RESEARCH OF HYBRID ENVIRONMENTALLY SAFE BIODEGRADABLE COMPOSITES BASED ON POLYLACTIDE, COFFEE GROUNDS AND HUMІС SUBSTANCES

Abstract

In the article, a study was conducted with the aim of establishing the characteristics of hybrid ecologically safe biodegradable filled composites based on polylactide, coffee grounds and humic substances. Hybrid ecologically safe biodegradable filled composites were obtained by extruding pre-prepared polylactide, coffee grounds and humic substances in a single-screw laboratory extruder at a temperature of 170–200 °C and a roll rotation speed of 30–100 rpm. When obtaining hybrid ecologically safe biodegradable filled composites, lactic acid polylactide polymer of the extrusion brand Terramac TP-4000 was used. Waste coffee grounds collected in 8 different coffee shops in the city of Kharkiv and dried to a moisture content of 0,5 % were used. Humic substances were used as hybrid modifiers. It was established that the hybrid modification of highly filled polylactide-coffee grounds systems with humic derivatives of lignite in the form of humic substances allows to significantly increase the main strength characteristics. It was established that there is a 2.5-fold increase in impact toughness and destructive bending stress during hybrid modification of environmentally safe biodegradable filled composites based on polylactide, coffee grounds, and humic substances, while the optimum from the point of view of strength characteristics is the content of coffee grounds at the level of 50 % by weight and 0.5 % wt. humic substances. For such hybrid ecologically safe biodegradable filled composites based on polylactide, coffee grounds and humic substances, the melting flow rate is characteristic at the level of 3.1 g/10 min. and the processing temperature range is 182–188 °С. It was also established that hybrid modification in the framework of obtaining hybrid ecologically safe biodegradable filled composites based on polylactide, coffee grounds and humic substances with a content of 0.5 % by mass. different types of humic substances in them and different contents of coffee grounds allow them to preserve biodegradation properties for 6 months.