Synthesis and characterization of cellulose acetate with high degree of substitution from miscanthus
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以芒草为原料,用Na OH/H_2O_2溶液体系预处理制备芒草纤维,在冰醋酸环境下,以浓硫酸为催化剂与醋酸酐酯化制备芒草醋酸纤维素。优化了预处理条件:温度、时间、次数和酯化条件:催化剂量、温度、时间、醋酸酐量,最佳条件下制备出的芒草纤维的纤维素、半纤维素和木质素的质量分数分别为75.3%、17.3%、5.1%,制备出芒草醋酸纤维素的取代度DS=2.8,特性黏度[η]=1.24 d L/g,达到美国联邦贸易委员会指南认定的三醋酸纤维素标准。利用扫描电镜(SEM)和热分析(TG、DSC)对制得样品进行表征。结果表明,可以利用Na OH/H_2O_2水溶液体系预处理芒草原料制备芒草纤维,并进一步酯化制备出高取代度的醋酸纤维素。A procedure for synthesizing cellulose acetate with high degree of substitution from miscanthus biomass is developed. The miscanthus fiber is prepared by pretreatment of miscanthus biomass with Na OH / H_2O_2,which is then reacted with acetic anhydride in an acetic acid solvent to synthesize cellulose acetate by using concentrated sulfuric acid as catalyst. The effects of the pretreatment factors( such as pretreatment temperature,time and number of times) and the esterification factors( such as catalyst volume,reaction temperature,reaction time and acetic anhydride volume) are studied. Under the optimal conditions,the contents of cellulose,hemicellulose and lignin for prepared miscanthus fiber are75. 3%,17. 3% and 5. 1%,respectively. The degree of substitution( DS) and the intrinsic viscosity( [η ]) of the obtained miscanthus cellulose acetate are 2. 8 and 1. 24 d L / g,respectively. The miscanthus biomass,fiber and cellulose acetate are characterized by SEM,TG and DSC. This study shows that cellulose acetate with high degree of substitution can be prepared from miscanthus biomass pretreated with Na OH / H_2O_2.