Abstract This work aimed to obtain and analyze composite materials made from green polyethylene and calcium carbonate extracted from chicken eggshells. The shells were collected and prepared for later extraction of calcium carbonate. With the X-ray diffraction analysis it was possible to confirm that both the in natura reinforcement and the calcined one, have the same polymorph mineral (calcite). With regard to thermal behavior, compounds with in natura reinforcement showed greater mass loss due to the moisture contained in them. The results showed a significant increase in Young’s moduli of the composites compared to the pure polymer. The scanning electron microscopy showed good dispersion and adhesion between the reinforcement materials and matrix. In view of the results, eggshells have the potential to be used as fillers, where greater rigidity is required. Since these materials come from a waste material, with low cost, their use becomes even more viable.

Abstract In this study, the influence of carbon black (CB) trimodal mixture, with different medium particle sizes, on the colorimetric and rheological properties of polyethylene was evaluated. Three different types of CB were selected, with particle sizes of 15nm (S), 38nm (M), and 75nm (L) and combined, generating a Design of Experiments (DOE) with 19 formulations to be dispersed at 30% in low density polyethylene (LDPE) in twin screw extruder. Such formulations were evaluated in performance and process properties, such as Tint Strength, Melt Flow Index (MFI), and Total Transmittance (TT). It was observed that the mixtures between small (S) and medium (M) particles developed greater tinting strength and lower viscosity, demonstrating the synergy of the mixture, which was superior in the performance of the mixture containing only a particular of 15nm (S) that would have greater potential for results.

Abstract In this work, the influence of Specific Mechanical Energy (SME) to disperse a trimodal distribution of carbon black (CB) by extrusion was studied to evaluating the effect on LDPE films properties (colorimetric and rheological). Three types of CB were previously evaluated (PART1) and determined that the best formulation was the combination between small (S) and medium (M) particles (F18 and F13), obtaining greater tinting strength with lower viscosity. In this work (PART2), these formulations were processed with different SME levels by varying the extrusion parameters, like screw rotation speed (N) and feed rate (Q), modulate the SME. The result of each process was evaluated by Tinting Strength, MFI, Total Transmittance and it was determined that the process with 600 rpm and 10 kg/h feed rate, generating a SME of 0.29 kWh/kg for F18-P03, developed the best results, mainly in the Tinting Strength, from 126.7% to 133.2% related to F18 (PART1).

Abstract The (de)hydrogenation properties of a TiFe intermetallic compound (IMC) alloy activated by cold rolling inside a glovebox at ambient temperature were investigated by kinetic measurements, x-ray powder diffraction (XRD), and transmission electron microscopy (TEM). Rate-limiting steps were identified by testing kinetic models on hydrogen absorption and desorption curves. To prevent surface poisoning during air exposure, the TiFe IMC was also cold rolled with polytetrafluoroethylene (PTFE) and ultra-high molecular weight polyethylene (UHMWPE). The addition of either PTFE or UHMWPE to nanostructured TiFe by cold rolling did not produce a polymer-metal composite with O2 poisoning resistance, regardless of the polymer-mixing way adopted. This occurred because large surfaces of the particles were not adequately coated with polymer. The results identify challenges to the TiFe IMC polymer-covered material that must be overcome before a methodology can significantly contribute to the formation of nanostructured TiFe-polymer composites with enhanced hydrogen storage properties. The diffusion-controlled reactions in the cold-rolled TiFe IMC without polymer were prevalent in all cases, as predicted by the Jander three-dimensional diffusion model. The main contribution of this work regards estimation of the amount of hydrogen released, which was 0.60% after 6 min and reproducible for the three subsequent cycles.

The effect of maleic anhydride (MA) content on morphological, thermal, thermomechanical and mechanical properties of PA6/AES/MMA-MA (66.5/28.5/5 wt%) system was investigated. In general, the simple incorporation of MMA-MA to PA6/AES system is responsible for enhancements in mechanical performance. PA6/AES/MMA-MA3% and PA6/AES/MMA5% exhibited similar morphology and final properties, indicating no MA content effect on the studied system. On the other hand, PA6/AES/MMA-MA10% exhibited a quite different morphology and lower mechanical performance compared to the other compatibilized blends. Such unexpected behavior was not attributed to the effective maleic anhydride content in this composition, but to the reduced molar mass resulted from the excess of non-reacted MA monomer during the synthesis procedure.

Nanocomposites of an organic-modified montmorillonite (MMT) and polyamide 6 (PA6) with a residual monomer were produced by melt mixing in a torque rheometer. By wide angle X-rays diffraction (WAXD), intercalated/exfoliated structures were observed in the PA6/MMT nanocomposites with 3 and 5 wt. (%) of MMT; on the other hand, when 7 wt. (%) of MMT was added, a nanocomposite with exfoliated structures was obtained due to the predominant linking reactions between the residual monomer and the "nanoclays" organic surfactant. Solutions of these PA6/MMT nanocomposites at 15, 17 and 20 wt. (%) in formic acid were prepared. The 3 and 5 wt. (%) nanocomposites were successfully electrospun; however, electrospinning of the 7 wt. (%) nanocomposite was not possible. WAXD, scanning and transmission electron microscopy results showed that the 3 and 5 wt. (%) nanofibers with average diameter between 80-250 nm had exfoliated structures. These results indicate that the high elongational forces developed during the electrospinning process changed the initial intercalated/exfoliated structure of the nanocomposites to an exfoliated one.