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首页> 外文期刊>Holzforschung >Determination of the absolute molar mass of acetylated eucalyptus kraft lignin by two types of size-exclusion chromatography combined with multi-angle laser light-scattering detectors
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Determination of the absolute molar mass of acetylated eucalyptus kraft lignin by two types of size-exclusion chromatography combined with multi-angle laser light-scattering detectors

机译：两种尺寸排阻色谱-多角度激光散射检测器测定乙酰化桉树牛皮纸浆木质素的绝对摩尔质量

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摘要

The molar mass (MM) and polydispersity indices (PDI) of acetylated hardwood kraft lignin (Ac-HWKL) and Ac-HWKL fractions were measured by size-exclusion chromatography with multi-angle laser light scattering (SEC-MALLS). The detectors worked at LL658 (nm) and LL785 (nm). The MM of Ac-HWKL measured at 785 nm was much smaller than that measured at 658 nm. The number-average (Mn) and weight-average (Mw) molar masses of Ac-HWKL determined at 785 nm were approximately 6.2 and 6.5 times larger, respectively, than the values estimated using a conventional calibration curve created with authentic polystyrene standards in tetrahydrofuran (THF). Based on the Mw of Ac-HWKL fractions, the Mark-Houwink-Sakurada equation for Ac-HWKL was established to be [eta]/ml g(-1) = 0.320 M-0.24 in THF and [eta]/ml g(-1) = 0.142 M-0.(26) in dimethyl sulfoxide (DMSO). These results demonstrate that Ac-HWKL has a more compact structure in an organic solvent than polystyrene.
机译：乙酰化硬木牛皮纸木质素（Ac-HWKL）和Ac-HWKL馏分的摩尔质量（MM）和多分散指数（PDI）通过多角度激光散射（SEC-MALLS）的尺寸排阻色谱法进行测量。探测器工作在LL658（nm）和LL785（nm）。在785 nm处测得的Ac-HWKL的MM远小于在658 nm处测得的MM。在785 nm处测得的Ac-HWKL的数均（Mn）和重均（Mw）摩尔质量分别比使用常规校准曲线估算的值大6.2倍和6.5倍，该标准曲线是使用真实的聚苯乙烯标准品在四氢呋喃中创建的（THF）。基于Ac-HWKL馏分的Mw，将Ac-HWKL的Mark-Houwink-Sakurada方程建立为在THF中的η/ ml g（-1）= 0.320 M-0.24和η/ ml g（ -1）= 0.142 M-0。（26）在二甲基亚砜（DMSO）中。这些结果表明，Ac-HWKL在有机溶剂中的结构比聚苯乙烯更紧密。

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