Abstract: Micron-magnesium hydroxide (MH), which was modified by titanate, silane and in-situ emulsion polymerization, respectively, was filled into polypropylene（PP）with the mass ratio of MH particle and PP was 20:80. The effects of surface treatment on the morphology, mechanical properties and rheology property of PP/MH composites were studied by DSC, morphology observations and rheological behaviors testing. It was shown that the modification of polymer encapsulated MH via in-situ polymerization improved the interfacial adhesion between MH and PP matrix, and increased the impact strength of PP/MH composites by 26.4%. In addition, the melt index (MI) of PP/MH composite filled with encapsulated MH particles was increased 64% compared to pure PP. The melt viscosity of PP/MH composites filled with encapsulated MH particles was decreased than that of PP/MH composites filled with unmodified MH particles at same shear rate. It was indicated that the polymer encapsulated on the surface of MH reduced the particles’ block effect and improved processing behavior of the composites.

Key words: polypropylene, magnesium hydroxide, modification, mechanical property, rheology property