Effect of Irradiated Poly(tetrafluoroethylene) Additive on Mechanical and Tribological Properties in Nitrile Rubber Composites

• Published in: ʻUlūm va tiknūlūzhī-i pulīmar Vol. 32; no. 4; pp. 339 - 348
• Main Authors: Jafari, Farid, Hosseini, Seyed Mostaffa, Razzaghi-Kashani, Mehdi, Pourhossaini, Mohammad Reza
• Format: Journal Article
• Language: Arabic; English; Persian
• Published: Tehran Iran Polymer and Petrochemical Institute 01-11-2019
• Subjects: Aging; Carbon black; Coefficient of friction; Energy levels; Friction; Friction reduction; irradiated polytetrafluoroethylene (ptfe); Lubricants; lubrication; Mechanical properties; Modulus of elasticity; Nitrile rubber; nitrile rubber (nbr); Organic chemistry; Polytetrafluoroethylene; Product design; Rubber; Solvents; Strength; Surface energy; Thermal resistance; Thermal stability; Tribology
• ISSN: 1016-3255; 2008-0883
• DOI: 10.22063/JIPST.2019.1681

Hypothesis: Poly(tetrafluoroethylene) (PTFE) powder, due to its low surface energy, reduces the friction of nitrile rubber (NBR) composite. Moreover, due to its chemical stability PTFE improves the resistance of the composite to oil solvents. Due to thermal stability, it can improve thermal resistance of rubber compound. However, the dispersion of PTFE particles in the rubbery matrix is limited and the latter may reduce in mechanical properties. Methods: To create better polymer-filler interactions and improve the dispersion of rubber, the type of irradiated PTFE powder was used. Samples were prepared and evaluated well by melt mixing. Findings: Distribution and dispersion of irradiated PTFE powder particles are suitable for filled samples. The irradiated PTFE powder not only does not endanger the sulfur curing of nitrile rubber compounds reinforced with carbon black, but also improves the Young's modulus and hardness of the samples. Thus, contrary to the references, irradiated PTFE powder, probably by affecting the reduction in the energy level of rubber compounds, could significantly reduce the friction coefficient and improve tribological properties. So that, with a reduction of mechanical strength about 4-5%, for 20 phr loading of the lubricant, under the test conditions the reduction in friction coefficient was 40%. For the aging properties, a small change in the strength-at-break was obtained after solvent conditioning and under its thermal aging a very small reduction in the strength-at-break was obtained for compounds. For a composite containing 20 phr of PTFE, about 7% decrease in strength and strain-at-break was observed after thermal aging and about 8.5% improvement after solvent aging.