Thermochromic silicone rubber composite heat dissipation pad and preparation method thereof

A method for preparing a silicone rubber composite heat dissipation pad, comprising:

• S1:
• preparing boron nitride nanosheet powder;
• S2:
• grafting a hydroxyl group on a surface of the boron nitride nanosheet powder to produce hydroxyl-functionalized boron nitride nanosheet powder;
• S3:
• dispersing the hydroxyl-functionalized boron nitride nanosheet powder into deionized water, stirring evenly, pouring it into a specialized container,
• wherein the specialized container comprises a square polytetrafluoroethylene cassette having an upper opening and a side opening, wherein a slot is provided at an edge of the side opening, and a brass baffle plate is mounted in the slot to seal the side opening of the cassette, thereby forming a square container with only the upper opening, using liquid nitrogen to pre-freeze for 50-70 s and then transferring the specialized container to a freeze dryer, freeze-drying for 48 h at a temperature of −40° C., removing the specialized container from the freeze dryer to warm up the specialized container to room temperature, and obtaining a boron nitride nanosheet skeleton arrayed in a horizontal direction;
• S4:
• uniformly dispersing thermochromic nanoparticles in acetone to obtain a dispersion, mixing the dispersion with liquid silicone rubber and stirring until the acetone is completely evaporated, adding a silicone rubber curing agent to continue stirring evenly, and obtaining a liquid silicone rubber pre-cure solution;
• S5:
• pouring the liquid silicone rubber pre-cure solution into a container containing the boron nitride nanosheet skeleton, placing the container in a vacuum environment, so that the liquid silicone rubber pre-cure solution is fully immersed in an interior of the boron nitride nanosheet skeleton while removing air bubbles;
• and
• S6:
• curing the liquid silicone rubber pre-cure solution containing the boron nitride nanosheet skeleton obtained in step S5 at elevated temperature under atmospheric pressure to obtain a flexible silicone rubber composite heat dissipation pad with functionalized boron nitride as a support and the thermochromic nanoparticles uniformly distributed inside.