Shape memory polyurethanes chemistry

Diisocyanate is often used in the chain extension reactions of biopolymers such as PEA, PCL, and their copolymers [97-101]. The combination of hard segment and soft segment may confer the resulting polyurethanes with shape-memory property [100,101]. Polyurethane is an important type of elastomeric polymer for biomedical applications [1,9,11]. Chain extension or cross-linking by diisocyanate can be adapted to many -OH-terminated or H-containing polymers or prepolymers [102]. The convenience of the urethane chemistry has made it into a very popular way of polymer chain extension method in biomaterial designs. 

Huang, W.M., Yang, B., Zhao, Y., and Ding, Z. (2010) Thermo-moisture responsive polyurethane shape-memory polymer and composites a review. Journal of Materials Chemistry, 20, 3367-3381. 

Xiao F, Shen D, Zhang X, Hu S and Xu M (1987) Studies on the morphology of blends of poly(vinyl chloride) and segmented polyurethanes, Polymer 28 2335-2345. Ahn T 0, Han K T, Jeong H M and Lee S W (1992) Miscibility of thermoplastic polyurethane elastomers with chlorine-containing polymers, Polymer 33 115-120. Flory P J (1953) Principles of Polymer Chemistry, Cornell University Press, Ithaca. Jeon H G, Mather P T and Haddad T S (2000) Shape memory and nanostructure in poly(norbornyl-poss) copolymers, Polym Int 49 453-457. 

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