The Filling Effect Of CNTs In Special Rubber

Carbon nanotubes had been considered as a new type of functional material and structural material because of their high mechanical strength,unique metallic or semiconducting property and adsorption ability.This paper mainly studied the effect of carbon nanotubes on the special rubbers,like silicone rubber,fluorine rubber,nitrile rubber and hydrogenated nitrile rubber,and properties including mechanical properties,curing characteristic,tensile properties at high temperature,aging resistance,abrasion resistance,electrical conductivity,thermal conductivity,compression heat build-up performance,dynamic mechanical properties,processing properties,and dispersion of carbon nanotubes in the rubber matrix were observed by scanning electron microscope.The results showed that,with the increase of carbon nanotubes contents,the hardness of silicone rubber and the modulus at 100% increased,but tensile strength and tear strength increased first and then decreased,and the elongation at break decreased gradually.Tensile strength,elongation at break and modulus at100% at high temperature decreased,but retention rate of tensile strength increased gradually after adding carbon nanotubes,so the heat resistance was improved.With the addition of carbon nanotubes,the electrical conductivity of silicone rubber was improved obviously,and the thermal conductivity was improved.The carbon nanotubes were dispersed uniformly in the rubber matrix,known by the tensile specimen section from SEM.When the content of carbon nanotubes was 6 phr,the mechanical properties of silicone rubber were the best.When the stretching direction and rolling direction were paralleled,tensile strength was larger and tear strength was smaller.Prolonging the rolling time,the mechanical properties were improved.The carbon nanotubes with smaller aspect ratio were dispersed better than those with larger aspect ratio in the silicone rubber,and the properties of rubber enhanced by them were better.With the increase of carbon nanotubes contents,torque of fluorine rubber increased,and the curing time was prolonged,and the hardness,tensile strength,modulus at 100% and tear strength gradually increased,but the elongation at break decreased gradually.For fluorine rubber filled with diatomite,the tensile strength under high temperature reduced,but retention rate of tensile strength increased after the addition of carbon nanotubes.With the increase of carbon nanotubes contents,thermal conductivity and wear resistance increased gradually.The carbon nanotubes were just dispersed uniformly partially in rubber matrix,known by the observation of tensile specimen section from SEM.With the increase of carbon nanotubes contents,the minimum torque and maximum torque of nitrile rubber increased,and scorch time and curing time decreased.Tensile strength and tear strength were increased first and then decreased,and the elongation at break decreased gradually,the modulus at 100% and modulus at 300% increased significantly.In tensile properties at high temperature,the tensile strength retention rate increased gradually.The thermal conductivity increased gradually,and DIN abrasion volume decreased.With the increase of carbon nanotubes contents,the static compression rate decreased,and the permanent deformation and fatigue temperature increased gradually.In the dynamic mechanical properties,the loss factor of rubber decreased and the storage modulus became larger after the addition of carbon nanotubes when the temperature was low.Carbon nanotubes predisppersants had many advantages,like convenient transportation,accurate weighing,feeding fast,and the properties were better,more uniform.Known by the tensile specimen section from SEM,the carbon nanotubes predispperants were dispersed more uniformly in the rubber.With the increase of carbon nanotubes contents,vulcanization time of nitrile rubber was shortened,and the torque was increased,and the tensile strength was basically unchanged,but hardness,modulus at 100%,modulus at 300% and tear strength increased,and elongation at break decreased.After the rubber was aged,no significant changes in tensile strength,but hardness and modulus at 100% increased,and the elongation at break decreased.About tensile properties at high temperature,the retation rate of tensile strength and modulus at 100% increased.The storage modulus increased and loss factor decreased after the addition of carbon nanotubes in dynamic mechanical properties.Rubber processing analyzer showed that the elastic modulus increased and loss factor decreased after the addition of carbonnanotubes.The overall dispersion of carbon nanotubes in the rubber matrix was uniform,but the local agglomeration existed.Compared with rubber reinforced by zinc methacrylate,the rubber reinforced by carbon nanotube had larger torque,and the curing time was shortened,and its mechanical properties,aging resistance,tensile properties at high temperature and good wear resistance were better.In rubber processing properties,the rubber reinforced by carbon nanotube had lager storage modulus and lower loss factor.