Characterization of functional bio-plasticizer from Millettia pinnata leaf biomass as a green alternative to petroleum-based plasticizers

With the increasing demand for sustainable and non-toxic alternatives, bio-based plasticizers derived from renewable sources are being developed as environmentally friendly replacements for conventional synthetic plasticizers such as phthalate esters, adipates, trimellitates, benzoates, sebacates, etc. This study investigated the extraction of solid plasticizers from the leaves of the abundantly available Millettia pinnata plant (MPL). It was chemically treated through processes including phytoremediation, slow pyrolysis, alkylation, and filtration to extract the plasticizers. Scanning electron microscopy revealed a porous, smooth surface, while atomic force microscopy further supported the morphological suitability of these materials for biofilm and composite preparation. Fourier transform infrared spectroscopy identified functional groups such as alcohol, amine, amide, hydrocarbon, alkene, and aromatic compounds, while UV analysis confirmed the presence of alcoholic, amino, and carboxyl constituents. The primary phytoconstituents detected in the MPL were molecularly docked to determine binding affinity. Thermal analysis demonstrated that the extracted plasticizer can withstand temperatures up to 267 °C. Furthermore, X-ray Diffraction analysis yielded a high crystallinity index (47.5%) and a low crystalline size (11.3 nm), desirable characteristics in plasticizers. These findings suggest that plasticizers extracted from MPL leaves could serve as a viable, eco-friendly alternative to conventional synthetic plasticizers, offering a sustainable replacement with considerable functional benefits. © The Author(s) 2025.