Interfacial Reinforced Effect And Mechanism Of PP/mica Composites

In this thesis, polypropylene(PP)/mica composites were prepared by molten process, with graft copolymers by reactive extrusion as interfacial modifier.For the preparation and performance of the graft copolymer, the effect of the dosage of monomer AA and catalyzer DCP on the graft ratio of PP-g-AA was discussed, and multi-monomer melt grafting on PP was studied, it was found that the addition of styrene monomer reduced the degradation of PP. The chemical titration and the FTIR were used on the evidence of the graft ratio. Nonisothermal crystallization kinetics of PP and PP-g-AA was analyzed, the result indicated that PP-g-AA could hasten the nucleation of polypropylene and accelerate crystallization rate of polypropylene, and lead to lower degree of crystallization than that of PP..The further researches on the preparation of PP/mica composite were done. Firstly, the effect of the different kind of mica and graft copolymer on the performance of PP/mica composites was analyzed, the effect of the content of mica and graft copolymer and the graft ratio of graft copolymer was investigated, and PP/mica composite with good mechanical properties could be prepared by the addition of PP-g-AA and PP-g-MAH together into the composite systems. The crystallization behavior and structures of PP/PP-g-AA/Mica composites were studied by differential scanning calorimetry (DSC) and wide angle X ray diffraction (WAXD), and the results indicated that mica and PP-g-AA have nucleation on PP, and the content of mica, the content and graft ratio of PP-g-AA have effect on the crystallization of polypropylene. Secondly, the effect of the grafted polypropylene and silane coupling agent on the PP/mica system was studied, it was found that there existed the coordinate action between the grafted polypropylene and silane coupling agent. Thirdly, by the analyse of SEM testing, we knew more about the interface of PP/mica composites which had treated by graft. Finally, the systems of PP/EPDM/mica were studied, in order to improving the impact properties of PP/mica composites. The effect of mica and EPDM on the properties of polypropylenes was investigated, and the most appropriate content of EPDM and mica was ascertained, comparing the effect of (PP/EPDM)-g-MAH on systems with that of PP-g-MAH.From the above-mentioned researches, we got hold of some information about the interface behavior of PP/mica composites when the graft copolymer is used as the reagent that can improve the interfacial performance of composites. Based on that, we did some tests about the change of graft copolymer, and the other PP/mica composites were made and studied, so more information could be concluded about the mechanism and action of graft copolymer that was used to improve the interface of PP/mica composites.Finally, the system of mica filled β crystalline form PP was investigated. If PP-g-MAH was used, the mechanical properties of mica filled β crystalline form PP were increased, comparing with those of mica filled a crystalline form PP. By the analysis of wide angle X-ray diffraction, the effect of mica and PP-g-MAH on the βcrystalline form, the parameter of crystalloid configuration, and microcrystal size was obtained. The microcrystal size of polypropylene was increased, the crystal cell parameter of which was diminished, when mica was appended. On the very reverse, PP-g-MAH was appended. PP-g-MAH was not good for the form of β crystalline form polypropylene, but was good for the orientation of mica and the improvement of the mechanical properties.