Predictive ageing of elastomers: Oxidation driven modulus changes for polychloroprene
Predictive ageing of elastomers: Oxidation driven modulus changes for polychloroprene
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DOI：
10.1016/j.polymdegradstab.2016.06.014
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发表时间：
2016-08-01
影响因子：
5.9
通讯作者：
Fayolle, Bruno
中科院分区：
文献类型：
--
作者：
Le Gac, Pierre Yves;Celina, Mathew;Fayolle, Bruno
通过FTIR光谱（双键消耗）、模量变化和氧吸收测量研究了硫硫化氯丁二烯在60℃-140℃范围内的氧化老化。在薄膜和厚样品上进行了实验，以研究均匀和非均匀（扩散控制）氧化，目的是建立氧化降解化学和机械性能变化之间的潜在相关性。使用已建立的橡胶弹性方法，氧化驱动的降解化学和模量之间的相关性是可能的，其中由于双键反应导致的有效交联产率对于该材料而言约为 30%（即 3 个双键的损失导致与材料硬化相关的一个有效交联）。然后可以预测硫化和不稳定的聚氯丁橡胶氧化引起的模量变化。引入了两个增长反应（氢提取和双键自由基加成）和涉及硫化过程中的含硫部分的两个稳定过程的动力学模型。求解了动力学方案并确定了相关的速率常数。该模型可以充分预测薄膜和厚样品中的模量变化作为时间和空间解析的函数。 (C) 2016 Elsevier Ltd. 保留所有权利。
The oxidative ageing in the range of 60 degrees C-140 degrees C of sulfur vulcanized polychloroprene has been studied by FTIR spectroscopy (double bond consumption), modulus changes and oxygen absorption measurements. Experiments were carried out on thin films and thick samples to investigate both homogeneous and inhomogeneous (diffusion controlled) oxidation with the goal of establishing the underlying correlation between oxidative degradation chemistry and mechanical property changes. A correlation between oxidatively driven degradation chemistry and modulus is possible using the established approaches of rubber elasticity where an effective crosslinking yield due to double bond reactions is of the order of 30% for this material (i.e. the loss of 3 double bonds results in one effective crosslink associated with material hardening). It is then possible to predict modulus changes induced by oxidation for vulcanized and unstabilized polychloroprene rubber. A kinetic model is introduced with two propagation reactions (hydrogen abstraction and radical addition to double bonds) and two stabilization processes involving sulfur containing moieties from the vulcanization process. The kinetic scheme was solved and the relevant rate constants determined. This model can adequately predict modulus changes in films and thick samples as a function of time and spatially resolved. (C) 2016 Elsevier Ltd. All rights reserved.