Preparation Of Lipophilic Sulfur And Its Vulcanization Behavior In Natural Rubber

Sulphur is the largest by-product of petroleum refining.It is reported that 60 to 70 million tons of waste sulfur will be produced every year in the world.Therefore,how to use these sulfurs reasonably and effectively has always been a huge challenge for all countries in the world.The material directly prepared with sulfur as the raw material is mainly sulfuric acid,and the area where sulfur is directly used is mainly the vulcanization of rubber.Organic sulfur compounds,as one of the most important types of lubricating oil extreme pressure antiwear agents,are another area of sulfur consumption.Among them,sulfurized olefins and sulfurized esters are widely used due to high sulfur content,good oil solubility,and excellent extreme pressure antiwear properties.Used in gear oil,metal working oil and grease.In this paper,the characteristics of the reaction between sulfur and AM are systematically studied,and a new organic sulfur-containing compound S-AM is prepared by the melting method.The organic sulfide is not only oleophilic and easy to dissolve in rubber compounds,so it has excellent frost resistance,and the-S-Cbond introduced in the structure greatly improves its thermal stability and solves the insoluble sulfur mixing temperature the limit of 105?cannot be exceeded.In addition,the organic sulfur-containing compound is not only lipophilic but also in a liquid state,and can be dissolved in lubricating oil,thereby having the potential to be used as an extreme pressure antiwear agent for lubricating oil.Using green chemical process,the products are low-toxic,non-toxic and environmentally friendly products.The influence of formulation factors on the application of organic sulfide S-AM in natural rubber was studied.The amount of S-AM was increased from 2.4 phr to 9.6 phr,the tensile strength was increased from 12.1 MPa to 21.5 MPa;the cross-linking density increased,and the elongation at break increased from 520% to 592%.Among the S-AM vulcanized NR rubbers of three vulcanization systems,CV,EV,and SEV,the vulcanizate of the EV vulcanization system has the largest crosslink density,and the CV vulcanizate has the best fatigue performance.In different vulcanization systems,the flexural fatigue performance of S-AM vulcanizates is significantly better than that of common sulfur vulcanizates in the same system,and the growth rate of cracks remains at a low level.Since there are both S-S bonds and S-C bonds in the S-AM,its vulcanization behavior will be different from ordinary sulfur containing only S-S bonds.This paper examines the effect of accelerators on the NR performance of S-AM vulcanization,and finds that the the mechanical properties of vulcanized rubber using only NS as an accelerator are inferior to vulcanized rubber using both NS and TT.The final deformation of compression fatigue of vulcanized rubber using only NS as an accelerator is about 22%,and the sample has undergone a huge permanent deformation,while the final deformation of vulcanized rubber using both NS and TT is only about 3%.The crack growth rate of vulcanized rubber using only NS as an accelerator is obviously lower than that of vulcanized rubber using both NS and TT,but the crack length of NS/TT vulcanizate with the largest crack length of 50,000 times of bending is less than 9mm.S-AM has an excellent effect on softening rubber and improving the flexural fatigue resistance of rubber.