Poly-D,L-Lactic Acid as a Compatibilizer for Nootkatone-Embedded Nylon 12 Fabric Manufacturing

Personal protection from mosquitos is dominated by topically applied aerosol sprays or lotions, which demonstrate efficacy durations of no longer than 10 h, thus encouraging the research and development of long-term insect-repelling devices. Repellent-loaded polymeric matrices have driven the development of insect-repelling apparel fabrics; however, most efforts either fail to offer the tensile properties demanded from apparel applications or only demonstrate repellency durations for multiple days. This study utilizes poly-D,L-lactic acid (PDLLA) as a compatibilizer between Nylon 12 and nootkatone for enhanced nootkatone retention throughout fabric manufacturing processes. Nootkatone-infused Nylon 12/PDLLA composites demonstrate up to a 14% increase in nootkatone retention throughout fabric manufacturing compared to pure Nylon 12, underscoring the importance of polymer/substrate miscibility on substrate retention. Moreover, while nootkatone-infused Nylon 12 filaments demonstrate decreasing tensile stress at breaks with increasing nootkatone content, Nylon 12/PDLLA filaments exhibit similar tensile properties regardless of nootkatone content. The PDLLA domains are suspected to behave as reservoirs for excess nootkatone to prevent its role as a defect within the Nylon 12 matrix. The resulting knits exhibit significant mosquito repellencies over 24 h dependent on the nootkatone concentration, thus demonstrating potential to embed insect repellent within high-performance polymeric filaments with effective mosquito repellencies. Therefore, the incorporation of PDLLA as a compatibilizer holds significant potential for enhanced nootkatone retention during Nylon 12 fabric manufacturing.