Application Of Oxidized Carbon Black In Epoxidized Natural Rubber And Natural Rubber

Carbon black is an ideal industrial filler with high colorability,good chemical stability,and excellent reinforcement.It is widely used in coatings,inks and rubber.However,due to the small particle size,large specific surface area,and high surface free energy of carbon black,the interaction between particles is strong,and it is easy to cohere into agglomerates,which reduces its dispersion in various application fields.At the same time,ordinary carbon black has few surface groups,low polarity,and relatively inert surface.As a reinforcing filler,it mainly plays a role of physical reinforcement,which also limits its further development.Surface modification of carbon black is one of the current research directions.In this paper,the ozone oxidation method was used to oxidize the surface of carbon black.This method is simple,safe,effective,and environmentally friendly.The modified carbon black has good properties.It is hydrophilic,and at the same time,a large number of reactive carboxyl,hydroxyl and other oxygen-containing functional groups are introduced on the surface of carbon black,which increases the surface polarity of carbon black.It is expected to apply in the field of rubber and to produce a rubber composite with better performance.The research contents in this paper are as follows:(1)In the first part,epoxidized natural rubber/oxidized carbon black composites were successfully prepared using the semi-effective vulcanization system,and the application of oxidized carbon black in epoxidized natural rubber was studied.The effects of different factors on the properties of epoxidized natural rubber/oxidized carbon black composites were explored,and it was found that oxidized carbon black greatly reduced the torque of the vulcanizate,reduced the mechanical properties,and increased the loss.Oxidized carbon black had an adverse effect on the vulcanization process of the rubber,reducing the crosslinking density of the epoxidized natural rubber/oxidized carbon black composites.With the increase of the oxidation time,the acidity of oxidized carbon black increased,and the adverse effect was more.The higher the epoxy degree of epoxidized natural rubber,the higher the tanδ of the composites at 0 °C,which can improve the wet skid resistance of the composites.For the epoxidized natural rubber/oxidized carbon black/Si69 system,Si69 weakened the interaction between the carbon black and the rubber chain,resulting in a further decline in performance.(2)In the second part,epoxidized natural rubber/oxidized carbon black composites with different oxidized carbon black loadings using the sulfur-free system were prepared.The chemical cross-linking could be formed between the epoxy group of epoxidized natural rubber and the carboxyl groups on the surface of oxidized carbon black,which could form a dynamic covalentβ-hydroxyester bond.The epoxidized natural rubber/oxidized carbon black composites with good mechanical properties,shape plasticity and repeatability were prepared through building a cross-linking network of epoxidized natural rubber-oxidized carbon black particles.The OCB-50 sample oxidized for 4hours had a tensile strength of 11.2 MPa,a tensile stress at 100% strain of 8.6MPa,and an elongation at break of 127%.The recovery ratios corresponding to tensile strength,tensile stress at 100% strain and elongation at break after the first reprocessing are 101%,58% and 160%,respectively,indicating good tensile strength retention and repeatability.(3)In the third part,natural rubber/oxidized carbon black/coupling agent composites with different coupling agents were prepared.The effects of the types and amounts of coupling agents on the properties of the composites were explored.The addition of coupling agent could not effectively improve the vulcanization performance and mechanical properties of the composites and it was difficult to construct an ideal rubber network.For the coupling agent system with dibenzothiazole disulfide and cystamine dihydrochloride,more amounts of coupling agent reduced the properties of the composite material due to too much coupling agent may affect the combination of oxidized carbon black and rubber molecular chains.