Photocurable vinyl esters have recently been introduced as suitable alternatives to (meth)acrylates in biomedical applications. While (meth)acrylates exhibit good mechanical properties, their cytotoxicity and degradation products principally disqualify them from medical use. Vinyl esters exhibit much lower cytotoxicity and give biocompatible degradation products, but their disadvantage are relatively low mechanical properties, particularly brittleness. This study focuses on the identification of suitable functional groups that are capable of introducing enhanced impact strength into the vinyl ester network, for example, cyclic structures or urethane groups. A new pathway for the synthesis of vinyl esters carrying these groups was established and resulting monomers were tested regarding their photoreactivity and cytotoxicity. Mechanical properties and degradation behavior of the new materials were investigated as well. In addition, the thiol-ene reaction was utilized to enhance photoreactivity and tune hydrolytical degradation. The new vinyl esters exhibit excellent biocompatibility and good photoreactivity that can be significantly enhanced with thiols on to the level of highly photoreactive acrylates. Ultimately, the impact strength was improved by a factor of more than ten compared to commercial vinyl esters.

Recently, vinyl carbonates have been demonstrated to be a versatile alternative to acrylates and methacrylates in biomedical applications as they exhibit photoreactivity and mechanical properties on a level or even above (meth)acrylates. Furthermore, much lower cytotoxicity as well as degradation via a surface erosion mechanism qualify them for medical use. However, it is highly desirable to improve the mechanical properties of vinyl carbonates to reach the performance of PLA. Thus, the main focus of this study lies on designing vinyl carbonates with suitable functional groups that are capable of augmenting mechanical properties of vinyl carbonates, e.g. cyclic structures or urethane groups, and implementing them into the vinyl carbonate structures. Resulting monomers were tested regarding their photoreactivity and cytotoxicity. Furthermore, cured specimens were investigated concerning their mechanical properties. In addition, the thiol-ene reaction was utilized to further improve photoreactivity. The new vinyl carbonates exhibit excellent biocompatibility and photoreactivity that can be significantly enhanced through the addition of thiols onto the level of highly photoreactive acrylates. Most importantly, results showed that the mechanical properties could be improved onto the level of PLA and above.