The invention relates to a preparation method of an SiC reaction modified PP (
polypropylene) thermal conductive
composite material. The preparation method comprises the following steps: adding a
reaction type flexibilizer into dilute sulphuric acid for full infiltration, and stirring and
drying the mixture; dissolving a
silane coupling agent in an
ethanol solution, stirring and hydrolyzing the
silane coupling agent, adding the prepared
reaction type flexibilizer
powder, stirring the
powder in a water bath at 70 DEG C for 3 h, and obtaining modified
reaction type flexibilizer
powder at the endof the reaction; preparing modified
silicon carbide by the same method, fully mixing
polypropylene and the modified
silicon carbide according to the formula, and adding the
silane coupling agent, themodified reaction type flexibilizer and an
antioxidant, and blending to obtain a premixed material; and adding the premixed material into a double-screw extruder, performing ultrasonic treatment in anextruding stage, and after the
extrusion is completed, obtaining the
composite material through steps of cooling and the like. By the adoption of reaction modification, ultrasonic treatment and
extrusion flexibilizing technologies, the preparation method solves the problem of non-uniform dispersion of a thermal conductive filler and is favorable for improving the interfacial compatibility of thesilicon
carbide and the
polypropylene.