.pet / Alooh Nanocomposites Preparation And Performance Study

PET/AlOOH nanocomposites were synthesized via the in-situ method.Firstly, terephthalic acid was reacted with excess ethylene glycol to form bis(hydroxyethyl) terephthalate(BHET);Second,the boehmite(AIOOH) was added into the BHET and mixed homogeneously with it,then concurrent with polycondensation of BHET to produce the PET matrix.The characterization and properties of PET/AlOOH nanocomposites prepared by in-situ method were investigated.The composites examined by FT-IR showed to be boehrnite,which indicated that boehmite had been added into PET matrix.The TEM image showed that the boehrnite particles ranged from about several to tens nanometers in diameter.The nanoparticles were dispersed well in PET matrix.The kinetics of thermal oxidative degradation of pure PET and PET/AlOOH nanocomposites were investigated by TGA.The results showed that nano AlOOH enhanced the activation energy of different degradation steps except the initial step of degradation,which showed that nano AlOOH made the degradation of PET become difficult at high temperature.The nonisothermal crystallization kinetics of pure PET and PET/AlOOH nanocomposites were examined by DSC.The results showed that these boehmite particles made the crystallization capability of PET decline.Because the crosslink structure of PET/AlOOH nanocrnpsite dramatically restricted the movement of PET chains so as to cause the decrease of crystallization capability.The flame retardancy was investigated by CONE.Although the initial ignition time of PET/AlOOH nanocomposite were shorter than that of pure PET,the heating release rate, peak of heating release rate and its time,total heating release of PET/AlOOH nanocomposites were all lower than those of pure PET.So the boehmite could retard the burning processes of PET/AlOOH nanocomposite.The carbon layers under SEM,the char of pure PET was very thin and the hole was bigger. The char of PET/AlOOH was very thick and the hole was smaller.The flame retardant can make more carbon formation during buming,so the carbon layer formed after addition of AlOOH.The existing of a lot of fine holes may be because of the action of AlOOH.