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Influence of wood pulp quality on the structure of carboxymethyl cellulose

机译：木浆质量对羧甲基纤维素结构的影响

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摘要

The quality of carboxymethyl cellulose (CMC) prepared from different wood-derived market pulps is examined. The pulps represent kraft and sulfite qualities with different levels of hemicellulose (1.5-22.8 wt %), intrinsic viscosity (391-780 mL g(-1)), and content of extractives (0.04-0.13 wt %). The pulps are carboxymethylated in aqueous medium at three different levels of sodium hydroxide concentration, resulting in three levels of degree of substitution (DS), 0.3, 0.7-0.8, and 1.3-1.4 (according to nuclear magnetic resonance spectroscopy and high-performance liquid chromatography). CMC with DS 0.7-0.8 is found to be near the limit for water solubility and the resulting ranking for that solubility is shown to be correlated to DS. The DS is found to be impaired by a high content of impurities and high degree of Cellulose II in the pulp. The sulfite pulps yield CMC with the best solubility in water. A high level of extractives does not interfere with reactivity. Moreover, it is found that impurities, such as lignin and xylan, inhibit thickening behavior even at high DS, and that the ratio of substitution on Position 3 is a measure of the xylan content, which suggests that this position in xylan has extremely high reactivity. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47862.
机译：检查由不同木材衍生的市场纸浆制备的羧甲基纤维素（CMC）的质量。纸浆代表牛皮纸和亚硫酸盐品质，具有不同水平的半纤维素（1.5-22.8wt％），特性粘度（391-780ml g（-1））和提取物含量（0.04-0.13wt％）。纸浆在三种不同水溶液的氢氧化钠浓度下羧甲基化，导致三种含量的取代度（DS），0.3,0.7-0.8和1.3-1.4（根据核磁共振光谱和高性能液体色谱法）。发现具有DS 0.7-0.8的CMC靠近水溶性的限制，并且该溶解度的所得排名显示与DS相关。发现DS在纸浆中通过高含量的杂质和高纤维素II损害。亚硫酸盐产生CMC，在水中最好的溶解度。高水平的提取物不会干扰反应性。另外，发现杂质，例如木质素和木聚糖，即使在高DS，也抑制增稠行为，并且取代位置3的比率是木聚糖含量的量度，这表明Xylan中的这种位置具有极高的反应性。 （c）2019 Wiley期刊，Inc.J.Phill。聚合物。 SCI。 2019,136,47862。

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