Research On Dopamine Modified Silicon Carbon Black And Basalt Fiber As Green Fillers For Rubber

With the rapid development of economy,people's awareness of environmental protection is more and more strong,and rubber as an essential part of life,its green and low pollution production has also attracted more and more attention.Rubber production involves a large number of material addition,of which the largest proportion is the traditional filler.The most common traditional filler is carbon black.When carbon black is filled with rubber,the performance of rubber will increase greatly.However,carbon black is a product of fossil fuels,and the whole production process involves a lot of pollution and energy waste,which is not consistent with the theme of green environmental protection.Therefore,it is necessary to seek green fillers to replace traditional fillers to meet the requirements of green production.Silicon carbon black(SiCB),as a C-SiO₂ dual-phase filler made from waste rice husk through controlled pyrolysis conditions,has the characteristics of green,environmental protection and renewable.It is a feasible method to replace traditional fillers.However,SiCB has poor dispersibility and is easy to agglomerate and is difficult to be effectively infiltrated by rubber.Therefore,it is necessary to modify SiCB to enhance its dispersibility and bond with the matrix to improve its applicability in industry.Basalt fiber(BF)is a kind of non-additive natural mineral fiber made by basalt melt drawing.Compared with traditional carbon fiber and glass fiber,it has the advantages of low pollution,degradability,and natural environmental protection.And it has good mechanical properties,it can be regarded as a kind of green filler for rubber reinforcement.However,the surface of BF is smooth and inert,it is not easy to be infiltrated by rubber,and its bonding with rubber is poor,so it needs to be modified to solve the problem of difficult bonding with the rubber matrix.1.(a)In this paper,the best amount(phr)of Natural Rubber(NR)/Butadiene Rubber(BR)reinforced by renewable green filler SiCB was explored by single factor method.When SiCB is 15 phr,the tensile strength,tear strength,and elongation at break of NR/BR/SiCB all reach the maximum,which are 14.2 MPa,34.4 k N/m,and 1384.2%respectively;b The optimal process of dopamine(DA)modified SiCB is explored through L₉(4)³(four factors and three levels)orthogonal experiment.When the concentration of dopamine is 2 g/L,the modification time is 24 h,the pH is 8.5,and the modification temperature is 25?,the effect of PDA-SiCB is the best;?the tensile strength of NR/BR/PDA-SiCB composites prepared by mechanical mixing dopamine modified filler is greatly improved,reaching 23.1 MPa,which is 63% and106% higher than NR/BR/SiCB and NR/BR rubber composites,respectively.Compared with NR/BR/SiCB,the elongation at break and glass transition temperature(T_g)of NR/BR/PDA-SiCB were increased by 30% and 3.87?,respectively,and the thermal stability was also improved.2.(a)The optimal conditions for H₂SO₄ to etch BF were determined as H₂SO₄ concentration 2 g/L and modification time 2 h.The fiber(BF^H)filled rubber material(NR/BR/2h-BF^H-2g/L)prepared under this condition has the best tensile strength,300%tensile stress,and tear strength,which are 8.24 MPa,3.14 MPa,23.85 k N/m,respectively.(b)The effects of three methods,H₂SO₄ etching,PDA graft modification and SiCB+PDA synergistic modification on the fabricated fiber-rubber composites were explored.These three treatments can improve the overall mechanical properties of the material compared with NR/BR/BF.Among them,NR/BR/PDA-BF^H-SiCB has the best overall performance.Its tensile strength,tear strength and elongation at break reach 13.68 MPa,27.07 k N/m and 1063.4%respectively,which are 79.3%,18.0%and 28.0%higher than those of NR/BR/BF.