Composite material from polylactic acid and modified fire flax: synthesis and properties

Abstract The paper presents data on the synthesis of a composite material based on polylactic acid and fire flax powder. To improve adhesion between the polymer matrix and the plant filler, the fire flax powder was modified (acylated) with acetic anhydride. The IR Fourier spectroscopy method established the acylation reaction of fire flax powder. After modification with acetic anhydride, an increase in the intensity of the following peaks is observed in the IR Fourier spectrum: at 1747 cm −1 , at 1374 cm −1 and at 1234 cm −1 . Composites based on polylactic acid were manufactured, which contained the modified filler in concentrations of 30%, 40% and 50% by weight. Physicomechanical, electron microscopic and thermal studies of the developed polymer composites are presented. The tensile strength of the studied composites was determined using standard methods according to ISO 527–2:2012. The composite containing 50 wt% modified fire flax powder has the following characteristics: tensile strength—6.53 MPa, relative elongation −13.89%, density −1.247 g cm −3 , maximum permissible operating temperature (sample weight loss up to 5 wt%) −254 °C. This study promotes the development of biodegradable materials by offering polylactide-based composites with the addition of fire flax as an alternative to non-degradable synthetic fillers. The use of agricultural waste not only reduces the cost of production, but also solves the problem of biomass utilization, which opens up prospects for the creation of environmentally friendly composites in various industries. The research methodology also makes it possible to modify natural components, expanding their use and potentially replacing traditional plastics.