Study On The Modification Of Terminal Groups Of Liquid Fluoropolymer And Its Application In Rubber

"Green tires",mainly based on SSBR,are committed to the dispersion of nanosilica in SSBR matrix,achieving the balance of high wet skid resistance and low rolling resistance.Liquid rubber,as a new surface modifier of nanosilica,has been gradually paid attention.Liquid fluoropolymer not only inherits the advantages of solid fluoropolymer,but also has good fluidity and shows good processing performance.Therefore,it is of great significance to develop liquid fluoropolymer as a processing modifier for surface modification of nanosilica.(1)The project modified the active terminal groups of the liquid fluoropolymer with silane coupling agent to prepare siloxyl-terminated liquid fluoropolymer.The surface hydroxyl groups of nanosilica were modified with different ratios of STLF and TESPT through high-temperature in-situ reaction.It was found that the filler of SSBR with 2phr STLF and 4phr TESPT had better distribution.Through the modification,the static and dynamic mechanical properties of the modified could reach a better state than those of the others,achieving the balance of high wet skid resistance and low rolling resistance.What is more,the thermal stability of SSBR composites was also been enhanced to a certain extent.(2)The terminal-group modified and unmodified liquid fluoropolymer were compared.It was found that the pre-modification of the terminal-group improved the compatibility with the rubber matrix,improving the dispersion of nanosilica.Pre-modification also could reduce the negative impact of the active end groups of unmodified liquid fluoropolymer on the thermal properties of the rubber matrix.(3)Finally,we explore the influence of the rotor speed of the Haake mixer on the high-temperature in-situ reaction.It was found that increasing the rotor speed could allow the surface hydroxyl groups of the nanosilica to fully react with the siloxyl-terminated liquid fluoropolymer and TESPT,improving the dispersion of nanosilica.What is more,increasing the rotor speed could improve the static and dynamic mechanical properties of composites and thermal properties.