连续聚铝碳硅烷纤维的预氧化

Curing of Continuous Polyaluminocarbosilane Fibers

聚铝碳硅烷(PACS)纤维预氧化过程是制备近化学计量比Si C(Al)纤维的关键步骤。而连续PACS纤维预氧化的氧含量控制是关键问题。采用实时测量设备对连续PACS纤维预氧化过程进行跟踪,用分段积分方法对PACS纤维进行非等温动力学模拟;利用实时测量数据用非线性优化方法求解,可以预测PACS纤维预氧化增重。本文在实验过程中,采用聚碳硅烷(PCS)纤维和PACS纤维进行对比研究。结果表明:在相同的预氧化条件下,两种纤维均在Si—H键反应程度为40%时出现凝胶点,反应后凝胶含量均达到100%,其氧含量分别为9.9wt%和14.7wt%;PACS纤维的Si—H键反应程度和增重均比PCS纤维低。利用实时增重数据,用Matlab的Lsqnonlin函数进行求解预氧化动力学方程,得到PACS的预氧化活化能为62.2 k J/mol,模型可准确的预测其预氧化过程中的增重率变化。

Curing of polyalumninocarbosilane（ PACS） is the key process to prepare near-stoichometric Si C（ Al）fibers. It is crucial to control the oxygen content of continuous PACS fibers during curing. In this work,a new method has been used to predict the oxygen content of PACS fibers during curing exactly and easily. The curing process of PACS fibers are traced by in-situ measurements. And a non-isothermal curing dynamics model has been established with section integration. The dynamics model is solved with non-linear function using in-situ data. As a result,the weight gains during the curing can be predicted. Polycarbosilane（ PCS） fiber was cured at the same condition as comparison. It is found that： at the same condition,PACS and PCS fiber both got gel point at the Si—H reaction content of 40%,their gel content both reached 100% after curing,when their oxygen content is 9. 7wt% and 14. 7wt%,respectively. The weight gains and Si—H reaction content of PACS fiber are both lower than that of PCS fibers. The curing dynamic equation is solved by lsqnonlin function in matlab using the in-situ data. It is calculated that activation energy of PACS is 62. 2 k J / mol. The model can predict the weight gains during curing.