Residual sisal fibers treated by methane cold plasma discharge for potential application in cement based material

Abstract

The use of residual sisal fiber is becoming more frequent as reinforcement element in organic or inorganic matrix due to its low cost, high abundance in some countries and constitutes a renewable material. However, a significant loss in the mechanical performance in long term has been observed in fibercement composites after natural aging. These alternative fibers can be utilized in a hybrid fiber-cement in order to decrease the content of traditionally used synthetic fibers. The objective of this work was to evaluate the potential of the methane cold plasma treatment of 10 min duration on structural and physical properties of the residual sisal fibers to mitigate the degradation mechanisms when applied to cementitious matrices. Moisture sensitivity evaluation by capacitance method, dielectric measurements, X-ray diffraction, Fourier transform infrared (FTIR), spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), angle contact and pullout test were carried out in order to follow the effect of the proposed treatment. Besides, mechanical behavior of untreated and treated sisal fibers was evaluated before and after accelerated aging in cementitious solution at 60 • C by 72 h. The results obtained in all these tests confirmed the high potential of the methane cold plasma treatment to delay the degradation of the residual sisal fibers in the presence of a Portland cement environment and these fibers present the higher pullout load and shear stress than one untreated.

Cellulose Nanofibrils Modification With Polyaniline Aiming at Enhancing Electrical Properties for Application in Flexible Electronics

“…For measuring the capacitance of the films, the parallel plate method 39 was used. The apparatus consists of two circular shaped metal plates with a nominal area of 26.4 cm² and pressed with pressure clips, as shown in Figure 2.…”

“…Barra et al 39 investigated the variation of the capacitance of CNF with their exposure to moisture saturated environment, and achieved capacitance values up to three-fold those of the dry nanofibers. CNF presents a large surface area and consequently high hydrophilicity created by more hydroxyl groups being exposed.…”

Painéis de partículas com maravalha de Pinus spp. e fibra de sisal

“…e das fibras de sisal. Além disso, outra hipótese que pode ser adicionada na discussão desses resultados físicos tem relação com o caráter hidrofílico das fibras de sisal (BARRA et al, 2015). A hidrofílicidade do sisal pode ter acarretado nos resultados superiores para AA 2h e 24 h, bem como IE 2h e 24 h dos painéis com maiores teores dessa fibra, visto que essa matéria prima tem potencial de absorção de água, devido ao elevado teor de microfibrilas de celulose (aproximadamente 78 %), e do baixo teor de lignina (aproximadamente 7%) (BARRETO et al, 2011;BISMARCK et al, 2002).…”

Compatibilization of natural fibres as reinforcement of polymeric matrices

“…The removal can be achieved by using a physical sputtering procedure, in which the material is removed by purely physical processes, due to the ion bombardment from the species present in plasma [17]. The main advantage from using plasma treatments is that the alterations do not affect the bulk properties of the material [26]- [29]. By using this technique, the compatibilization among composite constituents is achieved following a purely physical approach, by increasing the mechanical grip between the fibers and the polymer.…”