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In this work, PVDF composites containing 0.2% (m/m) of carbon nanotubes (MWCNTs), PVDF with 5.0% (m/m) of zinc oxide (ZnO), and composites containing both particles in the same contents in the matrix were melt processed in a mini-extruder machine with double screws, using the counter-rotation mode. Composites were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), dynamic-mechanical analysis (DMA), and contact angle tests (CA). The samples presented the predominance of the α phase, with an increased degree of crystallinity as well as an increase in dimensional stability by incorporating both fillers, showing a synergistic effect between these particles, as shown on FTIR, DSC, and XRD results. SEM images showed a good dispersion of high aspect ratio particles. In general, DMA and TGA analysis showed that composites had not decreased their thermal and mechanical performance when compared to neat PVDF. Results of CA analysis showed an increase in the hydrophobicity of the sample containing MWCNTs. Permeability tests were also performed using a differential pressure system, combining high temperature and pressure, obtaining permeability measures and time lag. This work presents an alternative of composite materials, suggesting its application in the internal pressure sheath layers of oil and gas flexible pipes. K E Y W O R D S composites, nanoparticles, nanotubes, oil and gas, thermoplastics 1 | INTRODUCTION Flexible pipes are transportation lines used to connect the wells, in the seabed, to the production units, transporting oil and gas fluids in offshore applications. These pipes possess a multilayer structure, with polymeric layers and helically wound metallic wires, designed to withstand tensile loads, high pressure, and temperature. 1-3 Different layer combinations are possible, depending on the intended service conditions. Still, in general, flexible risers present a typical configuration, with the following layers: interlocked carcass (metal),

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In this work, the preparation and characterization of nanocomposites of commercial polyamide‐11 reinforced with multi‐walled carbon nanotubes (MWCNT), untreated, oxidized or with the modified surface through silanization with 3‐aminopropyl trimethoxy silane (APTMS), in concentrations of 0.1%, 0.5%, and 1.0 wt% in the polymer matrix was investigated. The processing of the nanocomposites was carried out via mixing in the molten state in a twin‐screw mini‐extruder at 200°C under 60 rpm screw rotation speed, with a residence time of 7 min. The addition of the MWCNT increased the thermal stability of PA11, predominantly with 0.5% of silanized nanotubes, as observed by the thermogravimetric analysis. X‐ray diffraction and differential scanning calorimetry analyses indicated that the degree of crystallinity of the formulations increased with the nanofiller content. On the other hand, the use of the highest concentration generated agglomerates, suggesting less dispersion in the matrix and, consequently, a reduction in crystallinity. Dynamic mechanical thermal analysis showed that the silanization process promoted an increase in both loss and storage moduli. All produced nanocomposites obtained values of corrected inherent viscosity above 1.20 dl/g, before and after the aging test. The use of lower load levels promoted better processability due to the lubricating effect of the nanotubes and an increase in the hydrophobic character of the samples, as observed by the increase of the contact angle.

Compósitos de Polietileno de Baixa Densidade (PEBD), reforçados com sílica precipitada em presença de Viniltrimetoxi Silano (VTMS), destinados a composições de dutos de petróleo, foram obtidos e caracterizados. As composições foram processadas por extrusão variando o teor de sílica na matriz de PEBD em 1%, 3% e 5%, com e sem a presença do VTMS. O comportamento reológico das composições foi investigado durante o processamento, mostrando que a presença do silano provocou redução do valor médio do torque e viscosidade e dispersão da carga. Tais resultados foram corroborados pela Microscopia Eletrônica de Varredura com Espectroscopia de Raios X por Dispersão de Energia (MEV-EDS), exibindo, de um modo geral, melhor dispersão da carga na matriz polimérica e melhor processabilidade. Os resultados permitiram também inferir a possibilidade de ganhos de propriedades mecânicas e dinâmicas para tais composições.