The Preparation Mechanism And Experimental Study Of Modified Pyrolysis Carbon Black/natural Rubber Composites

Pyrolysis carbon black is the main product of waste tire pyrolysis,and its main components are carbon black,white carbon black,rubber additives and residual carbon in the process of tire pyrolysis.In the waste tire pyrolysis products,pyrolysis carbon black accounted for about 30%,if it can be recycled,it can bring huge economic benefits.Pyrolysis carbon black has the disadvantages of high ash content,large particle size,reduced surface activity and damaged structure,and the combined surface active point and the surface microporous structure of deposited carbon make it more difficult to use cracked carbon black for rubber.It has become an urgent problem for the industry to study the modification method and reinforcing mechanism of pyrolysis carbon black and develop the mixing process suitable for it,so as to improve the resource value and economy of cracked carbon black.In view of the problems such as the difficulty of dispersing filler and poor performance of rubber material in the rubber composite for reuse of pyrolysis carbon black,the modification method of pyrolysis carbon black and the preparation mechanism and experiment of modified pyrolysis carbon black/natural rubber composite were studied in this paper.The process technology of pyrolysis carbon black filling natural rubber material suitable for tread rubber formulation was developed,and the modified pyrolysis carbon black compound was prepared,and the properties of the modified pyrolysis carbon black compound were compared with that of N234 dry compound.The main work completed is as follows:(1)The reinforcing mechanism of pyrolysis carbon black in rubber was studied.Taking the basic properties of pyrolysis carbon black as the focus,the action mode of pyrolysis carbon black in rubber reinforcement was explored.Based on this,the reinforcing effect of pyrolysis carbon black on natural rubber of all-steel radial tire and semi-steel radial tire was further analyzed.It was found that the composite material of pyrolysis carbon black rubber of semi-steel radial tire had better comprehensive properties.Therefore,this paper selects semi-steel tire pyrolysis carbon black as the subsequent modification material.(2)The modification mechanism of pyrolysis carbon black and the preparation mechanism of modified pyrolysis carbon black/natural rubber composite were investigated.The surface structure and properties of pyrolysis carbon black were modified by oxidizer and low temperature plasma,respectively,and the influence of modified pyrolysis carbon black on the reinforcing property of natural rubber was analyzed.It can be seen from the experimental data that the oxidant modified cracking carbon black can effectively improve the tensile strength and wear resistance of rubber composites,and reduce the rolling resistance;The hardness,tensile strength and wear resistance of carbon black rubber composites modified by low temperature plasma were improved significantly,and the wet slip resistance was better.(3)A microflocculation technology(DMLI process)was developed to increase the concentration of carbon black dispersive system from low to high to dynamic equilibrium in wet mixing,and the flocculation mechanism of pyrolysis carbon black was studied.Compared with the traditional wet flocculation process,this process can effectively improve the dispersion degree of pyrolysis carbon black in rubber and enhance the comprehensive properties of rubber composites.Experimental results show that this process can effectively enhance the reinforcing effect of pyrolysis carbon black on rubber.(4)The experimental study on preparation of high performance composite materials by modified pyrolysis carbon black was carried out.A new technology for preparation of high performance composite materials by modified pyrolysis carbon black and different wet mixing processes was developed.The hardness,tensile strength,wear resistance and other properties of cracking carbon black rubber with this technology are significantly improved compared with those of unmodified cracking carbon black rubber,and it has lower rolling resistance and better wet slip resistance.The performance of the cracking carbon black rubber(CBp-c)prepared by this technology is equal to that of the N234 dry carbon black rubber(N234-b),which is the best modified process route.Although the performance of the modified cracking carbon black rubber is not better than that of N234 dry carbon black rubber under the same technological conditions,the performance of the modified cracking carbon black rubber is better than that of N234 dry carbon black rubber.In conclusion,high performance rubber composites can be prepared by using the modified scheme designed in this paper and DMLI process,which verifies the feasibility of cracking carbon black as a substitute for industrial carbon black in tread rubber formulation,and provides certain experimental data support for the practical application of cracking carbon black.