壳聚糖/纤维素生物质发泡复合材料多孔结构的表征

Porous structural characterization of chitosan/cellulose biomass foaming composites

以壳聚糖微粒为增强体,离子液体为纤维素溶剂,采用冷冻干燥法成功制备了壳聚糖/纤维素生物质发泡复合材料。利用SEM、XRD和TGA表征多孔复合材料微观结构、结晶性能以及热稳定性,测试了其孔隙率和吸水性能。实验结果表明:壳聚糖/纤维素多孔复合材料具有三维相互贯通的微孔结构,壳聚糖粉体有助于孔洞结构的形成,TGA结果显示纤维素多孔材料的热稳定性能得以提高。XRD结果显示纤维素经离子液体溶解再生后晶型结构由纤维素I转化为纤维素II。纤维素含量较低(≤4wt%)时,随1wt%壳聚糖粉体的加入,孔隙率明显提高。壳聚糖/纤维素多孔复合材料的力学性能随纤维素含量的增加而不断提高,而吸水性能有所下降。壳聚糖与纤维素质量比为1∶3时,壳聚糖/纤维素多孔复合材料孔隙率为72.7%,吸水率和相对保湿率分别为28.0g/g和17.6g/g,断裂强度和断裂伸长率分别为0.32 MPa和25.4%,能够作为一种优良的吸附材料用于制备高性能的医用敷料。

Chitosan/cellulose biomass foaming composites were successfully prepared by a freeze dry method using chitosan particles as reinforcement and ionic liquid as cellulose solvent.The microstructure,crystallization property and thermo-stability of porous composites were characterized by SEM,XRD and TGA,respectively.The porosity and water absorption ability were also analyzed.The results show that chitosan/cellulose porous composites exhibit3-dimensional interconnected porous structure and chitosan particles facilitate the formation of pores.TGA demonstrates that the addition of chitosan particles improves the thermal stability of cellulose porous materials.XRD presents that the crystalline structure of cellulose is converted from cellulose I to cellulose II in original cellulose during dissolution and regeneration.When the cellulose content is relatively low(≤4wt%),the incorporation of 1wt%chitosan powders increases the porosity of the chitosan/cellulose porous composites.Mechanical properties of chitosan/cellulose porous composites increase with increasing cellulose contents,while water absorption ability decreases.The porosity of the chitosan/cellulose(mass ratio is 1∶3)porous composites is 72.7%,the water absorption rate and relative retention rate are 28.0g/g and 17.6g/g,the breaking strength and breaking elongation are0.32 MPa and 25.4%,receptively.This chitosan/cellulose porous composites as excellent absorption material can be used for medical dressing with high performances.