A simple, direct method for generating a nanohybrid of CdS quantum dots (QDs) in functionalized waste polymer shows good optical properties combined with photocatalytic activities. Homogeneous sulfonation of expanded polystyrene waste (EPS) forms partially sulfonated polystyrene (PSS). Hydrogelation of the PSS facilitates the attachment of CdS QDs through sulfonic acid groups by ion-exchange mechanism, followed by trapping within the polymer network, ultimately generating an organic/inoganic nanohybrid. X-ray diffraction verifies the existence of the CdS nanocrystals and defines their cubic crystalline structure and crystallite size. High resolution transmission electron microscopy shows the formation of QDs in the nanohybrid. A blue shift in ultraviolet−visible absorption and photoluminescence confirm the QDs formation. The polymer chains effectively passivate the surface of CdS nanocrystals that exhibit exciton emission (455−471 nm) with less surface defect state emission (540 nm). In addition, the photocatalytic activity of the composite in degrading an organic dye is demonstrated.

No abstract

The acrylic acid content in the copolymer influences the size of the CdS QDs as well as the linear and nonlinear optical properties of the copolymer.

The improvement in thermal and mechanical properties of Nanocomposites prepared with unsaturated polyester (UP) as polymer matrix and various loadings of amino‐modified nano kaolinite clay as filler has been studied. Mechanical stirring and ultrasonication resulted in better dispersion of the clay. For curing polyester resin, cobalt naphthenate was used as accelerator and MEKP as initiator. Dynamic Mechanical Analysis (DMA) was carried out to find storage and loss modulus. Thermal stability was found through thermogravimetric analysis and the evaluation of structure and morphology of the nanocomposites were done through XRD, SEM, and TEM. Nanocomposite with 3 phr of amino modified clay has shown higher storage modulus and an improved thermal stability of UP/clay nanocomposites has been established. Tensile strength and toughness of the composite have been found to achieve maximum values at 1 phr of clay and the storage modulus has had an improvement of 38% compared to neat UPR. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43245.

A simple aqueous method has been used for the direct synthesis of water-soluble sulfonated polystyrene (SPS) encapsulated CdS quantum dots (QDs). The aqueous solution of the QDs, stabilized by two SPSs of different sulfonation level, shows a blue shift in ultraviolet−visible (UV−vis) absorption and band edge emission. High resolution transmission electron microscope (HR-TEM) establishes the presence of quantum confined CdS particles. The sulfonation level of SPS influences the size of QDs and strongly affects the photoluminescence (PL). The CdS QDs passivated by SPS with less sulfonation level exhibit only band edge emission (463 nm), while QDs in aqueous solution of SPS with high sulfonic acid content emits predominantly defect state emission (610 nm) against the band edge emission (463 nm). The PL of the SPS-CdS nanocomposites demonstrates an interesting variation in emission spectra and quantum yield via the change in sulfonation level, the change in pH and on keeping in aqueous solution. In addition, the z-scan measurements show negative nonlinear refraction coefficient, indicating self-defocusing phenomena. The absolute value of the third order nonlinear refractive index and nonlinear absorption are decided by the CdS QDs surface chemistry.