STUDY ON SOLID STATE POLYCONDENSATION OF POLYETHYLENE TEREPHTHALATE COPOLYMERS

The kinetic data of solid state polycondensation of PET and its copolymers are determined.It is shown that the reaction rate of copolycondensation is higher than that of PET polyconden-sation, and increases with the comonomers content. But the reaction rate of copolycondensationin melt state of this kind of copolymers is lower than that of PET. It is considered that the chemi-cal reactivity of comonomer is the main factor which affect the polycondensation in melt state,whereas the aggregative structure of the polymer is the main factor in solid state. The crystallinity and crystallite size of the copolymers have been measured by X-ray method.     

蒽／并四苯混晶的制备及其光谱性质

采用溶液法制备出一系列掺杂比例（摩尔比最高达100：1）的片状蒽／并四苯有机混晶,并对其进行了系统的表征。通过改变并四苯的掺杂浓度,可以实现对混晶发光颜色由蓝绿到绿进而到黄绿的调控。对蒽／并四苯混晶光学性质的研究发现,混晶的发射光谱中出现了并四苯的敏化荧光,同时葸的发光被部分地猝灭。并且在葸／并四苯混晶中,基质蒽的荧光衰减速率较其单晶时大大加快,而并四苯的发光寿命相对其单晶时则显著增大。上述实验结果表明该混晶体系中存在葸到并四苯的能量转移。     

EFFECT OF CHEMICAL STRUCTURE OF COMONOMERS ON THE PROPERTIES OF COPOLYESTERS

The effect of different kinds of comonomers with or without flexible chain on proper-ties of copolyesters, such as transition temperature, crystallization velocity, crystallinityand size of crystallites, is studied. The experimental results indicate the obvious differ-ence in properties between comonomers with iso- and ortho-structure of phenyl ring andcomonomers with flexible chain. The influence of chemical structure of comonomers onproperties of copolyesters is discussed.