Avaliação dos efeitos da acetilação nas propriedades das fibras de caroá

Lopes, Fernanda Ferreira; Araújo, Gilmar Trindade de; Nascimento, José Wallace Barbosa do; Vasconcelos, Robelsa F.; Dantas, Júlio M. E.

doi:10.1590/s1415-43662011000100012

Cited by 5 publications

(8 citation statements)

References 11 publications

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“…This behavior can be explained by the increased stiffness of the fiber caused by the removal of its amorphous fraction of cellulose during the mercerization process (Troedec et al 2008). Similar results for the mechanical properties of caroa fibers after acetylation have been reported by Lopes et al (2011). The results may be associated with the partial removal of lignin and polyoses, causing greater rigidity in the fibers.…”

Section: Thermogravimetric Analysissupporting

confidence: 75%

“…The appearance of a band at 1,730 cm -1 relative to the carbonyl group (C=O) confirmed acetylation of the fiber (Leite et al 2010). An increase in the intensity of the band in the region of 1,240 cm -1 was also observed, which could be attributed to C-O bonds, which tend to increase with acetylation (Lopes et al 2011). In the treated and untreated fibers, a band was observed in the region of 3,300-3,500 cm -1 because of the vibration of the hydroxyl groups (-OH).…”

Section: Resultsmentioning

confidence: 87%

“…The reactor was maintained at 95°C for 2 h. The fibers were separated by vacuum filtration, washed with distilled water to completely remove the solvents until reaching neutral pH and dried in an oven at 60°C for a 24-h period (Lopes et al 2011). …”

Section: Acetylationmentioning

confidence: 99%

“…Moreover, natural fibers are nontoxic, present good reinforcement properties and come from renewable natural resources, which require lower costs and cause less wear on manufacturing equipment compared to synthetic fibers. These fibers can also be easily modified by chemical agents, allowing obtaining similar properties to synthetic fibers (Lopes et al 2011). However, the difficulty in using lignocellulosic fibers as reinforcement is their incompatibility with polymer matrices, which are normally hydrophobic, while natural fibers are hydrophilic.…”

Section: Introductionmentioning

confidence: 99%

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Polymeric biocomposites of poly (butylene adipate-co-terephthalate) reinforced with natural Munguba fibers

2014

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In this work, polymeric biocomposites of poly (butylene adipate-co-terephthalate), PBAT, were reinforced with Munguba fibers (Pseudobombax munguba). This tree is found in great abundance in the marshy areas of the Amazon forest. The motivation for using this fiber in polymer composites comes from the fact that although research for this fiber has not been reported in the scientific literature, it is commonly used by the local population because its bark is strong and flexible. Most important is that the extraction of Munguba fibers does not damage the supplier tree because as it is extracted from the bark, its regeneration starts as it is removed. The fibers were chemically treated by mercerization/acetylation and evaluated by Fourier transform infrared spectroscopy, thermogravimetric analysis and tensile tests. The Munguba fiber presented mechanical properties similar to those of other natural fibers traditionally used in composites, and the chemical treatment provided improvements of its thermal stability and stiffness. The biocomposites showed a better elastic modulus in relation to the pure PBAT. The addition of fibers caused changes in the T g , T m and T c of PBAT as observed by differential scanning calorimetry analysis. The Russel, Halpin-Tsai and Maxwell models were employed to provide the theoretical elastic modulus of the biocomposites.

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Section: Thermogravimetric Analysissupporting

confidence: 75%

Section: Resultsmentioning

confidence: 87%

Section: Acetylationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Polymeric biocomposites of poly (butylene adipate-co-terephthalate) reinforced with natural Munguba fibers

2014

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“…A seguir foi seca em uma estufa com circulação de ar na temperatura de 80 °C por 24 horas. A armazenagem foi feita em um dessecador a vácuo [7][8][9] . Para cada formulação, foi utilizada uma massa total de 200 gramas de material.…”

Section: Materiais E Métodosunclassified

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

Mei

Oliveira

2017

Polímeros

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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.

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Polycaprolactone matrix composites reinforced with brown coir: Rheological, crystallization, and mechanical behavior

et al. 2018

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Polycaprolactone matrix composites reinforced with natural and chemically treated coir were prepared in a laboratory internal mixer and studied by differential scanning calorimetry (DSC) and tensile tests. The aim of this work was to evaluate the influence of the filler and its surface modification on the rheological, mechanical, and crystallization behaviors of the composites. According to rheological analysis, the higher the filler content, the higher the viscosity of the material and the lower its local pseudoplasticity index. DSC analyses showed that the presence of coir anticipates the crystallization process; however, it does not affect the absolute crystallinity of the matrix. Mechanical tests indicated that an increase in filler content leads to an increase in Young's modulus and a decrease in the elongation at break. Additionally, composites with filler content from 20% can stand higher tensile stress than the neat polymer, and this effect is intensified by the surface modification applied to the filler. POLYM.

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Avaliação dos efeitos da acetilação nas propriedades das fibras de caroá

Cited by 5 publications

References 11 publications

Polymeric biocomposites of poly (butylene adipate-co-terephthalate) reinforced with natural Munguba fibers

Polymeric biocomposites of poly (butylene adipate-co-terephthalate) reinforced with natural Munguba fibers

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

Polycaprolactone matrix composites reinforced with brown coir: Rheological, crystallization, and mechanical behavior

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