Dissolution of cellulose in aqueous NaOH solutions
Dissolution of cellulose in aqueous NaOH solutions
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DOI：
10.1023/a:1009272632367
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发表时间：
1998-12-01
期刊：
影响因子：
5.7
通讯作者：
Atalla, RH
中科院分区：
文献类型：
--
作者：
Isogai, A;Atalla, RH
研究了纤维素样品在氢氧化钠水溶液中的溶解情况，考察了分子量、晶型和结晶度对纤维素样品溶解的影响。开发并优化了微晶纤维素的溶解程序，并将其应用于不同晶型、结晶指数和分子量的其他纤维素样品。最佳条件包括将纤维素在8- 9wt%NaOH中溶胀，然后通过将其保持在-20 ℃下将其冷冻成固体物质。然后在室温下解冻冷冻物质，并用水稀释至5%NaOH。通过该方法，由微晶纤维素制备的所有样品都完全溶解在NaOH溶液中。通过该方法，由短绒纤维素和牛皮纸浆制备的具有纤维素II或无定形结构的所有再生纤维素也基本上溶解在NaOH水溶液中。当应用相同的程序时，原始棉绒纤维素、其丝光形式和由其制备的纤维素III样品具有仅26- 37%的有限溶解度值。研究的纤维素的溶解度的差异已被解释在固体纤维素样品中存在的一些长程有序已被破坏的过程中的预处理的程度方面。
Dissolution of a number of cellulose samples in aqueous NaOH was investigated with respect to the influence of molecular weight, crystalline form and the degree of crystallinity of the source samples. A procedure for dissolving microcrystalline cellulose was developed and optimized, and then applied to other cellulose samples of different crystalline forms, crystallinity indices and molecular weights. The optimum conditions involved swelling cellulose in 8-9 wt% NaOH and then freezing it into a solid mass by holding it at -20 degrees C. This was followed by thawing the frozen mass at room temperature and diluting with water to 5% NaOH. All samples prepared from microcrystalline cellulose were completely dissolved in the NaOH solution by this procedure, All regenerated celluloses having either cellulose II or an amorphous structure prepared from linter cellulose and kraft pulps were also essentially dissolved in the aqueous NaOH by this process. The original linter cellulose, its mercerized form and cellulose III samples prepared from it had limited solubility values of only 26-37%, when the same procedure was applied. The differences in the solubility of the celluloses investigated have been interpreted in terms of the degrees to which some long-range orders present in solid cellulose samples have been disrupted in the course of pre-treatments.