Study On The Preparation, Structure And Properties Of Polypropylene, Poly(Vinyl Chloride)/Montmorillonite Nanocomposites

This paper found two problems during the preparation processes of polypropylene /organophilic montmoriUonite (PP/OMMT) nanocomposite and poly(vinyl chloride) /organophilic montmorillonite(PVC/OMMT) nanocomposite: One was that PP/MMT nanocomposite was difficultly prepared by melt intercalation as a result of PP is non-polarity polymer; Other was that OMMT resulted in PVC degraded in preparation of PVC/MMT nanocomposite by melt intercalation. In this paper, MMT nano-masterbatches were prepared and characterization; PP/MMT and PVC/MMT nanocomposites were prepared with MMT nano-masterbatches by melt intercalation, and the structure and properties of these two nanocomposites were characterized.Preparation of MMT nano-masterbatch. Two sorts of MMT nano-masterbatches of organo-montmorillonite/polypropylene-g-maleic anhydride/epoxy resin(OMMT/MPP /EP) and organo-montmorillonite/polypropylene-g-maleic anhydride (OMMT/MPP) were successfully prepared by melt intercalation. In these masterbatches, MMT content reached 60wt%. The results from X-ray diffraction showed that OMMT/MPP/EP was a fully intercalated nano-masterbatch, the space of the layers increased from 1.95nm up to about 3.33nm; But OMMT/MPP was just partly intercalated nano-masterbatch. In addition, in the condition of high content of OMMT, poly(methyl methacrylate)/organophilic montmorillonite(OMMT/PMMA) prepared by in-situ polymerization was orderlessly intercalated nano-masterbatch, the space of the layers reached 3.65nm.PP/MMT nanocomposites. PP/MMT nanocomposites were successfully prepared with OMMT/MPP/EP(MMTOme) and OMMT/MPP(MMTOm) by melt intercalation, PP/OMMT nanocomposite was prepared with OMMT also. The results from X-ray diffraction demonstrated that PP/ MMTome was a fully intercalated nanocomposite, PP/ MMTom and PP/OMMT were partly intercalated nanocomposites, but the intercalation effect of PP/ MMTom nanocomposite was better; The crystallization characteristics of pure PP and PP/MMT nanocomposites were investigated by DSC, WAXD and POM. The result of these testing showed that MMT nano-layers acted as nucleating agents for the crystallization of PP, the addition of MMT had effect on the crystallization process, leading the increasing of crystallization temperature crystallization rate and crystallinity, but also the dimension of spherulite reduced. But the formation of PP crystal didn't change, the formation of PP crystal in three PP/MMT nanocomposites and pure PP were a-form on the whole; Influences of three sorts of MMT on mechanical properties of PP/MMT nanocomposites were studied, as a result, the addition of MMT comprehensively improved mechanical properties of PP: notched impact strength, tensile strength and flexural properties were all increasing, but the extent of increasing weren't large. Additionally, three sorts of MMT had different effect on the mechanical properties of PP: PP/MMTOm was best, PP/MMTOme was better and OMMT was last. Analyzed these results, the paper considered there were two causes: the influence of MMT on crystallization of PP and nano-function of MMT nano-layers.Hard PVC/MMT(HPVC/MMT) nanocomposite. PVC/MMT exfoliated nanocomposite were successfully prepared with MMTome by melt intercalation. The problem that OMMT resulted in PVC degraded was settled. But Na-MMT in PVC/Na-MMT composite was simply common filler, the space of the layers was 1.29nm. The mechanical properties of system of HPVC/MMT composites showed, the notched impact strength of HPVC/MMTOme nanocomposite was 1.08 times of that of pure HPVC, but the notched impact strength of PVC/Na-MMT composite increased only 29%.Soft PVC/MMT(SPVC/MMT) nanocomposite. OMMT can been directly used for the preparation of SPVC/MMT nanocomposite because dioctyl phthalate(DOP)plasticizer can improve the heat stabilization of PVC in some sort. The space of the layers of MMT in SPVC/MMT nanocomposite reached 3.73nm. The volatilization rate into air of SPVC composites were examined, the result showed that the addition of OMMT could significantly improv...