Study On The Application Of Spray Carbonization White Carbon Black In Silicone Rubber

Silicone rubber is widely used in our lives due to its excellent properties.Among them,methyl vinyl silicone rubber has the advantages of high and low temperature resistance,good aging resistance,excellent electrical insulation,and good physiological inertia.It has become a necessity for important parts of industry,agriculture,medical industry,and aerospace industry.However,the mechanical properties of raw silicone rubber are weak,it is usually necessary to add a reinforcing agent to expand its application range,and white carbon black is the most effective among many reinforcing agents.Based on the investigation of the application status of silica for silicone rubber,this paper adopts a special precipitation method to obtain silica-spray carbonization silica,which has the characteristics of environmental protection and good dispersibility.Used to replace the expensive fumed silica,and systematically studied its influence on the performance of silicone rubber,and obtained the following results:(1)The microscopic morphology,physical and chemical properties and reinforcing effect of spray carbonization silica and commercially available silica were compared.The spray carbonization silica has the characteristics of small particle size,high particle roundness,and uniform distribution.However,the commercial precipitation method agglomeration is more serious;the spray carbonization silica with a specific surface area of 200 m2/g has a positive effect on silicon.The reinforcing effect of rubber is better,with a tensile strength of up to 7.3 MPa,which is still far behind the reinforcing effect of commercially available fumed silica;compared to precipitation silica,vapor-phase silica Black has low moisture content,high purity,and low bulk density.The reinforcing effect of silicone rubber is higher than that of precipitation silica.And research shows that to obtain better performance silicone rubber,the specific surface area of white carbon black is usually 200 m2/g.(2)The influence of the physical and chemical properties of spray carbonization silica with different structures,such as oil absorption,specific surface area,pore size,purity,etc.,on the reinforcing effect of silicone rubber,the results show:when the spray carbonization silica has an oil absorption value of 3.0-3.2 mL/g,specific surface area of 200 m2/g,small pore size and high structure,and high purity,the reinforcing effect of silicone rubber is better.The effects of the bulk density,hydroxyl content and preparation process of the spray carbonization silica on the reinforcing effect of silicone rubber were also studied.The results showed that as the bulk density decreases,the dispersion of silica in the silicone rubber becomes better,the mechanical properties of materials continue to improve.Among them,the spray carbonization silica reinforced silicone rubber obtained by air jet pulverization and heat treatment at 105? for 30 min has a tensile strength of 8.8 MPa,which is better than commercially available precipitation silica,and is close to vapor-phase white carbon black.(3)Use polydimethylsiloxane to dry-modify spray carbonization white carbon black.The results of infrared spectroscopy and thermal weight loss analysis prove that polydimethylsiloxane has been successfully grafted onto silica.With the increase in the number of modifiers,the hydrophobicity of white carbon black increases,the contact angle increases,the tensile strength of the material shows a downward trend,and the elongation at break increases significantly.When the amount of polydimethylsiloxane is about 10 phr,the modification effect is the best,and the elongation at break of the reinforced silicone rubber can reach 1125%;through the determination of the activation degree,the hydrophobicity of the modified silica is high.The activation degree is close to 100%.