基于经典成核理论的聚乙烯自由发泡中成核过程研究

Bubble Nucleation During Free Foaming in Polyethylene Based on Classical Nucleation Theory

研究了聚乙烯自由发泡中的成核过程。通过提出合理的假设,依据经典成核理论推导了发泡剂质量分数和温度对气泡成核过程的影响,结果表明,随着发泡剂质量分数的增加,成核密度不断增加,成核加速度也逐渐增大;随着温度的升高,成核密度先增加,直至达到最大成核密度并保持不变,但温度进一步升高,成核密度反而减小。推导结果与实验结果基本一致,说明经典成核理论能较好地描述自由发泡成核的过程。

In this paper, bubble nucleation was studied during free foaming of polyethylene. Theoretical deduction on the effect of foaming agent concentraton and temperature on bubble nucleation was made based on classical nucleation theory and reasonable hypothesis. The deduced result basically agreed with the experimental one, which means that the classical nucleation theory can describe well the process of free foaming. The results indicate that the nucleation rate increases with increasing the foaming agent concentration, and the curve is depressed. As the temperature increased, the nucleation rate increased, reached a maximum and remained, finally decreased with further increasing the temperature.