·非金属材料老化及购存期评估·
红外光谱研究丁基橡胶老化机理及寿命预测
郑静向科炜黄光速
（四川大学高分子科学与工程学院，高分子材料工程国家重点实验室，成都610065）
文摘对丁基橡胶进行室内加速热氧老化实验，同时采用FTIR实时追踪丁基橡胶在老化过程中化学结构的演变，并进行二维相关分析。结果显示老化过程中C-—H和C一C氧化形成自由基的速率较慢，为确定热氧老化反应速率的关键步骤，随后进行的热氧老化反应速率很快，最终氧化降解形成醛，酮，酯等老化产物。在充分理解丁基橡胶热氧老化机理的基础上，建立了丁基橡胶热氧老化的基元方程，按照老化过程中各基元反应的质量作用定律，建立了材料老化的氧化动力学模型。采用Matlab编程，计算得到丁基橡胶在常温和高温之间的老化速率比。通过红外光谱追踪老化过程中基团变化的实验数据拟合建模计算得到的曲线，发现两者的变化趋势相同，表明采用该方法预测材料老化寿命具有极好的应用前景。
关键词丁基橡胶，热氧老化，二维相关分析，氧化动力学模型，寿命预测
Aging Mechanism and Lifetime Prediction of Butyl Rubber
UsingFTIRTechniques
ZhengJing
XiangKewei
HuangGuangsu
( College of Polymer Science and Engineering, State Key Laboralory of Polymer Malerials Engineering,
Sichuan University,Chengdu610065)
AbstractThermal-oxidative aging experiments on butyl rubber were conducted, and structural evolutions of the rubber during aging were traced by real time infrared technique,and the resulting data were analysized by a 2D corre-lation spectroscopy analysis. The results suggest that free radicals derived from saturated C-H and CC bonds which are attacked by oxygen atoms form slowly at the early stage ofthemal aging. And it is a key step to detemine there action speed. After that, the carbonyl species are generated rapidly, which results in formation of aldehydes, ketones and esters etc. and finally by degradation and oxidative. Based on a full understanding on the thermal-oxidative aging mechanism of butyl rubber, we constructed elementary reaction equations and furthermore, oxidation kinetic models according to mass action law of each elementary equation. The aging rate ratio of room temperature to high temperature is obtained by calculation of Matlab program. By ftting the curves described from the oxidation kinetic models with the data from FTIR tracing experimental for the aging process, it is found that both changes have the same tendency which promises an excellent prospect for predicting lifetime of materials.
Key words Butyl rubber, Thermal aging, 2D correlation analysis, Oxidation kinetic model,Lifetime prediction
0引言
丁基橡胶分子由大量的异丁烯及少量的异戊二烯结构单元构成，这些柔软的结构单元及双键的存在使丁基橡胶容易在热氧、光照及臭氧存在的情况下发生老化，或使橡胶材料和橡胶元件的性能参数偏离初始设计值而带来安全隐患，或使其降解而丧失使用性能。
收稿日期：201211-05
基金项目：国家自然科学基金重点项目(51133005)
一维红外光谱作为实验室便捷的结构表征手段被广泛应用于聚合物的老化研究。然而，由于吸收峰重叠或弱峰被掩蔽等往往导致其分辨率不高，且难以表征各基团变化的先后顺序。二维相关分析将一维红外谱图按照Noda定律(1-2]在二维谱图的直角坐标平面上展开，其同步相关谱Φ（v，V）表明在波数 V,和v下测量得到的光谱变化方向的相关性；异步
作者萄介：郑静，1978年出生，讲师，主要研究方向为高分子材料的老化和水溶性高分子。E-mail；zhengjing@scu.edu.cr 通讯作者：黄光速，1955年出生，教投。E-mail；huangguangsu@seu.edu.cn
宇航材料工艺http：//www.yhelgy.com2013年第1期万方数据
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