ABSTRACT
One of the shape memory polymer (SMP) material systems used in cold hibernated elastic memory (CHEM) technology was developed in late 1980s and early 1990s by Hayashi and his team at Nagoya R&D Center, Mitsubishi Heavy Industries (MHI), Japan. This SMP material system is a heat-activated polyurethane-based thermoplastic polymer that offers unique properties for a variety of different applications. The polyurethane-based SMP is designed and formulated by chemical constituents, molecular weight, and mixing molar ratio. It is a block polymer consisting of a polyol-based soft segment and a hard segment based on diisocyanate with a glycol chain extender. The MHI-developed SMP material utilizes specific types of diisocyates, polyols, and chain extenders, all of them bifunctional. By selecting a proper diisocyanate and polyol combination and/or soft-to-hard segment ratio, a modulus of elasticity, glass transition temperature and melting point of the SMP material can be easily tailored to the desired property values.
