Study on the Preparation of Polyethylene Naphthalate and Its Performance
|School||Beijing Institute of Clothing Technology|
|Keywords||Polyethylene Naphthalate polyester alcoholysis Solid State Polycondensation copolymerize Ⅳdecrease thermal weight loss kinetics|
In this paper, the direct esterification of PEN, the alcoholysis of PEN wastes to synthesize PEN, the solid state polycondensation, the copolymerization of PEN-PET, and the Intrinsic Viscosity decrease and thermal weight loss of PEN has been studied. The related results, such as crystallization, thermal properties, have been obtained.PEN was synthesized by 1,4-NDA（or 2,6-NDA） and EG, tetra-n-butyl titanate used as catalyzer. The intrinsic viscosity（IV） of PEN by1,4-NDA/EG was lower, the color is yellow seriously. Otherwise, the PEN with 2,6-NDA had a higher IV and a better crystallization. The activation energy（Ea） of the direct esterification of 1,4-NDA is bigger than that of 2,6-NDA. Besides, 1,4-NDA,TPA and EG are used to synthesize PET-PEN, the molar ratio of TPA/NDA （mol/mol） was 95/5,90/10,85/15,80/20.The alcoholysis condition of PEN was as follows: temperature 195～235℃, PEN/EG ratio 1/（1.3～2.0） （mol/mol）, the reaction time:150～180min. The activation energy （Ed） of thermal degradation（thermal weight loss） were: the new PEN, Ed=374.96kJ/mol; based on alcoholysis of PEN wastes（（PEN/EG（mol/mol）=1/1.3））, Ed=140.08kJ/mol; based on the new PEN （ （ PEN/EG（mol/mol）=1/1.3,1/1.8 ） ）, Ed=395.00 kJ/mol, 210.76kJ/mol, respectively.The solid state polycondensation of PEN has been studied, it has been shown that the longer reaction time and smaller dimension of the particles and the higher reaction temperature and the superior vacuum, the higher IV and good quality of PEN products can be gained.In the last, the thermal degradation of PEN has been studied. It has been gained that under isothermal condition, the higher temperature and the longer time, the bigger the IV decrease of PEN. The Ea of IV decrease in air is smaller than that in N2. In non-isothermality weight loss, the thermal weight loss Ea in air is lower than that in N2, the weight loss is easier in air.