Multifunctional PCL/Lignin-PCL Composite Films for Delivery of Atrazine and Metribuzin for Sustainable Agriculture Applications

Sustainable agriculture calls for the development of eco-friendly materials that possess desired properties and functionalities. In this study, the effect of incorporating lignin-grafted poly-(ε-caprolactone) (LN-PCL) into a PCL matrix was evaluated. LN-PCL was synthesized by ring-opening polymerization (ROP), yielding polymers with varying PCL degrees of polymerization (DP 26-101) and amphiphilic properties. Incorporating LN-PCL into PCL films enhanced hydrogen bonding, crystallinity, and doubled Young's modulus. SEM analysis showed smoother surfaces with higher DPs, while lower DPs reduced the contact angle from 78° to 68°. LN-PCL films absorbed >98% UVAB and >94% UVC light regardless of DP and degraded within 30 days. Release studies indicated controlled release rates of ATZ (<16%) and MTZ (46%) over 10 weeks. Overall, the UV protection, surface, mechanical, and controlled release properties of the LN-PCL/PCL films support the potential of these films as a carrier for chemicals with applicability in agriculture.