Physical Properties and Microphase Separation of Polyurethane Films Containing Poly(dimethyl siloxane) Component

Abstract

Polyurethanes (PUs) containing poly(dimethyl siloxane) (PDMS) unit in soft segment, PU-Si, were syn- thesized, and their mechanical properties and phase separation were investigated. Various amounts of PDMS units were incorporated into PU via a solution polymerization method in N,N'-dimethylformamide using poly(tetramethylene ether glycol) and PDMS diol as a soft segment and methylene diphenyl diisocyanate and 1,4-butanediol as a hard segment. Two series of PU-Si samples with an HS content of 23% and 32% were prepared and analyzed. Results showed that the elongation-at-break of the PU-Si films increased, breaking stress decreased, and the hydrophobicity of the film increased as the PDMS content in PU-Si increased. SAXS analysis indicated that the microphase separation of the PU-Si film between hard and soft segments decreased with increasing PDMS content, irrespective of the HS content.