Ethylene photo-cross-linking

The occurrence of these reactions is restricted to the amorphous phase. Therefore, the photo-cross-linking process has to be performed at temperatures exceeding the crystalline melting point in the case of highly crystalline polymers such as polyethylene. The cross-linking efficiency can be strongly enhanced by the addition of small amounts of multifunctional compounds such as triallyl cyanurate, TAG (see Chart 7.9), or by the incorporation of special diene moieties into copolymers such as ethylene propylene diene copolymers (EPDM elastomers) [33]. 

A gel electrolyte consists of an ion conducting polymer, such as polyoxyethylene or a polymer with polyoxyethylene segment, and an ion source. Hexafluorophosphate or tetrafluoroborate salts of lithium are commonly employed as the ion source. Other common components of the gel are liquid electrolytes like ethylene carbonate or propylene carbonate, both of which are used to increase the overall ion conductivity. Cross-linking agents, such as photo cross-linked acrylates or polyurethanes, can be incorporated to improve the mechanical stability of gel electrolytes. 

Chen, X.-S., and Wang, J. (2007) Synthesis and characterization of photo-cross-linked hydrogels based on biodegradable polyphosphoesters and poly(ethylene glycol) copolymers. Biomacromolecules, 8 (11), 3375—3381. 

Chen, S.-L., Benziger, J.B., Bocarsly, A. B., and Zhang, T. (2005). Photo-cross-linking of sulfonated styiene-ethylene-butylene copolymer membranes for fuel cells. IruL Eng. Chem. Res. 44, 7701. 

A simple formulation of a gel electrolyte may be composed of ethylene carbonate, lithium triflate, and poly(ethylene glycol)s as the polymeric component. To increase the mechanical strength cross-linking the polymeric component may contain acrylate groups that can be polymerized photo-chemically after the cell assembly and so modify the electrolyte to become an adhesive for fhe cell. ... 

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