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In the present research program, chitosan has been mixed with polycaprolactone (PCL) (80 : 20) for using them for control delivery of doxycycline. Organoclay, Cloisite 30B of different concentrations 1, 2.5, and 5% has been blended with the composite. Chitosan is a natural biodegradable polymer where as polycaprolactone is a synthetic biopolymer. The blending of the two polymers has been carried out varying the proportion of nanoclay so that the composite can be a better drug carrier. The blends were characterized by Fourier Transmission Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Xray Diffraction (XRD) analysis. From the FTIR spectra, the various groups present in chitosan and PCL blend were monitored. The homogeneity, morphology, and crystallinity of the blends were ascertained from SEM and XRD data, respectively. The swelling studies have been carried out at different drug loading. Swelling study is an important parameter to predict the diffusion of the drugs from the matrix. The kinetics of the drug delivery system has been systematically studied. Drug release kinetics was analyzed by plotting the cumulative release data versus time by fitting to an exponential equation which indicated the non-Fickian type of kinetics. The drug release was investigated at different pH medium, and it was found that the drug release depends upon the pH medium as well as the nature of matrix.

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Pitting corrosion and susceptibility to chloride attacks are the shortfalls of reinforcement steel used in concrete structures. The present work proposes the deposition of electroless nickel coatings to provide barrier protection due to their proven corrosion resistance. The effect of deposition of Ni-P, Ni-P-W and Ni-P-Cu coatings on the corrosion behavior of Fe-600 grade rebars in 3.5% NaCl has been investigated with the aid of potentiodynamic polarization and electrochemical impedance spectroscopy. The corrosion potential of bare rebar was observed to be −653 mV while that of electroless Ni-P, Ni-P-W and Ni-P-Cu coatings was −436, −391 and −356 mV respectively. The corrosion current density of the rebars also decreased significantly by the application of electroless nickel coatings. Nyquist plots also revealed a bigger semicircular loop for the coated rebars. The chloride attack was severe on the bare uncoated rebar and scanning electron micrograph revealed severe cracking. On the other hand, the vulnerability of the electroless coated rebars to pitting corrosion decreased greatly.

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