The fluorine rubber nanocomposites were prepared by using the silane‐coupling agents treated silica and diatomite, in which 3‐amino propyltriethoxysilane (KH550), 3‐mercapto‐propyl trimethoxysilane (KH590), and bis‐(γ‐triethoxysilylpropyl)‐tetrasulfide (Si69) of the coupling agent were used as the filler modifiers to increase the compatibility between filler and fluorine rubber. The structure and morphology of the composites were investigated by Fourier transform infrared spectroscopy and scanning electron microscopy. The Tg and thermal stability of the composites were investigated by dynamic mechanical analysis and thermogravimetric analysis. The results showed that the best coupling agent was KH550 and 2 phr (parts per hundred rubber). The KH550‐modified compound filler was crosslinked with fluorine rubber, and the compatibility between filler and fluorine rubber was improved and further confirmed to improve the thermal properties of fluorine rubber with the KH550‐modified filler. J. VINYL ADDIT. TECHNOL., 26:55–61, 2020. © 2019 Society of Plastics Engineers

To find the most suitable filler system for fluorine rubber, a simple and green method to introduce a limited content of silanol groups on the surfaces of silica and fluorine rubber was studied. Fluorine rubber nano-composites were prepared by using nano-silica, diatomite and carbon black as the reinforcement and filler and the coupling agents KH550, KH590 or Si69 as the compatibilizer between the filler and fluorine rubber. The structure and morphology of the composites were investigated by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The results showed that the most suitable filler system for fluorine rubber was the diatomite and silica compound (8:12 mass ratio), the best coupling agent was KH550 at 2 parts per hundred rubber (phr). The modified compound filler was silanized with the coupling agent KH550 for fluorine rubber by FTIR analysis, the compatibility between the filler and fluorine rubber was improved by SEM analysis and further confirmed by thermogravimetric analysis to improve the thermal properties of fluorine rubber with the filler compound system.

Diatomite is a kind of biomass sedimentary rock, which is widely used in chemical engineering, petroleum, building materials, biomedical medicine, health care and environmental protection, and other fields due to its characteristics of lightweight, large specific surface area, super adsorption, noise and abrasion resistance, thermal properties, and corrosion resistance. The diatomite is similar to silica in the composition structure and can be used as a substitute for silica to reinforce the rubber materials. In this work, the diatomite was modified with different modifiers to fill the rubbers such as natural rubber, styrene–butadiene rubber, butadiene rubber, nitrile butadiene rubber, ethylene propylene diene monomer (EPDM), chloroprene rubber, methyl vinyl silicone rubber, fluorine rubber (FKM), and acrylic rubber (ACM). The results showed that the obtained formula is the most suitable diatomite modifier for various rubber is Si69, and its amount is 2.5 parts per hundred rubber (phr), and the diatomite content is 20 phr. The diatomite is more suitable for FKM, ACM, and EPDM. The diatomite has better reinforced effect on FKM, EPDM, and ACM than silica, and FKM is the most prominent. The modified diatomite can be uniformly dispersed in the matrix of FKM, EPDM, and ACM; the compatibility is good; and the mechanical properties are excellent. It was demonstrated that the modified diatomite with green environmental protection and low cost can replace silica to reinforce and fill the three kinds of rubbers.