Poly(urethane-siloxane) networks based on hyperbranched polyester: mechanical and thermal properties

Mechanical and thermal properties, hardness as well as degree of microphase separation of novel poly(urethane-siloxane) networks based on hyperbranched polyester of the forth pseudo generation were investigated using a variety of experimental methods. According to the combined results obtained from DSC and DMTA experiments, these networks exhibit two glass transition temperatures, of the soft and hard segments, and one secondary relaxation process. The results showed increase of crosslinking density and microphase separation and improvement of mechanical properties with decreasing content of soft ethylene oxide-poly(dimethylsiloxane)-ethylene oxide segment