Study On The Role Of SiCB In Rubber Reinforcement And Improvement Method

Rubber products are widely used in daily life,agricultural production,medical and health care,electronic communication,automobile manufacturing and aerospace because of their excellent physical and chemical properties such as high elasticity,insulation and acid and alkali corrosion resistance.The filler plays a vital role in the rubber,which can make up for the defects of the rubber and enhance the performance of the product.At present,the reinforcing fillers commonly found in the industry are mainly carbon black and silica,but they are non-renewable petrochemical products.Due to the shortage of petrochemical resources and the serious pollution of the environment in the production process,it is urgent to find renewable resources as raw materials for the production of chemical products instead of carbon black and silica.Rice husk ash,a regenerative biomass resource,is a product of rice husk combustion.Because it contains both silica and carbon,rice husk ash is considered to have the potential to replace or partially replace carbon black and/or silica becomes a rubber filler.First,exploring the differences in physical and chemical properties of silica carbon black(SiCB)and commercial carbon black to provide basic data for the application of silica carbon black.Secondly,filling SiCB into the natural rubber,compared the influence of the filler fraction on the mechanical properties of the vulcanizate and analyzed the possibility and advantages and disadvantages of SiCB as a rubber filler.Finally,modifying the surface of SiCB,investigated the influence of modification conditions on the surface structure of SiCB and studied the interfacial interaction between SiCB and rubber matrix.The results obtained in the study are as follows:1.The mass ratio of silica to carbon in SiCB is approximately 1:1.Because of the natural nanostructure of rice husk,a part of carbon coated on the surface of silica nanoparticles after pyrolysis,which can effectively avoid aggregation of silica.The specific surface area of the SiCB is as high as 239.42 m~2/g,which is attributed to the pore structure formed by the SiCB inherited from the carbonization of the rice husk.Pore structure of SiCB formed by pyrolysis of the rice husk is different from that of carbon black.There is no cluster-like distribution of grape globules,but agglomerates of 300 nm formed by the aggregation of small spheres with a particle size of about 20nm.2.In order to evaluate the reinforcing effect of SiCB in rubber and infer the reinforcing ability and reinforcing mechanism model of SiCB,SiCB and carbon black of different fillers phr were filled into natural rubber.As the filler phr increases,the highest torque and the lowest torque in the vulcanization curve of the rubber compound increase.The scorch time and the curing time of vulcanized rubber filled by SiCB are lower than FEF(Fast Extruding Furnace Carbon Black).In a certain range,with the increase of the amount of filler,the tensile strength and elongation at break of vulcanizates decreased,but stress at 300%strain showed an increasing trend.And the elongation at break of SiCB is significantly better than FEF.3.The change of the network structure of composite elastomer of SiCB and natural rubber under dynamic strain can directly reflect the elastomer performance.Therefore,we will conduct a series of tests on the stress-strain description,Mullins effect and stress relaxation of SiCB filled rubber,and analyze the more potential applications of SiCB as a rubber filler.The experimental results shown that SiCB produced stress softening and stress relaxation in natural rubber like traditional fillers such as carbon black,and vulcanized rubber filled by SiCB exhibited better viscoelasticity than the corresponding sample filled by SRF(Semi-Reinforcing Furnace Carbon Black)under the same filler loading.In the case of uniaxial stretching,the maximum stress of 350%strain of 50 phr SRF and SiCB after the fourth cyclic loading and unloading decreases by 4.60%and3.30%,respectively,compared with the third cyclic loading and unloading.Relaxation factors of vulcanizates filled by 70 phr SRF and SiBC were 0.67 and 0.75 respectively.SiCB exhibits better stress softening resistance and anti-relaxation properties than SRF.4.The surface of SiCB is modified with phenolic resin.We investigated the influence of modification conditions on the surface structure of silica carbon black and studied the interfacial strength between SiCB and the rubber matrix.The results show that the modification conditions of SiCB have an important influence on the mechanical properties of SiCB filled NR/BR vulcanizate.When the amount of filler is 180 g,the modification temperature is 100°C,the reaction time is 10 min,and the amount of PF is 3%,the optimum modification conditions are obtained by using 200 ml biaxial mixing equipment.The tensile strength of the vulcanizates prepared by the modified silica carbon black under the optimum conditions was 7.07 MPa,tear strength is 26.42kN/m,stress at 300%strain is 3.34 MPa,and reached the reinforcing effect of SRF(the tensile strength is 6.46 MPa,tear strength is 27.36 kN/m,stress at 300%strain is 3.69MPa)5.According to the orthogonal experiment,the modification temperature has the greatest influence on stress at 300%strain.The reaction temperature was changed by single factor experiment.It was found that the tensile strength,tear strength and stress at 300%strain of SiCB-filled NR/BR vulcanizate increased first and then decreased with increasing temperature,reach a maximum at 100?,corresponding to an increase of 73.71%,21.08%and 16.78%respectively compared to the untreated case.