高CO_(2)/O_(2)选择透过性聚乳酸共混薄膜对荷兰豆贮藏品质的影响

Effectiveness of High CO_(2)/O_(2) Permselective Poly(lactic acid)Blend Film on the Storage Quality of Lotus Peas

通过在聚(L-乳酸)(PLLA)主段中引入聚己内酯(PCL)柔性聚合物作为中间链段,制备了PLLA-PCL-PLLA(PLCL)三嵌段聚合物,并与PLLA本体以不同比例进行溶液共混制得PLLA/PLLA-PCL-PLLA(PLLA/PLCL)薄膜。利用傅里叶变换红外光谱、热力学性能和阻隔性能等对薄膜进行表征,探讨了PLCL三嵌段聚合物调控PLLA薄膜对CO_(2)及O_(2)的选择透过性,并将PLLA/PLCL薄膜用于荷兰豆自发气调保鲜试验。结果表明,PLCL质量分数为30%时,气体的选择透过性和拉伸性能较好,同时袋内气氛浓度保持为5%CO_(2),3%O_(2),有效地抑制了荷兰豆的呼吸作用,减少了有害物质的积累,延长其货架期。

The PLLA-PCL-PLLA(PLCL)triblock polymer was prepared by introducing polycaprolactone(PCL)flexible polymer into the main sections of polylactic acid(PLLA)as intermediate segment,and mixed with PLLA body with different proportions to prepare the PLLA/PLLA-PCL-PLLA(PLLA/PLCL)thin films.The films were characterized by Fourier infrared spectroscopy,thermodynamic properties and barrier properties,and the selective permeability of CO_(2) and O_(2) of the PLLA films controlled by the PLCL triblock polymer was explored,then,using PLLA/PLCL films for spontaneous modified atmosphere preservation of lotus peas.The results show that when the PLCL mass fraction is 30%,the selective gas permeability and stretching performance are better,which reduce the water vapor permeability of the films and could maintain the bag’s inner atmosphere concentration at 5%CO_(2) and 3%O_(2),and effectively inhibit the respiration of lotus peas,and delay the loss of chlorophyll and prolong the storage period.