Types of Polymers

Polychloroprene rubbers are obtained by the polymerisation of chloroprene (2-chloro-1,3-butadiene) and are known by the popular name of Neoprene, DuPont’s registered trademark for this type of rubber.

Vulcanized products made from polychloroprene rubber have good resistance to weathering, ozone, aging, and chemical agents. They also have good mechanical properties and good elasticity at temperatures as low as -40°C, as well as being highly non-flammable and having good resistance to temperatures of around 100°C or, for short periods, 120°C. 

Their gas permeability is much lower than that of NR, IR, and SBR, being close to the permeability of acrylonitrile butadiene rubbers (NBR). In terms of chemical resistance, polychloroprene Vulcanizetes have good chemical resistance to paraffinic oils, medium chemical resistance to naphthenic oils, and aliphatic hydrocarbons, with poor resistance to aromatic hydrocarbons, chlorinated hydrocarbons, and polar solvents.

This is a polymer resulting from the copolymerisation of ethylene and propylene, resulting in a very long chain that is difficult to break. The diene is always located at the ends of the chain and is the location where crosslinking (vulcanization) takes place.

The properties of EPDM Vulcanizetes depend on the type of EPDM used and the Vulcanization system employed, whether it is sulphur-based or peroxide-based. In general, they have good resistance to heat and ageing, good resistance to low temperatures and sunlight, good elasticity, good insulating power, excellent resistance to ozone and weathering, and good resistance to certain chemical agents. 

Resistance to compression deformation is greatly improved when peroxide Vulcanization is used, as is heat resistance at temperatures of around 130°C to 150°C. Regarding chemical resistance, one highlight is resistance to hot water and steam, glycol-based brake fluid, a number of dilute organic and inorganic acids, salt solutions, silicone oil, and calcium carbonate and potassium carbonate solutions. EPDM, however, is not resistant to aliphatic, aromatic and chlorinated hydrocarbons. EPDM is used in the automotive industry (pipes, wiring harnesses, radiator hoses, and profiles for sealing windows and doors), in the joinery industry, and in many other uses where good resistance to ozone and weathering is essential. It is also used in structural profiles in architecture and for sealing refrigerated bodies

Viton rubber is a synthetic rubber compound with fluoroelastomers in its composition, also known as fluorocarbon or fluorinated rubber, among others.

It is a highly resistant material and is suitable for working at low (up to -55°C) or high temperatures (up to 300°C or more, depending on weather conditions). It is used in situations that require good resistance to swelling due to oil and other fuels or lubricants. It is durable and tends to offer an excellent service life. 

Nitrile rubber belongs to the class of special oil-resistant rubbers and is a copolymer of butadiene and acrylonitrile. Nitrile rubber (NBR) offers a good balance between resistance to low temperatures (between -10°C and -50°C), oil, and solvents, with this resistance being a function of the acrylonitrile content. These characteristics, combined with good resistance to high temperatures and abrasion, make NBR rubber a suitable material for a wide variety of applications. It also has good resistance to dynamic fatigue and low gas permeability. 

Oil resistance is the most important property of nitrile rubber. Most of the properties of NBR Vulcanizetes depend on the ACN content and the type and amount of plasticiser used in the formulation. Greater resistance to oil, petrol, benzine or other liquids translates into less volume increase (less swelling) of NBR specimens when immersed in these liquids.

Because of its price, NBR is used in applications where, in addition to good mechanical properties and/or good resistance to dynamic fatigue, good resistance to swelling in oil and/or petrol, good resistance to heat ageing and abrasion are also required. It is used in general industry, the automotive industry, and the mineral oil sector.

NBR is typically used in static O-rings, membranes, bellows, tubes and hoses for hydraulic or pneumatic applications, conveying aliphatic hydrocarbons (propane and butane), conveyor belts, friction material, roller covers for various purposes, particularly for the paint and textile industries, and soles for safety footwear. It is also widely used in the food industry.
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Styrene-butadiene rubber (SBR) is undoubtedly the most widespread synthetic rubber in the world. Butadiene (CH2=CH-CH=CH2) and styrene (C6H5-CH=CH2) are the base monomers for producing SBR, with a styrene content of approximately 23.5 per cent.

Vulcanizetes made with SBR offer better abrasion resistance than natural rubber (NR), as well as greater resistance to high temperatures (up to 100°C) and ageing. They have, however, less flexibility and elasticity at low temperatures (around -50°C). At high temperatures, SBR Vulcanizetes tend to harden, unlike natural rubber Vulcanizetes which soften. 

In addition to tyres and moulded items, SBR can be used in extruded seals, although it is not specifically weather- and ozone-resistant. 

Silicone is a synthetic polymer composed of silicon and oxygen atoms, being widely used in various sectors such as industry, medicine, and construction.

Known for its versatility, resistance and durability, it is a popular material that is present in our daily lives. It is resistant to decomposition by heat, water ,or oxidising agents, as well as being a good electrical insulator.