Application Of Inorganic Salts Neutralizing Alkaline Lignin And Its Products With Montmorillonite As Rubber Reinforcing Agent

Lignin is the second largest natural polymer material after cellulose.Its application and development research has attracted wide interest of researchers.The paper has carried out a series of research on the process route and environmental protection problems of alkalinelignin in the rubber application process.The specific research contents are as follows:1.Substituting inorganic acid to neutralize alkali lignin with zinc sulfate,aluminum sulfate,magnesium sulfate/aluminum sulfate mixture,and preparing three different inorganic salt modified alkali lignin-montmorillonite by wet ball milling with calcium-based montmorillonitecomplex:zincsulphatemodifiedalkali lignin-montmorillonite composite(Zn-LM),aluminum sulfate modified alkali lignin-montmorillonite composite(Al-LM),magnesium aluminum composite salt modified alkali lignin-montmorillonite composite(MgAl-LM).The particle types and sizes of substances produced during ball milling are analyzed by particle size analyzer.The acidity and alkalinity of the ball-milling composite is effectively controlled by the amount of the inorganic salt added.The experimental results show that lignin can effectively disperse montmorillonite,and the particle size of the composite can reach 3-4?m by ball milling for 4 h.In this paper,the dynamic process of the ball milling process is analyzed by particle size analyzer.The vulcanization characteristics of rubber composites is investigated by a non-rotor vulcanizer.The mechanical properties of rubber composites is studied by universal testing machine.Differential scanning calorimeter(DSC)is used to characterize the compatibility of the rubber composite interface.2.The prepared lignin-montmorillonite composites are respectively mixed with rubber of different polarity(nitrile rubber(NBR),styrene-butadiene rubber(SBR),butadiene rubber(BR)),mixed by an open mill,and hot pressed.Different rubber composite materials are prepared.The vulcanization characteristics of the rubber composites are investigated by a rotorless vulcanizer,and the optimum vulcanization process is obtained.The mechanical properties of the rubber samples are tested using a universal testing machine.The results show that the filler has good reinforcing performance.When Zn-LM/NBR is in m_L/m_M=1:7,and the filler fraction is 70 parts,the tensile strength can reach 14.2 MPa,and the elongation at break increases to 1041%.When Al-LM/NBR is in m_L/m_M=1:5,and the filler is 70 parts,the tensile strength can reach 13.0MPa,and the elongation at break increases to 925%.When MgAl-LM/NBR is in m_L/m_M=1:5,and the filler fraction is 60 parts,the tensile strength can reach 13.5 MPa,and the elongation at break increases to 968%.At this time,the mechanical properties of the nitrile rubber composite are ideal.When Zn-LM/SBR is in m_L/m_M=1:3,and the number of fillers is 60 parts,the tensile strength can increase to 18.3 MPa,and the elongation at break can reach 1830%.When Al-LM/SBR is in m_L/m_M=1:3,and the filler fraction is 70 parts,the tensile strength can increase to 18.4 MPa,and the elongation at break can reach 1754%.When the MgAl-LM/SBR is in m_L/m_M=1:5,and the filler fraction is 60parts,the tensile strength can increase to 16.4 MPa,and the elongation at break can reach 2317%.At this time,the mechanical and mechanical properties of the styrene-butadiene rubber composite are ideal.When Zn-LM/BR is in m_L/m_M=1:3,and the filler fraction is 60 parts,the tensile strength reaches 11.4 MPa,and the elongation at break reaches1717%.When Al-LM/BR is in m_L/m_M=1:3,and the filler fraction is 70parts,the tensile strength reaches 11.0 MPa,and the elongation at break reaches 2089%.When the MgAl-LM/BR is in m_L/m_M=1:3,and the filler fraction is 70 parts,the tensile strength reaches 10.5 MPa,and the elongation at break reaches 2630%.At this time,the mechanical properties of the butadiene composite are ideal.The results of differential scanning calorimetry(DSC)indicate that the rubber composite interface has good compatibility.The main raw materials of the filler prepared in this paper are inorganic salts,alkali lignin and montmorillonite.The raw materials come from a wide range of sources and the cost is superior to the traditional filler carbon black.It also solves the problems of equipment corrosion and wastewater caused by the traditional acid neutralized lignin/montmorillonite filler.Therefore,the composites prepared by the inorganic salt neutralizing alkali lignin and montmorillonite are expected to be a new type of rubber-friendly filler with high environmental friendliness and high economic value.