Preparation And Properties Of Poly(Propylene Carbonate)/layered Silicate Nanocomposites

Biodegradable polymers from renewable resources have attracted much attention in recent years. Renewable sources of polymeric materials offer an alternative to maintaining sustainable development of economically and ecologically attractive technology. The whole world polymers material output already exceed 120 million tons on every year. The waste coming into being has become a pollution source, lead to ground water quality and soil contaminated, and prevent animal and plant from growing, and endanger human being health. Restraint because of cost and factors such as technology and level, though to biodegradable polymers material already had studying and put on probation, but, it's the level developing and applying can not be all that could be desired.Poly(propylene carbonate) (PPC) is a new thermoplastic biodegradable polymers derived from carbon dioxide and propylene oxide. However, its poor mechanical properties and thermal stability has limited its application. If its mechanical and thermal properties could be remarkably enhanced through compounding layered silicate such as montmorillonite and rectorite. Will have bigger value suitable for use and economy significance.In this paper, the organic montmorillonite(OMMT) and organic rectorite (OREC) is synthesized through cation exchange reaction with two kinds of quaternary ammonium salt, poly(propylene carbonate)/montmorillonite and poly(propylene carbonate)/rectorite nanocomposites are prepared via melt blending. The microstructures of nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and atomic force microscope(AFM). And its composites is investigated by differential scanning calorimetry (DSC). and wide X-ray diffraction (WXRD). The mechanical properties, dynamic mechanical analysis (DMA), thermogravimeric analysis (TG), oil resistance and water resistance and air abing resistance properties of composites are also investigated. The main results obtained are as follows:(1) The organic ammonium modified montmorillonite and rectorite of different kinds has been prepared using cation exchange in water. The intercalation effect was characterized by XRD,FTIR and TGA. It is found that quaternary ammonium salt and alkylamine can react with montmorillonite and rectorite via cation exchange reaction and the resulting OMMT and OREC can act as nano-scale filler to PPC materials due to its increasingly swollen gallery spacing.(2) Poly(propylene carbonate)/OMMT and Poly(propylene carbonate)/OREC nanocomposites were prepared by melt blending PPC directly with OMMT and OREC. The microstructure, morphology of PPC/clay nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and atomic force microscope(AFM). The XRD pattern and TEM images show that the intercalation of OMMT and OREC in PPC matrix was achieved as revealed and OREC is finely dispersed in PPC matrix.(3) The tensile strength and impact strength of PPC/clay nanocomposites is maximal when the loading of OREC is 3phr and the elongation is minimum when the loading is 7phr, which is associated with the hood compatibility and strong interaction between clay and matrix.(4) The thermal stability properties and dynamic mechanical behavior of the nanocomposites are investigated by DSC,TGA and DMA. The results show that the glass transition temperature (Tg) is increased and that the thermal stability, the storage modulus (E') and the loss modulus (E") of NC are improved, but the tand are decreased.(5) Chemical Resistance results showed : intercalation better results of composite materials with high dielectric resistance to the better performance, Note composite material effect intercalation good clay layers can effectively prevent the solvent molecules into the interior of infiltration. PPC/OREC formation of intercalated nanocomposites, the PPC water resistance and oil resistance sexual improved noticeably.