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林产化学与工业

林产化学与工业 ›› 2013, Vol. 33 ›› Issue (6): 7-13.doi: 10.3969/j.issn.0253-2417.2013.06.002

• 1研究报告 • 上一篇    下一篇

杜仲胶的热稳定性、分解动力学及热老化贮存期

肖卓炳1, 郭满满1, 郭瑞轲1, 熊利芝1,2   

  1. 1. 吉首大学 林产化工工程湖南省重点实验室, 湖南 张家界 427000;2. 吉首大学 生物资源与环境科学学院, 湖南 吉首 416000
  • 收稿日期:2012-09-06 修回日期:1900-01-01 出版日期:2013-12-30 发布日期:2013-12-30

Thermal Stability, Decomposition Kinetics and Storage Time of Gutta-percha

XIAO Zhuo-bing1, GUO Man-man1, GUO Rui-ke1, XIONG Li-zhi1,2   

  1. 1. Key Laboratory for Forest Products and Chemical Industry Engineering, Jishou University, Zhangjiajie 427000, China;2. College of Biology and Environment Sciences, Jishou University, Jishou 416000, China
  • Received:2012-09-06 Revised:1900-01-01 Online:2013-12-30 Published:2013-12-30

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摘要： 以5、 7.5、 10、 15 ℃/min 的升温速率对天然高分子材料杜仲胶进行了热重和微分热重（TG-DTG）测试，应用多重升温速率法中的Starink法、Kissinger法和Flynn-Wall-Ozawa法以及单一升温速率法中的Coats-Redfern法和Achar法对杜仲胶的非等温热解过程进行了计算，推断了分解的最概然机制函数f（α），并求得了相应的动力学参数——表观活化能（Ea）和指前因子（A）。研究表明，杜仲胶的热分解一步完成，在268℃左右开始分解，至 459 ℃ 左右结束，且分解完全；升温速率的变化对杜仲胶的分解有影响，随着速率的升高，热分解曲线略微向高温移动，呈现了分解滞后现象；杜仲胶的热分解受化学反应机制控制，符合反应级数方程，Ea为 191.54 kJ/mol ，lnA为33.34；与文献报道的其他改性过的天然橡胶和合成橡胶相比，杜仲胶的热解特征参数说明了其具有较强的热稳定性，而指前因子亦呈现偏高趋势，说明一旦达到热分解点，杜仲胶的分解是相对快速的；经过对动力学的积分求解过程，计算推断杜仲胶在200 ℃下的热老化贮存期为170天。

关键词: 杜仲胶, 热重-微分热重, 热稳定性, 非等温动力学, 热老化贮存期

Abstract: The natural polymeric material, gutta-percha, was non-isothermally analyzed by thermogravimetric and differential thermogravimetric techniques at different heating rates of 5, 7.5, 10, 15℃/min under the nitrogen atmosphere. Thermal analysis kinetics methods of multi-heating rate methods (Starink, Kissinger and Flynn-Wall-Ozawa methods) and single heating rate methods (Coats-Redfern and Achar methods) were applied to infer the most probable reaction mechanism and calculate the corresponding kinetic parameters of apparent activation energy Ea and pre-exponential factor A. The results showed that thermal decomposition of gutta-percha began at 268℃ and ended at 459℃ with a complete mass loss. The increasing of heating rates had a significant effect on the decomposition. The TG-DTG curves moved to higher temperatures while a hysteresis effect of thermal decomposition occurred. The most probable thermal decomposition mechanism was Chemical Reaction, corresponding with Reaction Order Equation. The values of apparent activation energy Ea and pre-exponential factor lnA were 191.54 kJ/mol and 33.34, respectively. Compared with other modified natural or synthetic rubbers, characteristic parameters of gutta-percha revealed its strong thermostability while at high temperatures it decomposed fast. Through integral calculation for the differential kinetic equation, the storage time of heat resistance at 200℃ were 170 days.

Key words: gutta-percha, TG-DTG, thermal stability, non-isothermal kinetics, storage time of heat resistance

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