Effects of magnesium carbonate concentration and lignin presence on properties of natural cellulosic Cissus quadrangularis fiber composites.

Cissus quadrangularis biodegradable natural cellulosic fibers comprehensively characterized to assess their potential as reinforcing materials in polymer composites. Initially, the Cissus quadrangularis fibers were chemically treated with 5% Sodium hydroxide (NaOH) and 5% magnesium carbonate (MgCO3) to improvise the properties of the fiber. The mechanical test result shows that chemically treated 5% MgCO3 fiber show that 4% and 24% improved tensile strength compared to NaOH and untreated ones. The cellulose crystallinity of the treated fiber got increased as the amorphous constituents removed. Further, 5% MgCO3 treatment removed a larger amount of amorphous hemicellulose, lignin, and other impurities present on the fiber surface. Secondly, the composites were fabricated at different combination of MgCO3 (5%, 10%, 15%), plasticizer (5%, 7.5%, 10%), and fiber volume (20%, 25% and 30%) with L9 Taguchi orthogonal array approach. Based on the results, 5% MgCO3, 5% plasticizer, and 30% fiber volume showed significant improvement in Young's modulus, tensile, and flexural strength of 8%, 27%, and 16% respectively. Moreover, there was no notable improvement observed on impact strength for both treated (15.91 KJ/m2) and untreated (13.98 KJ/m2) fiber. The scanning electron microscopy (SEM) micrographs used to examine the interface bonding between fiber and the matrix.