Fibrous Basalt Role in the Formation of the Segregation Structure of Thermoplastic Elastomers

ABSTRACT The effect of the content of styrene‐butadiene synthetic rubber (SKS) on the tensile yield strength and tensile strength of polymer blends based on random copolymer polypropylene (RPP) was investigated. It was established that at 30 wt. % content of SKS, phase inversion occurs, that is, the dispersed medium of RPP becomes a dispersed phase and, conversely, the dispersed phase of SKS becomes a dispersed medium. This state corresponds to the formation of a region of highly elastic physical state, characteristic of thermoplastic elastomers (TPE). In order to increase the tensile strength of TPE based on RPP + 30 wt. % SKS and RPP + 40 wt. % SKS, little‐studied fibrous basalt (FBS) was used as a mineral filler. The content of FBS in the composition of TPE varied within the range of 5.0–40 wt. %. The results of a study of the influence of FBS concentration on the pattern of changes in the tensile strength, elongation at break, and melt flow index (MFI) of thermoplastic elastomers with 30 and 40 wt. % SKS content in its composition are presented. The use of crosslinking agents such as sulfur and dicumyl peroxide (PD) made it possible to evaluate the possibility of strengthening composite materials with properties characteristic of rubber and MFI values sufficient for their processing by extrusion and injection molding methods. The distribution of fibrous basalt in the polymer matrix was studied using SEM analysis methods. X‐ray phase analysis of the composites made it possible to determine the influence of the content of FBS and vulcanizing agents on their degree of crystallinity. Derivatographic analysis of composites made it possible to evaluate the influence of the FBS content on their thermal‐physical properties. Based on the results of the study of thermomechanical properties of composites based on TPE, the areas of their solid, highly elastic, and viscous flow states, as well as the softening temperature, were determined.