Studies on behavior for dissolution of native cellulose used bacterial cellulose in aqueous NaOH solutions

在这项研究中，我们研究了天然纤维素在NaOH水溶液中溶解的可能性，并获得了与形态相关的溶解信息：选择细菌纤维素是因为它的纤维素是一种超细纤维，而生物合成纤维的过程是相对众所周知的。用以下三种方法研究了细菌纤维素在NaOH水溶液中的溶解。首先，研究了细菌纤维素在氢氧化钠水溶液中180℃以上高温下的热处理。结果，没有观察到细菌纤维素的溶解。因为人们认为水解分解比溶解分解更快。然而，纤维素在高温下的分解显然不是由NaOH水溶液控制的，而是由Na_2SiO_3水溶液控制的。在结晶过程中会产生更多的红色成分，但这些结构实体对天然纤维素的溶解度是非常重要的。为了获得有关这些结构的新信息，对细菌纤维素的固相硝化进行了详细的研究。研究发现，无序组分分布在纤维的整个区域，高酸浓度反应介质的扩散破坏了分子内和分子间的氢键。为了只破坏这种氢键，在高酸的反应介质中对细菌纤维素进行-80℃的处理。这种处理过的纤维素溶解在NaOH水溶液中。再次，对细菌纤维素的水解进行硫酸处理，探讨纤维素的溶解度与聚合度的关系。这种低聚合度的细菌纤维素在低温下在8%的NaOH溶液中迅速溶解。目前对纤维素的溶解度与聚合度之间关系的详细分析正在进行中。少

In this study, we examined the possibility of dissolution of native cellulose used bacterial cellulose in aqueous NaOH solutions, and to obtain information about the morphology-relating dissolution: Bacterial cellulose was chosen because its cellulose is a superfine fiber and the biosynthetic process to fibril is relatively well known. The dissolution of bacterial cellulose in aqueous NaOH solutions has been investigated by the following three methods. First, the heat-treatment of bacterial cellulose was examined at high temperature above 180°C in aqueous NaOH solutions. As a result, the dissolution of bacterial cellulose was not observed. Because it is thought that decomposition by hydrolysis proceed more rapidly than dissolution. However, it became apparent that the decomposition of the cellulose at high temperature is not controlled by aqueous NaOH solution but by aqueous Na_2SiO_3 solution. Secondly, it is not yet known how intra-and inter-molecular hydrogen bonding and the disorde … More red component are produced during the crystallization, but these structure entities are very important in relation to solubility of native cellulose. In order to obtain new information about these structures, solid-phase nitration of bacterial cellulose has been investigated in detail. It is found that the disordered component is distributed in the whole areas of the fiber, and the diffusion of the reaction medium with high acid concentration breaks intra-and inter-molecular hydrogen bonding. In order to break only this hydrogen bonding, bacterial cellulose was treated at -80°C in the reaction medium with high acid. Such treated cellulose dissolved in aqueous NaOH solution. Thirdly, the treatment of hydrolysis of bacterial cellulose was carried out by sulfuric acid to discuss the relationship between solubility and polymerization degree of cellulose. This bacterial cellulose with low polymerization degree rapidly dissolved in 8% NaOH solution at low temperature. The detailed analysis for the relationship between solubility and polymerization degree of cellulose is in progress at present. Less