Yu Yang,Shen Guoliang,Xu Tie jun,Wen Ruiyang,Wang Yong jie,Huo Yue,Xu Shi jie
Silicon catalysts have very low catalytic activity in polyester (PET). However, titanium catalysts have high catalytic activity in polyester. The simultaneous use of titanium and silicon catalysts is effective in reducing the activity of a single titanium catalytic base agent. In addition, the glycol salts of titanium and silicon (Ti-EG and Si-EG) prepared in the present invention for use in the polyester catalytic process can avoid the introduction of other groups of impurities during the polyester catalytic process, which would lead to premature capping of the polyester in the process of polycondensation and chain building and make it difficult to increase the molecular weight, and thus affect the quality of the polyester. It has been verified that the ratio of Ti:Si is 1:1 (mol), and total amount added to the catalyst is 0.15% of the raw material amount, and the polycondensation temperature was 260-280 °C for 60 min. Compared with the single Ti-EG catalyst, the b* value of the synthesized PET was significantly reduced, and the molecular weight and other indexes did not change too much. In addition, at the end of catalysis, the catalyst was uniformly dispersed in the reaction system, which could be used as a matting agent for PET.
The perovskite CaMn x Zr (1- x ) O 3 ( x = 0, 0.05, 0.10, 0.15) (CMZO) NTC (Negative Thermal Coefficient) thermo-sensitive ceramic were prepared by the solid phase method that can be used as high temperature thermistor materials in the range of 200–1200 °C.The XRD pattern showed that CMZO is a finite solid solution and that a second phase, CaMnO 3 , will be formed after exceeding the solid solution limit (i.e., at x = 0.1). The thermal constant B value was found to decrease from 19521 K to 9217–9535 K, with a corresponding decrease in activation energy , E a , from 1.69 eV to 0.82 eV. The Nyquist plot indicates that the grain boundary resistance determines the overall complex impedance. Moreover, the aging drift rate (ΔR/R 0 ) was found to be lower than 4.3%, which is an indication of an excellent high temperature stability of the CMZO ceramic material.
危险品化学品经营许可证（带存储）