聚乳酸/聚氨酯复合多孔材料制备及吸油性能研究

以聚乳酸（PLA）为基体，添加不同含量聚氨酯（TPU）熔融共混制备具有不同相形态的PLA/TPU共混物，基于超临界二氧化碳（scCO₂）微孔发泡工艺，研究不同发泡温度下PLA/TPU复合多孔材料泡孔结构、发泡倍率和开孔率对样品吸油性能的影响。结果表明，随着TPU含量从10 %（质量分数，下同）增加到50 %，共混物从典型的“海?岛”相形态转变为部分共连续相形态，PLA基体黏弹性提升，结晶能力下降；PLA70组分发泡后泡孔结构更为均匀，随着发泡温度的增加，泡孔尺寸和发泡倍率先增大后减小，在94 ℃发泡温度下发泡样品发泡倍率达到29.1倍，最大开孔率75 %；TPU的加入显著增加了PLA基体的弹性回复能力，94 ℃发泡温度下的发泡样品具有最大的抗压强度，永久形变量最小；针对硅油和环己烷的吸油测试发现对硅油的吸油量大于环己烷，发泡材料的吸油量与发泡倍率和开孔率的乘积成正比，针对硅油单次最大吸油量为10.4 g/g。

Preparation and Oil Absorption Performance of Porous Polylactide/Polyurethane Composites

A series of poly（lactic acid） （PLA）/polyurethane （TPU） blends with different phase morphologies were prepared through melt blending using PLA as a matrix and then foamed through a supercritical carbon dioxide （scCO₂） microcellular foaming process. The effects of cell structure， expansion ratio， and open?cell content on the oil absorption performance of the porous composite material at different foaming temperatures were investigated. The results indicated that with an increase in TPU content from 10 wt % to 50 wt %， there was a phase morphology from a typical “sea?island” phase morphology to the partially co?continuous one occurring in the porous composite material. Meanwhile， the viscoelasticity of the PLA matrix increased， but its crystallization ability decreased. The porous composite material containing 70 wt % PLA exhibited a more uniform cell structure. The cell size and expansion ratio increased at first and then tended to decrease with an increase in foaming temperature. The expansion ratio reached 29.1 times at the foaming temperature of 94 ℃ and the maximum open?cell content was 75 %. The addition of TPU significantly increased the elastic recovery ability of the PLA matrix. The porous composite material showed the largest compressive strength and the smallest permanent deformation at a foaming temperature of 94 °C. The oil absorption test results indicated that porous composite material exhibited a greater oil absorption rate for silicone oil than for cyclohexane. Its oil absorption rate was proportional to the product of the expansion ratio and the open?cell content， giving a maximum oil absorption rate of 10.4 g/g for silicone oil.