Adhesion of pineapple-leaf fiber to epoxy matrix: The role of surface treatments

Abstract

Natural fibers are considered to have potential use as reinforcing agents in polymer composite materials because of their principle benefits: moderate strength and stiffness, low cost, and be an environmental friendly, degradable, and renewablematerial. Due to their inherently hydrophilic nature, they are prone to absorb moisture, which can plasticise or weaken theadhesion of fibers to the surrounding matrix and by this affect the performance of composites used in atmospheric humidity,particularly at elevated temperatures. The surface treatments are often applied to the fiber to improve the bond strengthbetween the fibers and matrix. This work discussed the effect of sodium hydroxide (NaOH) treatment and epoxy resin as acompatibilizing agent on interface properties of pineapple leaf fiber (PALF)-epoxy composites. A single-fiber fragmentationtest coupled with data reduction technique was employed to assess interface quality in terms of apparent interfacial shearstrength (IFSS or a) of untreated, NaOH, and epoxy resin treated PALFs-epoxy composites. Tensile properties of untreatedand treated PALFs were also examined. It was found that both treatments substantially increase a, corresponding to animproved level of adhesion. The improvement in the level of adhesion for the alkali and epoxy treated fiber composites wasdue to an increase in the physical bonding between the alkali treated fibers and the matrix, and due to a promoted compatibilitybetween the epoxy treated fibers and matrix, respectively.

Keywords

• pineapple fiber (PALF)
• epoxy resin
• single-fibre fragmentation test
• fibre-matrix interfacial adhesion
• surface treatments