Effects of weathering on mechanical and morphological properties cork filled green polyethylene eco-composites

Abstract

This study aims to evaluate the effects of natural weathering in the city of Teresina, State of Piauí, Brazil, on the morphology and mechanical properties of eco-composites based on high-density green polyethylene, powdered cork and compatibilizer processed in a twin-screw extruder and injection molded. The analyses revealed that although weathering induced surface bleaching of eco-composites and cracking, these effects were not intense in the compatibilized samples. The tensile properties of the investigated materials were affected by abiotic degradation, which led to a reduction of the tensile strength and elastic deformation of the eco-composites, however, the incorporation of PEgMA was fundamental for the maintenance of mechanical performance after natural aging. In general, the results obtained were satisfactory for external applications of the compatibilized eco-composite with 15% cork in the proposed weathering range, which indicates its possible use in temporary constructions.

Floating TiO2-Cork Nano-Photocatalysts for Water Purification Using Sunlight

“…In fact, the absorption of UV light by pristine cork under natural sunlight might lead to the photooxidation of cellulose, hemicellulose, and degradation of some lignin content present in cork, which could generate chromophore groups, such as carboxylic acids, quinones and hydroperoxide radicals. As a result, these chromophore groups could trigger photochemical reactions on the cork surface, thus promoting a faster decolorization of RhB, in comparison with solar simulating light exposure [119][120][121]. For the TiO 2 functionalized cork substrates, as observed, an increase in decolorization efficiency by 31% was obtained under natural sunlight when compared to solar simulating for 4 h. In contrast with the solar spectrum, which is composed of around 5% UV light, 43% visible light and 50% IR light [122], the LED solar simulator used in the photocatalytic experiments mainly provides visible light (the irradiance is cut for shorter wavelengths (high UV energy)), as observed in Figure S5.…”

Avaliação da inflamabilidade e do envelhecimento natural de compósitos de polímero verde e argila vermiculita para potencial uso na construção civil

“…A durabilidade dos plásticos e sua resistência ao intemperismo são também alguns dos maiores entraves para seu uso como material de construção civil, principalmente para aplicações externas. O calor, a radiação solar ultravioleta, o oxigênio atmosférico, a umidade e o tipo de ambiente químico são fatores primordiais que influenciam no processo de degradação dos plásticos quando expostos ao envelhecimento natural (VASCONCELOS et al, 2020;RATANAWILAI;TANEERAT, 2018;LUCAS et al, 2008;HALLIWELL, 2002). Nesse sentido, uma simples descoloração ou uma fratura no material, resultado de seu envelhecimento natural, pode indicar sua inviabilidade de produção, uma vez que os aspectos estéticos e funcionais são determinantes na indústria da construção civil (ANDRADY et al, 1998).…”

“…São muitos os danos que o envelhecimento natural causa nos materiais poliméricos, entre eles podem ser citados: descoloração, amarelecimento, perda de brilho e opacidade dos produtos; perda de propriedades mecânicas como resistência à tração, impacto e extensibilidade; aumento da capacidade de absorver água; desenvolvimento de fragmentação e trincas internas no material; redução do peso molecular, entre outras modificações químicas (VASCONCELOS et al, 2020;WANG et al, 2018;LUCAS et al, 2008;YANG et al, 2005;QIN et al, 2003).…”