As a kind of non-polar rubber with saturated main chain, ethylene propylene rubber has excellent performance in weather resistance, polar media resistance, aging resistance, ozone resistance, etc. However, there are many grades of ethylene propylene rubber. However, there are many grades of ethylene propylene rubber, different grades of ethylene propylene rubber with different ethylene content, third monomer type and content, mooney viscosity, etc. In order to facilitate the technicians to choose the appropriate grade of ethylene propylene rubber, this paper selects a few typical types of the ENB type ethylene propylene rubber which is the most widely used in the industry, and makes a certain study on the effects of ethylene content, third monomer content and mooney viscosity on the performance of the material. A certain research has been done, which has some guiding significance.
With the development of technology and society, people's demand for light-colored products is also increasing, light-colored and colored rubber products are gradually entering into people's lives, silica as the main reinforcing agent for light-colored rubber products is playing an increasingly important role.
As a reinforcing agent mainly used in light-colored rubber products, silica is playing an increasingly important role.
Results and Discussion
1 Vulcanization performance of different ethylene propylene rubber
The effect of ethylene content on the burn-in time (tc10) and process positivity of ethylene propylene rubber.
（The effect of ethylene content on the curing time of ethylene propylene rubber (tc10) and process vulcanization time (tc90) is large, with the increase of ethylene content, the tc10 and tc90 of the material are shortened gradually, the content of the third monomer also has a certain effect on the tc10 and tc90, when the material is close to the same content of ethylene or the same, the lower the content of the third monomer, the shorter the material's tc10 and tc90; the minimum torque (ML) of the material, the lower the content of the third monomer.
The minimum torque (ML) of the material is mainly affected by the ethylene content, the higher the ethylene content, the greater the ML of the material, the worse the mobility at the beginning of vulcanization, because the maximum torque (MH) can reflect the modulus of the rubber, it can be seen that with the increase of ethylene content, the modulus of the rubber also increases gradually, the third monomer content on the modulus of the material is positively proportional to the contribution of the third monomer content is the higher the content of the material, the greater the modulus of the material, the greater the modulus of the material, the greater the modulus of the material. For the same or similar ethylene content, the higher the third monomer content, the higher the modulus. The difference between the highest torque and the lowest torque (MH -ML) is used to characterize the cross-linking degree of the rubber material, and it can be seen that the ethylene content and the third monomer content have the same effect on the cross-linking degree, the higher the ethylene content the greater the cross-linking degree, and the higher the content of the third monomer, the higher the cross-linking degree of the material is also higher.
2 Mechanical properties of different ethylene propylene rubber research
The hardness of the rubber is mainly affected by the ethylene content, the higher the ethylene content, the higher the hardness of the rubber, the third monomer content has less effect on the hardness; material tensile strength and tear strength by ethylene is more obvious, with the increase of ethylene content, the material tensile strength and tear strength are gradually increased, when the ethylene content is similar or the same, the higher the third monomer content, the higher the material tensile strength and tear strength, indicating that ethylene content is the same, the higher the material tensile strength, the higher the material tensile strength, the higher the material tensile strength, the higher the material tensile strength, the higher the material tensile strength, the higher the material tensile strength and tear strength. Similarly, the higher the third monomer content, the higher the tensile strength and tear strength of the material, indicating that the ethylene content and the third monomer content on the strength of the effect of synergistic effect; ethylene content and the third monomer content of the material stretching stress is similar to the impact on the strength of the material, the higher the ethylene content of the material, the higher the third monomer content of the material tensile stress correspondingly the greater; ethylene content of the tensile elongation of a smaller effect, within a certain range of the tensile elongation of the material with the increase of the ethylene content, to a certain point, the tensile strength and tear strength of the material is gradually increasing, to a certain point, the higher the third monomer content. Within a certain range, the elongation at break gradually increases with the increase of ethylene-based content, and then starts to decrease gradually after a certain degree, the third monomer content is inversely proportional to the change of elongation at break, for the same or similar ethylene-based content, the lower the content of the third monomer is, the greater the elongation at break of the material is; the abrasion performance of the material has a greater relationship with its hardness and strength, generally speaking, the higher the hardness and strength, the abrasion volume will be smaller accordingly, and the abrasion performance will be better; as the ethylene-based content increases, there is a certain relationship between the hardness and strength and the abrasion performance of the material. Material hardness and strength have a certain degree of increase, the abrasive volume gradually decreased, the two sides of the third monomer content will also affect the material's abrasive properties, manifested in the increase in the third monomer content, will reduce the abrasive volume of the material, but compared to the effect of ethylene content, the third monomer content has less impact on its abrasive properties.
3 Different ethylene propylene rubber heat-resistant air aging performance
It can be seen that, after aging at 160 ℃ for 24h, the hardness of the material changes very little, the constant tensile stress increases slightly, but the overall retention rate is higher, the tensile strength decreases slightly, the overall retention rate remains high, and the tensile elongation rate is slightly improved; this is because ethylene-propylene rubber is a rubber with a saturated main chain, which has superior heat-air aging resistance. Because of the excellent hot air aging resistance of ethylene propylene rubber, it is difficult to show the effect of ethylene content and third monomer content on the aging performance of the material in a short period of hot air aging.
4 Different ethylene propylene rubber low temperature resistance
With the increase of ethylene content, the low temperature resistance of the material gradually deteriorates.
With the increase of ethylene content, the low temperature resistance of the material gradually deteriorates, the same or similar ethylene content, the lower the content of the third monomer, the better the low temperature resistance of the material, this is because the ethylene content of ethylene propylene rubber increases, the degree of its molecular regularity will be higher and higher, and the ability of the macromolecules to crystallize is also gradually rising [10]. The increase of crystallization ability will lead to the increase of hardness and strength of the material, but also reduce the flexibility of the molecular chain as a whole, so that the low temperature resistance of the material deteriorates. When the content of ethylene group is close to each other, the lower content of the third monomer will lead to the lower degree of cross-linking of the material, which will increase the flexibility of the molecule as a whole, and improve the low temperature resistance of the material.
Conclusion
(1) Different grades of ethylene propylene rubber, its ethylene content has the greatest influence on all aspects of performance, followed by its third monomer content, mooney viscosity has a greater influence on its processing performance, and has a smaller influence on other properties.
(2) For the same third monomer type and content of ethylene propylene rubber, the higher the ethylene content, the greater the mechanical strength, the better the resistance to heat and air aging performance, but its resistance to low temperature performance is poor.
(3) For the same ethylene content of ethylene propylene rubber, the higher the content of the third monomer, the greater the mechanical strength, the better the heat and air aging resistance, but the lower temperature resistance.
