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The poly(vinyl chloride) was modified by polyhedral oligomeric silsesquioxane with 3-chloropropyl groups (CP–POSS) by POSS concentration between 0.5 and 5 wt%. Two methods of POSS incorporation were applied, i.e. direct solid powders mixing or addition of POSS to PVC solution in THF. The final samples were produced by melt mixing in the Brabender mixer chamber. By means of the glass transition temperature (T g ) determination the influence of a low contain of CP–POSS on the effect of plasticization of the PVC compounds was investigated. Depending on the measurements method (dynamic mechanical analysis DMA and differential scanning calorimetry DSC) and on the DMA measurement frequency various values of the T g were observed. It was found that CP–POSS may act as a plasticizer, leading to certain lowering of the glass transition temperature of poly(vinyl chloride). [ABSTRACT FROM AUTHOR]

Nanofibrous zirconia (ZrO 2) meshes were prepared from precursor fibers which were synthesized using the method of free-surface, high-yield alternating field electrospinning (AFES). The weight ratio of zirconyl chloride salt to polyvinylpyrrolidone (PVP) polymer in liquid precursors was investigated for its effect on the spinnability and formation of precursor fibers as well as on the resulting fibrous ZrO 2. The precursor fiber generation measured at a rate up to 5.6 g/h was achieved with a single flat 25-mm diameter alternating current (AC) electrode, which corresponded to production of up to 1.5 g/h of fibrous ZrO 2. The calcination process involved annealing the fibers at temperatures which ranged from 600 °C to 1000 °C and produced 0.1–0.2 mm thick fibrous ZrO 2 meshes. Individual nanofibers were found to have diameters between 50 and 350 nm and either a tetragonal (t -ZrO 2) or monoclinic (t -ZrO 2) structure depending on the calcination temperature. The annealed meshes with total porosity between 98.0 ± 0.2% and 94.6 ± 0.2% showed little deformation or cracking. Tensile strength and modulus of fibrous t -ZrO 2 meshes strongly depended on porosity and varied from 0.07 ± 0.03 MPa to 1.05 ± 0.3 MPa and from 90 ± 40 MPa to 388 ± 20 MPa, respectively. The m -ZrO 2 meshes resulted similar moduli, but much lower strengths due to their brittleness. A power-law relationship between the elastic modulus and porosity of AFES-derived nanofibrous t -ZrO 2 meshes, in comparison with other porous zirconia materials, was also investigated. The results of this study have demonstrated the feasibility of free-surface AFES in sizeable production of zirconia nanofibers and highly porous nanofibrous ceramic structures. [ABSTRACT FROM AUTHOR]

The goal of the study was to prepare a graphene (GN) dispersion in a poly (vinyl chloride) (PVC) solution with enhanced stability of the nanofiller thanks to the application of curcuma extract (CE). The stable dispersion was used to obtain PVC/GN nanocomposites with more homogeneous graphene by the solvent evaporation method. The CE effectiveness was compared with two commercially available dispersants in the form of oleic acid (OA) and polysorbate 80 (P80). The chemical composition of the CE was examined by Fourier-transform infrared spectroscopy. The dispersion stability was tested by the multiple light scattering method (Turbiscan Lab) and evaluated visually over a period of 40 days. The homogeneity of the filler's dispersion in the PVC matrix was evaluated by scanning electron microscopy and Raman spectroscopy. The application of the dispersing agents led to improved stability of the graphene dispersion in PVC solution. CE was the agent that most effectively improved the homogeneity of graphene dispersion, both in dispersions in a PVC solution and in PVC/GN nanocomposite films. Image 1 • PVC nanocomposites with graphene were prepared by solution casting method with the use of dispersing agents. • The dispersion stability of graphene in PVC solution was tested by turbidimetric method.. • Structure and graphene dispersion level in PVC matrix were investigated by SEM and Raman spectroscopy. • The use of Curcuma longa L. rhizome extract has significantly improved GN dispersion in poly (vinyl chloride) matrix. [ABSTRACT FROM AUTHOR]

The goal of the paper was to investigate the influence of graphene (GN) on properties and structure of suspensive poly(vinyl chloride) (PVC). PVC/GN nanocomposites were obtained by the solvent evaporation method, and their structures were evaluated using optical microscopy, SEM, FT-IR, XRD and Raman spectroscopy methods. Thermal properties of the obtained materials were studied by TGA. Electrical properties and swelling behaviour were also determined. The microscopic observations confirm a uniform distribution of graphene in the PVC matrix. The investigations carried out indicated an effect of graphene on a decrease in resistivity to a value which enabled to include the PVC/GN nanocomposites into anti-static materials group. On the basis of swelling studies, it has been found that the PVC/GN nanocomposites have a higher chemical resistance against acetone while compared to pure poly(vinyl chloride). The properties of the obtained materials depend significantly on content and dispersion level of graphene in the PVC matrix. An impact of GN on the acceleration of the PVC degradation process was found. • Poly(vinyl chloride) nanocomposites with different contents of graphene (GN) were prepared by solution casting method. • Structure and graphene dispersion level in PVC matrix by optical, SEM microscopy and XRD method were studied. • Thermal stability, swelling degree and electrical resistivity of the PVC/GN nanocomposites were studied. • The addition of graphene causes an increase in chemical resistance of poly(vinyl chloride) against acetone. • The obtained electrical properties of PVC/5% GN nanocomposite allow for including it into anti-static materials group. [ABSTRACT FROM AUTHOR]

New foaming method, enhanced by microwave irradiation, was elaborated and applied to obtain porous poly(vinyl chloride) and its composites with fine cell structure. The so called “thermal runaway” effect was observed during the heating of poly(vinyl chloride) under microwave irradiation. The temperature of this effect decreases as a result of additives incorporation into polymer matrix. Microwave irradiation allowed effective heating of extruded poly(vinyl chloride) and its composites with carbon black (CB) filler, behind the extruder head and decomposing azodicarbonamide (ADC) to obtain porous products. The use of CB additive to poly(vinyl chloride) significantly increased its ability to be heated under microwave irradiation as well as improved the cell structure and decreased the apparent density of final products. Among additionally used fillers (1 wt%) the montmorillonite caused the apparent density decrease of foamed materials ca. 10%, however beneficially influenced on the quality of cells structure, giving the products with isotropic cells and the highest cell density as well as keeping the tensile strength on similar level as in the case of the materials with CB and ADC only. [ABSTRACT FROM AUTHOR]