Structure-Property Correlation Study of Novel Poly(urethane-ester-siloxane) Networks

Novel poly(urethane-ester-siloxane) networks, based on hydroxypropyl terminated poly(dimethylsiloxane) (PDMS), 4,4-methylenediphenyl diisocyanate, and hyperbranched polyesters (HBPs) of the second and third pseudogenerations, were synthesized by two-step polymerization. The effects of the PDMS content and pseudogeneration number of HBPs on the structural, thermomechanical, thermal, and surface properties of polyurethanes were investigated. Thermomechanical and thermal properties of polyurethanes and FTIR, SAXS, and SEM results indicated good microphase separated structure. SAXS data suggested that the difference in the HBP pseudogeneration number affects only the global properties of the structure and is much less pronounced than the dependence on the PDMS content, while local properties depend only on the PDMS content. Surface characterization of samples indicated the slightly amphiphilic nature of polyurethanes. The results revealed that the synthesized polyurethanes have good thermal, thermomechanical, and surface properties, which can be tuned and adjusted for coating application by changing the PDMS content or type of the HBP