Abstract
AbstractMacro‐azonitriles were prepared by the reaction of azobis‐alcohol with diisocyanate of polyalkylene oxide and were used as initiators for the polymerization of various vinyl monomers such as vinyl acetate, styrene, methyl methacrylate and vinyl chloride, yielding block‐copolymers consisting of polyalkylene oxide and polyvinyl sequences. These block copolymers were characterized by their dynamic properties. The polymers were found to possess two transition points, one arising from the polyalkylene oxide blocks and the other from the polyvinyl sequences. A thermoplastic elastomer was obtained from the block polymerization of styrene with poly(oxytetramethylene)glycol, whose intrinsic viscosity was 2.3 dl/g and the styrene content was 33.2 wt. –%, the ultimate strength and elongation being 57 kg/cm2 and 475%, respectively. The block copolymers of polystyrene and branched polyether were also synthesized and their viscoelastic properties were investigated.
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