碱预处理对制备微晶纤维素的影响

Effect of Alkali Pretreatment on Preparation of Microcrystalline Cellulose

关键词:  碱预处理  微晶纤维素  酸渗透速率  粒径分布

Key Words:alkali pretreatment  microcrystalline cellulose  acid permeation rate  particle size distribution

摘要:为了加快酸水解制备微晶纤维素（Microcrystalline cellulose，MCC）时酸液的渗透效率，提高酸水解反应在纤维素纤维细胞壁内的区域反应均匀性，从而提升MCC的质量。本研究采用NaOH溶液对针叶木溶解浆进行有限润胀预处理，并通过激光粒度分析仪、X射线衍射仪（XRD）、扫描电子显微镜（SEM）、傅里叶变换红外光谱仪（FT-IR）及热重分析仪（TGA）等对MCC的各项质量指标进行检测，探究了碱预处理对酸水解制备MCC的影响。结果表明，在最佳NaOH质量分数（9%）预处理后，MCC平均粒径由52.1 μm降低至41.8 μm，粒径分布更加集中，MCC结晶度基本保持不变；碱预处理对纤维素纤维及MCC化学结构和热稳定性均无明显影响。

Abstract:In order to accelerate the acid permeation efficiency in preparation of microcrystalline cellulose (MCC) by acid hydrolysis process，and improve the uniformity of the reaction of the acid hydrolysis reaction in the cell wall of cellulose fiber，thereby improving the quality of the MCC，NaOH solution was used to pretreat softwood dissolving pulp for limited swelling. The effect of alkali pretreatment on the preparation of MCC by acid hydrolysis was investigated through characterization of the properties of microcrystalline cellulose by laser particle size analyzer，X-ray diffractometer (XRD)，Scanning electron microscope (SEM)，Fourier transform infrared (FT-IR) and Thermo gravimetry(TGA). The results showed that the average particle size of MCC decreased from 52.1 μm to 41.8 μm after pretreatment with the optimum alkali concentration（9%），the particle size distribution was more concentrated， and the MCC crystallinity basically unchanged. It showed that alkali treatment had no major influence on the chemical structure and thermal stability of cellulose fibers and MCC.