The mechanical properties of the composites obtained with these three fibers were found to be superior to those of the neat polymer. Addition of various amount of reinforcement fibers yielded noticeable increases in both tensile and flexural modulus as well as the torsion parameter. 56–75% increases in tensile modulus were observed by the use of alfa, coir and bagasse while the flexural modulus increased by 30–47% when compared to neat PP. An increase in torsion modulus is also observed when the fiber content exceeds a threshold level. A power law model was developed using an experimental data to calculate the torsion
modulus of fiber-reinforced composites at various fiber loading and frequencies.