The results of a study of the influence of the basalt fiber content on the thermal deformation properties of composite materials based on polypropylene random copolymer are analyzed. The filler content was varied in the range 1.0 – 30.0% wt. It is shown that with an increase in the content of basalt fiber (BF), an uneven change in the temperature of the first-order phase transition is observed. The loading of 1.0 wt% BF contributes to a significant increase in the softening temperature of the composites, which is interpreted as a structure-forming effect and a decrease in the defectiveness of the crystalline phase. The appearance of some bends in the thermomechanical curve of composites with 20 and 30 wt% BF content was established, which is explained by the appearance of multi-level crystalline formations in highly filled samples. The effect of BF content on the temperature range of melting and thermal destruction was studied using the method of derivatographic analysis. It has been shown that with increasing filler content, an expansion of the melting temperature range from 28 to 57°C is observed. The possibility of obtaining sparsely networked and densely networked cross-linked structures is considered using the example of polypropylene random copolymer sample with 5.0 wt% BF content. Sulfur and dicumyl peroxide were used as a crosslinking agent. The influence of the content of cross-linking agents on the pattern of changes in thermal deformation curves has been established. The fundamental possibility of the appearance of a region of highly elastic state in the composite is shown at a sulfur content of 3.0-5.0 wt% and dicumyl peroxide in the range of 0.25-0.50 wt%. At a content of dicumyl peroxide of 1.0-2.0 wt%, the composite vitrifies and loses the ability to melt flow.

doi.org/10.32737/0005-2531-2025-3-63-70