棉纤维的热降解动力学研究

Study on the thermal degradation kinetics of cotton fiber

在高纯氮气保护下,采用不同的升温速率,利用TG-DTG技术对棉纤维的热降解行为和热降解动力学进行了研究。采用Flynn-Wall-Ozawa方法确定了棉纤维的热降解动力学参数,并与Coast-Redfern法所求得的参数进行比较,通过对不同机制的模型筛选,提出并建立了棉纤维主降解过程的动力学机制及非等温动力学模型方程,通过模型描述了棉纤维的降解过程。结果表明:棉纤维的降解是从非结晶区到结晶区的化学变化过程,其主降解阶段的动力学机制为扩散控制,控制反应过程的方式为平面对称扩散;降解速率主要受温度和分解率的影响,随温度的升高而逐渐增大,随分解率的增大而减小。

Thermal degradation behavior and kinetics of cotton fiber were investigated by thermogravimetric analysis （TG） and differential thermogravimetric（DTG） at different heating rates under highly purity N2. The thermal degradation kinetic parameters of cotton fiber were determined using Flynn-Wall-Ozawa and Coast- Redfern methods, which established its kinetic equation and isothermal kinetic model of the major degradation process through selecting different thermal degradation mechanisms, The model obtained could describe the decomposition behaviour of cotton fiber. The results indicated that the main thermal degradation process probably generated chemical reaction from amorphous region to crystalline field. The major kinetic mechanism model was described as a diffusion-controlled process via one-dimensional diffusion. The thermal degradation velocity of cotton fiber was mainly depended on temperature and degree of decomposition, which increased with the increase of temperature and decrease of degree of decomposition.