Novel bio-renewable castor oil based polyurethane (PU)–silica nanocomposite films were prepared using castor oil, 1,6-hexamethylene diisocyanate and dibutyltin dilaurate in tetrahydrofuran at room temperature. ATR-FTIR spectra confirm the formation of polyurethane and the presence of silica nanoparticles in the polyurethane matrix. The increase of Si nanoparticle content shifts the peak position of N–H and CO (both hydrogen and non-hydrogen bonded) groups present in the polyurethane structure. Furthermore, Raman spectra confirmed the urethane–amide interaction present in the polyurethane–silica nanocomposites. ²⁹Si CP/MAS NMR spectra evidence the formation and the presence of completely condensed SiO₂ species in the polyurethane nanocomposite films. The incorporation of silica nanoparticles increases the thermal stability of the above-mentioned polyurethane films, which can be seen from the increase in activation energy (E_a) values of the degradation process. The E_a values at two stages (T_max1 and T_max2) of the degradation process are 133, 139 and 157, 166 kJ mol⁻¹ for PU control and PU-5AMS (5 wt% amine modified silica nanoparticles), respectively. DSC results prove the interfacial interaction present between silica nanoparticles and the polyurethane hard segment, which decreases the melting temperature. Optical transmittance of the polyurethane films decreased with increasing silica content due to the scattering at the interfaces between the silica nanoparticles and polyurethane. It is interesting to note that the presence of silica nanoparticles gives reinforcement to polyurethane film, thereby increasing the storage modulus up to 24% for PU-5AMS. FE-SEM and HR-TEM images confirm the presence of silica nanoparticles in the polyurethane matrix.

Wastewater, spent solvent, spent process solutions, and sludge are the major waste streams generated in large volumes daily in electroplating industries. These waste streams can be significantly minimized through process modification and operational improvement. Waste minimization methods have been implemented in some of the electroplating industries. Suggestions such as practicing source reduction approaches, reduction in drag out and waste, process modification and environmental benefits, have also been adopted. In this endeavor, extensive knowledge covering various disciplines has been studied, which makes problem solving extremely easy. Moreover, available process data pertaining to waste minimization (WM) is usually imprecise, incomplete, and uncertain due to the lack of sensors, the difficulty of measurement, and process variations. In this article waste minimization techniques and its advantages on the improvement of working atmosphere and reduction in operating cost have been discussed.

The present investigation attempts at fabricating collagen-based scaffolds impregnated with sago starch capped silver nanoparticles (AgNPs), useful for biomedical applications, and aims at studying their physicochemical aspects. AgNPs synthesized through a chemical reduction method, capped using different concentrations of sago starch, are incorporated into collagen derived from fish scales, and lyophilized to form scaffolds. FT-IR spectra confirm and validate the interaction of sago starch capped AgNPs with collagen in the scaffolds. TGA and DSC results indicate enhanced thermal stability of collagen scaffolds impregnated with sago capped AgNPs compared to collagen alone. All the collagen scaffolds containing sago starch capped AgNPs show high tensile strength values for their use as wound dressing materials. Moreover, lower minimum inhibitory concentration values are obtained for the above capped AgNP collagen scaffolds, which indicate higher antibacterial activities compared to uncapped AgNPs tested against both gram positive and negative bacterial strains. The novelty is that the developed scaffolds are biodegradable and in vitro studies reveal them as biocompatible and suitable for tissue regeneration applications.