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The First Example of Main‐Chain Cyclic Azobenzene Polymers
Author(s) -
Xu Xu,
Zhou Nianchen,
Zhu Jian,
Tu Yingfeng,
Zhang Zhengbiao,
Cheng Zhenping,
Zhu Xiulin
Publication year - 2010
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201000218
Subject(s) - azobenzene , chain (unit) , polymer , polymer science , polymer chemistry , materials science , chemistry , physics , composite material , quantum mechanics
A novel main‐chain azobenzene cyclic polymer, cyclic‐ PEHPA, has been successfully synthesized by ‘click’ cyclization of the α ‐alkyne‐ ω ‐azido hetero‐difunctional linear precursors ( linear‐ PEHPA), which is synthesized by a step‐growth polymerization of the 3′‐ethynylphenyl[4‐hexyl‐(2‐azido‐2‐methyl‐ propionate) phenyl] azobenzene (EHPA). Gel permeation chromatography, and 1 H NMR and FT‐IR spectra confirmed the complete transformation of linear ‐PEHPA into cyclic‐ PEHPA. With the same molecular weights, the cyclic‐ PEHPAs are found to have higher glass transition temperatures than the linear‐ PEHPAs, but almost the same decomposition temperatures. In addition, the obtained cyclic azobenzene polymer with lower molar mass shows a slightly better trans–cis–trans photoisomerization ability than the corresponding linear‐ PEHPA.