Mechanical and morphological characterizations of epoxy composites reinforced with surface modified woven cotton structures using vacuum bagging technique

Woven fabric structures facilitate the mechanical interlacement of textile yarns for increased strength, which leads to more balanced mechanical properties in a composite. This study worked on epoxy matrix composites reinforced with surface-modified cotton fabrics of different woven structures. The composites were fabricated using the resin vacuum bagging technique and mechanically characterized for tensile, three-point bending, and impact properties. Surface modification was conducted by alkali treatment using a 6% concentration of sodium hydroxide (NaOH). The interfacial adhesion of the various fabric structures and epoxy matrix was examined using a scanning electron microscope (SEM). The results obtained show that surface-treated composites yielded improved mechanical properties than untreated composites, with improvements of up to 14.4%, 36.2%, and 26.7% for impact, flexural, and tensile strengths, respectively. The different woven structures also significantly affected the mechanical performance of the composite. The composites of plain, herringbone, and twill woven structures presented better mechanical properties compared to the other woven composite structures in that order. The plain-woven composite structure, respectively, had the maximum impact, flexural, and tensile strengths of 80.03 KJ/mm2, 38.6 MPa, and 43.7 MPa. This was closely followed by the herringbone and twill-woven composite structures. SEM results revealed complete impregnation of fibers and a strong interfacial relationship between the thermoset matrix and the treated cotton fabrics in the composite laminate structures produced via the vacuum bagging technique. In conclusion, the study indicated that different weave structures and fiber surface treatments, as well as the vacuum bagging technique used, are of significant importance in enhancing the overall mechanical performance of woven fabric composites.