes during temperature-induced phase transition in D2O solutions of poly(2-ethyl-2-oxazoline) (PEOx) and P(EOx-grad-2-methyl-2-oxazoline (MOx)) copolymers were investigated by 1H NMR methods combination with dynamic light scattering. spectra showed that PEOx on molecular level structures formed gradual heating are preserved subsequent cooling. Phase P(EOx-grad-MOx) as revealed exists irrespective the solution is turbid or nonturbid at higher temperatures. In contrast to homopolymers it very broad, virtually independent copolymer composition weight, reversible some hysteresis. Reduced intensities cross-peaks NOESY elevated temperatures mainly due changed mobility segments. all two types water, “free” “bound” long short spin–spin relaxation times T2, respectively, detected region above transition. The existence T2 components shows exchange between water slow regarding values.
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