Study On Core-shell Sericite/PMMA Composites And Modification Of Polymer Materials

Sericite is a new type of mineral filler. As hydrophilic inorganic fillers, sericite interface properties are different from that of polymer materials. Because of their poor compatibility, surface modification is an important method to improve the performance of sercite filled polymer materials.In this paper, core-shell sericite/PMMA composites were prepared by emulsion polymerization. Firstly, sericite was coated with coupling agent containing C=C functional group, a surface actived sericite was prepared. Then, vinyl monomer was grafted onto the surface of the actived sercite by emulsion method. Finally, a new type of core-shell sericite/PMMA composite was prepared. The process conditions were studied. The optimal polymerization parameters were obtained as below, reaction time is about 12 hours and the reaction temperature is 80℃.The properties and structure of sericite/PMMA composites were characterized. The surface micromorphology was investigated by SEM, the chemical structure was characterized by FT-IR spectroscopy, the heat resistance was studied by TG, and the crystal structure was studied by XRD. The results showed that sericite/PMMA composite materials have a flake core-shell structure with sericite as the core and PMMA as the shell. PMMA was linked to sercite by chemical bonds via coupling agent.Sericite/PMMA-PVC blends were prepared and their mechanical properties and microstructure were studied. The results indicated that the heat deformation, the mechanical properties and UV shielding performance of PVC were improved by filling the composites. The blends showed better performance than blend of PVC with coupling agent coated sericite, calcium carbonate and silica. The SEM photos of the blends cross-section showed that the PVC has good interfacial compatibility with the sericite/PMMA composite.The mechanical properties of sericite /PMMA-ABS blends were also studied. The results showed that the mechanical properties, such as, the impact, tensile and flexural strength of the blends were improved by filling sericite/PMMA composites into ABS. Especially, the blends showed better performance if the filled composites prepared with 5%VTEOS and 15%MMA in their mass ratio.And the blends showed good performance even the blends at 40 phr.