甘蔗渣显微结构对聚乳酸/甘蔗渣复合材料结构与性能的影响

采用碱处理、硅烷偶联剂处理以及碱处理配合硅烷偶联剂处理等方式改性甘蔗渣(BF),采用傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)、热重分析(TGA)以及力学性能测试等研究改性后BF结构的变化。结果表明,不同改性方法均明显改变了BF的结构及改性剂的键合方式。碱处理能够去除BF中的半纤维素等小分子聚合物以及部分非晶区的纤维素,导致BF热稳定性降低,结晶度上升。碱液浓度偏高以及碱处理时间过长会导致BF的纤维表面原纤化,虽然能增加与偶联剂反应的面积,但BF的强度大大下降,不利于BF的增强作用。因此,硅烷偶联剂处理的BF/PLA复合材料的相容性及力学性能最佳,其次为碱处理配合硅烷偶联剂处理的BF/PLA复合材料,最后为碱处理的BF/PLA复合材料。

Effect of Microstructure of Bagasse on Structure and Propertiesof Polylactic Acid/Bagasse Composites

Methods in terms of alkali treatment, silane coupling agent modification and combination of alkali treatment and silane coupling agent modification were used to modify bagasse fiber (BF). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), thermogravimetry (TGA) and mechanical properties testing were used to characterize and analyze the structure and properties of modified BF. Results showed that the used methods changed the structure of BF and their bonding modes. Alkali treatment removed the small molecular compounds such as hemicellulose and parts of amorphous cellulose, resulting in the decreasing of thermal stability of BF and increasing of crystallinity of BF. The concentration of alkali solution was too high and the time for alkali treatment was so long that BF was fibrillated. The fibrillation of BF increased the reaction area of BF with the coupling agents, but decreased the strength of BF that is adverse to the reinforcement of BF. Therefore, BF/PLA composites modified by silane coupling agents demonstrated the best compatibility and mechanical properties, BF/PLA composites modified by combination of alkali treatment and silane coupling agents demonstrated better compatibility and mechanical properties, while BF/PLA composites modified by alkali treatment did not demonstrate good compatibility and mechanical properties in the compared BF/PLA composites.