Polyamide self-lubricating composites filled with thermolysis products of lignin: composition, structure, properties

Compositions of antifriction composites with a polyamide matrix filled with carbon additives obtained by modifying hydrolytic lignin (graphite from lignin, graphite bisulfate from lignin, thermally expanded graphite from lignin) have been developed. Powders of carbon materials were impregnated with cylinder oil before being added to the polyamide matrix. The tribotechnical characteristics of filled polyamide composites, their microstructure and water absorption kinetics have been investigated. It was found that the lowest values of the friction factor are observed in composites filled with thermally expanded graphite from lignin. The friction factor for such composites is 1.5-2 times less than the indicators obtained for currently used graphites. Thus, at specific loads of 0.67 and 2.33 MPa, the friction factor was 0.065 and 0.064, respectively. The investigated antifriction composites have low water absorption compared to pure polyamide. The maximum water absorption (2.2%) in the series of the studied composites had the samples filled with graphite from lignin with an oil content of 9%. According to the data of microstructural analysis, the structure of composites with additives of carbon materials from lignin is homogeneous. The components, including the oil plasticizer, are evenly distributed, the bulk of the oil is localized in the interlayer spaces. The elemental composition of the composites indicates the high chemical purity of the composites. Antifriction composites with the proposed additives are recommended for use in friction units operating in an aqueous mediumor an environment with high humidity.

Methods of Chemical and Thermochemical Processing of Hydrolytic Lignin

The analysis of the latest publications on the use of hydrolytic lignin, which is a large-tonnage waste of wood chemical processing, was carried out. In its original form, the hydrolytic lignin is used as fuel, fuel briquettes and pellets, binders and adhesives, organic fertilizers, fillers and enterosorbents. The processing of hydrolytic lignin by chemical and thermochemical methods allows to significantly expand the range of valuable products obtained from it. They are used in chemical, oil and gas and construction industries, metallurgy and other areas. Hydrolytic lignin is most widely used for the production of carbon sorbents. Recently, methods of thermochemical processing of lignin into porous carbon materials with the required texture and strength characteristics as well as into valuable organic products have been developed

Possibilities of using hydrolytic lignin in the production of wood-splicing materials

The problem of improving the environmental safety of the waste management system of chemical processing of biomass of wood is quite acute in every forest producing and timber processing region. Study of the possibility of using to investigate hydrolytic lignin as a modifier of phenol-formaldehyde resin for the production of plywood have been conducted. Used materials: phenol-formaldehyde resin SFZh-3013; technical hydrolyzed lignin. Mathematical models of the process of pressing glued plywood were developed and the optimal parameters for the production of plywood were determined based on the use of SFZh-3013 resin modified with hydrolytic lignin. The optimal mode of pressing is: the amount of injected hydrolytic lignin in the SFZh-3013 resin grade is 5-10 parts by weight; pressing pressure 1.6 MPa, pressing temperature 135 °C and pressing time 9-10 minutes. The introduction of regimes developed using regression equations, with a sufficient degree of accuracy describing the pressing process, will significantly improve the efficiency of plywood production by saving energy and material costs and preserving product quality.

Study of the efficiency of energy use of willow chips and torrefied hydrolytic lignin pellets

The lack of raw materials to provide power plants with biofuel requires the search for new energy sources. In the European North of Russia, it is recommended to grow plantings of the willow (Salix L.) in the form of trees or tree-like shrubs, while ensuring a short interval between fellings. The studies show that the artificial cultivation of willow plantations on postagrogenic lands is economically more expedient than the exploitation of natural willow forests. This study examines the energy efficiency of willow wood, which is necessary when planning its use for the production of biofuel (wood chips or fuel pellets) and pellets obtained from torrefied hydrolytic lignin. A comprehensive study of the energy efficiency of willow chips, willow chips with bark, hydrolytic lignin pellets during the operation of the “Firematic 60” hot water boiler was carried out. The elemental composition of the fuels and the resulting ash was studied using an EDX-8000 X-ray fluorescence spectrometer and a Euro EA-3000 analyzer. The components of the heat balance and emission of harmful substances were determined. The emissions of particulate matter and the content of soot particles were studied.

New Energy-Consuming Carbon Materials Derived from Hydrolytic Lignin

Hydrolytic lignin (HL) has been used in manufacturing of graphitized carbon via HL one-step physical activation. It was found that the layered carbon products of pyrolysis of hydrolytic lignin (AHL) at different temperatures may be used as cathode materials in primary current sources. The galvanostatic discharge of lithium battery at a current density of 100 μA/cm2 between 3.0 and 0.5 V shows that the specific capacity of thermally activated derivative is equal to 845 mA·h/g, while the untreated lignin yields only 190 mA·h/g. The fluorination of both the lignin and its thermally activated form results in higher operating voltage of lithium battery, as seems, due to the involvement of fluorine bound to carbon in electrochemical process. Some fluorinated AHL samples show the promise of their use as supercapacitor electrodes.