60Co-γ射线对塑料包装材料性能的影响

Effect of 60Co-γ Irradiation on the Properties of Plastic Packaging Materials

目的为了确定常用塑料包装材料的最优耐辐射吸收剂量工艺,研究60Co-γ射线辐照对塑料包装材料的颜色、抗拉强度及伸长率的影响。方法选取市场上常见的以聚乙烯(PE)、聚丙烯(PP)、聚酰胺与聚乙烯复合袋(PA/PE)等为主要材料的10种塑料包装材料;用60Co-γ射线进行不同剂量辐照,分析其色差值、抗拉强度(Rm)及伸长率(εt)的变化规律。结果当辐照强度大于6 kGy时,PE、聚偏二氯乙烯(PVDC)、聚氯乙烯(PVC)的ΔE>6,是肉眼可见的大色差;其余7种材料的总色差(ΔE)值<1.51,总色差无显著变化。聚碳酸酯(PC)、聚酯/聚乙烯复合袋(PET/PE)的Rm,εt组内差异显著(P<0.05)。辐照对PA/PE、聚酯/铝箔/聚酰胺复合袋(PET/AL/PA)的力学性能无影响(P>0.05);PA,PVDC的Rm组内差异显著,εt组内差异均无显著性;其余6类材料的Rm,εt均达到显著或极其显著水平(P<0.01)。结论将PE,PVDC,PVC类塑料包装材料的辐照强度控制在≤3 kGy范围内时效果较好;PP辐照强度需控制在≤10 kGy范围内效果较好;PC辐照强度需控制在≤15 kGy范围内效果较好;PET/PE在0~40 kGy的辐照强度内比较耐辐照,需控制辐照剂量在≤40 kGy。

The work aims to determine the optimal radiation-tolerance absorbed dose process of common plastic packaging materials and then study the effect of 60Co gamma irradiation on the color,tensile strength and elongation of the plastic packaging materials.Ten kinds of plastic packaging materials commonly used in the market were selected,including polyethylene(PE),polypropylene(PP),polyamide,polyethylene composite bag(PA/PE),et al.and then irradiated by 60Co gamma in different irradiation dosage to analyze the variation of the chroma value,tensile strength(Rm)and elongation(εt).When the irradiation intensity was greater than 6 kGy,theΔE value of PE,polyvinylidene chloride(PVDC)and polyvinyl chloride(PVC)was larger than 6,which was visible to the naked eye.The total color difference(ΔE)value of the other seven materials was less than 1.51,and there was not significant change in the total color difference.There were significant differences between Rm andεt in polycarbonate(PC)and polyester/polyethylene bags(PET/PE)(P<0.05).Irradiation had no effect on the mechanical properties of PA/PE,polyester/aluminium foil/polyamide composite bags(PET/AL/PA)(P>0.05).There was significant difference in Rm of PA and PVDC,but not significant difference inεt.The Rm andεt of other six kinds of materials were significant or extremely significant(P<0.01).The irradiation dose of PE,PVDC and PVC plastic packaging should be controlled within≤3 kGy;The irradiation dose of PP should be controlled within≤10 kGy;The irradiation dose of PC should be controlled within≤15 kGy;The irradiation dose of PET/PE in the range of 0~40 kGy is relatively tolerant,and the irradiation dose should be controlled within≤40 kGy.