Meyer, Thorsten

A method for preparing a graphene thermal conductive pad is referred. Graphene foam sheets are used as base materials for the graphene thermal conductive pad. The graphene foam sheets are processed by surface crust removal, laser perforation and edge trimming, plasma activation, and multiple modification treatments to yield the graphene thermal conductive pad. The plasma activation causes the hydroxyl functional groups to be generated on the graphene surface. By using hydroxyvinyl silicone oil diluted with xylene, a small amount of hydroxyvinyl silicone oil uniformly covers the graphene surface. Heating induces dehydration condensation between the hydroxyvinyl silicone oil and the hydroxyl groups generated by plasma activation, forming chemical bonds. In such a way, a tighter interface between the graphene and the subsequent adhesive is achieved, pores at the interface are reduced, thereby lowering thermal contact resistance, improving heat transfer efficiency, and enhancing tensile strength and compression resilience.

The present disclosure discloses a polymer additive, a flame retardant, a polymer molding material, and a preparation method and a use thereof. The polymer additive comprises aluminum diethylphosphinate and aluminum ethylbutylphosphinate; the polymer additive satisfies a relationship of 0.90 ≤ ΔH ≤ 1.05, wherein ΔH is a dual enthalpy ratio and defined by Equation (1); the polymer additive further satisfies following relationships: 135 °C ≤ T1 ≤ 160 °C, 165 °C ≤ T2 ≤ 185 °C, and 180 °C ≤ T3 ≤ 200 °C; and the Equation (1) is as follows: ΔH = (H2+H3)/H1. The polymer additive has a specific crystal transition state, and a polymer molding material comprising the polymer additive has lower molding shrinkage during the molding process.

A flexible silicone thermal conductive composition includes a core thermal conductive composition, an insulating layer, and an isolating layer, from inside to outside. The core thermal conductive composition includes the following components by mass fraction: silicone base polymer 5-30%, silicone crosslinking agent 0.2-5%, silicone chain extender 1-8%, thermal conductive filler 60-93%, powder dispersant 0.1-1.2%, catalyst 0.02-0.2%, retarder 0.02-0.1%, and toughening agent 0.5-6%. The insulating layer includes the following components by mass fraction: silicone base polymer 85-95%, silicone crosslinking agent 0.2-8%, silicone chain extender 1-10%, dehydrating agent 0.1-0.5%, catalyst 0.05-0.15%, retarder 0.02-0.1%, and toughening agent 0.4-15%. The isolating layer includes the following components by mass fraction: metal oxide 95-99%, and powder dispersant 1-5%. The flexible silicone thermal conductive composition as thermal conductive gap filling materials in the range of 1-8 W/mk has ultra-high electrical insulation performance, wider gap filling range, and an extremely low oil bleeding rate.

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