Physical, chemical, thermal, and mechanical assessments of Roselle-reinforced composites

Hibiscus sabdariffa stem fiber has 73.9% cellulose, high mechanical strength and is found in abundance throughout the world. Hibiscus sabdariffa graft copolymers were synthesized, characterized by FTIR, XRD, TGA, DTA, and SEM techniques, and evaluated for physicochemical changes in properties such as moisture absorption, chemical resistance against 1 N NaOH and 1 N HCl. These graft copolymers were reinforced in phenol-formaldehyde polymer matrix to form biocomposites that were characterized by advanced techniques and evaluated for physicochemicothermal resistance. The mechanical strength was accessed on the basis of hardness, flexural strength, Young modulus, and stress at the limit of proportionality, which was found to be high. These novel materials could have numerous scientific and industrial application to pave the way for development of technology.