Effect Of Ionic Liquid On Properties Of Natural Rubber Filled With Silica

The influences of ionic liquids on vulcanization of rubber,dispersion of silica and interfacial interaction between silica and natural rubber were studied.The effects of content of ionic liquids,the length of alkyl chain and anionic types were explored.The effects of silica modified by ionic liquid,coupling agent or the combination of ionic liquid and coupling agent on the reinforcement of NR were compared.It was found that imidazole ionic liquids can activate the vulcanization reaction as stearic acid,and greatly improve the vulcanization rate and crosslinking density according to the study on vulcanization mechanism and comparison of curing characteristics.There is an ionic dipole interaction between ionic liquid and silica,the variation of Payne effect and the calculation results of degree of filler dispersion showed that the ionic liquid can improve the dispersion of silica in natural rubber.The results showed that ionic liquids can improve the interfacial compatibility between rubber and filler through the determination of bound rubber content and the observation of tensile fracture surface.And with the increase of dosage from 0phr to 3phr,the longer of the length of alkyl chain from ethyl to hexyl,the improvement effect was more and more obvious.And the effect of bromate was better than that of tetrafluoroborate when they were based on 1-butyl-3-methyl imidazole cation.Under the combination of three functions of ionic liquid,NR got a maximum increase of tensile strength and tear strength respectively by 114% and 201%,a maximum reduction of DIN wear loss by 50% and a smoother surface after abrasion.The mechanical properties of vulcanizates were best when the dosage was 3phr.Coupling agent is the most commonly used surface modifier of silica,which can greatly weaken the surface polarity of silica.When used with ionic liquid,it can further enhance the dispersion of silica in natural rubber and the interfacial interaction between silica and rubber,thus obtaining natural rubber composites with better comprehensive properties.