Properties of polylactide, obtained from lactic acid in the process of lactic fermentation of lactose in whey post production (waste)

Abstract

Purpose: This publication provides a description of RDC Glokor’s own research into the effectiveness of the lactic fermentation process of lactose, lactic acid concentration and polylactide (PLA) production by ring-opening polymerization obtained from the condensation of two molecules of lactic acid. Furthermore, this publication sets out to determine potential applications of the PLA as a commercial material with a selection of thermal properties. Design/methodology/approach: In the described research works, a lactic fermentation process was used in which lactose is converted to lactic acid with the participation of Lactic Acid Bacteria. Polylactide was obtained indirectly by Ring Opening Polymerization and by direct polymerization, straight from lactic acid, omitting the intermediate stages. Next, the obtained lactide and polylactide were examined by spectroscopic methods (IR, NMR) to determine their purity. Thermal methods (TG, DSC) to determine thermoplastic properties, i.e. softening point, decomposition temperature and glass transition temperature. Findings: Obtained from waste whey, PLA and its copolymers are excellent biodegradable polymers that have the potential to be used in medicine as resorbable surgical strands, biopolymers for implant production, as well as in many industries including for the production of biodegradable bottles and disposable packaging, 3D printer cartridges. Research limitations/implications: The research on lactic acid and lactide polymerization described in this article is still a new issue that requires further research to optimize PLA processes with industry-specific thermoplastic and physicochemical properties. Originality/value: In the basic waste processing of milk, there is a large volume of whey sour, which is ecologically dangerous for waste treating. Due to the high content of lactose (up to 6%) this waste can be used as a raw material in the lactic fermentation process in which lactose is converted to lactic acid with the participation of lactic acid bacteria. Lactic acid can be concentrated and subjected to a dehydration process to lactide, which in the final stage is subjected to the process of ring-opening polymerization in order to produce biodegradable polylactide. The described process of carrying out the lactose contained in PLA whey is an innovative way to obtain a biodegradable usable polymer, which can be used to replace plastics such as polypropylene and polyethylene.