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In this article, bamboo nonwoven fabric (BF) is introduced as reinforcement into the vinyl ester (VE) matrix for the manufacturing of BF/VE composites through Vacuum Assisted Resin Transfer Mold process. Eco-friendly (NaHCO3) and other common treatments (NaOH and Silane) are applied to BF to modify the surface chemistry, thereby improving the mechanical strength (tensile modulus 10(NHTB), 11(NCTB) and 11% (SiTB); flexural modulus 11(NHTB) and 90% (SiTB) and impact strength 23% (SiTB)) and thermal properties. Besides, the three flame retardants (FRs) (chitosan (CS), ammonium polyphosphate (APP), and zinc borate) are incorporated with various percentages (3 and 6) for the improvement of flame retardancy of the BF composites and the experiments are proceeded by Taguchi L9 orthogonal array (OA) through the layup method. The nature of pure and modified BF is analyzed using Fourier transform infrared spectroscopy, x-ray diffraction and scanning electron microscopy exhibited the removal of the constituents and formation of reactive sites, etc. The effect of treatment on the thermal and flame retardant properties is analyzed by thermogravimetric analysis, horizontal burning test, and microcalorimeter, respectively. The thermal stability, burning rate, and peak heat release rate were significantly changed than that of pure BF composites. [ABSTRACT FROM AUTHOR]

Self-healing panels were prepared using vinyl ester (VE) and vascular abaca fibers (unidirectional) through the hand lay-up process. Initially, two sets of abaca fibers (AF) were prepared by filling the healing resin VE and hardener and stacking both core-filled unidirectional fibers in a 90° direction to obtain sufficient healing. The experimental results demonstrated that the healing efficiency increased by approximately 3%. SEM-EDX analysis further confirmed the healing process by exhibiting spill-out resin and the respective fibers' major chemical elements at the damaged site after self-healing. The tensile, flexural, and Izod impact strengths of self-healing panels indicated improved strengths of 7.85%, 49.43%, and 53.84%, respectively, compared with fibers with empty lumen-reinforced VE panels due to the presence of a core and interfacial bonding between the reinforcement and matrix. Overall, the study proved that abaca lumens could effectively serve as healing carriers for thermoset resin panels.

Self-healing on the engineering applications is smart, decisive research for prolonging the life span of the materials and the innovations have been mounting still smarter. Connecting to advancements in self-healing carriers, in altering the chemical structure by optimizing the brittleness for self-healing performance and introducing the bio-degradability, for the first time TPS was blended to PVDF for the synthesis of nanofibers, as carriers of a vinyl ester (VE) resin (medication), by the coaxial electrospinning technique. TPS was mechanically mixed with PVDF base polymer and optimized the TPS content (10 wt%) based on mechanical performance. The novel nanofibers were characterized via field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy, X-ray diffraction, thermal, moisture analysis, and a mechanical line with FESEM and energy-dispersive X-ray analysis studied the self-healing. The TPS/PVDF fibers having hydrogen bonding and increased the crystallinity (40.57 → 44.12%) and the diameter (115 → 184 nm) along with the surface roughness of the fibers with increasing the TPS content. Microanalysis presented the flow-out of the VE resin at the scratched parts in the pierced fibers; interestingly, after some time, the etched part was cured automatically by the curing of the spread resin. Mechanical stretching of the nanofibers in the tensile tests up in the plastic region showed a decrement in the elasticity (TPS/PVDF fibers) and an increment in the brittle nature (cured VE resin) with the increase in Young's modulus at each stretching, clearly elucidating the healing performance.

This article highlights the development of biodegradable flame-retardant composites using a compression technique on low-cost starch, flax fabric (FF) and ammonium polyphosphate (APP) raw materials. The starch was plasticized into thermoplastic starch through a mechano-ball milling process and composites were developed by reinforcing the FF and incorporating varying amounts of APP. The effects of APP on the flammability and thermal properties of the composites were studied. Limited oxygen index and horizontal-burning tests exhibited significant sustainability of the composites toward flame and direct flame self-extinguishment. It was observed that at higher temperatures, APP leads to formation of thermally stable char. The flame retardant properties of the composites were speculated to be due to the protective compact crosslinked network (POP and POC) of the char. The reported effects of APP include improvement in mechanical and biodegradation properties. This investigation provides the design of novel flame-retardant green composites with excellent properties., (Copyright © 2017. Published by Elsevier Ltd.)