Study On Melting Intercalation Nanocomposites Of Organic Rectorite/Polymer

Rectorite (REC) is a kind of natural clay and can be represented by regular (1:1) stacking of mica-like and montmorillonite-like layers, with exchangeable hydrated cations between galleries and the d-space about 2 run, so the characteristics is much similar to montmorillonite (MMT) as well as the structure, such as cation exchangeability and expansibility after water absorption. Polar organic compounds or cations can be intercalated into the rectorite layers via ion-exchange reaction and obtain an expanded gallery structure and organophilic layered structure.In this paper, the organic rectorite (OREC) is synthesized through cation exchange reaction with a particular kind of alkylamine or two kinds of quaternary ammonium salt, and OREC/thermoplastic polyurethane (TPUR) named OREC/TPUR, OREC/polypropylene (PP) named PR and OREC/ polyethylene-octene elastomer (POE)/PP named PRE nanocomposites are prepared via melt blending. The structure of composites is investigated on X-ray diffraction (XRD) and transmission electron microscope (TEM). The rheological properties of pure resins and their composites are characterized by capillary rheometer. The crystallization kinetics of PP and its composites is investigated by differential scanning calorimetry (DSC). The crystallization morphology is studied by polarized light microscope (PLM) and wide X-ray diffraction (WXRD). The mechanical properties, dynamic mechanical analysis (DMA), thermogravimeric analysis (TG), oil resistance and air aging resistance properties of composites are also investigated.It is found that quaternary ammonium salt and alkylamine can react with REC via cation exchange reaction and the resulting OREC can act as nano-scale filler to modify polymer materials due to its increasingly swollen gallery spacing. The stronger polarity of matrix and smaller loading of OREC can carry better-intercalated performance. The rheological tests show that the composites can be classified as pseudoplasticity. Theapparent viscosity of the OREC/TPUR systems is higher than that of pure TPUR, while non-polarized OREC/PP systems is lower than pure PP, and PRE systems is higher than corresponding POE/PP systems. In general OREC may act as efficient nucleating agent for the crystallization of PP. and can accelerate the crystallization process and enhance the crystallization rate of PP, while the crystallinity of pure PP is slightly changed and the crystal form is not.The tensile strength of OREC/TPUR system is maximal when the loading of OREC is 2phr and the elongation is maximal when the loading is 5phr, which is associated with the good compatibility and strong interaction between clay and matrix. The tensile strength, elongation and impact strength of PR system are maximal when the loading of OREC is 2phr, which connects with the crystallization morphology of composites as well as the intercalated performance of OREC in PP matrix. OREC has synergistically toughening and strengthening effects on POE/PP systems, and more loading of POE has better effects, which is explained by the magnitude and distribution of POE as well as the intercalation performance of OREC and crystallization performance of PP in composites. Proper dimension and broader distribution of POE and fine PP grain in composites can carry good toughness. The storage modulus of composites is higher with more loading of OREC than that of pure resins, and it increases more when compared OREC/TPUR system with PR and with PRE systems. The glass transformation temperature (Tg) of OREC/TPUR systems is enhanced because of the strong interaction of OREC and TPUR, and that of PR and PRE system is almost no changed.Well-intercalated composites have higher Tg, better oil resistance and air aging resistance properties, which shows that the clay platelets well exhibit air and other reagents barrier effect to final composites.