Poly(methyl methacrylate)/hyperbranched polysiloxane hybrid prepared by gamma-radiation polymerization: Thermal stability, optical transparence, and UV shielding

It is challenging to endow poly(methyl methacrylate) (PMMA) with good dielectric properties and UV absorption capacity while simultaneously overcoming its poor heat resistance. Herein, we report for the first time a novel organic-inorganic hybrid (PMMA-HBPSi) derived from methyl methacrylate (MMA) and hyperbranched polysiloxane (HBPSi) fabricated via gamma-radiation curing. The typical properties (thermal stability, optical characteristics, and dielectric properties) of the hybrids were systematically investigated and discussed. The results demonstrated that the incorporation of HBPSi into the PMMA resin not only increased the thermal resistance, dimensional stability, and dielectric properties but also remarkably reduced the UV transmittance. Specifically, in comparison with pure PMMA, the initial degradation temperature (T-di) of PMMA-HBPSi increased by 31 degrees C, with no phase transition occurred in a temperature range of 60-230 degrees C, thus illustrating a significant improvement in the glass-transition temperature. Moreover, the thermal expansion coefficient decreased by 86.9% at temperatures exceeding 118 degrees C. The UV transmittance of PMMA was also found to decrease by 80% at 295 nm after the introduction of HBPSi. These attractive features of PMMA-HBPSi demonstrate that the new approach proposed here is suitable for developing high-performance organic glasses for optical, aviation, and electronic applications.