The Effects Of Ionic Liquids On The Properties Of NR Compounds Reinforced By Silica

By this time,it has been more than a century since the rubber industry used silica as a reinforcing filler.In today's society,people are paying more and more attention to non-renewable resources and their awareness of environmental protection is getting stronger and stronger.The concept of"green tires"is also quite consistent with the concept of energy saving and emission reduction in the new era.As reinforcing filler,Silica has many advantages,but the modification technology of silica need further improvement.In this paper,NR is used as the rubber matrix,a series of performances of ionic liquid[Bmim]BF₄?Hereinafter BMI?in modifying silica were investigated.The effects of different fractions of ionic liquid BMI on the properties of NR compounds were explored by means of internal mixer mixing and compared with Si69modified silica filled NR.The Mooney viscosity of the compounds,the dispersion of silica,the vulcanization curve,the mechanical properties of the vulcanizates,the wear properties,and the crosslinking density were analyzed.As the phr of BMI increases,the scorch time of the compound shortens and the vulcanization speed increases substantially.The RPA strain scan results showed that different phr of Si69 had better dispersibility of silica than BMI.The SEM images showed that different levels of agglomeration were observed in the silica with BMI added.BMI increases the crosslink density of vulcanized samples,increases tensile strength and tear strength,and improves wear resistance.BMI was used to modify silica by wet process,and then BMI wet modified silica filled NR and BMI dry modified silica filled NR were prepared by different mixing processes.Examine the effect of the wet and dry modification and mixing process on the performance of NR.It was found that the BMI was successfully loaded on silica from infrared spectrogram analysis;compared with the Si69-modified silica,the scorch time and the vulcanization time of the BMI-modified silica rubber were relatively Short,tensile strength and tear strength have been greatly improved,wear resistance is close,and lower heat build-up.After comparing the mixing process,the comprehensive performance of the vulcanizate used in the mixing process of the internal mixer is better,while the dry and the wet modification process of the silica have little effect on the properties of the compounds.The effect of BMI on the properties of NR compounds filled with silica and carbon black were investigated.The processing safety of compounds added BMI become better with the percentage of carbon black;BMI can promote the curing rate of carbon black filled vulcanizate.Without the modifier,carbon black phr increase made the properties of the compounds obviously improved;The delay vulcanization of silica was weakened by BMI modification,A lot of properties can be achieved or even more than carbon black filled rubber;Both BMI and Si69 have more significant influence on silica filled rubber,but limited on the properties of carbon black filled rubber;A good performance rubber can be obtained by filling NR with small percentage silica,large percentage carbon black and a little BMI.The mechanism of BMI promoting NR vulcanization is explored by differential scanning calorimeter,rotors vulcanizer and Mooney viscometer.The addition of BMI makes the scorching time and curing time of the three kinds of NR compounds?containing active agent and accelerator,only accelerator,only active agent?obviously shorten,and increase the tensile strength and the tear strength.The results of DSC test showed that the initial temperature of the crosslinking reaction of the compounds was reduced by BMI;BMI has the most obvious effect on the compounds with active agent and accelerator.BMI are effective for thiazole,sulfonamide and thiolam accelerators.The crystallization phenomenon of BMI was observed in NR vulcanizate without active agent,it indicates that BMI has aggregation tendency in NR vulcanizate.The zinc salt of the accelerator undergoes a complex coordination reaction with the imidazolium cation in the BMI to produce accelerator zinc salt complex containing BMI,thus promote the vulcanization reaction.