LIGNIN AS THE BASIS FOR OBTAINING BIOPLASTICS

Abstract

Background. The limited reserves of fossil organic sources (petroleum and biogas), the need to solve the problems of utilization and recycling of plastic raises the task of finding alternative materials for traditional plastics. One such source is bioplastics, which include lignin, the second most widespread renewable biopolymer. Lignin can be included in various polymer matrices, including both synthetic polymers (polyethylene, polypropylene, polystyrene, etc.) and polymers derived from products of microorganisms' vital activity (polylactic acid, polybutylene succinate, polyhydroxybutyrate, etc.). The purpose of modern research is to search and create bioplastics that have similar properties to traditional plastic and are characterized by the main feature – the ability to biodegradation. Objective. Analysis of the properties of biopolymers, which include ligni n, depending on the methods of its obtaining, polymers structure, and lignin content. Conclusions. Among the types of lignin considered, alkaline lignin, which has a structure similar to natural lignin, is the most promising for further research and is better suited to natural polymers that are capable of biodegradation (polylactic acid, cellulose, polyhydroxy-butyrate, etc.). The addition of lignin to biopolymers slows down the process of decomposition, and when interacting with syn thetic polymers, it gives them the property of minor biodegradation. The best ability to combine with lignin is made up of polymers containing a large number of polar groups, among biopolymers – polyesters polyhydroxybutyrate and polyethylene terephthalate. When using lignin in polymer mixtures, the mechanical properties improve (provided that the lignin is completely mixed with the polymer matrix), the plastics stabilize, and the combustion rate decreases. Among all the considered mixtures of natural polymers and lignin, the best mechanical properties were observed for the mixture of lignin and cellulose.