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Polymer blends along with 1-(4-methylphenyl)-3-(4-N,N, dimethyl amino phenyl)-2-propen-1-one (MPDMAPP) NLO-chromophore-doped composite films were prepared by solvent casting method using DMF. The optical properties were studied using UV-visible, refractive index, steady state fluorescence, and fluorescence microscopic imaging techniques. The UV-vis absorption spectra showed three absorption bands and were assigned to localized n ? p*, n ? p* inter band, and p ? p* transition of charge transfer groups. The observed changes in the absorption peak, edges, and intensity with dopant concentration are understood based on charge transfer complex (CTC) formation. The refractive indices of the composite films varied from 1.4937-1.5398 for red and 1.5165-1.5516 for green light respectively. The steady state fluorescence data showed both emission peak wavelengths and intensity changes with MPDMAPP doping level in blend. The fluorescence anisotropy (r) variations in the composite films indicate the suppressed molecular motion of MPDMAPP in the solid composite film. The fluorescence microscopic image of these composite films showed that the films are photochromatic in nature. These modified properties are thought to be due to the charge transfer upon excitation from the donor to the acceptor connected through benzene ring and CTC formation. POLYM. ENG. SCI.,

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The current paper explores the preparation of PVA nanocomposites by doping with zinc oxide (ZnO) nanoparticles using the method of coagulation and solvent casting technique. The dopant zinc oxide nanoparticle is prepared by simple precipitation method and is confirmed by the X-ray diffraction (XRD) studies. The XRD studies explore that the average particle size of the synthesized nanoparticles is 55 nm and show that the crystallinity factor of PVA nanocomposites is influenced by the interaction occurring between the PVA main chain and the ZnO nanoparticle. The FTIR spectroscopy suggests that the formulation of complexes occurring between the dopants and the PVA main chain is due to inter or intra molecular hydrogen bonding. UV-vis spectra explore the dramatic decrease in the optical energy gap of nanoparticles doped polymer composites and the variations of Urbach energy ( u ) related to crystallinity for various dopant concentrations. The mechanical properties of the PVA nanocomposites were explored using universal testing machine (UTM) that reflects that, for = 15% doping concentration, there is an increase in the tensile strength, stiffness, and Young's modulus, whereas, for = 7.5% concentration, the percentage total elongation at fracture is found to be the maximum. The morphological behavior and homogenous nanoparticle distribution in the composites were examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX).

Polymer composites of ZnO and WO3 nanoparticles doped polyvinyl alcohol (PVA) matrix have been prepared using solvent casting method. The microstructural properties of prepared films were studied using FTIR, XRD, SEM, and EDAX techniques. In the doped PVA, many irregular shifts in the FTIR spectra have been observed and these shifts in bands can be understood on the basis of intra/intermolecular hydrogen bonding with the adjacent OH group of PVA. The chemical composition, phase homogeneity, and morphology of the polymer composites of the polymer film were studied using EDAX and SEM. These data indicate that the distribution of nanosized ZnO and WO3 dopants is uniform and confirm the presence of ZnO and WO3 in the film. The crystal structure and crystallinity of polymer composites were studied by XRD. It was found that the change in structural repositioning and crystallinity of the composites takes place due to the interaction of dopants and also due to complex formation. The mechanical studies of doped polymer films were carried out using universal testing machine (UTM) at room temperature, indicating that the addition of the ZnO and WO3 with weight percentage concentration equal to 14% increases the tensile strength and Young’s modulus.