氧化解聚壳聚糖改性水性聚氨酯的制备与性能

Preparation and Properties of Oxidatively Depolymerized Chitosan M odified w aterborne Polyurethane

利用壳聚糖(CS)氧化解聚后的低分子量壳聚糖(LCS)制备改性水性聚氨酯(WPU)。LCS与聚氨酯之间的相互作用可影响壳聚糖聚氨酯复合膜的力学性能、热稳定性、亲水性、抗菌活性以及生物相容性。当LCS添加量为0.5%时,粒径分布结果表明,乳液中的LCS与聚氨酯相容,而且分散均匀。与未改性的WPU相比,壳聚糖聚氨酯的拉伸应力由13.3 MPa提升至17.6 MPa,T_(10%)由254.3℃提高至269.6℃,水接触角由76.6°降低至58.8°。此外,壳聚糖聚氨酯复合膜对金黄色葡萄球菌和大肠杆菌具有抗菌活性,其抗菌效率可达90%。最后,MTT方法用于验证聚氨酯复合膜的体外细胞毒性。当培养液中样品浓度增大至0.25 mg/mL时,WPU-LCS-0.5的细胞存活率仍可达70%以上。添加壳聚糖后,壳聚糖聚氨酯的体外细胞毒性显著降低,生物相容性较好。

Chitosan(CS)was oxidized and depolymerized to obtain low molecular weight chitosan(LCS)to prepare waterborne polyurethane(WPU).The interaction between LCS and polyurethane affected the mechanical properties,thermal stability,hydrophilicity,antibacterial activity and biocompatibility of chitosan polyurethane composite films.The particle size distribution showed that the LCS in the emulsion was compatible with the polyurethane and dispersed uniformly,when the amount of LCS added was 0.5%.Compared with the unmodified WPU,the tensile stress of chitosan-polyurethane was increased from 13.3 MPa to 17.6 MPa,the T_(10)%was improved from 254.3℃to 269.6℃,and the water contact angle was decreased from 76.6°to 58.8°.In addition,chitosan-polyurethane films had antibacterial activity against Staphylococcus aureus and Escherichia coli,the antibacterial efficiency could reach 90%.Finally,the MTT method was used to verify the in vitro cytotoxicity of the polyurethane films.It was found that the cell survival rate of the LCS-WPU-0.5 could reach 70%,when the sample concentration in the culture solution was increased to 0.25 mg/mL.After the addition of chitosan,the in vitro cytotoxicity of chitosan-polyurethane was significantly reduced,and the biocompatibility was better.