What is the chemical modification of EVA?

• EVA is shorter from the Ethylene Vinyl Acetate

Although the VAc group inherent in EVA makes it a polar elastomer, the compatibility of EVA with polar polymers and inorganic fillers remains to be improved. By grafting reactions to EVA by polar or non-polar monomers, more groups can be introduced into the EVA molecular chain, improving EVA performance as a compatibilizer for polyolefin with other polar polymers or inorganic fillers.

EVA workshop

Chemical analysis laboratory of EVA

The grafted monomers can be divided into polar functional monomers and non-polar functional monomers. Polar grafting monomers include carboxylic acids or their esters, carboxylic acid anhydrides, etc., such as maleic anhydride (MAH), acrylic acid (AA), and methyl methacrylate (MMA). In addition to grafting polar monomers to polyolefin molecular chains to improve its polarity and realize its functionalization, non-polar monomers such as styrene can also be grafted to polyolefin molecular chains to improve its properties.

Black and white eva foaming texture

Blue eva foamed texture

Melt grafting is a common method for EVA grafting, especially when the grafting monomer is maleic anhydride, and the molten polymer, grafting monomer and initiator are added to the screw extruder or banbury mixer under heating conditions. The melting reaction is suitable not only for polar monomers, but also for non-polar monomers, such as styrene.

Custom-made EVA and PU foam sheets

Custom-made EVA and PU foam sheet

• What are the characteristics of EVA foam products?

1.  Water resistance: Airtight cell structure, no water absorption, moisture resistance, and good water resistance.
   

2.  Corrosion resistance: Resistant to chemical corrosion such as seawater, grease, acid, alkali, antibacterial, non-toxic, tasteless, and pollution-free.

3. Processability: Easy to process such as hot pressing, cutting, gluing and laminating.
   

4. Anti-vibration: high resilience and anti-tension, high toughness, good anti-vibration, anti-skid and cushioning properties.

5. Thermal insulation: Excellent thermal insulation, cold insulation and low temperature performance, and can withstand severe cold and exposure.

6. Sound insulation: Closed cell foaming, good sound insulation effect.

7. Environmental protection: EVA foam is divided into two types: non-environmental protection and environmental protection. At present, most of EVA are environmentally friendly products and can be used with confidence.

Shockproof  EVA 0.5mm

Shockproof  EVA 1.5mm

• How to find the right EVA foam sheet for you?

No matter what type of application you have or the style of EVA foam sheet required, our expert team will help you find the perfect material based on shore hardness, please link to here What is Shore hardness in EVA foam sheet? , or contact us at  sales@shunhogroup.com.hk