Process Development Of Rubber Powder Dry Regeneration And Performance Analysis Of Reclaimed Rubber

In this paper,the twin-screw extruder was used to study the dry regeneration of powder,different regeneration conditions were explored.The structure and properties of the blends were systematically studied by microstructure analysis,thermal analysis and dynamic mechanical analysis.At the same time,the relationship between the change of cross-linking density and the free radical signal with the properties of the reclaimed rubber were studied.The main conclusions are as follows:1.The process parameters of temperature,extrusion time and screw speed of the twin-screw extruder were investigated.The optimum parameters were as follows:the extrusion temperature was 90 ? the modification time 2-3min,the screw speed was 350rpm.In order to further guide the development of a dedicated twin-screw extruder for waste rubber powder dry regeneration.The working state of the waste rubber powder in the extruder was simulated by simulation software,and the optimum mechanical shear force is 88?95MPa.After modification of 20 mesh crude rubber powder,the tensile strength of reclaimed rubber can reach 10.2MPa and the elongation at break reaches 260%,compared to the unmodified before were increased by 124%and 164%,has greatly improved.2.The cross-linked structure of the powder was partially destroyed by the twin-screw extruder,resulting in a decrease of crosslink density and the change of the signal strength of free radicals accordingly.There is a close correlation between the cross-linking density of the rubber powder,the free radical concentration and the properties of the reclaimed rubber.The crosslink density of rubber powder decreases first and then increases with the increase of mechanical shearing force.The free radical concentration increases first and then decreases with the increase of mechanical shear force.When the cross-linking density is low,the corresponding free radical concentration is high,the desulfurization effect of the rubber powder is the best,and the properties of reclaimed rubber are the best.By using the change of free radical signal,crosslink density can guide the modification process of rubber powder and get the optimal process parameters.The results of nano-indentation showed that the weak interface between the rubber powder and the matrix rubber,and the macroscopically showed the poor mechanical properties of vulcanized rubber.3.In the transmission electron microscope,the rubber additives,fillers distributed in the rubber matrix evenly,the particle size from 50 to 500 nm range,carbon black particles to form agglomeration,uniform distribution in the matrix play a role in reinforcement.It is easy to form small defects on the surface of rubber powder products,which is easy to induce cracks under the action of external force,leading to material fracture.Modified rubber powder to add a small amount of natural rubber can make rubber products maintain good comprehensive performance.The thermal stability of reclaimed rubber and natural rubber blends is not changed.The dynamic mechanical property test shows that the glass transition temperature of the rubber is shifted to low temperature with the increase of the proportion of natural rubber.The blends of modified powder with the thermoplastic elastomer SEBS have good mechanical properties,anti-compressive properties and anti-aging properties.Modified rubber powder and thermoplastic elastomer SEBS has better compatibility and good processability,Heat-resistant properties of the material have been greatly improved...