Preparation Of Pyrolysis Carbon Black/Cellulose Hybrid Materials And Their Application In Natural Rubber

Pyrolysis carbon black(CBp)accounts for more than 35%of the pyrolysis products of waste tires.Its poor reinforcing ability and low added value seriously limit the wide application of pyrolysis technology in solving the problem of“The black pollution”of waste tires.The traditional modification methods of pyrolysis carbon black,such as ash removal treatment,surface chemical modification,plasma treatment,etc.,generally have the problems of large amount of waste liquid,serious environmental pollution and high energy consumption.In this paper,a new method for CBp modification was developed.CBp and microfibrillated cellulose(MFC)were ball milled together to obtain the hybrid material(CNCH)aqueous dispersion of CBp and nanocellulose.Then,CNCH powder was prepared by spray drying of CNCH aqueous dispersion and compounded with natural rubber(NR).The reinforcing performance of CNCH on NR was investigated,and the reinforcing ability of CNCH on NR was systematically analyzed with CBp and pyrolysis carbon black(MCBp)after ball milling.The reinforcing mechanism of pyrolysis carbon black hybrid modified NR was discussed in detail.In order to further improve the performance of CNCH reinforced NR,CNCH was pretreated with different silane coupling agents to partially replace commercial carbon black(CB).The properties of the blend and vulcanizate prepared before and after CNCH silane treatment were investigated.This work is expected to provide theoretical basis and technical guidance for the application of pyrolysis carbon black in tires,accelerate the industrialization of waste tire pyrolysis technology and solve the problem of“The black pollution”.The main research contents of this paper are as follows:(1)CBp and microfibrillated cellulose(MFC)were ball milled together to realize the hybridization of CBp and cellulose to improve the quality and reinforcement ability of CBp.A series of tests showed that the refinement of CBp,the nanocrystallization of MFC and the hybridization of the two were realized simultaneously under ball milling.The obtained CBp/nanocellulose hybrid material has a bead-like morphology,and small CBp particles are tightly attached to cellulose nanofibers through hydrophobic and hydrogen bonding interactions.(2)The vulcanization characteristics and mechanical properties of CNCH prepared by different mass ratios of CBp/MFC and CNCH and natural rubber composites with different addition amounts were systematically studied.The results showed that when the mass ratio of CBp and MFC was 4:1 and the addition amount was 30 phr,the scorch time of the blend was the longest,and the vulcanization rate was faster,and the mechanical properties of the vulcanizate were the best.The properties of natural rubber reinforced by CNCH,CBp and ball milled cracked carbon black(MCBp)were compared.The results showed that the reinforcing ability of CNCH was much higher than that of CBp and MCBp.Moreover,CNCH reinforced NR has lower hysteresis and higher wear resistance than CBp or MCBp.(3)The silane coupling agents Si₆₉ and KH550 were used to pretreat CNCH(denoted as CNCH-Si,CNCH-K),and they were applied to NR instead of 20phr commercial carbon black CB.The vulcanization characteristics,mechanical properties,SEM characterization,compression heat generation,wear and dynamic mechanical tests of the compound were tested.The results showed that when the commercial carbon black N330 was replaced by CNCH-Si after Si₆₉ treatment,the T₉₀ of the vulcanizate remained basically unchanged,the scorch safety of the compound was improved,and the mechanical properties of the composite remained unchanged.Compared with unmodified CNCH,the volume loss of natural rubber vulcanizates filled with CNCH-Si and CNCH-K decreased by 14%and 16%,and the compression heat generation decreased by 4.5^oC and 4^oC,respectively.The above results show that commercial carbon black N330 can be partially replaced by Si69 modified hybrid material,and the replacement mass is 20%of natural rubber per 100 phr.The experimental process is simple,environmentally friendly and suitable for large-scale industrial applications.This means that CNCH has obvious advantages as reinforcing filler of tires.