Study On The Properties And Microwave Heating Effect Of Rubber Nano-Composite Mixed By Wet Process

Rubber products are widely used in all aspects of today's society,which puts forward higher requirements for the performance of rubber.The research shows that the addition of nanomaterials can make rubber obtain better thermal properties,mechanical properties and dielectric properties,and rubber nanocomposites have become an important research object in the rubber field.The mixing process is essential in the preparation process of rubber products.The wet mixing technology is prominent in the mixing process by virtue of its advantages of good dispersion,low consumption and carbon reduction of carbon nanomaterials,and cleanliness.Compared with the traditional vulcanization technology,microwave vulcanization technology with its advantages of fast heating rate,easy to control,energy saving and emission reduction,has become the favored object of rubber science and technology workers.Therefore,in this paper,the wet mixing process was used to prepare carbon nano rubber composites,and the effects of the type,mass fraction and mixing process of carbon nano materials on the thermal properties,mechanical properties and dielectric properties of the mixed rubber were studied.At the same time,the influence of the dielectric constant and dielectric loss factor of the compound on the microwave heating effect of rubber nanocomposites was explored by finite element simulation.The main conclusions are as follows:(1)The thermal conductivity and tensile properties of graphene/natural rubber composites are high.The thermal conductivity and elongation at break reach the highest when the mass fraction of graphene is 2%,which are 0.172W/(m·K)and 537.9%,respectively.The specific heat and tear strength of carbon nanotubes/natural rubber composites are higher,and the highest when the mass fraction of carbon nanotubes is3%,which are 1235J/(kg·K)and 42N/mm,respectively.(2)The relative permittivity of carbon black/natural rubber composites and carbon nanotubes/natural rubber composites is higher than that of graphene/natural rubber composites.When the mass fraction of carbon black is 4% and the mass fraction of carbon nanotubes is 3%,the average maximum relative permittivity is 12.70 and 22.55,respectively.(3)Wet mixing process can significantly improve the properties of composite rubber.Under the condition of the same mass fraction of carbon nanomaterials,the graphene/natural rubber composites prepared by wet mixing process,carbon nanotubes/natural rubber composites and carbon black/natural rubber composites are compared with the dry mixing method.The thermal conductivity increased by 20.14%,20.16% and 26.85%,the specific heat increased by 13.77%,16.29% and 9.35%,the elongation at break increased by 20.37%,23.47% and 21.51%,and the tear strength increased by 4.06%,7.59% and 33.33%,respectively.The dielectric constants of carbon nanotubes/natural rubber composites and carbon black/natural rubber composites were significantly improved.Compared with water dispersing agent,the carbon black/natural rubber composite can obtain higher properties when the carbon black mass fraction is higher by using anhydrous ethanol.(4)No matter what kind of carbon nanomaterials are added,the microwave curing temperature distribution of rubber nanocomposites is not uniform.In addition,the difference of dielectric properties caused by different types and mass fractions of carbon materials has a significant influence on the distribution of microwave vulcanization temperature of rubber nanocomposites,which cannot be ignored.(5)The maximum temperature,minimum temperature and maximum temperature difference of graphene/natural rubber composites decrease with the increase of graphene mass fraction;With the increase of carbon nanotube mass fraction,the maximum temperature of carbon nanotube/natural rubber composites continued to rise,and the lowest temperature decreased first and then rose,and the lowest temperature was when the carbon nanotube mass fraction was 3%.When the relative dielectric constant and dielectric loss factor are different,the carbon black/natural rubber composites have different temperature variations.When the dielectric constant and dielectric loss factor are fixed,the rubber nanocomposites can obtain higher vulcanization temperature and smaller temperature difference,that is,the heating efficiency and uniformity are the best.