γ射线辐照法降解等规聚丙烯

Degradation of isotactic polypropylene byγ-ray irradiation

利用放射性^(60)Co产生的高能γ射线在室温和空气气氛下降解等规聚丙烯(iPP),考察了不同辐照剂量的γ射线对iPP流动性能、熔融行为和非等温结晶动力学的影响。随着辐照剂量的增加,iPP的熔体流动速率显著增加。经γ射线辐照后,iPP的熔融温度和结晶度降低,同时用Avrami和Ozawa方程计算发现,γ射线辐照明显提高了iPP熔体的结晶速率,当辐照剂量为200 kGy时,半结晶时间减少到原来的37%,结晶活化能降低。X射线衍射谱图显示,γ射线辐照不影响iPP的结晶形式,未产生次级β结晶。

The authors utilized the high energy γ-ray emitted from radioactive ^60Co to degrade isotactic polypropylene （iPP） at ambient temperature and atmosphere, aiming at examining the impact of irradiation dose of γ-ray on flowability, melting behaviour and non-isothermal crystallization kinetics of iPP. The melt flow rate of iPP remarkably increased with the irradiation dose of γ-ray. The melt temperature and crystallinity of iPP reduced after being subject to the irradiation of γ-ray. The calculation by Avrami and Ozawa equations found out that the irradiation of γ-ray evidently raised the crystallization rate of iPP melt. When the irradiation of γ-ray was 200 kGy, the semi-crystallization time reduced to 37% of its original value of iPP and the crystallization activation energy lowered. The X-ray diffraction pattern of iPP showed that γ-ray did not influence the crystal structure of iPP, and no secondary β crystal formed either.