EVALUATION OF THE INFLUENCE OF WOLLASTONITE FROM TECHNOGENIC WASTE ON THE PROPERTIES OF A POLYMER COMPOSITE BASED ON POLYTETRAFLUOROETHYLENE

The paper presents the results of a study of synthetic wollastonite from boric acid production waste (borogypsum) on the physical, mechanical and tribological properties of polymer composite materials based on polytetrafluoroethylene. Wollastonite was synthesized from borogypsum by its hydrothermal treatment in alkaline medium and subsequent calcination of the obtained precipitate at 900-1000 °C for 1 h. The product with a specific surface area of 1.4 m2/g and a density of 3.06 g/cm3 obtained under the above regimes is characterized by the presence of wollastonite of triclinic modification and the presence of CaSO4 anhydrite. The wollastonite particles are needle-shaped with a needle diameter of ~100 nm. Needle-shaped wollastonite particles are shown to be interconnected and form conglomerates and agglomerates ranging in size from 10 to 70 μm. Particle agglomerates are characterized by a wide unimodal distribution of pores with a maximum of 3.78 nm with conical and slit-like shapes. It was found that the use of wollastonite results in increased wear resistance of polymer composites based on PTFE. Composites filled with 10 and 20 wt.% of wollastonite are characterized by a 700-fold decrease in the rate of mass wear relative to the initial polymer. Physical and mechanical studies of PCM show that the introduction of wollastonite increases compressive strength and modulus of elasticity. However, a decrease in strain-strength parameters was observed. Scanning electron microscopy shows the formation of secondary structures on friction surfaces, which plays a role in the adaptation of the composite to wear. The method of IR spectroscopy of friction surfaces registered the appearance of new peaks corresponding to hydroxyl, carbonyl and carboxyl compounds. This indicates a certain contribution of wollastonite particles to tribochemical processes. For citation: Danilova S.N., Tarasova P.N., Yarusova S.B., Kapitonova Yu.V., Osipova V.N., Okhlopkova A.A., Gordienko P.S. Evaluation of the influence of wollastonite from technogenic waste on the properties of a polymer composite based on polytetrafluoroethylene. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 12. P. 102-112. DOI: 10.6060/ivkkt.20246712.7064.