乳液冷冻干燥法制备壳聚糖/聚乳酸复合材料

亲水性细胞外基质聚糖和疏水性脂肪族聚酯材料之间的复合是生物材料研究面临的巨大挑战。本研究以亲水性壳聚糖(CS)的醋酸溶液为水相,疏水性聚乳酸(PLA)的CHCl3溶液为油相,Tween80为表面活性剂,采用乳液冷冻干燥法制备了CS/PLA复合材料。FTIR分析发现,复合材料中CS和PLA组分间存在强烈的氢键相互作用。SEM观察表明,控制PLA的体积分数不高于50%,则复合材料的孔隙结构相互贯通,CS和PLA分布均匀。CS/PLA复合材料的孔隙率介于85%~90%,并且随PLA用量的增加,孔隙率略有下降。当PLA用量体积分数由25%增加到75%时,复合材料的力学性能介于CS和PLA的力学性能之间,其压缩强度由0.20 MPa增加到0.33 MPa,压缩模量由2.84 MPa增加到4.83 MPa。这种CS/PLA两亲复合体系为新型生物材料的设计和构建提供了新方法。

Chitosan/polylactic acid composites prepared by emulsion freeze-drying technique

The combination between hydrophilic extracellular matrix polysaccharides and hydrophobic aliphatic polyesters is a challenge in the biomaterial field. Here we investigated the formation of chitosan/polylactic acid (CS/PLA) composites using a novel emulsion freeze-drying technique, in which CS solution, CH₃ in PLA solution and Tween80 were used as water phase, oil phase, and surfactant, respectively. FTIR revealed that there are strong hydrogen bond interactions between CS and PLA. The composites showed well interconnected pore structure and homogenous distribution of CS and PLA as the PLA volume fraction was not higher than 50% by SEM observation. The porosity of the CS/PLA composites was in the range of 85%-90% and showed slight decrease with increasing PLA dose. When the PLA contents increased from volume fraction of 25% to 75%, the compressive strength of the composites increased from 0.20 MPa to 0.33 MPa, while the compressive modulus increased from 2.84 MPa to 4.83 MPa. The successful CS/PLA amphiphilic composites offer a novel strategy for biomaterial design and configuration.