1. Adhesiveness
Ethylene-propylene rubber has low cohesive energy due to the lack of active groups in its molecular structure. In addition, the rubber is easy to bloom, and its self-adhesiveness and mutual adhesion are very poor.
Ethylene Propylene Rubber Modified Varieties
Since EPDM and EPDM rubber were successfully developed in the late 1950s and early 1960s, a variety of modified ethylene propylene rubber and thermoplastic ethylene propylene rubber (such as EPDM/PE) have appeared in the world, thus providing The wide application of ethylene propylene rubber provides numerous varieties and grades. Modified ethylene-propylene rubber mainly involves bromination, chlorination, sulfonation, maleic anhydride, maleic anhydride, silicone modification, and nylon modification of ethylene-propylene rubber. Ethylene-propylene rubber also has grafted acrylonitrile, acrylate and so on. Over the years, many polymer materials with good comprehensive properties have been obtained by means of blending, copolymerization, filling, grafting, reinforcement and molecular compounding. Ethylene-propylene rubber has also been greatly improved in performance through modification, thereby expanding the application range of ethylene-propylene rubber.
Brominated ethylene propylene rubber is processed by brominating agent on an open mill. After bromination, ethylene-propylene rubber can improve its vulcanization speed and adhesion performance, but its mechanical strength decreases, so brominated ethylene-propylene rubber is only suitable for the intermediary layer of ethylene-propylene rubber and other rubbers.
Chlorinated ethylene propylene rubber is made by passing chlorine gas through EPDM rubber solution. Chlorination of ethylene-propylene rubber can increase the vulcanization speed and compatibility with unsaturated negotiable, flame resistance, oil resistance, and adhesion performance are also improved.
Sulfonated ethylene propylene rubber is made by dissolving EPDM rubber in a solvent and treating it with a sulfonating agent and neutralizing agent. Sulfonated ethylene propylene rubber will be widely used in adhesives, coated fabrics, building waterproof lean meat, and anti-corrosion linings due to its thermoplastic elastomer properties and good adhesion properties.
Acrylonitrile-grafted ethylene-propylene rubber uses toluene as a solvent and perchlorinated benzyl alcohol as an initiator to graft acrylonitrile onto ethylene-propylene rubber at 80°C. Acrylonitrile-modified ethylene-propylene rubber not only retains the corrosion resistance of ethylene-propylene rubber, but also obtains the oil resistance equivalent to nitrile-26, and has better physical and mechanical properties and processing properties.
Thermoplastic ethylene propylene rubber (EPDM/PP) is based on EPDM rubber and polypropylene for mixing. At the same time, it is a product that makes ethylene-propylene rubber reach the expected degree of crosslinking. It not only retains the inherent characteristics of ethylene-propylene rubber in terms of performance, but also has remarkable technological performance of injection, extrusion, blow molding and calendering of thermoplastics.
2. Low density and high filling property
The density of ethylene propylene rubber is a lower rubber, and its density is 0.87. In addition, a large amount of oil can be filled and fillers can be added, so the cost of rubber products can be reduced, and the disadvantage of high price of ethylene-propylene rubber raw rubber can be made up for. For ethylene-propylene rubber with high Mooney value, the physical and mechanical energy can be reduced after high filling. not big.
3. Corrosion resistance
Due to the lack of polarity and low degree of unsaturation of ethylene-propylene rubber, it has good resistance to various polar chemicals such as alcohols, acids, alkalis, oxidants, refrigerants, detergents, animal and vegetable oils, ketones and fats, etc. ; But in aliphatic and aromatic solvents (such as gasoline, benzene, etc.) and poor stability in mineral oil. The performance will also decline under the long-term action of concentrated acid. In ISO/TO 7620, nearly 400 kinds of corrosive gaseous and liquid chemicals are collected on the properties of various rubbers, and 1-4 grades are specified to indicate the degree of action, and the impact of corrosive chemicals on rubber properties :
Grade Volume Swelling rate/% Hardness reduction value Effect on performance
1 <10 <10 slight or none
2 10-20 <20 smaller
3 30-60 <30 Moderate
4 >60 >30 severe
4. Water vapor resistance
Ethylene-propylene rubber has excellent water vapor resistance and is estimated to be better than its heat resistance. In superheated steam at 230°C, there is no change in appearance after nearly 100 hours. Under the same conditions, fluororubber, silicone rubber, fluorosilicone rubber, butyl rubber, nitrile rubber, and natural rubber will experience obvious deterioration in appearance after a relatively short period of time.
5. Resistance to superheated water
Ethylene-propylene rubber also has better resistance to superheated water, but it is closely related to all vulcanization systems. The ethylene-propylene rubber with dimorpholine disulfide and TMTD as the vulcanization system has little change in mechanical properties after being soaked in superheated water at 125°C for 15 months, and the volume expansion rate is only 0.3%.
6. Electrical properties
Ethylene-propylene rubber has excellent electrical insulation properties and corona resistance, and its electrical properties are superior to or close to those of styrene-butadiene rubber, chlorosulfonated polyethylene, polyethylene and cross-linked polyethylene.
7. Elasticity
Because there are no polar substituents in the molecular structure of ethylene-propylene rubber, the cohesive energy of the molecule is low, and the molecular chain can maintain flexibility in a wide range, second only to natural rubber and butadiene rubber, and can still maintain it at low temperatures.
8. Aging resistance
Ethylene-propylene rubber has excellent weather resistance, ozone resistance, heat resistance, acid and alkali resistance, water vapor resistance, color stability, electrical properties, oil filling and room temperature fluidity. Ethylene-propylene rubber products can be used for a long time at 120°C, and can be used temporarily or intermittently at 150-200°C. Adding suitable anti-aging agent can increase its service temperature. Food grade EPDM rubber hose (EPDM hose) cross-linked with peroxide can be used under harsh conditions. Under the conditions of ozone concentration of 50pphm and stretching of 30%, EPDM rubber can reach more than 150h without cracking.
Post time: Mar-31-2023