| During melt extrusion of the mixture of ground tire rubber and EPDM,2-butyl alcohol was added as devulcanization accelerator,and the effect of screw rotating speed and reaction temperature on the gel content of devulcanized blends,molecular structure of gel and physical properties of SBR/devulcanized blends was investigated.The results showed that,as the screw rotating speed and reaction temperature increased during extrusion,the mechanical shear stress on ground tire rubber enhanced,which made cross-linking network break up,degrade or retro-crosslink,resulting in low gel content of devulcanized blends and small size of gel particles in SBR/devulcanized blends.By adding 2-butyl alcohol,the process of devulcanization was accelerated,side-reactions were restrained,double bonds were protected,and the gel content of devulcanized blends was further decreased.With the 2-butyl alcohol accelerated devulcanization condition of screw rotating speed at 1 000 r·min-1and reaction temperature at 240 ℃,the tensile strength and elongation at break of SBR/devulcanized blends were 19.3 MPa and 567% respectively. |
