The factors that would affect the unstable phase transition in polymer processing were analyzed and the research in metastable state in extrusion was carried out for the first time.

• 6、借用一个前人无法解释的现象，引出研究成型加工过程中相态变化行为的必要性，介绍了加工过程中非稳态相变行为的原因及影响因素。