The rubber powder made from waste rubber as the main raw material through mechanical processing, crushing or grinding can be re-added to the production of rubber products to reduce production costs. In actual production, the physical and mechanical properties of vulcanized rubber with rubber powder will change to some extent. The particle size, hardness, filler content in rubber powder, the amount of rubber powder added and the interaction among rubber powder and rubber matrix will affect the physical properties of vulcanized rubber; The physical properties of different kinds of rubber after adding rubber powder are different. Xiaobian will share this with you today.
In actual production, the modified activated rubber powder is added to the lower strength nitrile rubber and cis-polybutadiene rubber, and the rubber powder plays a certain reinforcing role in the lower strength vulcanizate. For example, adding 20 parts of modified tire rubber powder into nitrile rubber can significantly improve the tensile strength and tear strength of vulcanizate, while the elongation at break remains basically unchanged. For nitrile rubber with low strength, whether the rubber powder is modified or not, the addition of rubber powder will not reduce the physical and mechanical properties of the vulcanizate.
The activated rubber powder after plasma surface modification improved the interface among the activated rubber powder and the polar nitrile rubber matrix due to the increase of the content of oxygen-containing groups on the surface, thus significantly improving the mechanical properties of the vulcanizate.
When self-reinforcing rubber such as natural rubber is filled with rubber powder, the addition of rubber powder will lead to a certain degree of decline in the mechanical properties of vulcanized rubber, especially the unmodified vulcanized rubber powder. Therefore, rubber powder 2SLYY314 is added to natural rubber. It is recommended to select active rubber powder to effectively improve the interface compatibility among waste tire rubber powder and NR matrix, and form an interface layer among tire rubber powder and NR matrix to realize its reinforcement effect.
When the filling amount of rubber powder is not more than 50 phr, the tensile strength, tear strength and elongation at break of the vulcanizate are equivalent to that of NR vulcanizate filled with carbon black with the same content, and the carbon black can be partially or completely replaced as a reinforcing filler.
The physical properties of the vulcanizate prepared by adding rubber powder into the rubber compound are characterized by changes. Because the rubber powder still retains its original crushing form and is dispersed in the vulcanizate, the vulcanizate has a heterogeneous structure. When it is subjected to external stress (or strain), its surface and internal stress (or strain) are uneven, thus affecting the various properties of the vulcanizate. For vulcanized rubber mixed with different amounts of rubber powder, apply a certain strain to measure the concave-convex condition on its surface. The results show that the average value of concave-convex on the surface is roughly proportional to the volume fraction of rubber powder and the elongation deformation, and its local concave-convex amount is about 10 times of that of the control sample without rubber powder.
The activation modification of rubber powder by various physical or chemical methods can improve the interface among the waste rubber phase and the rubber matrix phase in the rubber powder filled vulcanizate, thus improving the physical and mechanical properties of the vulcanizate, and preparing the waste rubber composite with low cost and high performance.
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