木质素含量调控的阳离子化竹浆结构-性能协同机制 及其抗菌功能强化研究

Study on synergistic mechanism of structure and properties of cationized bamboo pulp regulated by lignin content and strengthening of its antibacterial function

关键词:  木质素  阳离子化  2,3-环氧丙基三甲基氯化铵  抗菌性能  

Key Words:Lignin  Cationization  EPTAC  Antibacterial Performance

摘要:本研究以化学机械竹浆为原料,通过酸性亚氯酸钠法梯度调控木质素含量(18.67%至2.47%),并以2,3-环氧丙基三甲基氯化铵(EPTAC)为醚化剂进行阳离子化改性。采用FT-IR、XRD、TGA及Zeta电位分析等手段系统表征了改性纸浆的结构与性能。结果表明,EPTAC成功接枝季铵基团,Zeta电位显著提升；木质素含量与阳离子取代度呈正相关(HPY0取代度0.098,HPY180降至0.078)。抗菌实验表明,阳离子化纸浆对大肠杆菌和金黄色葡萄球菌的抑菌效果随木质素含量增加而显著增强,其归因于木质素的天然抑菌特性、高木质素体系大尺寸纳米纤维的物理穿刺效应及阳离子电荷的协同作用。本研究为开发高效环保抗菌纸基材料提供了理论依据与工艺优化路径。

Abstract:This study utilized chemi-mechanical bamboo pulp as raw material, achieving gradient delignification (lignin content adjusted from 18.67% to 2.47%) via acidic sodium chlorite treatment, followed by cationization using 2,3-epoxypropyltrimethylammonium chloride (EPTAC) as an etherifying agent. The structural and functional properties of the modified pulp were systematically characterized through FT-IR, XRD, TGA, and Zeta potential analysis. Results demonstrated the successful grafting of quaternary ammonium groups by EPTAC, accompanied by a significant increase in Zeta potential (e.g., from negative to +18.4 mV). A positive correlation was observed between lignin content and cationic substitution degree (DS) (e.g., DS of HPY0 = 0.098 vs. HPY180 = 0.078), attributed to the competitive reactions of lignin phenolic hydroxyl groups and its three-dimensional network-induced steric hindrance. Antibacterial tests revealed that the cationized pulp exhibited enhanced inhibitory effects against Escherichia coli and Staphylococcus aureus with increasing lignin content, achieving inhibition rates of 92.3% and 87.6%, respectively. This enhancement was ascribed to the synergistic effects of lignin’s intrinsic antimicrobial activity, the physical puncturing effect of large-sized lignin-containing nanofibers, and the cationic charge-driven membrane disruption. The study elucidates the lignin-mediated structure-property relationships in cationized pulp, providing theoretical insights and sustainable strategies for designing high-performance antibacterial paper-based materials.