Influence of Poly (Titanium Oxide) on the Kinetic of the Formation, Viscoelastic and Optical Properties of the Interpenetrating Polymer Networks

The organic-inorganic interpenetrating polymer networks (OI IPNs) based on the cross-linked polyurethane (PU), poly (hydroxyethyl methacrylate) (PHEMA) and poly(titanium oxide) ((–TiO2–)n) previously synthesized by the sol-gel method in the presence of 2-hydroxyethyl methacrylate (HEMA) were obtained. The features of the kinetics of OI IPNs formation with different content of inorganic component were studied by calorimetric method. It was shown, that the rate of HEMA polymerization decreased with increasing of (–TiO2–)n content. The viscoelastic properties and the thermal transition behavior of OI IPNs were investigated by the dynamic mechanical analysis (DMA). The data obtained by DMA method indicate that OI IPNs are two-phase systems. It was shown, that the increase of cross-linking density of OI IPNs with increasing content of the inorganic component occurs due to the chemical grafting of (–TiO2–)n to HEMA. It was found that the topology of (–TiO2–)n structure affects the relaxation behavior of OI IPNs polymer systems. Also we report that the reversible darkening of OI IPNs took place due to Ti4+ + e ↔Ti3+ transition under UV-irradiation.