Study On Improving Performance And Application Of Tire Pyrolysis Carbon Black

Waste tires,which is known as "black pollution",may cause severe environmental problems.Because of the high resource recovery rate and low secondary pollution,Pyrolysis is recognized as the most promising way to recycle waste tires.Pyrolysis carbon black(CBp)is the main solid-phase product after high-temperature pyrolysis of waste tires.As the reinforcing effect of CBp on rubber is rather poor,CBp is a low valueadded product,which can only be used with commercial carbon black in low-end rubber products with very low content.In this project,the microscopic structure and characteristics of CBp are systematically characterized by modern analytical apparatuses,such as of X-ray photoelectron spectrometer(XPS),elemental energy spectrometer(EDS),transmission electron microscope(TEM),Malvern laser particle size meter,and thermal gravimetric analyzer(TGA).the CBp is modified with physical and chemical methods and added into different rubber recipe to study its reinforcement effect and reinforcement mechanism.According to the performance requirements corresponding to the different parts of the tire,through formula adjustment and modification of CBp,the replacement amount of CBp reaches 50% of carbon black amount in the tire tread and sidewall respectively,so as to achieve the high-value utilization of CBp and promote the development and application of waste tire pyrolysis technology.The main research contents of this project are as follows:The basic properties and microstructure of waste tire CBp are systematically characterized and analyzed.The results showed that the CBp contained a large amount of inorganic ash,as high as 17%,which was much higher than the ash content of commercial carbon black-0.5%;the surface of the CBp was rich in oxygen-containing groups-in the form of carboxyl groups,hydroxyl groups and esters;The particle size test showed that the particle size of CBp was large and the particle size distribution was wide,with a average particle size Dx(50)of 9.6?m,and a bimodal normal distribution curve;the tensile strength of the natural rubber filled with CBp after modification exceeds that of the commercial carbon black N330.The CBp was added into the passenger tire tread compound,and the effect of CBp on the properties of the tread compound was compared by changing the ratio of CBp and commercial carbon black N375.The results showed that the mechanical properties of the rubber tread compound decreased with the increase of the amount of CBp,and the properties of the compound filled with pure CBp was the worst.Compared with the N375 filled compound,the tensile strength decreases by 30%,and the modulus at 300%decreases by 26%,the wear resistance decreased by 50%.After grinded in an air jet mill with a frequency of 40 Hz and chemical modified by maleic anhydride-ethylene glycoldicyclopentadiene copolymer with the amount of 2% of CBp,the modified CBp and8.5phr carbon black N234 was used to jointly replace the 50% of N375 in the styrenebutadiene rubber tread compound,the properties are close to the original formula.The addition of 2 phr anti-wet slip resin FN-609 improved the tear performance and wet-slip resistance of the tread compound,reduced the rolling resistance of tires without affecting the tensile properties.Therefore,the modified CBp could replace 50% of carbon black N375 in the passenger car tread compound.CBp was used to replace 50% of N375 in the formulation of natural rubber/butadiene rubber sidewall compound.The results showed that the reinforcing effect of unmodified CBp was much lower than that of N375,the tensile strength is reduced by nearly 30%,and the tear strength is reduced by 20%,and the specimen were cracked after only 300,000 flexural fatigue tests.50% of N375 was replaced by physically modified pyrolysis carbon black,and the physical and mechanical properties of the sidewall rubber were slightly improved compared with unmodified CBp.The particle size of cracked carbon black is reduced from a dozen microns to about 5 microns after grinded in a air-jet mill,and the physical modification effect is not obvious.The CBp modified with physical and chemical methods and 9phr carbon black N234 jointly replaced 50% of carbon black N375 in sidewall compound,the tensile strength of the sidewall compound increases by 20%,the modulus at 300% increased by 30%,and the tear strength is also increased.The overall performance of the sidewall compound is basically the same as that of the pure N375 compound.so a certain proportion of carbon black N375 can be replaced in the natural rubber/butadiene rubber sidewall compound,the cost was reduced,and the economic benefit was obvious.