纳米SiO_2/纤维素复合材料的非均相制备及其性能

Heterogeneous preparation and properties of nano-SiO_2/cellulose composites

采用硅酸四乙酯(TEOS)作为无机前聚物,纤维素为有机组分,利用溶胶-凝胶法在非均相乙醇溶液中制备了纳米SiO2/纤维素复合材料。通过傅里叶红外光谱(FTIR)、透射电镜(TEM)和热重分析(TGA)对复合材料的形貌、结构以及热稳定性进行表征。讨论了SiO2含量对材料力学性能的影响。研究了主要因素碱催化剂氨水对纤维素与SiO2复合效果的影响。结果表明,纳米复合材料的弹性模量、拉伸强度随SiO2含量的增加先增加后减少,质量分数分别为3.1%、10.6%时弹性模量、拉伸强度达到最大。氨水加入量为3.70×10-4mol/L时,纤维素与SiO2的复合效果最佳。非均相制备的纳米SiO2/纤维素复合材料同样也明显提高了纤维素材料的疏水性、热稳定性和力学性能。

The nano-SiO2/cellulose composites were successfully synthesized by a sol-gel method using tetraethylorthosilicate （TEOS） as the silica precursor and cellulose in heterogeneous ethanol solution. The morphology, structure and thermal stability of the composite materials were characterized by TEM, FTIR and TGA. The influence of SiO2 content on the mechanical properties of composites was discussed. The effect of basic catalyst ammonia on the content of silica in cellulose was studied. The results indicate that the elastic modulus of the composites increases with the increasing of SiO2 mass fraction until 3.1% and then decreases, and the same is true of tensile strength when SiO2 mass fraction is 10.6%. SiO2 is incorporated into cellulose most effectively when the dosage of ammonia is 3. 70×10^-4 mol/L. The hydrophobicity, thermal stability and mechanical properties of nano-SiO2/cellulose composites in the heterogeneous system are also higher than those of the cellulosic materials.