Hollow glass microspheres/silicone rubber composite materials toward materials for high performance deep in-situ temperature-preserved coring

Deep petroleum resources are stored under high temperature and pressure conditions, with the temperature having a significant influence on the properties of rocks. Deep in-situ temperature-preserved coring (ITP-coring) devices were developed to assess deep petroleum reserves accurately. Herein, hollow glass microspheres (HGMs)/silicone rubber (SR) composites that exhibit excellent thermal insulation properties were prepared as thermal insulation materials for deep ITP-coring devices. The mechanism and process of heat transfer in the composites were explored, as well as their other properties. The results show that the HGMs exhibit good compatibility with the SR matrix. When the volume fraction of the HGMs is increased to 50%, the density of the HGMs/SR composites is reduced from 0.97 to 0.56 g/cm3. The HGMs filler introduces large voids into the composites, reducing their thermal conductivity to 0.11 W/m·K. The addition of HGMs into the composites further enhances the thermal stability of the SR, wherein the higher the HGMs filler content, the better the thermal stability of the composites. HGMs significantly enhance the mechanical strength of the SR. HGMs increase the compressive strength of the composites by 828% and the tensile strength by 164%. Overall, HGMs improve the thermal insulation, pressure resistance, and thermal stability of HGMs/SR composites.