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Synthesis and properties of photosensitive rubbers. IV. Photosensitive rubbers from hydroxyethyl cinnamate and polyisoprene modified with maleic anhydride
Author(s) -
Azuma Chiaki,
Hashizume Naoko,
Sanui Kohei,
Ogata Naoya
Publication year - 1983
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1983.070280210
Subject(s) - photosensitivity , glass transition , maleic anhydride , polymer chemistry , isoprene , pyridine , succinic anhydride , polymer , materials science , triphenyl phosphite , copolymer , chemistry , organic chemistry , optoelectronics
Abstract Polyisoprene in o ‐dichlorobenzene solution were reacted with maleic anhydride at 180°C under nitrogen atmosphere to form modified polyisoprene with α‐substituted succinic anhydride groups. These groups were converted by reaction with hydroxyethyl cinnamate in pyridine at 25°C to cinnamate groups. Various amounts of cinnamate groups as photosensitive groups could be easily introduced into polyisoprene up to 75 mol % toward polyisoprene repeating units. Polymer glass transition temperatures of the products rose linearly from −70°C for polyisoprene to 60°C with increasing amounts of the side groups. The solution viscosity of the products in chloroform decreased from 9.34 for polyisoprene to 0.77 with increasing amounts of the side groups. The photosensitivity of the polyisoprene, which is based on the photodimerization of the cinnamate groups, was higher than that of polypentenamer having cinnamate groups due to the interaction by the free carboxylic acids neighboring with the cinnamate groups. The photosensitivity of the cinnamate group was kinetically evaluated in terms of the dependence on the polymer glass transition temperature. The interaction by the free carboxylic acid groups in the polyisoprene reduced the dependence of the photosensitivity on the mobility of the polymer segments. Linear relationship between observed rate constants of the photodimerization and ( T UV − T g + 50) −1 was obtained and the slope of the line changed and became very small at higher glass transition temperatures.