Expanders lignin derived

The discovery of mediators (small molecules which when oxidised by peroxidases or laccases form highly reactive species), which have the abihty to oxidise high redox potential substrates difficult to be oxidised by the enzyme alone, has further expanded the applications of these enzymes in modifying inert polymers. Examples of widely investigated mediators are 1-hydroxybenzotriazole (HBT), violuric acid (VA), A-hydroxyacetanilide (NHA) and 2,2 -azinobis-(3-ethylbenzothiazoline)-6-sulphonate (ABTS). Alternatively, active research is aimed at developing natural cost-effective lignin-derived mediators [10]. 

Traditionally, the organic components of expander formulations are derived from natural products such as wood pulp. The composition of such materials is poorly defined. Lignin extracts, frequently obtained from waste sulfite liquors in the papermaking industry, are purified by removing sugars and various metals, and then depolymerized to different degrees. Lignin molecules are formed from three primary precursors, p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol the... 

The organic components of expanders are mainly chemically treated lignins or derivatives of the latter. These are complex polymer substances containing different functional groups such as methoxyl, phenolic, carboxylic, ketonic, carbinol structural groups, etc. The correlation... 

When the battery is cycled at 60 °C and is of the VRLA type, expanders containing lignin and its derivatives disintegrate, as a result of which the battery cycle life is reduced almost twice. In order to improve the cycle life performance of the negative plates, the battery temperamre should be kept equal to about 40 °C. 

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