Robust silicone rubber with high transparency by loading with porous hollow glass microsphere

Two kinds of porous hollow glass microsphere (HGM) were synthesized using HGM as a raw material. Then, silicone rubber (SR) based composites with porous HGM as inorganic filler were prepared. The microstructures of the composites were characterized by a scanning electron microscope (SEM), and the relationship between the interface structure and strengthening mechanism was explained. Due to the formation of interpenetrating networks through SR chains inserting into porous HGM, the interfacial adhesion was enhanced. Therefore, tensile strength and elongation at break of SR were greatly improved by porous HGM. Especially for HGM-2 with high specific surface area and through-hole, tensile strength of SR/HGM-2 composite with only 2 phr HGM-2 increased from 0.41 MPa to 0.91 MPa, and elongation at break increased from 103 to 251%. The densities of composites with filler content ranging from 2 phr to 15 phr were also examined. Particularly, the density of SR/HGM-1 composite with 15 phr HGM-1 further decreased to 0.75 g/cm3 compared with that of SR/HGM (0.82 g/cm3). In addition, the thermal stability of SR composites with porous HGM was also significantly improved. Along with through-hole structure of HGM-2, another straightforward consequence of SR/HGM-2 composite was high transparency caused by reduction of light scattering.

Automated summary

Two kinds of porous hollow glass microspheres were synthesized and used as fillers in silicone rubber composites. The microstructure and strengthening mechanism were investigated, showing enhanced interfacial adhesion and improved mechanical properties of the composites. The density and thermal stability were also improved, and the composite with HGM-2 exhibited high transparency due to reduced light scattering.