DSC法研究PAN纤维的低温热解特性

AN INVESTIGATION OF THE CHARACTERISTICS FOR THE LOW TEMPERATURE PYROLYSIS OF THE POLYACRYLONITRILE FIBRES BY THE METHOD OF DSC

利用DSC法(差示扫描量热法)考察了三种PAN(聚丙烯腈)纤维在空气条件下热稳定化过程。实验结果表明:不同的样品其环化反应热效应各不相同,吉林丝呈现出两个放热峰,而榆次丝仅有一个放热峰。同时,随着样品本体羧基基团的引入,环化反应活化能下降,使其反应易于进行。而且,利用Sharp法和Ellerstein法对反应动力学参数进行了求解,其值较为接近。另外,还讨论了温速对其放热量的影响。

The thermal behaviour of three polyacrylonitrile fibres used for making carbon fibres have been measured continuously during low temperature (below 350℃) pyrolysis in air atmosphere by the differential scanning calorimetric (DSC) method. From the qualitative and quantitative informations of the heat flow curve of three fibres, it was obtained that the characteristic feature of these chemical transformations is the evolution of considerable heat during the course of stabilization. The general relationship between thermal stability of fibre and its oxotheramic quantity was described. Heat effects of cyclization reaction for three samples are different. With ifltroducting of carboxy group of samples, activation energy of cyclization reaction is decreased. Two interrelated analytical methods, Shaps and Ellersteins methods, were used to process dynamic DSC data for characterizing the kinetic parameters or overall activation energy, as well, two methods were applied to a thorough differential-integral analysis of single DSC curve to evaluate the kinetic parameters. In addition, the effect of the heating rate for the oxotheramic quantity of three samples is discussed in detaill.