静电纺纤维素纳米晶体/壳聚糖-聚乙烯醇复合纳米纤维的制备与表征

通过探索纤维素纳米晶体（CNC）添加量对壳聚糖-聚乙烯醇（CS-PVA）基体性能的影响，为静电纺CNC/CS-PVA复合纳米纤维的制备提供理论支撑。以CNC、CS和PVA为原料，采用静电纺丝法成功制备不同CNC含量（质量分数）的静电纺CNC/CS-PVA复合纳米纤维，并通过SEM、TGA和FTIR等分析手段对CNC/CS-PVA复合纳米纤维的微观结构和性能进行了表征。结果表明：添加CNC后静电纺CNC/CS-PVA复合纳米纤维直径变大，表面变粗糙，力学性能和热学性能提高；随着CNC含量的增加，静电纺CNC/CS-PVA纤维的杨氏模量（E）和抗拉强度（σ）先增强后减弱，而外延起始温度继续上升。当CNC含量为3wt%时，静电纺CNC/CS-PVA复合纳米纤维力学性能最好，相比于CS-PVA复合纳米纤维，E和σ分别提高了43.9%和24.8%；当CNC含量为20wt%时，静电纺CNC/CS-PVA复合纳米纤维直径分布不均匀，可以观察到单根纤维表面存在少量的球状结构物质，同时外延起始温度达到328.83℃；FTIR分析得出，CNC与CS和PVA之间只存在分子间的相互作用而没有发生化学反应；随着溶液的酸性减弱，碱性增强，不同CNC含量的静电纺CNC/CS-PVA复合纳米纤维稳定性逐渐提高，而CNC含量对其稳定性影响不大。

Preparation and characterization of electrospun cellulose nanocrystals/chitosan-polyvinyl alcohol composite nanofibers

The effect of cellulose nanocrystals (CNC) addition on the properties of chitosan/polyvinyl alcohol (CS-PVA) matrix was explored, and the theoretical support for the fabrication of electrospun CNC/CS-PVA composite nanofibers was further provided. Using CNC, CS and PVA as raw materials, the CNC/CS-PVA composite nanofibers with different CNC content (mass fraction) were successfully prepared by the method of electrospinning. The microstructure and properties of the composite nanofibers were analyzed by SEM, TGA and FTIR. The results show that the addition of CNC leads to increased average diameter of the CNC/CS-PVA composite nanofibers, while the composite nanofibers surface becomes rougher. The mechanical properties and thermal behavior are significantly improved. With the increase of CNC content, the Young's modulus (E) and tensile strength (σ) of CNC/CS-PVA composite nanofibers first enhance and then weaken, while the epitaxial starting temperature continues to rise. When the content of CNC is 3wt%, the mechanical properties of electrospun CNC/CS-PVA composite nanofibers have the maximum values. Compared with CS-PVA composite nanofibers, E and σ of the nanofibers with CNC incorporation increase by 43.9% and 24.8%, respectively. As CNC content is 20wt%, the electrospun CNC/CS-PVA composite nanofibers diameter distribution is not uniform, some spherical structure is observed on the surface of the single fiber, and the epitaxial initiation temperature reaches to 328.83℃. FTIR analysis showes that only physical interaction is present among CNC, CS and PVA, but no chemical reaction occurres. The stability of the electrospun CNC/CS-PVA composite nanofibers with different CNC contents gradually increases with increased acidity of the solution, while the CNC loading has little effect on it.