Facile exfoliation and physicochemical characterization of Thespesia populnea plant leaves based bioplasticizer macromolecules reinforced with polylactic acid biofilms for packaging applications.

Plasticizers are active ingredients added to the polymer to increase its workability. Since synthetic plasticizer is not ecofriendly and toxic in nature, it is a real cause for concern. On this basis, our study focuses on plasticizer extraction from plant-based resources. In this research work, Thespesia populnea leaves are utilized for the isolation of biological macromolecules with a plasticizing effect for biofilm applications. This extraction process is done through solvent extraction, amination, slow pyrolysis, and surface catalysis process. The physico-chemical and microstructural characterization of novel plasticizer particles were studied for the first time. The lower crystallinity index and crystalline size obtained from X-ray diffraction is 50.08 % and 20.45 nm respectively. Energy dispersive spectroscopy, particle sizer analysis, atomic force microscopy, and scanning electron microscopy are used to assess surface morphology of this plasticizer. The thermogram and differential thermal analysis curves give the information about degradation behavior of plasticizers and their thermal stability. The glass transition temperature of the extracted plasticizer is 60.56 °C. The plasticizing effect of the plasticizer is studied through film fabrication of polylactic acid which was blended with the extracted plasticizer. The mechanical property of biofilm was improved with the addition of plasticizer. The elongation break percentage (for 5 % plasticizer 46.12 %) was increased compared to others with moderate tensile strength. However, the tensile and elongation modulus decreases with the increase of plasticizer content. The crystallinity of the PLA film was improved after the plasticization. The thermal stability also increased with 3 % addition of the plasticizer. The isolated plasticizer was soluble in water and its molecular weight ≈380.

Preparation and characterization of carrageenan/silver nanoparticles/Laponite nanocomposite coating on oxygen plasma surface modified polypropylene for food packaging.

In this work, the nano composites of carrageenan/AgNPs/Laponite were prepared and coated on the oxygen plasma surface modified polypropylene film to enhance the barrier and adhesion properties. The mechanical, barrier, adhesion and antimicrobial properties were also studied to use for food packaging applications. The polypropylene film was surface modified with oxygen plasma treatment for 60 s. The AgNPs are prepared by green synthesis method from the Digitalis purpurea plant. Then the carrageenan based nanocomposites were coated by roller coating method with the thickness of 24 µm. By using scanning electron microscopy, the morphology of the coating was investigated. The Laponite and AgNPs dispersion was analyzed by X-ray diffraction analysis. The tensile and adhesion strength of the coated film was increased and the OTR and WVTR were decreased after the incorporation of Laponite and AgNPs. It exhibited the strong antimicrobial activity against the E. coli and S. aureus.