Nuclear spin relaxation and molecular motions in sebacate polyesters
作者:
MichaelF. Froix,
AndreasO. Goedde,
期刊:
Journal of Macromolecular Science, Part B
(Taylor Available online 1975)
卷期:
Volume 11,
issue 3
页码: 345-358
ISSN:0022-2348
年代: 1975
DOI:10.1080/00222347508018916
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
In this study, pulsed NMR techniques were used to probe the molecular motions occurring in poly(hexamethylenesebacate) (HMS), and its amorphous isomer poly(2-methyl-2-ethyl-1,3-propylenesebacate (MEPS), and in particular, to examine the perturbations in the molecular motions of HMS and MEPS that arise as a result of block copolymerization. The results show a low-temperature β-relaxation due to local motion of the methylenes of the chain backbone, an α-relaxation associated with the glass transition, and an αc-relaxation due to the melting of the crystalline phase. Both α-and β-relaxations in the block copolymer are only slightly perturbed, and this suggests that the blocks are incompatible. The β-relaxation of HMS is confined to the amorphous regions of the polymer. Although sample preparation had little effect on the degree of crystallinity, large differences in the relaxation behavior were observed when the sample preparation was varied.
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