聚萘二甲酸乙二酯的制备及其性能研究

Preparation and performance of PEN

采用2种方法合成聚萘二甲酸乙二醇酯(PEN):一种是NDA与EG直接酯化法;另一种是PEN废料醇解再缩聚法。直接酯化阶段分别采用2种工艺条件进行研究:一种是n(NDA)/n(EG)=1/1.8,w(催化剂)/w(NDA)=0.05%;另一种是n(NDA)/n(EG)=1/2.0,w(催化剂)/w(NDA)=0.03%。用零级反应动力学方程研究NDA直接酯化动力学,得到上述2种工艺条件下的酯化反应活化能分别为40.01 kJ/mol和86.80 kJ/mol。借鉴PET醇解工艺研究PEN的醇解,得到PEN的醇解条件为:醇解反应温度:195～235℃;配比:n(PEN)/n(EG)=1/(1.3～2.0);反应时间:150～180 min。BHEN的缩聚条件为:反应温度:285～290℃;反应时间:取决于反应配比与催化剂的加入量;真空度:优于65 Pa。通过对废料醇解[n(PEN)/n(EG)=1/1.3]再合成的PEN和PEN新切片醇解[n(PEN)/n(EG)=1/1.3、1/1.8]再合成的PEN的热失重研究,得到热分解活化能分别为:140.08 kJ/mol、395.00 kJ/mol和210.76 kJ/mol。

Two methods are used to synthesize PEN in this study：one is direct esterification of NDA and EG, the other is the alcoholysis of PEN polymer （waste or chip） then to polymerization PEN. The esterification is carried out under the following two conditions： （ 1 ） 1/1.8 molar ratio of NDA/EG and 0.05% catalyst （ w （catalyst）/w （NDA） ）, （2） 1/2. 0 molar ratio of NDA/EG and 0. 03% catalyst （w（ catalyst）/w（NDA） ）. Zero-order kinetics model is used to describe the esterification. The activation energy （Ea） obtained for the two conditions as mentioned above are 40. 01 kJ·mol^-1 and 86. 80 kJ·mol^-1 , respectively. Based on the alcoholysis of PET, the technology of alcoholysis of PEN is ： 195 - 235℃ of the temperature, 1/（ 1.3 - 2.0） molar ratio of PEN/EG and 150 - 180 minutes of the reaction time. The conditions of the polycondensation of BHEN is：285 -290℃ of the temperature, lower than 65 Pa of vacuum, and the reaction time depending on reactants ratio and the amount of catalyst. From the thermal weight loss （TG） curves of three kinds of PEN, the activation energy （Ed） of thermal degradation （ thermal weight loss） for PEN wastes （ PEN/EG （ mol/ mol） = 1/1.3 ）, new PEN （ PEN/EG（mol/mol） = 1/1.3 and 1/1.8） are 140.08 kJ/mol,395.00 kJ/mol and 210.76 kJ/mol, respectively.