Application Of Pyrolysis Carbon Black In Natural Rubber Composites

In this work,the effects of pyrolysis temperature(450?,500?,550?and 600?)and plasma modification conditions on the properties of pyrolytic carbon black(CBp)and its filled vulcanized natural rubber(NR)were studied by means of thermogravimetric analyzer(TGA),laser confocal Raman spectrometer(Raman),X-ray photoelectron spectroscopy(XPS),Laser granulometer,Super resolution microporous physical adsorption,transmission electron microscope(TEM),scanning electron microscope and energy spectrometer(SEM-EDS),combining with the determination of the crosslink density and the mechanical properties tests both in dynamic and static state.The experimental results showed that the more filled oil and residual rubber molecular chains remained on the surface of CBp pyrolyzed at 450?(CBp450),which results in the lowest physical and mechanical properties of CBp450 filled NR vulcanized rubber(NR/CBp450).There are still a small amount of rubber hydrocarbon on the surface of CBp500 and CBp550,and the tensile strength and tear strength of the vulcanized rubber filled with CBp500 and CBp550 increase considerably.However,there are only small groups remained on the surface of CBp600 and the average particle size is higher due to the condensation phenomenon between particles,which further improves the hardness,stress at definite elongation and dynamic mechanical properties of NR/CBp600.The CBp obtained from semi-steel radial tire was modified by plasma with different atmospheres(NH₃,Ar,He and H₂O).It was found that polar groups were introduced on the surface of the modified CBp,the particle size was reduced,and the specific surface area and surface roughness were increased.The crosslinking density of NR vulcanized rubber filled with plasma modified CBp increased,and the modulus and stress at definite elongation increased significantly.Among them,CBp modified by Ar plasma filled NR vulcanizates have the highest cross-linking density,stress at definite elongation and storage modulus.The CBp obtained from all-steel radial tire was modified by plasma with different discharge power(100W,200W,300W and 400W).It was found that the particle size and specific surface area of CBp100 and CBp200 increase greatly.Compared with the CBp modified at 300W,the content of C=C on the surface of CBp400 was improve dramatically,while the particle size and specific surface area had little change.The stress at 300%and tensile strength of NR/CBp0 vulcanized rubber are weak.The static mechanical properties of NR/CBp100 were improved,but the dynamic mechanical properties were decreased.The cross linking density of NR/CBp200 is higher,the stress at definite elongation increases significantly,and the storage modulus increases slightly.The physical and mechanical properties of NR/CBp300 and NR/CBp400 are poor.Based on the analysis of the experimental results,a basic model of the interaction between CBp modified by plasma and NR matrix was proposed:It has been introduced of active groups on the surface for CBp modified by plasma,which enhanced the degree of particle network;However,the residual rubber hydrocarbons on the surface of CBp were etched intensely due to the excessive plasma action,and the active sites were destroyed,which will eventually weaken the interaction between CBp and rubber matrix.