AB-polymer networks based on oligo(epsilon-caprolactone) segments showing shape-memory properties

Although shape-memory metal alloys have wide use in medicine and other area s, improved properties, particularly easy shaping, high shape stability, an d adjustable transition temperature, are realizable only by polymer systems . In this paper, a polymer system of shape-memory polymer networks based on oligo(epsilon -caprolactone) dimethacrylate as crosslinker and n-butyl acr ylate as comonomer was introduced. The influence of two structural paramete rs, the molecular weight of oligo(epsilon -caprolactone) dimethacrylate and the weight content of n-butyl acrylate, on macroscopic properties of polym er networks such as thermal anti mechanical properties has been investigate d. Tensile tests above and below melting temperature showed a decrease in t he elastic modulus with increasing comonomer weight content, The crystalliz ation behavior of the new materials has been investigated, and key paramete rs for the programming procedure of the temporary shape have been evaluated . Shape-memory properties have been quantified by thermocyclic experiments. All samples reached uniform deformation properties with recovery rates abo ve 99 % after 3 cycles. Whereas strain recovery increased with increasing n -butyl acrylate content, strain fixity decreased, reflecting the decreasing degree of crystallinity of the material.