Preparation of Zinc Hydroxystannate Coated Dendritic-Fibrillar Barium Carbonate and its Flame Retardant Effect on Soft Poly (Vinyl Chloride)

Abstract

Zinc hydroxystannate (ZHS) coated dendritic-fibrillar barium carbonate (ZHS/BaCO_3-F) was obtained by a simple ultrasonic assisted method at room temperature without any guide reagent; the flame retardant soft poly (vinyl chloride) (S-PVC) treated with ZHS/BaCO_3-F was prepared by melt blending and studied by the limiting oxygen index (LOI), univeral tensile testing machine, thermogravimetric analyzer-Fourier transform infrared spectroscopy (TGA/FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that ZHS/BaCO_3-F had a good dispersion in the PVC matrix, increased the LOI value and reinforced the S-PVC. The ZHS/BaCO_3-F played its role during the first degradation stage of S-PVC; the integrated effects of the earlier dehydrochlorination of ZHS on PVC, the reaction of ZHS/BaCO_3-F and HCl, and the thermal degradation of ZHS resulted in the production of H₂O, CO₂, olefins, aryl compounds, carboxylic compounds and alcohols, and the decrease of HCl production.     

Modification of cycloolefin copolymer and poly(vinyl chloride) surfaces by superimposition of nano- and microstructures

Cycloolefin copolymer (COC) and poly(vinyl chloride) (PVC) surfaces were patterned with nanopillars or with microbumps on which nanopillars were superimposed. The area of patterned surfaces was several square centimeters. Patterning was achieved by applying nanoporous anodized aluminum oxide (AAO) membrane as a mask in injection molding or imprinting. Nanostructures superimposed on microstructures were achieved by patterning the AAO mask with microstructures before anodization. Micro- and nanometer-sized structures could then be transferred simultaneously to polymer surfaces. Structures were characterized by SEM, AFM, and contact profilometry. The effect of different-sized structures on properties of the polymer surface was studied by contact angle measurements. Relative to the smooth surface, the increase in water contact angle on a COC surface with nanostructures superimposed on microstructures was up to 50°.     

Single/Double Soft-Templates Involved Synthesis of Polyaniline Blends: Interfacial Polymerization and Characterization by AC Impedance Analysis

Polyaniline (PANI) blends with single and double soft-templates (polyvinylpyrrolidone – PVP and/or sodium dodecylbenzenesulfonate – SDBS) were synthesized using interfacial polymerization. Fourier transform infrared (FTIR) spectral study confirmed blend formation. Polyaniline-polyvinylpyrrolidone (PANI-PVP) blend had submicron aggregates of 50–150 nm nanoparticles while PANI-SDBS blend had extensively agglomerated large size flakes/grains. Polyaniline-polyvinylpyrrolidone-sodium dodecylbenzenesulfonate (PANI-PVP-SDBS) blend had larger aggregates, besides significant number of smaller grains. Alternating current (AC) impedance analysis was performed to determine their electrical properties. At room temperature the AC conductivity of the blend materials was in the increasing order, PANI < PANI-PVP < PANI-SDBS < PANI-PVP-SDBS. But other parameters, like critical frequency and power law index s, exhibited a decreasing trend in the blend materials. With regard to frequency-dependence, all the materials showed constant AC conductivity at low frequencies, but at higher frequencies and at higher temperatures conductivity increased gradually. The obeyance of a universal power law and the range of s values (0.12 < s < 0.78) suggested a correlated barrier hopping (CBH) mechanism for AC conductivity of all the materials. The trends in electrical properties that were characteristic of the role of single/double soft-templates were explained in terms of improved π-electron delocalization and hopping mechanism.