Both POE and EPDM belong to the polyolefin family, however POE is classified as a thermoplastic elastomer, whereas EPDM is a synthetic rubber. Why are they so different from one another? Let's examine their composition, functionality, processing method, and application

Both POE and EPDM have good qualities including aging resistance, ozone resistance, and chemical medium resistance. In general, their primary chain structures are extremely comparable. POE has a little lesser hardness and wear resistance than EPDM. While EPDM has greater mechanical qualities overall, it requires vulcanization during production and is challenging to recycle later. POE is easily recyclable after being discarded and may be mixed and injected directly.

1. Composition

The terpolymer of ethylene, propylene, and non-conjugated dienes is known as EPDM (EPDM, Ethylene-Propylene-Diene Monomer).

The primary chain of the EPDM macromolecule is saturated. In EPDM, E stands for ethylene, P for propylene, and D for the third unit, which in this case is diene, which has two double bonds. As a result, each of these compounds—ethylene, propylene, and diene—has a double bond that contributes to the polymerization of the main chain and ultimately results in the formation of a saturated main chain.

An ethylene–olefin copolymer elastomer is known as POE, and a -olefin is a single olefin with a double bond at the end of the molecular chain. The commercially available kinds at this time include propylene, butene (4C), hexene (6C), and octene (8C).

POE is essentially branching polyethylene; the polyethylene chain crystalline area serves as a physical crosslinking site; and the addition of -olefin weakens the polyethylene chain crystalline region and transforms it into an amorphous region with rubber-like flexibility. As a result, POE possesses elastomer-like characteristics.

The picture depicts two common POE basic structures. Ethylene and octene make up the A structure. Octene has 8 Cs. Ethylene and butene make up the B structure. Benzene has four Cs. The so-called 8C and 4C points are these.

2. Execution

The major performance qualities of EPDM are:

Only the side chains of EPDM include unsaturated double bonds, giving it good aging resistance like ozone resistance, heat resistance, and weather resistance. The main chain of EPDM is made up of chemically stable saturated hydrocarbons.

EPDM has excellent insulating qualities, is non-polar in nature, is resistant to polar solutions and chemicals, absorbs little water, and has low water absorption.

The main chain is highly flexible, and a side methyl group on the propylene breaks up the macromolecules' close-knit arrangement, prevents ethylene and propylene from crystallizing, and increases EPDM's durability.

The polyolefin family member EPDM has superior vulcanization properties. Among all rubbers, it has the lowest specific gravity. Without significantly changing its characteristics, it can absorb a lot of oils and fillers. Thus, cheap rubber compounds may be made.

The third monomer's kind and amount, the ratio of ethylene to propylene, molecular weight, and distribution may all be altered during the manufacturing of EPDM rubber to alter its properties.

The following structural characteristics of POE, together with their accompanying superior performance

Octene has exceptional toughness and outstanding processability due to the physical cross-linking sites provided by the soft chain coil structure and the crystalline ethylene chain;

It has excellent physical and mechanical properties (high elasticity, high strength, and high elongation), as well as good low temperature performance. Because of its very narrow relative molecular mass distribution and short chain branches, the material is suitable for injection and extrusion. During the output process, deflection is difficult to achieve.

Because of its saturated molecular structure and few tertiary carbon atoms, it possesses exceptional heat and UV resistance;

High extrusion and increased production can be achieved with strong melt strength and shear sensitivity;

A product's weld line strength and the dispersion impact of fillers can both be enhanced by good fluidity.

3.Processing technology

The processing of EPDM rubber involves a number of steps, including banburying, pulling, filtering, calendering (or extrusion molding), vulcanization, and others.

However, POE may be processed using thermoplastic processing machinery and has high processing performance. It is possible to process it at exceptionally high processing rates while maintaining somewhat higher processing temperatures and pressures.

POE can be processed in calenders into sheets or films, blown, and other processes in addition to injection molding and extrusion molding. POE does not require mixing or vulcanization during production, however crosslinking can increase tensile strength, heat resistance, and chemical resistance.

Commercialized POE is available as granular material that may be put directly to other materials, such PP, for modification. This can significantly lower production costs.

4.Application 

It's common to utilize EPDM. EPDM rubber can be used for wiring, cables, building door and window insulation, tires, plastic runways, and other things. It is frequently employed in the modification of PP (polypropylene) and the creation of TPV (thermoplastic vulcanizate). It may also be utilized in conjunction with EVA (ethylene-vinyl acetate copolymer) materials as shoe materials.

EPDM plastic runway

Used together with EVA rubber and plastic, applied in the midsole of shoes

PP-EPDM-TD15 rear bumper

Application of POE materials may be divided into three primary categories: impact modifiers (also known as tougheners), molded goods, and extruded products.

Due to the structural similarities between POE and PP, EVA, EPDM, etc., these materials work well together, and POE is frequently used in wires and cables, toys, medical equipment, modified PP vehicle components (bumpers, fenders, etc.), and modified EVA shoe midsoles.

When used as an impact modifier for PP, POE offers many benefits over conventional EPDM:

First, the difficult granulation or premixing procedure of bulk EPDM is eliminated since granular POE and granular PP are simple to combine;

Second, POE and PP combine and disperse more effectively. Compared to EPDM, the blend's phase state is more refined, increasing impact resistance;

The use of POE can retain high yield strength and fluidity while toughening, in contrast to the use of ordinary rubber, which enhances impact strength while decreasing the product's yield strength.

These are a few POE application examples.

POE and EVA are used together for foaming, and have been widely used in foaming products such as beach shoes, slippers, midsoles of sports shoes, mouse pads, seat cushions, Styrofoam materials, thermal insulation materials, cushioning sheets, and bag linings.

Adding POE blending granulation to PP or PE recycled materials, or direct injection molding, will greatly improve the performance of PP/PE recycled materials, such as plastic pallets, plastic turnover boxes, plastic tool boxes, plastic office and chair accessories, beach Chair etc.

The product obtained by mixing EVA and POE is more flexible, has better bending resistance, lighter product, and better resistance to environmental stress. It is widely used in vacuum cleaner hoses, washing machine hoses, and drainage pipes.

POE can be filled with a large amount of Al(OH)3 or Mg(OH)2, and its hardness and strength change rate is low. It has become a trend to replace EVA or use it together with EVA to produce halogen-free flame-retardant cable materials.