No abstract

No abstract

Nanocomposites containing polypropylene (PP), PET, and montmorillonite were prepared in a twinscrew extruder. X-ray diffraction, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, polarized optical microscopy, and differential scanning calorimetry were used to characterize the samples. Intercalated and exfoliated morphology were observed in the nanocomposites. The PET domains usually presented spherical shapes and they were the start point to PP crystallization. The average diameter and number of PET domains was evaluated. The influence of addition of PP-MA as compatibilizer on PP/PET was investigated. The interconnected morphology was observed in the nanocomposite containing PP-MA. The clay located predominantly in the interphase and in the PET phase. The crystallization process was monitored and the PET crystallization rate was slower in the nanocomposites.

No abstract

No abstract

The combination of rheological and interfacial properties is utilized in this work to explain the thermal and mechanical properties of a random polypropylene copolymer (RPP) toughened with an ethylene-propylene copolymer (EPR). RPP/EPR blends are directly prepared by injection molding. The EPR exhibits higher viscosity in comparison with the RPP over the evaluated shear rate, while the RPP/EPR blends show similar viscosities at high shear rates. The interfacial properties indicate a strong interaction between the RPP and EPR domains. Differential scanning calorimetry analyses indicate that the EPR does not act as a nucleating agent for the RPP, with the RPP crystallinity only decreasing at high EPR contents, suggesting that the EPR can modify the RPP crystallite size. Scanning electron micrographs of the blends demonstrate a ductile fracture surface, indicating that EPR can increase the RPP tenacity. The RPP impact strength is improved by up to 102% in the RPP/EPR 90/10 wt.% blend, while the RPP deformation at break is increased from 183% to 246% after the incorporation of 10% EPR. The tensile strengths of the RPP and RPP/EPR blends are very similar, indicating that the RPP achieves a good balance between stiffness and toughness after being blended with the EPR.

No abstract

Ela é servidora pública lotada na Gráfica UFRGS. Durante sua trajetória na universidade, como diretora da Gráfica da UFRGS, adquiriu experiência na produção gráfica, gestão de pessoas, ecodesign, coordenação de projetos de extensão, visando melhorias dos processos produtivos da Gráfica, sustentabilidade e inovação. E esse conhecimento adquirido foi fundamental para que ela desenvolvesse o seu doutorado na própria Universidade Federal do Rio Grande do Sul (UFRGS) no programa de Pós-Graduação em Design, na qual pesquisou possíveis soluções para o reaproveitamento do resíduo de papel descartado pela Gráfica UFRGS. <00006708@ufrgs.br>Abstract This research presents an alternative material that follows innovative and sustainable standards constituted by the union of the gelatinized starch matrix with paper waste as load. Since starch and paper are hydrophilic nature, limitations in the applications of this biocomposite may occur if no barrier is created to restrict moisture absorption. For this, waterproofing tests were performed to analyze the behavior of the material in relation to water absorption (2 and 24 hours) with four different waterproofing agents applying one, two and three layer. Satisfactory results were obtained from the second coat in 2 h and third coat in 24 h with the polyurethane based waterproofing agents. Therefore, comparing to the other waterproofing agents tested, and searching for more sustainable results, it can be concluded that the polyurethane-based waterproofing agent of vegetable origin proved to be the one that best meets the objectives of this research. Estudio sobre la impermeabilización del compuesto de almidón / papel de desechoResumen Esta investigación presenta un material alternativo que sigue estándares innovadores y sostenibles constituidos por la unión de la matriz de almidón gelatinizado con una carga de residuos de papel. Teniendo en cuenta que el almidón y el papel tienen una naturaleza hidrófila, puede haber limitaciones en las aplicaciones de este biocompuesto si no se crea una barrera para restringir la absorción de humedad. Para este fin, se realizaron pruebas de impermeabilización para analizar el comportamiento del material en relación con la absorción de agua (2 y 24 horas) con cuatro agentes impermeabilizantes diferentes con una, dos y tres capas. Se obtuvieron resultados satisfactorios de la segunda capa en 2 horas y la tercera capa en 24 horas, con productos impermeabilizantes a base de poliuretano. Por lo tanto, en comparación con la otra impermeabilización probada y buscando resultados más sostenibles, se puede concluir que la impermeabilización a base de poliuretano a base de plantas demostró ser la que mejor cumple con los objetivos de esta investigación.Palabras clave Biocompuesto, Almidón, Residuos de papel, Impermeabilización, Absorción de agua.