【摘要】 在PET 的合成中,Ti(Ⅳ)是高效缩聚催化剂,催化缩聚速度快,同时催化热降解速度也快。本工作是对用Ti(Ⅳ)合成的PET 树脂,在受热后其粘度降、羧基增长及失重动力学的研究,证明了使用Ti(Ⅳ)做缩聚催化剂时,只要选用适当的催化—稳定体系,即可得到热稳定性优良的树脂。在此过程中与用Sb(Ⅲ)催化所得PET 树脂进行了比较。对金属催化剂催化缩聚及热降解的机理,作者从晶体场理论出发,进行了探讨。更多还原

【Abstract】 In the poiycondensation of PET,Ti(Ⅳ)is a high efficiency catalyst.It accelerates either the olycondensation or the thermodegradation.By studying the viscosity reduction,Carboxyl end groups increase and weightloss kinetics of PET during its thermodegradation,the authors prove that thermos table PET resin is obtainable with Ti(Ⅳ)as catalyst,as long as a suitable catalyst-stabilizer system is employed.A comparison is made in this paper between PET resins catalyzed by Sb(Ⅲ)and by Ti(Ⅳ).The mechanism of polycondensation and thermodegradation catalyzed by metal catalysts is discussed from the viewpoint of crystal field theory.更多还原