Aalto University, School of Chemical Technology, Department of Forest Products Technology, P.O. Box 16300, 00076 Aalto, Finland.
Carbohydr Polym. 2014 Jan 30;101:792-7. doi: 10.1016/j.carbpol.2013.10.001. Epub 2013 Oct 14.
Fresh birch chips were treated with different concentrations of sodium hydroxide and sodium sulfide in deuterium oxide in typical kraft pulping conditions and the extent of irreversible deuteration of the chips/pulps was followed by Fourier transform infrared (FT-IR) spectroscopy. Water retention values (WRV) of pulps were measured to evaluate accessibility of cellulose. The kraft pulping with deuterium oxide led to significant proton-deuterium exchange that was not reversed when the chips/pulps were washed with water. The deuteration followed a first order dynamics with a maximum obtained in the beginning of delignification stage. Higher dosages of effective alkali resulted in a higher degree of deuteration and lower WRV. An inverse relationship between the extent of deuteration and WRV suggests that both were induced by cellulose microfibril aggregation. Results also indicate that hemicellulose dissolution plays an important role in the induction of cellulose microfibril aggregation, while lignin dissolution has less influence.
新鲜桦木片在氘化水中用不同浓度的氢氧化钠和硫化钠在典型的硫酸盐制浆条件下进行处理，通过傅里叶变换红外（FT-IR）光谱法跟踪芯片/纸浆的不可逆氘化程度。通过测量纸浆的保水值（WRV）来评估纤维素的可及性。用氘化水进行硫酸盐制浆会导致显著的质子-氘交换，当芯片/纸浆用清水洗涤时，这种交换不会逆转。氘化反应遵循一级动力学，在脱木质素阶段的开始时达到最大值。有效碱的较高用量导致更高程度的氘化和更低的 WRV。氘化程度和 WRV 之间的反比关系表明，这两者都是由纤维素微原纤维聚集引起的。结果还表明，半纤维素的溶解在诱导纤维素微原纤维聚集中起着重要作用，而木质素的溶解影响较小。
