ポリウレタン系形状記憶ポリマーの変形特性

概要

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Mechanical properties of shape memory polymer vary at glass transition temperature T_g. In the present study, the influence of loading temperature upon shape recoverability, shape fixity and the cyclic properties of shape memory polymers of the polyurethane series has been investigated experimentally for uniaxial tension under thermomechanical cycling. The results are summarized as follows. (1) Deformation resistance of the materials increases with an increase in the number of cycles. (2) In the case of the loading temperature at T_g + 20 K, residual strain which appears after cooling and unloading recovers at temperatures in the vicinity of T_g. In the case of loading temperatures below T_g, strain recovers at temperatures in the vicinity of the midpoint glass transition temperature T_<mg>. (3) In the case of loading temperatures above T_g, recovery stress which appears upon cooling under constant maximum strain is about twice as large as the stress in the loading process. The recovery stress occurs at temperatures in the vicinity of T_<mg>. (4) Excellent shape fixity can be obtained if the material is cooled under maximum strain and unloaded.
社団法人日本機械学会の論文
1994-07-25