Caracterização de um compósito polimérico biodegradável utilizando Poli (ε-caprolactona) e borra de café

Abstract

ResumoEste trabalho teve por objetivo avaliar a influência do tratamento químico da borra de café em relação as propriedades mecânicas e térmicas, morfologia e suscetibilidade à biodegradação quando utilizada na preparação de compósitos com Poli(ε-caprolactona) comparando-o com o polímero puro. A borra de café foi submetida ao tratamento álcali com hidróxido de sódio, seguida da acetilação. Os compósitos foram preparados utilizando diferentes porcentagens de borra de café. Com tratamento químico houve um aumento na estabilidade térmica da borra de café. Houve um aumento significativo no módulo elástico para o compósito com 10% de borra de café acetilada. As imagens obtidas por MEV mostraram uma parcial interação fibra/matriz para compósitos com borra acetilada. As análises térmicas mostraram que a adição de borra de café deslocou positivamente 10º C o pico máximo de degradação térmica em relação ao polímero puro. As amostras mais suscetíveis à biodegradação foram as que continham borra de café acetilada. Palavras-chave: compósito polimérico, borra de café, poliéster biodegradável. AbstractThis study aimed to evaluate the influence of chemical treatments of coffee grounds in relation to mechanical, thermal and morphological properties, and its susceptibility to biodegradation when used in the preparation of composites with poly (ε-caprolactone) as compared to pure polymer. The coffee grounds were submitted to alkali treatment with sodium hydroxide followed by acetylation. The composites were prepared using different percentages of coffee grounds. There was an increase in the thermal stability of coffee grounds using chemical treatment, and a significant increase of the elastic modulus for the composite with 10% acetylated coffee grounds. The images obtained by SEM showed a partial interaction between fiber/matrix for composites and acetylated coffee grounds. The Thermal analysis showed that the addition of coffee grounds positively shifted 10°C, the maximum peak of thermal degradation, as compared to pure polymer. The most susceptible samples to biodegradation were those that contained acetylated coffee grounds.

Polycaprolactone (PCL)/alumina and PCL/niobium pentoxide composites: Rheology, crystallization, and mechanical properties

“…These results are supported by the DSC data, which show that the degree of crystallinity of the alumina composites decreased (more than 10%) with filler addition whereas that of niobium pentoxide composites were not affected by the presence of this oxide. Studies by Rosa et al [36] and Mei and Oliveira [37] also reported a decrease in tensile strength and elongation at break in PCL/starch and PCL/coffee grounds composites, respectively. For these cases, as well as for the present study, the decrease in mechanical properties may be associated with the chemical interaction at the filler-matrix interface that was not as efficient as expected or, maybe, there is a critical value of filler content for optimization of mechanical properties of these composites, and the amount of filler added to the composites in this study was not close to that.…”

Influência de fatores ambientais nas propriedades mecânicas de biocompósitos de pla reforçado com fibra de coco e borra de café

“…Sendo assim, uma maneira de minimizar essa problemática, aliada à destinação nobre para esse resíduo, é o reaproveitamento de borra de café, por meio da sua utilização como carga e/ou reforço natural em compósitos poliméricos [22][23][24]. Existe um número limitado na literatura de trabalhos relacionados com o desenvolvimento de compósitos poliméricos utilizando a borra de café como carga e/ou reforço [25][26].…”

The influence of fiber size on the behavior of the araucaria pine nut shell/PU composite

“…Composites made of biodegradable polymers and reinforced by natural fibers are an attractive option, since these fibers have some advantages when compared to synthetic ones, such as lower density, lower cost, and lower abrasivity during manufacturing. Besides, natural fibers are derived from renewable sources, are not toxic, and do not cause environmental impacts [1,[5][6][7] .…”

“…Mei & Oliveira [7] studied the morphological, mechanical and thermal properties and the biodegradability of composites containing chemically treated coffee grounds and poly(ε-caprolactone). Thermal analysis showed that the addition of coffee grounds increased the maximum peak of thermal degradation by 10°C when compared to pure polymer.…”