The glass transition temperatures (T g) of native, residual, and technical lignins are important to lignocellulose pulping, pulp processing and side stream utilization; however, how the structural changes from native to residual and technical lignin influences T g has proven difficult to elucidate. Since the T g of macromolecules is greatly influenced by the molecular weight, low-molecular-weight fractions, such as milled wood lignin (MWL), are poor representatives of lignin in the cell wall. To circumvent this problem, lignins of both high yield and purity were isolated from Norway spruce and softwood kraft pulp using the enzymatic mild acidolysis lignin (EMAL) protocol. Technical softwood kraft lignin was also fractionated into groups of different molecular weights, to acquire lignin that spanned over a wide molecular-weight range. A powder sample holder for dynamic mechanical analysis (DMA), was used to determine the T g of lignins, for which calorimetric methods were not sensitive enough. The T gs of EMAL were found to be closer to their in situ counterparts than MWL.

中文翻译：

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分离的天然木质素、残余木质素和工业木质素的玻璃化转变温度

玻璃化转变温度（时间 G) 天然木质素、残余木质素和工业木质素对于木质纤维素制浆、纸浆加工和侧流利用非常重要；然而，从原生木质素到残余木质素和工业木质素的结构变化如何影响时间 G已被证明难以阐明。自从时间 G大分子的结构受分子量的影响很大，低分子量部分，例如磨碎的木质素（MWL），不能很好地代表细胞壁中的木质素。为了解决这个问题，使用酶促温和酸解木质素 (EMAL) 方案从挪威云杉和软木牛皮纸浆中分离出高产率和纯度的木质素。工业软木牛皮纸木质素也被分成不同分子量的组，以获得跨越较宽分子量范围的木质素。用于动态机械分析 (DMA) 的粉末样品架用于确定时间 G木质素，量热法对此不够敏感。这时间 GEMAL 的 s 被发现更接近他们的就地与 MWL 相当。