Abstract:Summary: The use of lignocellulosic fibers as reinforcement in polymer composites has increased worldwide recently. Vegetal fibers have low cost and they are commonly available in Brazil. The curaua fibers in particular are of great importance for the development of the Amazon region. The mechanical behavior of the composites reinforced with fibers depends on the effectiveness of the transfer of the applied load by the matrix to the fibers, which is determined by the magnitude of the interfacial bonding betwee… Show more
“…Other treatment of natural fiber involves the exposure in hot water at 80°C for 1h and then after both treatments dried in air for 48h. These procedures improve the mechanical interaction between hydrophobic epoxy resin and hydrophilic fibers, removing the waste components (lignin, hemicellulose) from the fibers [11][12][13][14] . The degradation of natural fiber is strongly connected with moisture and climatic conditions.…”
The research of natural fiber composites is growing due to the fact that the green materials combine low weight with good mechanical properties. Curaua fiber arises as a competitive natural fiber due to its abundance, low cost and a variety of applications. In this work, different weight fractions of Curaua fiber were used in order to obtain this natural composite material. Specimens of Curaua/Epoxy composites were tested in tensile and in flexion to observe the quasi-static mechanical properties and its physical properties due to temperature variation were evaluated by Dynamic Mechanical Analyses (DMA) analyses. An increase in fiber quantity showed an increase in both the modulus and the strength, leading to a stiff and less ductile material. The results also showed an increase in the viscoelastic stiffness of the epoxy matrix by the incorporation of Curaua fibers. The interaction between Curaua fibers and epoxy matrix affects segmental mobility of the epoxy chains.
“…Other treatment of natural fiber involves the exposure in hot water at 80°C for 1h and then after both treatments dried in air for 48h. These procedures improve the mechanical interaction between hydrophobic epoxy resin and hydrophilic fibers, removing the waste components (lignin, hemicellulose) from the fibers [11][12][13][14] . The degradation of natural fiber is strongly connected with moisture and climatic conditions.…”
The research of natural fiber composites is growing due to the fact that the green materials combine low weight with good mechanical properties. Curaua fiber arises as a competitive natural fiber due to its abundance, low cost and a variety of applications. In this work, different weight fractions of Curaua fiber were used in order to obtain this natural composite material. Specimens of Curaua/Epoxy composites were tested in tensile and in flexion to observe the quasi-static mechanical properties and its physical properties due to temperature variation were evaluated by Dynamic Mechanical Analyses (DMA) analyses. An increase in fiber quantity showed an increase in both the modulus and the strength, leading to a stiff and less ductile material. The results also showed an increase in the viscoelastic stiffness of the epoxy matrix by the incorporation of Curaua fibers. The interaction between Curaua fibers and epoxy matrix affects segmental mobility of the epoxy chains.
“…This is in accordance with what has been observed in literature that after certain time of treatment and for higher solution concentrations, the mechanical properties tend to decrease, showing the fiber is starting to erode. 36–38 In Nam et al 36 it is also observed that the experiments on fiber with more than 72 h of treatment, result in lower tensile strength.…”
In recent decades, it has become essential to find and develop materials from non-petroleum sources that are more compatible with nature. The present work describes the mechanical properties of a composite with epoxy matrix reinforced with natural Curaua fibers. To improve the matrix-fiber interaction, the Curaua fibers were immersed in solutions with different concentrations of sodium hydroxide (NaOH) for different treatment times. After washing, they were mixed in epoxy and specimens were cut for use in tensile, flexural, and dynamic mechanical analysis tests. The results were compared to untreated fibers, showing improvement of maximum tensile strength up to 30% and 10% for maximum flexural strength. For this test, the flexural modulus improved by 12%. On the other hand, Young’s modulus did not change as much. This can be associated with degradation of the fibers when immersed for many hours in a high concentration of NaOH. In the conclusion, this topic is analyzed as a factor of how the alkaline solution can affect the fiber surface.
“…Still, there is some evidence of fiber pull-out, as pointed in Figure 10(a), indicating low adhesion with the polymeric matrix. 28 Figure 10.Scanning electron microscope images of tensile-fractures surfaces of composite samples with in natura (a), KOH-treated (b), and NaOH-treated (c) curaua fibers.…”
Section: Resultsmentioning
confidence: 99%
“…Still, there is some evidence of fiber pull-out, as pointed in Figure 10(a), indicating low adhesion with the polymeric matrix. 28 Figures 10(b) and (c) exhibited the composites with treated fibers showed a higher degree of fibrillation, with greater evidence of fiber breakage rather than pull-out, ratifying the increase in reinforcement/matrix interaction. 11 Matrix cracking and fiber debonding were observed.…”
Section: Mechanical Properties and Fracture Morphology Of Composite L...mentioning
This work manufactured prepregs by impregnating discontinuous curaua fibers with B-stage epoxy resin. The prepreg layers were then stacked to produce laminates by hot compression. Alkaline treatments were previously applied to the curaua fibers to improve their interface with the polymer matrix. Then, the prepregs and the final composites were studied regarding their thermal, dynamic mechanical, mechanical, and morphological behavior. The treatments promoted defibrillation by removing lignin and hemicellulose from the fibers, which allowed better impregnation of the treated fibers with epoxy resin. In general, laminates that used treated fibers exhibited the largest storage modulus in the glassy region. The mechanical results showed the laminates produced with treated fibers prepregs presented a highest tensile and flexural resistance than those manufactured with untreated fibers and neat epoxy resin. The NaOH-treated curaua/epoxy laminate exhibited high tensile strength (56.2 MPa) and modulus (3.3 GPa). Overall, fracture morphology indicated better fiber adhesion for the treated fiber composites. The results demonstrate that natural fibers prepregs can be successfully produced and present proper physical and mechanical behavior in components.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
