Study On Microstructure And Dispersion Of Three Types Of Large Particle Carbon Black In NR

As a traditional carbon material,large particle size carbon black?primary particle size of carbon black over 50 nm?is widely used in non-tire rubber products because of its large particle size,excellent filling and certain reinforcing properties.However,there is rarely reported about the basic research on large particle size carbon black.In this paper,three typical large size carbon black are selected as the research object.The first category is the traditional N series of carbon black?such as N550^N990?that is low in surface area and structure.The second category is the spray carbon black?PW?in recent years,it is famous for its large particle size and high structure and it is applied to some special purpose hoses.The third category is a new type of carbon black?NCB?that is made in Sichuan University of Science and Engineering and has the properties of large particle size,low specific surface area and high structure.The purpose of this paper is to explore the morphology and structure of the above three types of carbon black and the degree of micro-dispersion in rubber,which is helpful to clarify the reinf orcing effect of large particle size carbon black on rubber and to improve the processing performance from the micro-scale,especially to explain why the latter two kinds of large particle size carbon black are still reinforcing and maintaining good elasticity of rubber.In this paper,the microscopic morphology and structure of six kinds of large size car bon black such as N550,N660,N770,N880,N990 and spray carbon black?PW?were characterized by atomic force microscopy?AFM?.The effect of carbon black morphology and structure on NR performance was analyzed.The degree of dispersion of carbon black in rubber was analyzed by statistics and analysis,and the correlation between microdispersion and tensile strength and adhesive content was also studied.Th e microstructure and surface properties of NCB black before and after modification were studied by FT-IR,XRD,SEM,TEM and AFM.?1?The morphology of aggregates varies with the carbon black.The smaller the particle size,the better the strengthening effect of carbon black on rubber,and the more obvious the structure of carbon black on rubber.?2?The dispersion of carbon black shows that the distribution of structural degree coefficients of N880 and N990 with large particle size is the largest at about 0.9 and the smallest at about 0.3,while that of N550 and PW is the opposite;when the selected area is 2000 nm×2000 nm,the correlation between the dispersion index of carbon black and the binder content,structural degree coefficient and tensile strength reaches the maximum,and increases with the dispersion index.With the increase of structural degree coefficient,the tensile strength decreases.?3?The specific surface area of alkali-heat modified NCB carbon black particles is increased by about 40 times,and the iodine absorption value is 669 g·kg^-1.Graphene-like lamellar structure appeared on the surface,the roughness become larger and the structure become lower.Tan?peak value of N-NCB/NR composites is 1.680,and that of NCB/NR composites is 1.227.