Research On Modified Pyrolysis Carbon Black And Its Application In Natural Rubber

Pyrolysis is a commonly used method for recycling waste tires,which can not only realize the harmless treatment of waste tires,but also achieve the goal of waste resource utilization through the recycling of pyrolysis products such as pyrolysis carbon black（CBp）.In this work,a series of characterization techniques such as X-ray photoelectron spectroscopy（XPS）,transmission electron microscopy（TEM）,scanning electron microscopy（SEM）,Raman spectroscopy and laser particle size analysis combined with cross-linking density determination,bound rubber content determination,physical and mechanical properties and mechanical properties testing,were used to determine the optimum ratio of CBp/commercial carbon black（CB）N330 before and after argon（Ar）plasma modification,and the effects of different modification methods（Airflow mill and Ar plasma modification after airflow mill screening）as well as the effect of plasma modification with mixed atmosphere on the properties of CBp and the reinforced natural rubber（NR）composites were investigated.The main research methods and results are as follows:The hybrid filler made from CBp and N330 was used to reinforce the NR composites and the mechanical properties were found to decrease significantly with increasing of the CBp content.The comprehensive properties of the NR composites filled with CBp（MCBp）/N330 hybrid after Ar plasma modification were significantly better than those with the unmodified components.The physical and mechanical properties of the NR composites filled with the hybrid filler with the ratio of CBp 20 phr and N330 30 phr were close to that with 50 phr N330,which was related to the smaller particle size and increased surface activity of MCBp as well as the promoted dispersion of N330 in the NR matrix.The excellent mechanical properties of the MCBp-filled NR composites were related to the strong filler-rubber interaction based on the combined adhesive test and Mooney-Rivlin theory analysis.Based on the optimum combination ratio of CBp and N330,the vulcanization characteristics and mechanical properties of the reinforced NR composites were investigated.The particle size of gCBp（gCBp）modified by airflow mill became smaller and more uniform,and the particle size of gmCBp（gmCBp）decreased further with an increased specific surface area under the action of plasma etching effect.As a result,the vulcanization rate of gmCBp filled rubber increased,the torque differenceΔM_HLincreased,the cross-linking density and the bound rubber content became higher,the tensile strength,tearing strength,resilience and dynamic mechanical properties of the NR composite material were also enhanced.CBp was modified by a mixed atmosphere of 50%each of ammonia（NH₃）and Ar,and compared with the CBp modified by single Ar or NH₃ atmosphere plasma.It was found that the Ar atmosphere have a more pronounced etching effect than the NH₃atmosphere,and more polar groups were introduced into CBp modified by the mixed atmosphere.According to the optimum combination ratio of CBp and N330,the modified CBp and N330 were incorporated into the NR matrix.It was found that the CBp treated with mixed atmosphere had smaller particle size and better dispersion in the rubber matrix.The mechanical properties such as abrasion resistance,300%modulus and tearing strength of the NR composite with CBp modified by mixed atmosphere were better than those of Ar and NH₃ atmosphere alone.