What Is the Difference Between Neoprene and EPDM?

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Neoprene and EPDM are both elastomers--long chain polymers that can be vulcanised. The vulcanisation process is responsible for the elastic properties of all the materials we commonly call rubber. Not all elastomers are the same, though. EPDM and Neoprene each have their own specific properties, and are the best choice in certain situations. Learning the properties of these elastomers can help you choose the right product for your needs.

History

Neoprene is the oldest of the two rubbers. It was invented in 1930 by scientists at DuPont, and has been used in all kinds of applications, such as electrical insulation, fan belts in vehicles, wet suits and laptop sleeves. The generic name for Neoprene is polychloroprene. EPDM, or ethylene propylene diene monomer, was developed in the 1960s, and is commonly used on flat roofs. EPDM is also used in seals and tubing, as electrical insulation, in pond liners and as a motor oil additive

Performance

Neoprene and EPDM are similar in cost, resilience, tear strength and ability to resist damage from ozone. Both are easily damaged by petroleum-based fuels and are reasonably resistant to abrasion. They can withstand similar temperatures--a high of 149 degrees C for EPDM and 121 degrees Cor Neoprene, and a low of -60 and -40 respectively. EPDM has a significantly lower resistance to grease and oil than Neoprene and a significantly better resistance to water swell.


Benefits

Each type of rubber is best for some uses. For instance, EPDM's resistance to ozone, UV rays, temperature extremes and water make it an excellent choice for waterproof roofing membrane. The material is available in liquid and sheet forms, and is usually applied using seamless techniques that reduce leakage. Neoprene has similar environmental resistances, withstands damage from twisting and flexing and resists burning relatively well. It can be made into an elastic foam that makes excellent insulation and cushioning material.

Warning

Some people are allergic to Neoprene, or contract contact dermatitis from one of the compounds used to vulcanise it. Some Neoprene adhesives also contain a substance called rosin, which is considered a skin sensitiser. Human allergies to EPDM are comparatively rare, and it is used in some non-latex rubber products, such as rubber bands.

Considerations

Anyone interested in using an elastomer in manufacturing, construction or any other area should take the time to test the choices in actual application. While performance guides for each rubber can be useful in narrowing down the possibilities, there is no substitute for real world testing. A hasty decision could result in a poorly performing end product.

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Neoprene

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A neck seal, wrist seal, manual vent, inflator, zip and fabric of a neoprene dry suit. Here the soft thin rubber-like seal material at neck and wrists is made from non-foam neoprene for elasticity; the blue area is a thin blue knit fabric laminated onto spongy foamed neoprene for insulation.
Chemical structure of the repeating unit of polychloroprene

Neoprene or polychloroprene is a family of synthetic rubbers that are produced by polymerization of chloroprene.[1] Neoprene exhibits good chemical stability, and maintains flexibility over a wide temperature range. It is used in a wide variety of applications, such as laptop sleeves, orthopedic braces (wrist, knee, etc.), electrical insulation, liquid and sheet applied elastomeric membranes or flashings, and automotive fan belts.[2]

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Mina i added picture your topic.

Neopren is PCP but Neopren is trade mark of Dupont

DuPont™ Neoprene polychloroprene

DuPont™ Neoprene polychloroprene is an extremely versatile synthetic rubber with more than 75 years of proven performance in a broad industry spectrum. It was originally developed as an oil-resistant substitute for natural rubber. Neoprene is noted for a unique combination of properties, which has led to its use in thousands of applications in diverse environments.

A Balanced Combination of Properties

    Resists degradation from sun, ozone and weather
    Performs well in contact with oils and many chemicals
    Remains useful over a wide temperature range
    Displays outstanding physical toughness
    Resists burning inherently better than exclusively hydrocarbon rubbers
    Outstanding resistance to damage caused by flexing and twisting

The basic chemical composition of Neoprene synthetic rubber is polychloroprene. The polymer structure can be modified by copolymerizing chloroprene with sulfur and/or 2,3 dichloro 1,3-butadiene to yield a family of materials with a broad range of chemical and physical properties. By proper selection and formulation of these polymers, the compounder can achieve optimum performance for a given end-use. Neoprene is available as a solid and as a liquid dispersion.


EPDM is ;

EPDM rubber (ethylene propylene diene monomer (M-class) rubber),[1][2] a type of synthetic rubber, is an elastomer which is characterized by a wide range of applications. The E refers to ethylene, P to propylene, D to diene and M refers to its classification in ASTM standard D-1418. The M class includes rubbers having a saturated chain of the polymethylene type. Dienes currently used in the manufacture of EPDM rubbers are dicyclopentadiene (DCPD), ethylidene norbornene (ENB), and vinyl norbornene (VNB). EPDM rubber is closely related to ethylene propylene rubber (ethylene propylene rubber is a copolymer of ethylene and propylene whereas EPDM rubber is a terpolymer of ethylene, propylene and a diene-component).
A roll of EPDM foil, used for waterproofing roofs

The ethylene content is around 45% to 75%. The higher the ethylene content the higher the loading possibilities of the polymer, better mixing and extrusion. Peroxide curing these polymers gives a higher crosslink density compared with their amorphous counterpart. The amorphous polymer are also excellent in processing. This is very much influenced by their molecular structure. The dienes, typically comprising from 2.5% up to 12% by weight of the composition, serve as crosslinks when curing with sulphur and resin, with peroxide cures the diene (or third monomer) functions as a coagent, which provide resistance to unwanted tackiness, creep or flow during end use

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Generally Neopren use as sheath of cable for mechanical and chemical prevent to bad effects. EPMD is using as insulation. formulation is difference.

Properties

EPDM exhibits satisfactory compatibility with fireproof hydraulic fluids, ketones, hot and cold water, and alkalis, and unsatisfactory compatibility with most oils, gasoline, kerosene, aromatic and aliphatic hydrocarbons, halogenated solvents and concentrated acids.

The main properties of EPDM are its outstanding heat, ozone and weather resistance. The resistance to polar substances and steam are also good. It has excellent electrical insulating properties. It has good resistance to ketones, ordinary diluted acids and alkalines.

Typical properties of EPDM vulcanizates are given below. EPDM can be compounded to meet specific properties to a limit depending first on the EPDM polymers available, then the processing and curing method(s) employed. EPDMs are available in a range of molecular weights (indicated in terms of Mooney viscosity ML(1+4) at 125 °C), varying levels of ethylene, third monomer and oil content.

for example is skyprene is the same but different company formul is ,



SKYPRENE polychloroprene rubbers are often specified by design engineers because of their superior properties, such as their resistance to cold, hear, abrasion, ozone, oil and chemicals.

SKYPRENE Family Relationship



PCP=CR=NEOPRENE=SKYPRENE=BAYPRENE

What is Baypren®?


Baypren® is the name of the LANXESS range of polymers based on 2-chloro-1,3-butadiene (chloroprene), which are manufactured by water-based emulsion polymerization in the presence of emulsifiers, activators etc. The importance of Baypren® is derived essentially from its attractive combination of key technical properties that are unattainable with other kinds of rubber at a comparable price. This has led to the development of many product variants to meet diverse requirements. Articles made from appropriately formulated Baypren® compounds are suitable for moldings and extrudates of all types, reinforced hoses, roll covers, belting, including conveyor belts, air spring bellows, cable sheathing and insulation for low-voltage cables, sponge rubber, including open and closed-cell sponge rubber, corrosion-resistant linings, sheeting, fabric proofings and footwear (boots). The flame-retardant behavior of Baypren® vulcanizates can be adjusted to meet special requirements.

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Neoprene (Chloroprene Rubber):

Chemical Structure:

Neoprene is a polymer of chloroprene (2-chloro-1,3-butadiene). Its structure can be represented as:

CH2=C(Cl)−CH=CH2

In its polymerized form, it looks like this:

−[−CH2−C(Cl)=CH−CH2−]n−


Properties and Hydrocarbon Resistance:

Neoprene: Neoprene is known for its good resistance to oils, greases, and many chemicals. It performs well against hydrocarbons due to the chlorine atom in its structure, which imparts some flame resistance and oil resistance. However, prolonged exposure to hydrocarbons can lead to swelling and a decrease in mechanical properties.

Applications: Neoprene is used in various applications including automotive belts, hoses, gaskets, and seals, where resistance to oils and chemicals is required.



EPDM (Ethylene Propylene Diene Monomer):

Chemical Structure:


EPDM is a copolymer made from ethylene, propylene, and a small amount of a diene monomer (typically dicyclopentadiene, ethylidene norbornene, or 1,4-hexadiene). Its general structure is:

(CH2CH2)x(CH2CH(CH3)y(CH2CH=CH2)z


Properties and Hydrocarbon Resistance:

EPDM: EPDM has excellent resistance to heat, ozone, and weathering due to its stable saturated backbone structure. However, it does not have the same level of resistance to oils and hydrocarbons as Neoprene. Prolonged exposure to hydrocarbons can cause some deterioration.

Applications: EPDM is widely used in automotive weather-stripping and seals, roofing membranes, and in applications where good weather resistance is needed.

Summary:

Neoprene is preferred for environments with exposure to oils and greases, thanks to its oil-resistant properties.

EPDM is preferred for outdoor applications requiring resistance to weather, ozone, and UV radiation, but it is not as resistant to hydrocarbons as Neoprene.

These structural differences account for their varying properties and suitability for different applications.

What are the differences between CR, CPE and CSPE with Hydrocarbon Structure ?

1. Chloroprene Rubber (CR)
Chloroprene Rubber, commonly known as Neoprene, is produced by polymerizing chloroprene (2-chloro-1,3-butadiene). The presence of the chlorine atom in its structure provides CR with unique properties such as resistance to oil, chemicals, and weathering.

Hydrocarbon Structure of Chloroprene Monomer (2-chloro-1,3-butadiene):
    H      Cl
    |      |
    C = C — C = C
    |      |    H
    H      H

Polymerized Structure of CR:

    H      Cl      H      Cl      H
    |      |        |      |        |
- C — C — C — C — C — C — C -
    |      |        |      |        |
    H      H        H      H        H

2. Chlorinated Polyethylene (CPE)

Chlorinated Polyethylene is made by chlorinating high-density polyethylene (HDPE). This process involves adding chlorine atoms to the polyethylene chain, enhancing properties such as chemical resistance and flame retardancy.

Hydrocarbon Structure of Polyethylene (PE) Base Polymer:

  H      H      H      H      H      H
  |      |      |      |      |      |
- C — C — C — C — C — C -
  |      |      |      |      |      |
  H      H      H      H      H      H

Chlorinated Polyethylene (CPE) Structure:

  H      Cl      H      H      Cl      H
  |      |      |      |      |      |
- C — C — C — C — C — C -
  |      |      |      |      |      |
  H      H      Cl      H      H      Cl

3. Chlorosulfonated Polyethylene (CSPE)
CSPE is produced by chlorosulfonating high-density polyethylene (HDPE), introducing both chlorine and sulfonyl groups into the polymer chain. This modification provides excellent chemical, weather, and UV resistance.

Hydrocarbon Structure of CSPE:

  H      Cl      H      SO2Cl  H      Cl
  |      |      |      |      |      |
- C — C — C — C — C — C -
  |      |      |      |      |      |
  H      H      Cl      H      H      SO2Cl

Comparative Chart



Detailed Differences and Properties
Chemical Composition:

CR is based on the polymerization of chloroprene, which includes chlorine atoms in its structure.

CPE is produced by chlorinating polyethylene, introducing chlorine into the polyethylene chain.

CSPE involves the chlorosulfonation of polyethylene, adding both chlorine and sulfonyl groups to the polymer.

Properties:

CR:

Chemical Resistance: Excellent resistance to oils, fuels, and many chemicals.

Weather Resistance: Very good resistance to weathering, ozone, and UV radiation.

Temperature Range: Typically operates from -40°C to 120°C.

Flame Retardancy: Good inherent flame-retardant properties.

Flexibility: Maintains good flexibility, making it suitable for dynamic applications.

CPE:

Chemical Resistance: Very good resistance to chemicals and oils, though slightly less than CR.

Weather Resistance: Good resistance to weathering and ozone.

Temperature Range: Typically operates from -50°C to 135°C.

Flame Retardancy: Good flame-retardant properties due to chlorine content.

Flexibility: Remains flexible at low temperatures, beneficial for cable sheathing and other dynamic uses.

CSPE:

Chemical Resistance: Excellent resistance to a wide range of chemicals, including acids and alkalis.

Weather Resistance: Highly resistant to weathering, ozone, and UV radiation.

Temperature Range: Operates from -50°C to 150°C.

Flame Retardancy: Enhanced flame-retardant properties due to the presence of sulfonyl groups.

Flexibility: Maintains good flexibility and mechanical properties, even at low temperatures.

Applications:

CR: Commonly used in automotive parts, wetsuits, diving gear, gaskets, and electrical insulation due to its durability and resistance to oils and weathering.

CPE: Widely used in wire and cable sheathing, industrial hoses and tubing, and roofing membranes due to its balance of chemical resistance and flexibility.

CSPE: Ideal for roofing membranes, industrial linings, and cable insulation, thanks to its superior chemical, weather, and UV resistance.

These differences highlight the unique properties and applications of CR, CPE, and CSPE, making each material suitable for specific industrial uses depending on the required performance characteristics and environmental conditions.

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