Preparation Of Nano-silica Loaded Accelerator And Its Application In Solution Styrene-butadiene Rubber/Butadiene Rubber Composites

Rubber is the only highly elastic material among three polymeric materials and cannot be replaced by others due to its importantly strategic position.As an important raw material of tires,rubber should possess excellent mechanical properties,good wear resistance,wet skid resistance and low rolling resistance.Nano-silica as an important reinforcing filler in rubber,has some disadvantages,such as high polarity,poor dispersion and easy agglomeration.How to conquer the above-mentioned problems is of significant importance to both the academic research and practical application.One effective way is the surface modification on nano-silica,which can not only overcome these drawbacks but also endow excellent mechanical properties and dynamic mechanical properties to rubber matrix.In the present research,we apply liquid-phase in-situ surface modification method to prepare surface-functionalized nano-silica,in which N-cyclohexyl-2-benzothiazole sulfonamide(rubber vulcanization accelerator CZ)and diphenyl guanidine(rubber vulcanization accelerator D)are used as surface-modifiers,and nano-SiO2 as the carrier.Through varying the loading amount of modifiers,we obtain two types of rubber additives silica-loaded rubber vulcanization accelerator DNS-CZ and DNS-D and evaluate their applications on SSBR/BR.A series of as-prepared DNS-CZ samples with different CZ loadings are applied to SSBR/BR rubber system.On the premise of safe processing performance,the optimum cure time of SSBR/BR/DNS-CZ composite tends to decline as the CZ loading increases,and the vulcanization rate tends to rise,accordingly.It indicates that the interaction of filler-rubber tends to enhance therewith.The chemical bonds between CZ and nano-silica effectively reduce the polarity of the nano-silica and enhance its dispersion in the rubber matrix,thereby attenuating the Payne effects of mixing rubber and vulcanized rubber.The mechanical properties of the vulcanized rubber have been improved with the increase of the loading amount of the accelerator CZ.More analyses from wear and rolling resistance reveal that DNS-CZ can offer better balance between one another.Particularly,when the loading amount of the CZ is set as 81.10 mmol/kg,the resultant SSBR/BR/DNS-CZ composite exhibits the best rolling resistance and wear resistance,exhibiting synergistic effects of reinforcement from nano-silica and processing ability from vulcanization accelerator CZ.This basically fulfill our anticipation to prepare multi-functional rubber additives.A series of as-prepared DNS-D samples with different D loadings are applied to SSBR/BR rubber system.The effect of the vulcanization accelerator D,the vulcanization accelerator D modified byγ-(2,3-epoxypropoxy)propytrimethoxysilane and silica-loaded rubber vulcanization accelerator DNS-D on SSBR/BR nanocomposites such as rheological behavior,cure characteristics,mechanical properties,abrasion resistance and dynamic mechanical properties are studied.The mechanism and the cause are analyzed.Moreover,compared with Z-1165MP,which is commonly used in green tire reinforcing filler,the addition of DNS-D can apparently improve the mechanical properties of SSBR/BR.The optimum cure time of SSBR/BR/DNS-D composite tends to decline as the D loading increases,improving vulcanization rate and enhancing anti-aging performance of SSBR/BR/DNS-D composites,accordingly.Particularly,when the loading amount of the D is set as 135.25 mmol/kg,the DNS-D has the best dispersion in the rubber matrix,and the resultant SSBR/BR/DNS-D composite exhibits the shorter optimum cure time,the higher vulcanization rate,the better mechanical properties and the lower Akron abrasion compared with the counterparts filled with unloaded DNS.The DNS-D-3 makes an important contribution to the wet skid resistance and low rolling resistance of SSBR/BR/DNS-D nanocomposites.The nano-silica-loaded rubber vulcanization accelerator D is given both functional characteristics of the reinforcing agent nano-silica and vulcanization accelerator D at the same time,and showing promising application for green tire tread.