一种尼龙老化评价的新方法

作为一种广泛使用的工程塑料，尼龙的老化备受关注。当作为电力系统芯片的封装材料时，尼龙在自然环境下的老化有可能会导致封装失效，从而影响芯片使用的可靠性，严重时甚至导致芯片的失效，给电力行业带来巨大损失。常规的自然老化和人工加速老化评价周期非常漫长，不同因素对尼龙老化的影响机理十分复杂，且这种影响难以研究，使得评价尼龙的老化稳定性成为一大难题。采用自主开发的原位老化评价系统，对尼龙6（PA6）和尼龙66（PA66）的老化稳定性及湿度对老化的影响进行了研究。该系统可以实现光照/温度/湿度/氧气等环境因素的加载，通过高灵敏度地测定材料在综合环境因素作用下产生的气相降解产物来评价材料的老化稳定性，评价时间缩短到几小时。实验表明，PA6和PA66的气相降解产物以H₂O和CO₂为主，由于H₂O在气相中的浓度不稳定，因此以CO₂的产生量作为老化评价指标。通过对不同自然老化时间PA6和PA66的原位老化评价，并与其ATR-FTIR红外光谱图进行对照，证明了原位老化评价方法能够较好地反映尼龙的老化程度，自然老化时间越长，PA6和PA66的稳定性越低，CO₂的产生量越大。进一步，采用该方法研究了湿度对PA6和PA66老化反应的影响，证明增大湿度对尼龙老化存在促进作用，而且升高温度会进一步促进湿度对老化的促进作用。研究表明，原位老化评价方法是一种快速评价尼龙老化稳定性及环境因素影响的有力手段。

A Novel Aging Evaluation Method of Nylon

Nylons are widely used as engineering plastics.When used as packaging materials for power system chips,the aging of nylons in the natural environment may cause package failure,reliability deterioration of chips,or even chip failure,and finally,lead to great loss in the power industry.Therefore,aging evaluation of nylons has attracted great attention.Conventional aging evaluation methods include natural weathering and artificial accelerated aging.Both of these two methods are time-consuming.Furthermore,the effects of various environmental factors on aging of nylons can not be investigated.In this paper a novel in-situ aging evaluation method was proposed and the corresponding system was developed to study nylon 6(PA6)and nylon 66(PA66)’s aging stability.The system can combine environmental factors such as irradiation,temperature,humidity and oxygen.By measuring the generation of gaseous degradation products during aging process of nylons,the stability can be compared.The results show that the gaseous degradation products of PA6 and PA66 are mainly H₂O and CO₂,and CO₂ is used as an indicator to evaluate the aging status.Nylons with different natural pre-aging times were detected.Longer pre-aging time responds to more generations of CO₂,demonstrating poorer stability.Furthermore,this method was applied to study the effect of humidity on the aging of PA6 and PA66.It was proved that humidity accelerates nylon aging,and high temperature further promotes this acceleration effect.The novel in-situ aging evaluation method can evaluate aging stability of nylons under versatile environmental factors in only several hours.It is also expected to be a powerful and promising aging evaluation method for other polymer materials.