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Natural Kosa silk is one of the textile fibers to be used in apparel application. Since it is proteinous and hygroscopic fiber and gets affected easily by microbes during usage and storage. Hence, this special type of silk produced in Chhattisgarh state of India, needs to be treated for the antimicrobial treatment for its better applications in various fields. Therefore, in the present work, the Kosa silk was modified by grafting of quaternary ammonium compound-containing monomer through thermo-chemical route. Experimental conditions for achieving optimum grafting of ionic monomer [2-(methacryloyloxy)ethyl] trimethyl ammonium chloride (MAETC) was investigated. Redox combination of ceric ammonium nitrate as a redox initiator and nitric acid (HNO3) as catalyst, by successively varying reaction conditions like concentration of initiator, catalyst and desired monomers under optimized reaction conditions were performed. The grafted silk material was characterized by Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction Analysis (XRD) techniques. The antibacterial study of grafted silk material having quaternary ammonium groups is an emerging group of antibacterial agents, which can be used as disinfectants. Using agar well method demonstrated that the grafted silk (KS-g-MAETC) inhibited the growth of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. As this grafted silk material has potent antibacterial activity, it may be used in the garment industry as well as for various biomedical applications, thus, serving the humanity. [ABSTRACT FROM AUTHOR]

Global warming and environmental pollution issues are the challenges that have prompted researchers around the world to recognize biodegradable material as an alternate solution for fossil fuel dependency. The previous literature motivates the researchers to identify alternatives to artificial reinforcement in composite materials. This work utilizes Calotropis gigantea fiber as a strengthening agent, which is generously available as an unused plant in India. Compression molding technique was used for the preparation of specimens with different fiber orientation (0°, 15°, 30°, 45°, 60°, 75°, 90°, 0°/90°, and 0°/45°/90°) Specimen with 0° fiber orientation registered a maximum value of 142.46 MPa, 93.13MPa, and 81.21 kJ/m2 in Flexural test, Tensile test and Impact test, respectively, than the other orientations. Mechanical testing results establish that the orientation of the fiber will prominently influence in improving the strength. The thermal studies on Calotropis gigantea fiber-epoxy composites through Thermogravimetric Analysis and Differential Scanning Calorimetry reveal that the composite will withstand more than 600°C temperature and confirm its thermal stability. The combined findings show that Calotropis gigantea fiber in polymer composite can be a possible reinforcing material and suitable for manufacturing accessories for automobile and household applications. [ABSTRACT FROM AUTHOR]