| Ionic liquid modification conditions are mild and designable.Its polarity,hydrophilicity and solubility can be adjusted by changing anions,cations and substituents.Ionic liquid modified carbon black or white carbon black is used to reinforce rubber.It has become a hot spot in the research field of high-performance rubber composites in recent years.In this paper,styrene-butadiene rubber(SBR)is used as the matrix,and carbon black and graphene nanoplatelets modified by ionic liquids containing double bonds that can participate in vulcanization are used to explore non-covalent networks and vulcanized covalent networks based on cation-?conjugation and hydrogen bonding.Synergistically build the rubber-filler interface,the effects of modification process and ionic liquid content on the mechanical properties was investigated,thermal conductivity,compression heat generation,high temperature pressure change,and heat-resistant oxygen aging of styrene butadiene rubber,and the excellent thermal properties of rubber composites through ionic liquid modification and the comprehensive performance of mechanics were explored,for the purpose of further expanding its application field.The main research contents of the thesis include:1)Carbon black(CB)was modified by the ionic liquid 1-allyl-3-methylimidazole chloride salt[AMIm]Cl containing double bonds.The cationic imidazole ring on[AMIm]Cl could be combined with the?electron cloud on the surface of CB produced cation-?interactions,and the anion Cl-could also form hydrogen bond interactions with a small amount of oxygen-containing functional groups on the surface of CB,which could reduce the surface energy of CB and improve the dispersion in the SBR matrix;In addition,the cationic imidazole ring in[AMIm]Cl could also form a cation-?conjugation with the benzene ring on SBR,and the double bond could participate in the vulcanization and crosslinking of the rubber macromolecular chain to enhance the interface between the filler and the SBR matrix binding force.The research adopts three processes of mixing method,spray method and solution method to modify CB.The reults showed that the solution method could effectively adsorb[AMIm]Cl on the surface of CB and improve the interaction between CB and rubber.The tensile strength of the contrast mixing method and spray method was increased from 17.0 MPa,18.9 MPa to 19.7 MPa;150?×24h high temperature compression set rate reduced from 42.7%,41.3%to 38.1%;compression fatigue temperature rise of rubber center decreased from 56.9?,53.2?to 48.4?;The retention rates of tensile strength and elongation at break after heat aging at 100?×48h were 83.7%and 74.4%,which are improved to different degrees compared with the mixing method and the spray method.2)Based on the solution modification process,the effect of different[AMIm]Cl content modified CB on the performance of SBR was explored.The results showed that with the increase in the amount of[AMIm]Cl,the vulcanization rate of SBR gradually increased,tc90decreased from 12.2 min to 4.5 min;the filler network of the rubber compound was weakened,and the dispersion in SBR was improved.When the amount of ionic liquid added was 0.5 phr,the cross-linking density was the largest,and the overall performance of the CB/SBR composite was the best.Besides,the tensile strength and elongation at break increased by 26.5%and27.1%;The compression set rate at 150?×24h was reduced from 46.5%to 38.1%;compared with unmodified carbon black,the modification of[AMIm]Cl reduced the interface thermal resistance,and the thermal conductivity of CB/SBR increased by 14.1%;the fatigue temperature rise of the rubber center was reduced from 58.8?to 48.4?;the tensile strength was maintained after thermal aging The rate of elongation at break increased from 77.1%to83.7%,and the retention rate of elongation at break increased from 68.0%to 74.4%;the analysis of dynamic mechanical properties showed that the tan?at 0°C increased by 8.5%,that was,the anti-slip ability of the composite material had improved,and the tan?at 60°C decreased by10.3%,indicated a decrease in rolling resistance.3)CB and graphene nanoplatelets(GNP)were modified by[AMIm]Cl.on the one hand,the cationic imidazole ring on[AMIm]Cl could produce cation-?interaction with GNP,reduced its surface energy;in addition,CB played the role of peeling towards GNP,effectively reduced the size and number of layers of GNP agglomeration,and a filler network could be formed between CB and GNP,which effectively strengthened the SBR composite material.The SEM picture shows that the agglomerate size of modified GNP in SBR was reduced,and the compatibility with the matrix was better.When the filling amount of GNP reached 4 phr,compared with unmodified GNP,the tensile strength of the rubber increased from 18.2 MPa to22.9 MPa,the elongation at break increased from 737.9%to 923.5%,and the compression set rate increased from 37.3.%to 31.2%;the filler network could build a heat conduction path in the rubber,and the addition of[AMIm]Cl could also effectively reduce the interface thermal resistance between GNP and the rubber matrix.The vertical thermal conductivity of the composite material increased from 0.25 W·m-1·K-1to 0.48 W·m-1·K-1,and the horizontal thermal conductivity increased from 0.27 W·m-1·K-1 to 0.96 W·m-1·K-1;the compression fatigue temperature rise of the rubber center was reduced from 66.2°C to 52.8°C;the tensile strength retention rate after 100°C×48h heat aging increased from 79.1%to 86.1%,and the retention rate of elongation at break increased from 71.8%to 78.6%.The rubber product had the advantages of good elasticity,high thermal conductivity,low heat generation and pressure change,etc.,and could not only be applied in the field of special tires,but also has certain application prospects in integrated circuit thermal interface materials. |
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