Effects of water immersion ageing on the mechanical properties of flax and jute fibre biocomposites evaluated by nanoindentation and flexural testing

Abstract

Flax and jute fibres are inexpensive and easily available bast fibres and they are extensively used as reinforcement in polymer matrix composites. However, due to their susceptibility to moisture absorption, their application is restricted to non-structural interior products. In this study, flax and jute fibre reinforced bioresin based epoxy biocomposites were fabricated using hand lay-up method and their nanoindentation and flexural properties were investigated. In order to study the effects of water absorption on the nanoindentation and flexural properties, the biocomposites were subjected to water immersion tests by immersing specimens in a de-ionised water bath at 25 oC for a period of 961 hours. The nanoindentation behaviour and flexural properties of water immersed specimens were evaluated and compared alongside with dry specimens. The percentage of moisture uptake and diffusion coefficient ()was recorded higher for jute reinforced specimens compared to flax. The flexural properties for both types of specimens were found to decrease with increase in percentage moisture uptake. Comparison of flexural strength and flexural modulus between flax dry and flax wet biocomposites showed that wet samples lost almost 40% of its strength and 69% of its modulus respectively, compared to dry flax samples. The jute wet samples lost 60% of its strength and 80% of its modulus, respectively, compared to dry samples. The nanohardness value decreased from 0.207 GPa to 0.135 GPa for dry flax sample after immersion in water. http://mc.manuscriptcentral.com/jcm

Dynamic Mechanical Behavior Analysis of Flax/Jute Fiber-Reinforced Composites under Salt-Fog Spray Environment

“…These results can be explained, taking into account the different interactions of the investigated natural fibers (i.e., flax and jute) with the sodium bicarbonate treatment. As shown in our previous paper [48], bicarbonate treatment softens jute fibers, due to their higher amount of lignin (i.e., up to 25-27%) in comparison to flax fibers (i.e., up to 5%) [1,56,57]. Conversely, this mildly alkaline treatment is able to remove the impurities from the surface of flax fibers without any chemical interaction with the fiber bulk because of the lower lignin content and the more compact structure, compared to jute fibers [58].…”

“…This result indicates that composites reinforced with untreated Jute fibers (i.e., Jute-AR) are characterized by better fiber-matrix interfacial adhesion than surface treated ones (i.e., Jute-T) [56]. Due to the soaking of jute fibers in the NaHCO3 solution, a reduction of lignin and hemicellulose components from the fiber bulk occurred [44], thus favoring the triggering of damage phenomena at the interface.…”

Influence of Moisture Absorption and their Effect on the Physho-Mechanical Properties of Coir-Luffa Fibre Reinforced Polymer Matrix Composites

“…The cause of the reduction of strength may be fiber entanglement. This may be observed by the results and consequence drawn by literature reference [13][14].…”

Carbon nanotubes array reinforced shape‐memory epoxy with fast responses to low‐power microwaves

“…To extract the mechanical properties of pristine ESMP, the random CNTs/ESMP composite, and the CNTs array/ESMP composite, they were subjected to room‐temperature nanoindentation tests. Due to the small size of the CNTs array/ESMP composite (10 mm × 10 mm × 0.5 mm; see Figure ), it cannot be subjected to regular mechanical loads such as tensile and flexural tests . The illustrations for nanoindentation tests are shown in Figure .…”