Approaching new biomaterials: copolymerization characteristics of vinyl esters with norbornenes, allyl esters and allyl ethers

Abstract

Vinyl ester-based monomers for radical photopolymerization have recently been shown to be promising alternatives to (meth)acrylates through lower irritancy and cytotoxicity. Vinyl ester monomers are becoming increasingly important on account of new, more cost-efficient synthetic production methods, not to forget their increased reactivity and improved material properties in combination with thiol–ene polymerization. Due to their biocompatibility and degradability, these monomers are more frequently used in tissue engineering. Nevertheless, the material properties can be improved by possible copolymerizations with other monomers. Therefore, the copolymerization behavior of vinyl ester with norbornene, allyl ether and allyl ester has been studied fundamentally in a photoreactor via free radical photopolymerization. Here, the consumption of double bonds of the monomers has been identified using NMR spectroscopy. Copolymerization parameters have been determined using the Kelen–Tüdös method. Results show equal consumption of vinyl ester and co-monomer double bonds leading to alternating copolymerizations. The double bond conversion was confirmed via in situ real-time near-infrared photorheology. Mono- and difunctional vinyl esters with co-monomers have also provided further insight into the polymer network of these copolymers.