Department of Chemistry, Institute for Chemistry of Renewable Resources , University of Natural Resources and Life Sciences, Vienna , Konrad Lorenz Strasse 24 , A-3430 Tulln , Austria.
Johan Gadolin Process Chemistry Centre , Åbo Akademi University , Porthansgatan 3 , Åbo/Turku FI-20500 , Finland.
Biomacromolecules. 2019 Nov 11;20(11):4117-4125. doi: 10.1021/acs.biomac.9b00956. Epub 2019 Oct 23.
Although efficient and inexpensive, conventional viscometry to determine the average degree of polymerization (DP) of cellulose may mislead the final DP because cellulose degradation occurs in the used solvents, which consist of alkaline amino complexes of transition metals, such as cupri-ethylenediamine (CED). For oxidatively damaged pulps or celluloses, viscosity-DP determinations may be more inaccurate because alkali-induced β-elimination reactions render such oxidized celluloses even more vulnerable. Despite the risk identified in many studies, a systematic investigation of the parameters affecting the viscosity-DP assessed by reliable analytics is still required. Here, a new approach evaluating the effects of CED on oxidized cellulosics was used (i.e., immediate pulp regeneration after dissolution in CED). In-depth molecular feature characterization (e.g., absolute molar masses and oxidized groups' profiling related to molecular weight distribution) by gel permeation chromatography coupled with fluorescence and multiangle laser light scattering clarified the behavior of oxidized celluloses and the influencing parameters upon dissolution in CED.
虽然传统的粘度法测定纤维素的平均聚合度（DP）既高效又廉价，但由于纤维素在碱性过渡金属氨基酸络合物（如铜-乙二胺（CED））等所用溶剂中会发生降解，因此可能会导致最终 DP 出现偏差。对于氧化损伤的纸浆或纤维素来说，粘度-DP 测定可能会更不准确，因为碱诱导的β消除反应会使这些氧化纤维素更加脆弱。尽管在许多研究中都发现了这种风险，但仍需要对通过可靠分析评估的粘度-DP 所受参数进行系统研究。在此，采用了一种新方法来评估 CED 对氧化纤维素的影响（即，在 CED 中溶解后立即进行纸浆再生）。通过凝胶渗透色谱法与荧光和多角度激光散射相结合进行深入的分子特征分析（例如，与分子量分布相关的绝对摩尔质量和氧化基团分布），阐明了氧化纤维素在 CED 中的溶解行为及其影响参数。
