Microstructure and tribological properties of epoxy composites modified by methyl silicone oil-loaded microcapsules and/or reinforced with potassium hexatitanate whiskers

Abstract

Self-lubricating functional microcapsules using melamine-formaldehyde resin encapsulating methyl silicone oil as core materials were synthesized by in situ polymerization method. And they are further adopted as antifriction additive to improve the tribological properties of binary and ternary epoxy (EP) composites, which were fabricated by incorporating microcapsules and the potassium hexatitanate whiskers (PTWs) into the EP matrix. The tribological behaviors of the as-synthesized EP composites have been evaluated by means of a block-on-ring high-speed wear tester. The results demonstrated that the friction coefficient and wear rate of EP /microcapsules binary composites decreased with the increase of microcapsule concentration due to the self-lubricating effect of the core material. For the EP /microcapsules/PTWs ternary composites, not only the mechanical properties and thermal stability PTWs were improved, but also the friction reduction and antiwear effect of the ternary composite are further enhanced due to the synergistic effect of PTWs and microcapsules.

Significantly Affected Lubrication Behavior of Silicone Oil Lubricated Si3N4/Glass Contact after Cleaning with Different Solvents

“…17 Moreover, its strong antiadhesion property prevents direct contact between the friction pairs (a friction system is formed by two objects in contact) and improves friction and wear performance. 18 However, conventional methyl silicone oils perform poorly in boundary lubrication regions, particularly for steel/steel and ceramic/oxide point contact lubrication. 19−21 These combinations have high coefficients of friction (COFs) of approximately 0.33, as measured by the modified Kyropoulos pendulum, in comparison with values between 0.14 and 0.16 for a good petroleum oil, and they permit excessive wear.…”

“…Methyl silicone oil has low volatility, nonflammability, high thermal stability, oxidation stability, a low melting point, and low vapor pressure, among other properties, and is a key research constituent in polymer silicone materials. , As a type of high-performance lubricating oil, methyl silicone oil has high-temperature resistance, enabling its pronounced buffering effect on frictional heat and loading . Moreover, its strong antiadhesion property prevents direct contact between the friction pairs (a friction system is formed by two objects in contact) and improves friction and wear performance . However, conventional methyl silicone oils perform poorly in boundary lubrication regions, particularly for steel/steel and ceramic/oxide point contact lubrication. − These combinations have high coefficients of friction (COFs) of approximately 0.33, as measured by the modified Kyropoulos pendulum, in comparison with values between 0.14 and 0.16 for a good petroleum oil, and they permit excessive wear .…”

“…Petroleum ether, acetone, and absolute ethanol are representative examples of volatile organic small molecules; they are also the most frequently employed organic solvents in friction and wear experiments and are frequently used to clean friction pairs . In recent years, several researchers have studied the adsorption behavior of organic solvents on solid surfaces using macroscopic and microscopic experimental measurements and computational simulation. − Using a precision ellipsometer, Yakovlev et al measured the adsorption and desorption kinetics of ethanol on silicon oxide substrates.…”