The Difference in Molecular Orientation and Interphase Structure of SiO2/Shape Memory Polyurethane in Original, Programmed and Recovered States during Shape Memory Process.

摘要: In order to further understand the shape memory mechanism of a silicon dioxide/shape polyurethane (SiO2/SMPU) composite, thermodynamic properties and behaviors prepared SiO2/SMPU were characterized. Dynamic changes in molecular orientation interphase structures during cycle then discussed according small angle X-ray scattering theory, Guinier’s law, Porod approximation, fractal dimension theorem. this paper, dynamic mechanical analyzer (DMA) helped determine glass transition start temperature (Tg) by taking onset point sigmoidal change storage modulus, while (Ttrans) was defined peak tan δ, test calculated results indicated that Tg 50.4 °C, Ttrans 72.18 °C. showed good performance. The programmed quite obvious microphase separation orientation. Large-size sheets long-period formed SiO2/SMPU, which increases electron density difference. Furthermore, some hard segments had been rearranged, their gyration radii decreased. addition, several defects at interfaces caused generation space charges, thus leading local fluctuations. blurred structure intermediate layer there evident crystal damage chemical bond breakage recovered SiO2/SMPU. Finally, original samples belong surface system, but sample belongs mass reforms two-phase structures. This study provides an insight into composite.