ABSTRACT:The preparation of nanocomposites of poly (ethylene terephthalate) (PET) and lamellar zirconium phosphorous compounds by melt extrusion was investigated. Two types of zirconium phosphorous compounds were synthesized by the direct precipitation reaction method: a-zirconium bis(monohydrogen orthophosphate) monohydrate (ZrP) and organic-inorganic hybrid layered zirconium phenylphosphonate (ZrPP). Composites containing 2 and 5 wt % ZrP and ZrPP were prepared in a twin-screw extruder and specimens were obtained by injection molding. The extent of dispersion of the layered filler in the composite matrix was investigated by X-ray diffraction and transmission electron microscopy (TEM). The crystallization and thermal properties were analyzed by differential scanning calorimetry and thermogravimetry, and the mechanical properties were evaluated by tensile tests. Whereas ZrP-containing composites showe characteristic diffraction peaks at 2y 11.78 (d ¼ 7.54 Å ), indicative of no delamination, ZrPP showed practically no low-angle diffraction peak at 2y 5.58 (d ¼ 15.24 Å ), indicating loss of the layered order. TEM images of ZrPP particles indicated the formation of an intercalated/partially delaminated nanocomposite. The behavior was attributed to the higher affinity of the polyester with phenyl groups on the platelet surface of ZrPP. In both cases, the addition of the fillers increased the crystallization rate and the modulus.
In order to study the influence of different sulfonation routes on its thermal and structural properties sulfonated polyaniline (SPAni) was prepared. FT-IR revealed that the formation of PAni salt or ring sulfonation depends on the route. UV-visible spectra pointed out that the level of the PAni protonation was dependent on the sulfonation route. A new approach was given for TG/DTG and DSC results correlating different energy levels with the distinguished sulfonation routes. The TG/DTG degradation steps and the amount of the released material corroborated the structural differences of the polyanilines. For each DSC first regime of heating, a broad and intense peak (from -30 to 250 °C) with different level of energy was noticed. That peak could be ascribed to the multiple relaxations and breaking of the PAni intra and inter hydrogen bonds after sulfonation.
In this paper, a continuous polymeric matrix highly filled with fiber of sugarcane bagasse has been obtained and its feasibility as an ink-absorbing material has been evaluated. In order to study the effect of the amount of cellulose fiber on the surface printability, contact angle measurement using different liquids—water-based inks, ethanol and ink for ink-jet printers—and printing tests were performed on composites of high density polyethylene (HDPE) and sugarcane bagasse (SCB). The composites were processed in a Haake internal mixer, using the SCB without any previous chemical treatment or compatibilizer. The differential scanning calorimetry (DSC) and derivative thermogravimetry (TG/ DTG) revealed an increase in the thermal stability and in the degree of crystallinity of the HDPE. The optical microscopy (OM) and scanning electron microscopy (SEM) showed that the cellulosic material was homogeneously embedded within the HDPE matrix. In order to assess the resistance of the composite sample to the pull strength of the printer, tensile tests were applied to the composites and the results were compared to known paper samples. The best result was achieved in the composite with the highest content of SCB, as well as the shortest drying time
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