EVA Crosslinking with Organic Peroxides

Organic Peroxides – The Critical Crosslinking Agents for EVA Materials

Ethylene Vinyl Acetate (EVA) copolymer is a versatile thermoplastic widely used in solar encapsulant films, foam products, adhesives, and wire insulation due to its flexibility, transparency, and low processing cost. However, unmodified EVA suffers from poor thermal stability, low mechanical strength, and inadequate resistance to environmental stress. Organic peroxides solve these limitations by acting as high-efficiency crosslinking agents, transforming linear EVA molecular chains into a robust three-dimensional network.

Organic peroxides  initiate EVA crosslinking through a free radical chain reaction, triggered by thermal activation. The process unfolds in three stages:

Stage 1: Peroxide Decomposition. When heated to 130–170°C (typical EVA processing temperatures), the weak peroxide bond (–O–O–) breaks, releasing highly reactive free radicals. For example : XJ-BIPB decomposes into benzyl radicals,XJ-TBEC (a leading photovoltaic-grade peroxide) breaks down into tert-butoxy radicals at 135–140°C, ideal for low-temperature EVA film curing.

Stage 2: Free Radical Attack on EVA Chains . The released radicals abstract hydrogen atoms from EVA’s ethylene or vinyl acetate (VA) segments, creating reactive sites on the polymer chains. This step is critical for crosslinking efficiency

Stage 3: Crosslink Formation. Reactive EVA chain radicals combine with each other, forming covalent bonds between adjacent chains. This results in a three-dimensional network structure that eliminates EVA’s thermoplastic flow and enhances structural integrity. 

Organic peroxide crosslinking delivers transformative improvements to EVA’s core properties, making it suitable for high-demand applications,  Solar Photovoltaic (PV) Industry,Footwear & Sports Equipment,Wire & Cable,Automotive,Packaging & Protective Materials,Medical Devices and construction.

Common Organic Peroxides Used in EVA Manufacturing :