Thermo-optic response and mechanical properties of hybrid polyurethane elastomers via silicon group-induced microphase separation evolution

Abstract

In this study, silicon hybrid polyurethane elastomers (SPUs) with flower-like microstructure were constructed by a two-step method according to incorporating diphenylsilanediol (DPSD) into hard segments. The reinforced microphase separation of SPUs was estimated by combining Fourier transform infrared spectrometer (FT-IR) characterization with differential scanning calorimeter (DSC) and dynamic mechanical analyzer (DMA). The silicon heteroatom-inducing flower-withering like morphology for SPUs was found with increasing silicon groups, which revealed an evolution from flowers-blossoming to broken petals like microdomain due to the ordered aggregation of hard segments. In addition, the reversible thermo-optic response of SPUs, a sharp transition from light opaque at room temperature to more than 55% transmission at 160 °C, was observed, attributing to “sea-island” or bi-continuous structural evolution owing to hydrogen bond dissociation or recombination with changing the temperature. Comparing with pure PU, the enhanced mechanical properties of SPUs were achieved, more than 20 times tensile strength (14.75 ± 2.52 MPa) and more than 3 times elongation at break (293.31 ± 2.87%). In sum, the study was of great significance for designing novel functional segmented PU materials.