In the present work, chitosan was applied on to the braided silk sutures at three different concentrations and the effects of chitosan coating on the characteristics of braided silk suture were explored. The frictional characteristics of BSS were studied by determining the dynamic coefficient of friction at various normal loads and sliding speeds. At higher normal loads and sliding speeds, both the chitosan coated and uncoated braided silk suture showed lower value of dynamic coefficient of friction. Furthermore, for all the tested normal loads and sliding speeds the chitosan coated braided silk suture showed lower value of dynamic coefficient of friction than the untreated BSS. Instron tensile tester was used to measure the tenacity and knot strength. The result showed that the tenacity and knot strength of braided silk suture increases with the increase in chitosan concentration. The scanning electron microscopy reveals the uniform deposition of chitosan on to the surface of the braided silk suture. The antimicrobial activity of chitosan coated braided silk suture against Escherichia coli and Staphylococcus aureus were evaluated using agar diffusion method (SN 195920) and shake flask method (AATCC 100). The braided silk suture treated with higher chitosan concentration exhibits excellent antimicrobial activity against both the bacteria.

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In this study, an attempt was made to enhance the oil sorption capacity of nettle fibers by grafting of butyl acrylate. Box–Behnken experimental design was used to study the effect of parameters such as reaction time, reaction temperature and monomer concentration-to-fiber ratio on graft add-on (%) and oil sorption capacity. At 4-h reaction time, 70℃ temperature and 2% monomer concentration-to-fiber ratio, highest graft add-on (%) and oil sorption were attained. Maximum oil sorption capacity of grafted nettle was 36.60 g/g and 25.56 g/g against crude oil and vegetable oil, respectively. Grafted nettle fibers were also subjected to characterization by Fourier-transform infrared spectroscopy, scanning electron microscopy and contact angle tests. Reusability test results showed that grafted nettle exhibited better oil sorption capacity than unmodified nettle even after seven sorption–desorption cycles. It is also observed that the oil sorption capacity of grafted nettle was higher than that of commercial polypropylene material. Based on these results, it is concluded that functionalized nettle prepared by grafting technique can be a potential material for oil spill treatment.

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