Synthesis of a castor oil-based quaternary ammonium surfactant and its application in the modification of attapulgite

Castor oil-based quaternary ammonium surfactant (COQA) was synthesized by an ester-exchange reaction of refined castor oil (CO) (raw material) with N,N-dimethyl ethanol amine followed by quaternization with epichlorohydrin (ECH). Its surface activity and structural features were determined. The critical micelle concentration (CMC) of the surfactant at 25 °C was 1.79 × 10−3 mol/L. The surface tension of an aqueous COQA solution at CMC was 38.19 mN/m. Subsequently, the synthesized COQA was used to modify attapulgite (ATP) by binding it to the surface of ATP. The change in the morphology of the modified-ATP (M-ATP) was attributed to the presence of the COQA bound to the surface of the rod-shaped crystals, although the crystal structure of the silicate did not change. Compared to ATP, the microstructure of the M-ATP was less rigid.

Smart Textiles Coated with Eco-Friendly UV-Blocking Nanoparticles Derived from Natural Resources

Herein, eco-friendly iron titanate nanoparticles, FeTiO₃ (FT), derived from natural resources (like ilmenite sand) were coated onto cotton fabrics (CF) to develop smart textile with enhanced UV-shielding property. The FT nanoparticles were dispersed in a polyurethane (PU) matrix, and the resulting nanocomposite was coated on CF. In addition, few sandwich architectures were designed by rationally stacking CF coated with PU and FT nanoparticles. The resulting sandwich structures blocked UV rays mainly by absorption. FT nanoparticles were comprehensively characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-vis, vibrating sample magnetometer, and thermogravimetric analysis. FT was suitably surface-functionalized to enhance the quality of dispersion in PU, thereby facilitating effective coating on CF. The latter was systematically evaluated by microscopic and spectroscopic techniques. In addition, flammability of the coated CF was evaluated and the char was assessed to gain insight into the fire-retardant properties. Interestingly, CF coated with FT exhibited a strong UV-shielding ability in sharp contrast to CF coated with PU. Further, the sandwich architecture consisting of CF with FT and PU resulted in an increase in the ultraviolet-protecting factor value to >50 compared to only PU-coated CF. Our results indicate that the sandwich structure holds excellent promise in the quest of designing smart textiles with enhanced UV shielding.