The effects of mercerization and acetylation treatments on the properties of sisal fiber and its interfacial adhesion characteristics on polypropylene

Abstract

The objective of this work was to investigate the influence of chemical treatment processes namely mercerization and acetylation on the surface morphology, structure and interfacial adhesion characteristics of sisal fiber within a polypropylene matrix. the effect of these treatments was studied using SEM, FT-IR, XRD, tensile and single fiber pull-out test. the two pre-treatment processes were observed to enhance removal of deleterious surface impurities and increase fiber roughness. this is advantageous for fiber to matrix adhesion as it facilitates mechanical interlocking from the increased surface area available for contact with matrix. interfacial adhesion shear strength for alkali treated and acetylated fibers improved by 173% and 435% correspondingly compared to untreated fiber. the FT-IR analysis revealed a reduction of lignin and hemicelluloses which are detrimental to the bonding strength of composite. fibers treated with Naoh showed greater exposure of cellulose cell walls. The degree of cellulose swelling was found to be influenced by pre-treatment scheme variables such as mercerization time and concentration of the solution. improvement in both crystallinity and tensile modulus of the fibers was observed. fiber extraction technique was also observed to have an impact on fiber quality as shown by fractures sustained by cellulose helical spirals from the adopted green retting protocol. Keywords : acetylation, mercerization, sisal, tensile, single fiber pull-out