Study On Poly(Ethylene Terephthalate)/inorganic Nano-particle In-situ Composites

In this paper, poly(ethylene terephthalate)(PET)/inorganic particle compositeshave been synthesized by means of in-situ melt polycondensation, in which PET wasused as polymer matrix, attapulgite(ATP), nano-CaCO₃ and micron-CaCO₃ asinorganic components. A 1 liter reactor has also been designed and manufactured inrespect of the specialty of polycondensation. Surface modifications have been applied to ATP, and the results of IR, XPS,XRD and BET shows chemical adsorption between ATP and titanate coupling agentor tetraalkyl ammonium salt, and the soakage of modified ATP has been improved.The visual observation of SEM and TEM demonstrates that modified ATP can be welldispersed in ethylene glycol(EG).Nano-CaCO₃ and micron-CaCO₃ modified by titanate coupling agent can also bedispersed well in EG.In-situ melt polycondensation is an available method to synthesizePET/inorganic particle composites. The value of intrinsic viscosity and contents ofcarboxyl end group shows that ATP and CaCO₃ have slight effect on relativemolecular mass. The results of SEM and TEM delineate that ATP, nano-CaCO₃ andmicron-CaCO₃ can be well dispersed in PET matrix. The thermal properties and crystallization behavior of PET composites wereinvestigated by performing DSC. The results show that the glass transitiontemperature, melting temperature and crystallization temperature of PET compositesare lower than those of PET. The presence of ATP can accelerate the crystallizationrate, while nano-CaCO₃ and micron-CaCO₃ can embarrass the nucleating of PET.The morphology of crystalline phase in PET composites observed by polaroptical microscopy appears to be spherulite. The manipulation of Hv in small anglelaser scattering (SALS) experiments shows the parameters of correlation distance,gyration radius and fractals dimension.Both the structure and dimension of crystalline of PET in composites weremeasured by wide angle X-ray diffraction (WAXD) measurement. It shows that threekinds of inorganic particle decrease the spherulite dimension of PET in size.The mechanical and rheological properties of PET composites were measured.The effect of types, content and particle size of inorganic fillers on tensile strength,impact strength and melting viscosity of PET composites were investigated.