热分析在PVA纤维预处理中的应用

STUDY ON THE PVAF DURING PRETREATMENT WITH THERMAL ANALYSIS

用差热、热重法对原丝的热性能及由不同预处理方法所引起的PVA纤维的热行为变化进行了研究;并通过模拟脱水条件,用不同升温速率,求出了经不同预处理纤维的脱水反应活化能。结果表明,PVA原丝在230℃有一软化点,三种预处理都不同程度地影响了原丝的热效应变化;纤维在180～340℃主要为脱水反应;原丝及经脱水剂、O_3和O_3综合脱水剂处理的纤维,其脱水反应的表观活化能分别为:164.3kJ/mol,92.9kJ/mol,130.5kJ/mol和117.6kJ/mol。

DTA and TG were used in this paper to study on the thermal properties of the oreiginal poly vinyl acohol fiber (PVAF) ,and as well as the thermal changes caused by the three pretreat-ments to the precusor.The apparent activation energies of dehydrations were calculated from DTA and TD curves made in different heating rates. The results show that,at 230℃PVAF is being softening station,the thermal behaviours were influenced by the three pretreatments.and the main dehydration were found at the range of 180-340℃.The apparent activation energies of dehydrations (of the precusor and the fibers treated by dehydrators,O3 and O3 dehydrotor) are 39. 27 kcal/mol, 22. 20kcal/mol, 31. 20kcal/mol and 28. 12kcal/mol respectively.