INFLUENCE OF PHOTOCURABLE CHEMISTRY ON THE BIODEGRADATION OF UV-CURED PCL NETWORKS: English

Photocurable polyesters are studied extensively due to their rapid processing capabilities and potential environmental degradability. Poly(ε-caprolactone)-based resins are attractive because of their hydrolysable backbone and compatibility with UV-curing technologies.

The results show clear differences in biodegradation behaviour between the two photocurable chemistries. During the soil burial experiments, the PCL-acrylate networks exhibited significantly higher mass loss compared to the PCL-alkene systems, reaching approximately 6–7 % mass loss after ~80 days, while the PCL-alkene samples remained below 0.5 % mass loss over the same period.

Microbial metabolic activity, quantified through CO₂ evolution, also showed distinct trends between the two networks. During the initial stage of soil exposure, the acrylate networks generated substantially higher CO₂ levels, reaching approximately 70–80 mg CO₂ within the first 30 days, whereas the alkene networks produced roughly 35 mg CO₂ over the same time interval. At longer degradation times the CO₂ production of the alkene systems gradually increased and approached similar values to the acrylate networks after approximately 150 days (~100 mg CO₂).

These observations indicate that the network structure formed during photocuring strongly influences the accessibility of the PCL backbone to microbial degradation processes. The higher mass loss and faster initial CO₂ evolution observed in the acrylate systems suggest that differences in crosslinking mechanism and network architecture affect the interaction between microorganisms and the polymer matrix.

The polymer networks were first prepared via UV photopolymerization and buried in soil for extended periods of time. Every few days, the buried specimens were examined. The degradation process was evaluated by tracking the mass loss, evolved CO2, morphology thermophysical and mechanical properties as a function of degradation time.

Overall, this study provides new insights into the relationship between photocurable network chemistry and biodegradation behaviour, contributing to the development of UV-curable polymer systems with improved environmental performance.