Synthesis and Characterization of Temperature-Sensitive TSPU/PNIPAAm semi-IPN Polymer

Thermo-sensitive polyurethane (TSPU) was synthesized from poly(epsilon-caprolactone) and 4,4'-methylenebis (phenyl isocyanate) by a two-step process with 1,4-butanediol as the chain extender. Following that, a novel temperature-sensitive material was created by the strategy of IPN from TSPU and PNIPAAm in the method of in situ polymerization. The chemical structure and thermo properties of the semi-IPN were characterized with FT-IR and DSC. The results prove that intensive inter-molecular interactions exist between TSPU and PNIPAAm chains, which have significant influence on the phase transition behaviors of the material. According to these results, the transition temperature of the semi-IPN can be adjusted in the range of 30 similar to 40 degrees C by controlling the composition of TSPU and the semi-IPNs.