Mechanical and Dynamic Properties of Biocomposites. Группа авторов
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СКАЧАТЬ with short JF and short bagasse fiber (BF) bundles reinforcement was carried out by Saw and Datta [20]. They used epoxidized phenolic novolac (EPN) as resin matrix and investigated various fiber surface treatments and fiber ratios. Sodium hydroxide (NaOH) alkali solution was used to treat the JF bundles. The BF bundles were either modified using chlorine dioxide (ClO2) and furfuryl alcohol (C5H6O2) or left untreated. The modification of the fiber surface was necessary for quinones creation in the lignin areas of the BF bundles. The created quinones then reacted with the furfuryl alcohol, and thereby improved the BF bundles' (modified) ability for better adhesion. Their result revealed greater mechanical responses (flexural, tensile and impact properties) for hybridized BF (modified) and JF bundles (alkali‐treated) in the EPN resin matrix than the BF bundles that were not modified. They obtained an optimum mechanical behavior at a BF/JF ratio of 50 : 50, as depicted in Table 1.5.

      1.4.1.2 Bamboo/MFC FRP Hybrid Composites

      Asian giants, India and China, are the chief producers of bamboo fiber with more than 80% of global production [21]. This biofiber is highly attractive, due to its renewable nature and low environmental impact. It grows rapidly and has comparative high strength to other biofibers, such as cotton and jute [22].

      An unprecedented biocomposite (hybrid) that contained biodegradable poly‐lactic acid (PLA) matrix with microfibrillated cellulose (MFC) and bamboo fiber bundles reinforcements was developed by Okubo et al. [23]. Various nomenclatures have been used for describing MFC in the literature, such as microfibril, microfibrillar cellulose, microfibril aggregates, nanofibril, nanofibrillar cellulose, nanofiber, and fibril aggregates [24]. They conducted an investigation on how MFC dispersion influenced the responses of composites reinforced with bamboo fibers by dispersing MFC in a polymer matrix of PLA by a three‐roll mill calendering process. This calendering process helps to compress or smoothen a material. They used the PLA (bio‐based and biodegradable) polymer matrix for interfacial bonding enhancement with the MFC. The diameter of bamboo fiber bundles was about 200 μm, while that of MFC was just a few microns, which was much smaller. Using gap settings in decreasing order of 70, 50, 35, 25, 15, 10, and 5 μm, they processed the mixture of the MFC and PLA in the three‐roll mill. About 200% increase in the fracture energy was realized when they added 1 wt.% of MFC to the PLA matrix and milled the MFC/PLA composite at the smallest gap setting of 5 μm, which was quite significant. This hybrid composite combination of bamboo fiber and the PLA matrix with 1 wt.% MFC reinforcement was observed to prevent an abrupt crack channel through the bamboo fiber effectively, and thus produced a significant improvement in fracture strength. The results of other mechanical behaviors are presented in Table 1.5.

      1.4.1.3 Banana/Kenaf and Banana/Sisal FRP Hybrid Composites

      Source: Nguyen et al. [4]. © 2017, Elsevier.

СКАЧАТЬ
Hybrid biocomposites Fiber ratio (by weight or volume) Flexural modulus (GPa) Flexural strength (MPa) Tensile modulus (GPa) Tensile strength (MPa) Impact strength (kJ/m2)
Natural fibers
Bagasse/jute Bagasse fiber bundles (untreated) and jute fiber bundles (treated)
0 : 100 0.645 31.15 0.302 11.45 6.90
20 : 80 0.789 36.46 0.356 16.02 7.46
35 : 65 1.101 45.32 0.420 19.45 9.53
50 : 50 1.480 55.63 0.492 23.07 10.66
65 : 35 1.311 51.19 0.399 21.15 8.33
100 : 0 0.502 26.78 0.227 9.87 6.67
Bagasse fiber bundles (treated) and jute fiber bundles (treated)
20 : 80 1.178 42.72 0.526 18.72 10.00
35 : 65 1.484 54.57 0.635 22.57 13.33
50 : 50 1.748 65.22 0.753 26.77 15.93
65 : 35 1.518 60.12 0.704 23.54 10.93
100 : 0 0.632 30.78 0.286 11.20 8.66
Bamboo/MFC MFC/PLA composites (milled to 5 μm)