Study On The PET/MgO Composite

In this thesis,the Poly (ethylene terephthalate) (PET) /magnesia (MgO) composite was synthesized by adding inorganic powder, MgO, to the direct esterification system. The MgO podwer was dispersed with supersonic wave after grinding. The thermal property, crystallization, and the dispersion of the powder of the composites with 1~4% magnesia were investigated by DSC, TG, WAXD, SEM. The esterification kinetics was also studied.The results showed that the addition of MgO lead the esterification to the longer time, higher activation energy(Ea), and lower intrinsic viscosity of the composites. The SEM results have shown that after grinding and supersonic wave treatment MgO was dispersed better in PET.The results of DSC and TG testing indicated that the composites have lower Tcc, higher Tmc, and better thermal stabilities.The WAXD results showed that with the addition of MgO, the crystallinity increased, the crystal size changed. The WAXD results also approved that in the esterification MgO has partially reacted with the carboxyl end groups of PTA to produce a new product. This reaction and new product might lead to the ratio of PTA/EG changed, then to influence the molecular weight of the composites, and furtherly to affect the crystallization of the composites.