Aggregation of Lignin Derivatives under Alkaline Conditions. Kinetics and Aggregate Structure
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- 作者：Magnus Norgren ; Hå ; kan Edlund ; and Lars Wå ; gberg
- 刊名：Langmuir
- 出版年：2002
- 出版时间：April 2, 2002
- 年：2002
- 卷：18
- 期：7
- 页码：2859 - 2865
- 全文大小：161K
- 年卷期：v.18,no.7(April 2, 2002)
- ISSN：1520-5827
文摘
The kinetics of kraft lignin (KL) aggregation at alkaline conditions was studied by quasi-elastic lightscattering (QELS) and turbidity measurements. Stability ratios (W) for KL were obtained at 70 
C andvarious concentrations of sodium chloride. By analyzing the early-time evolution data of aggregate growthobtained from QELS, fractal dimensions of flocs formed in both reaction-limited cluster-cluster aggregationregimes and diffusion-limited cluster-cluster aggregation regimes were determined. Correlations betweenthe fractal dimension and the W-ratio were found in accordance to recent studies of a system containingmonodisperse polystyrene colloids. By cryogenic transmission electron microscopy, the fractality of KLaggregate structures in the system was also shown. It was seen from stability studies of KL solutions thatthe effects of specific co- and counterions follow the Hofmeister series. From the outcome of the investigation,different modes of aggregation occurring in a KL system are proposed. Starting from the macromolecularstate of KL and evolving through larger aggregates, the KL clusters finally exhibit a supramolecularstructure similar to what earlier has been proposed for native softwood lignin.
C andvarious concentrations of sodium chloride. By analyzing the early-time evolution data of aggregate growthobtained from QELS, fractal dimensions of flocs formed in both reaction-limited cluster-cluster aggregationregimes and diffusion-limited cluster-cluster aggregation regimes were determined. Correlations betweenthe fractal dimension and the W-ratio were found in accordance to recent studies of a system containingmonodisperse polystyrene colloids. By cryogenic transmission electron microscopy, the fractality of KLaggregate structures in the system was also shown. It was seen from stability studies of KL solutions thatthe effects of specific co- and counterions follow the Hofmeister series. From the outcome of the investigation,different modes of aggregation occurring in a KL system are proposed. Starting from the macromolecularstate of KL and evolving through larger aggregates, the KL clusters finally exhibit a supramolecularstructure similar to what earlier has been proposed for native softwood lignin.