Preparation Of Nanometer Calcium Carbonate/nano Diamond/natural Rubber Composites

Natural rubber is widely used in industrial production of automobile tires,transport belts and various sealing devices due to its good insulation,elasticity and air tightness.However,with the development of the rubber application field,people have put forward higher requirements for the mechanical strength and the function of natural rubber.In this paper,two kinds of fillers of detonation nano-diamond and nanoCaCO3 were used to reinforce natural rubber.Latex mixing process was used to prepare natural rubber masterbatch,and then natural rubber nanocomposites were prepared by mixing and vulcanizing process.The optimum condition for preparation of natural composites was determined through orthogonal experiment:the mass ratio of sulfur to accelerator was 1:1,the mass ratio of reinforcing filler to natural rubber was 1:10,the mass ratio of nano-diamond to nanoCaCO3 was 6:4 and the mixing temperture was 70?.The tensile strength of natural rubber composites which prepared under this condition was 28.1 MPa,increased by 836.7%compared with the pure natural rubber;tear strength was 31 KN/m,increased by 55%compared with the pure natural rubber;thermal conductivity was 0.1907 W/(m·K),58.9%higher than the pure natural rubber.In a addition,we treated the nanoCaCO3 and nano-diamond as single filler respectively,nanoCaCO3 and nano-diamond as composite fillers,natural rubber as matrix,then prepared a series of natural rubber nanocomposite materials by using the the latex mixing process in order to investigate the effects of filling amount of different fillers on the properties of natural rubber nanocomposites.When the filling amount of nanoCaCO3,nano-diamond and composite fillers were 5 wt%,NR composites have the best mechanical properties.The tensile strength were 27.3 MPa,26.2 MPa and 27MPa respectively,the tear strength were 35KN/m,32KN/m and 32KN/m respectively,and the elongation at break and fracture work were also improved.When the amount of nano-diamond and composite fillers were 20 wt%,the thermal conductivity of NR composites reached the maximum.Finally,the influence of nanoCaCO3 filling amount,the amount of coupling agent Si-69 and the temperature of internal mixer on the properties of NR nanocomposites were also explored when we treated different amount of nanoCaCO3 as a single filler to prepare a series of NR nanocomposites by applying the dry blending technology.When the filling amount of nanoCaCO3 were 5 wt%,the natural rubber composite had the best mechanical properties.At this time,the tensile strength and the tear strength reached the maximum value of 28.3 MPa and 38 KN/m respectively,which were increased by 843%and 90%compared with the pure natural rubber respectively.When the amount of coupling agent Si-69 were 5 wt%and the mixing temperature was 80?,the natural rubber composites had the best mechanical properties.In this paper,a kind of creative latex blending process was designed,meanwhile the NR nanocomposites prepared by this technology had excellent mechanical properties and thermal conductivity.