Influence of Mercerization Process on the Surface of Coconut Fiber for Composite Reinforcement

Abstract

The high consumption of green coconut water, especially in tropical countries like Brazil, generates an aggravating factor to the environment, which is associated with the waste generated after its consumption. Thus, one of the possible ways of reusing the coconut shell after consumption is through the extraction of its fibers, which are considered for several applications. In general, natural lignocellulosic fibers (NLFs) have been used for many purposes, such as reinforcement filler in composite materials, since they have low cost and good mechanical properties. With the intention of providing a better compatibility between the NLFs and the composite polymeric matrix, different types of surface treatments are carried out on the fibers, including mercerization, a chemical treatment in which a basic solution is used. In this sense, the present work aims to verify the influence of mercerization with 3% sodium hydroxide (NaOH) on coconut fiber. Among the analyses carried out, stands the scanning electron microscope (SEM) on fresh and treated coconut fibers. The SEM analyses, allowed to observe that after treatment via mercerization, the fibers displayed a greater surface roughness. This indicates the partial removal of lignin, hemicellulose and some other extracts present on the outer layer of the coconut fiber. Therefore, mercerization will probably enable a better mechanical anchoring between fiber and matrix. Results obtained suggest the effectiveness of the mercerization process. However, it was also of concern that such treatment tends to generate NaOH residues, which is a negative factor regarding sustainability.