A Review on the Mercerization of Natural Fibers: Parameters and Effects

Natural fibers are environmentally friendly materials incorporated into polymer matrices as reinforcement agents. Several fibers are available in nature, such as cotton, jute, sisal, bamboo, hemp, banana, coir, and flax. However, in some cases, poor compatibility between fiber/polymer is observed, limiting their utilization. To overcome this disadvantage, chemical treatments can be applied to the fibers to alter their chemical composition, surface morphology, and mechanical properties. In comparison with other methods, mercerization is a popular methodology largely used to modify the properties of fibers once is inexpensive and does not require toxic chemicals. The main modifications caused by mercerization regarding chemical composition are the removal of wax, oils, and impurities of the surface of the fibers, besides a decrease in lignin and hemicellulose contents, and an increase in cellulose content. Fiber surface morphology becomes cleaner, and mechanical parameters, such as tensile strength and rigidity, are generally improved. Although these are some common modifications, mercerization process parameters must be well-adjusted to obtain optimized results. Unlike other published articles, this review covers the mercerization parameters adopted for several types of natural fibers to establish a correlation between the main effects of the process on the physical-chemical, morphological, and mechanical properties of the fibers.