Surface modification of bamboo fiber with sodium hydroxide and graphene oxide in epoxy composites

Abstract

Bamboo fibers (BFs) have high mechanical properties and are candidate reinforcement for epoxy matrix composites. However, to improve performance, good fiber‐matrix interaction is required. In this work, unidirectional long BF reinforced epoxy composites at fiber volume content of 22%, 40%, and 50% were made by compression molding. The 40 v% untreated BF reinforced composites exhibited 107% and 439% increase for flexural strength and modulus, respectively, compared to neat epoxy. Sodium hydroxide (NaOH) treatment was used to modify the surface of the BFs, and then the NaOH modified BFs were coated with graphene oxide (GO). The 40 v% NaOH modified BF composites showed an improvement from 259.9 to 327.5 MPa for flexural strength and from 16.7 to 21.5 GPa for flexural modulus, compared to 40 v% untreated BF composites. Slight improvement in properties up to 334.6 MPa for flexural strength and up to 23.8 GPa for flexural modulus was achieved for composites made of 40 v% NaOH/GO modified BF. Surface modification of BF after the NaOH and NaOH/GO treatment was confirmed by X‐ray photoelectron spectroscopy and by scanning electron microscopy, which showed differences on the fiber surface morphology and on the composite fracture surface. This BF surface modification approach with GO has potential to impart other properties beyond mechanical to produce multifunctional composite and lead to the use of sustainable plant fibers as alternatives to synthetic fibers.

Mechanical properties of rice husk and rice husk ash filled maleated polymers compatibilized polypropylene composites

“…6,52 Untreated bamboo natural fiber reinforced epoxy matrix composite was also found to exhibit little matrix adhering leading to gaps and interfacial debonding between the composite constituents. 53 Such spaces do not support effective stress transfer from the matrix hence, results in diminishing tensile strength of the composite relative to neat PP matrix. Also, traces of fiber pull-outs 52 can be seen in the micrograph represented by point 3, evidencing points of weak fiber-matrix adhesion.…”

Physical and dynamic mechanical properties of continuous bamboo reinforcement/bio-based epoxy composites

“…In this work, bamboo fibres were extracted based on a hybrid mechanical-chemical method using sodium hydroxide (NaOH). The alkali solution allows the extraction of technical fibres due to the solubilization of hemicelluloses and lignin [31,32]. Moreover, this treatment increases the accessibility of the free hydroxyl groups on the fibre surface, allowing physical interactions with the polymeric matrix.…”

“…Moreover, this treatment increases the accessibility of the free hydroxyl groups on the fibre surface, allowing physical interactions with the polymeric matrix. It also produces a rougher surface topography which favours interactions with the matrix [31,33]. In fact, this situation optimizes stress transfer at the fibresmatrix interfaces.…”

Energy absorption performance of Kevlar/snake grass fiber composites under ballistic impact test with nano Al2O3 inclusion

“…Despite its usage, natural fiber has problems like weak interfacial bonding with matrix, poor wettability, and high moisture absorption, which can lower the strength of composite materials. [11][12][13] The surface treatments on fibers before production can solve those problems. The consequence of alkali treatment on the interfacial and mechanical behavior of coir fiber biodegradable composites was investigated by Nam et al, [14] who found that treating coir fibers with 5 wt% NaOH for 72 h enhanced surface roughness and wettability of coir fiber.…”