The diffusion coefficient is an important parameter in the field of migration and diffusion. Different diffusion theories have been established to estimate the diffusion coefficient, including the weight gain rate. However, the research was based on the migration of different solvents into simple polymers. Few reports focused on the migration of components from propellant and liner into ethylene‐propylene terpolymer (EPDM) insulation. In this paper, a new parameter named surface area diffusion rate was proposed to measure the migration of components from propellant and liner at interfaces of EPDM insulation, and the comparison with the traditional weight gain rate was made. The result shows that the surface area diffusion rate is independent of the shape of the material and is more reliable than previously used methods. Furthermore, the relationship of the surface area diffusion rate with time and temperature was investigated. In addition, the diffusion activation energy and the relationship of surface area diffusion rate with the bonding properties were discussed.

中文翻译：

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推进剂和衬里成分在EPDM绝缘界面处的扩散

扩散系数是迁移和扩散领域的重要参数。已经建立了不同的扩散理论来估计扩散系数，包括重量增加率。但是，这项研究是基于不同溶剂向简单聚合物中的迁移。很少有报告着重于组分从推进剂和衬里向乙烯-丙烯三元共聚物（EPDM）绝缘材料的迁移。本文提出了一种新的表面积扩散率参数，用于测量三元乙丙橡胶绝缘层界面处推进剂和衬里的组分迁移，并与传统的增重率进行了比较。结果表明，表面积扩散率与材料的形状无关，并且比以前使用的方法更可靠。此外，研究了表面积扩散速率与时间和温度的关系。此外，还讨论了扩散活化能以及表面积扩散速率与结合性能的关系。