聚碳酸酯新料和回收料中双酚A含量及迁移规律分析

Analysis of bisphenol A content and migration rule in new and recycled polycarbonate

目的对比分析聚碳酸酯(polycarbonate,PC)新料和回收料中双酚A(bisphenol A,BPA)含量并研究其在食品模拟液中的迁移规律。方法利用高效液相色谱仪配荧光检测器对比研究PC新料与回收料中BPA的含量及迁移量。利用凝胶渗透色谱仪(gel permeation chromatography,GPC)测量PC分子量,分析分子量对BPA迁移的影响。结果多次熔融挤出加工后PC粒料的分子量逐步降低,分子量分布(Mw/Mn)变宽,回收料经过多次熔融挤出后分子链断裂加剧,大分子降解增加,因此释放出更多的游离BPA。BPA在95%酒精溶液中迁移量远大于10%酒精及水。温度对迁移性影响很大,相同迁移时间下60℃的迁移量比25℃高10倍左右。PC回收料的游离BPA含量及迁移量大于新料。结论 PC回收料用于食品接触材料可能会造成更多的BPA的迁移。

Objective To compare and analyze the bisphenol A（BPA） content in polycarbonate（PC） new and recycled materials in plastic food contact materials, and investigate its migration rule in food simulants. Methods The content and amount of migration of BPA in PC new and recycled materials were compared and analyzed by high performance liquid chromatography with fluorescent detector. The molecular weight of PC was measured by gel permeation chromatography（GPC） to analyze the effect of molecular weight on the migration of BPA. The migration rules under different migration conditions and simulants, and the effects of temperature and time on migration were investigated. Results The molecular weight of PC granules gradually decreased after repeatedly melt extrusion processing, the molecular weight distribution（Mw/Mn） became wider, the molecular chain fracture of recycled PC increased after repeatedly melting and extrusion, and the degradation of macromolecules increased, so more free BPA were released. The migration of BPA in 95% alcohol solution was much larger than that in 10% alcohol and water. Temperature had a great influence on migration, and the migration at 60 ℃was about 10 times higher than that at 25 with the same migration time. The free BPA content and migration of recycled PC was greater than that of newmaterial. Conclusion The recycled PC used for food contact materials may cause more BPA migration than new PC material.