To improve the adhesion and wetting between the abaca fibers and matrix, the surface of abaca fabric was modified using plasma polymerization. Different plasma exposure times were conducted to determine the effect of plasma treatment on the properties of the composites. A combination of plasma and other surface modification processes was also investigated to determine whether double treatments could further enhance the properties of these composites. Combined treatments involve plasma polymerization of the fabric after pretreatment with one of the following surface-modification reagents: a) γ -methacrylopropyltrimethylsilane, b) triethoxyvinylsilane, and c) 2% w/w NaOH (aq).The abaca fabric/unsaturated polyester composites were fabricated using the vacuumassisted resin transfer molding (VARTM) technique.SEM results showed that 10 to 20 seconds plasma treatment gave the right amount of surface roughness for maximum fiber and matrix adhesion leading to improved mechanical properties of the composites. Longer plasma treatment time and double treatment however resulted in composites with lower mechanical properties. Although the composite with alkali and plasma-treated fabric showed the lowest mechanical properties it exhibited the lowest water uptake in both distilled water and brine solution.
The application of natural fiber-reinforced composites is gaining interest in the automotive, aerospace, construction, and marine fields due to its advantages of being environmentally friendly and lightweight, having a low cost, and having a lower energy consumption during production. The incorporation of natural fibers with glass fiber hybrid composites may lead to some engineering and industrial applications. In this study, abaca/glass fiber composites were prepared using the vacuum-assisted resin transfer method (VARTM). The effect of different lamination stacking sequences of abaca–glass fibers on the tensile, flexural, and impact properties was evaluated. The morphological failure behavior of the fractured-tensile property was evaluated by 3D X-ray Computed Tomography and Scanning Electron Microscopy (SEM). The results of mechanical properties were mainly dependent on the volume fraction of abaca fibers, glass fibers, and the arrangement of stacking sequences in the laminates. The higher volume fraction of abaca fiber resulted in a decrease in mechanical properties causing fiber fracture, resin cracking, and fiber pullout due to poor bonding between the fibers and the matrix. The addition of glass woven roving in the composites increased the mechanical properties despite the occurrence of severe delamination between the abaca–strand mat glass fiber.
The current pandemic brought to our attention the need for continuous research and development on the fight against pathogens. The use of derivatives of starch nanocrystals (SNC) with antimicrobial activities offers a good alternative to conventional antimicrobial agents since they can be sourced from readily available, biodegradable, and biocompatible raw materials. In this study, starch nanocrystals were prepared by acid hydrolysis and oxidized using hydrogen peroxide. The resulting oxidized starch nanocrystals showed inhibitory effect against E. coli. FTIR analysis showed that the antimicrobial activity could be due to the introduction of carbonyl groups in the starch chain. Due to the versatility of starch nanocrystals, other derivatives with improved antimicrobial activity or other tailored properties could also be developed.
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