Utilization of Hemicelluloses to Cellulose Acetate

以α-纤维素含量在90%以下的低品位溶解木浆为原料，制备醋酸纤维素，并对其制备过程中存在的问题及解决方法进行了探讨。将低品位针叶木亚硫酸盐溶解浆(α-纤维素含量为87.5%)和阔叶木预水解硫酸盐浆(α-纤维素含量为89%)分别在醋酸/乙酸酐/硫酸和添加有机溶剂的反应体系中进行乙酰化反应，并对其不溶残留物和可溶部分进行了表征。结果表明，它们在溶液中的透过率与高级溶解纸浆的透过率一样高。此外，制得的三醋酸酯纤维具有良好的热稳定性。这些发现表明，半纤维素醋酸酯不会使醋酸纤维素的性能变差，它们可以与醋酸纤维素一起使用。这些结果对于木材资源的有效利用是令人满意的，但都是基于小规模的实验。因此，有必要对醋酸纤维素的中试生产进行更多的实用化研究。在未来的一段时间里，全球资源短缺将会越来越严重。因此，为了将生物质资源适当地化学转化为纤维素乙酸酯，地球上有效利用生物质的实用泥浆是必要的。

The low-grade wood dissolving pulps with alpha-cellulose content below 90% were studied to prepare cellulose acetate and problems in their preparation and their remedies were studied. To do so, the low-grade softwood sulfite dissolving pulp (alpha-cellulose content, 87.5%) and hardwood prehydrolyzed Kraft pulp (alpha-cellulose content, 89%) were acetylated in the reaction system with acetic acid/acetic anhydride/sulfuric acid as will as that with an addition of organic solvent, and insoluble residues and soluble portions were studied for their characterization. As a result, atransmittance was achieved in their solution as high as that from high-grade dissolving pulps. Additionally, obtained cellulose triacetate was good in its thermal stability. These findings imply that hemicellulose acetates do not make cellulose acetate inferior in its properties and that they canbe used together with cellulose acetate. These lines of results are satisfactory for useful utilization of wood resources, but are based on small-scale experiments. Therefore, more practical preparation of cellulose acetate with a pilot plant will be becessary to investigate.In the future, global shortage of lorest resources will be more and more serious. Therefore, apractical sludies for effective use of biomass on earth will be desired for appropriate chemical conversion of biomass resources to cellulose acetates.