Dynamic mechanical properties of sisal fiber reinforced polyester composites fabricated by resin transfer molding

The dynamic mechanical properties of sisal fiber reinforced polyester composites fabricated by resin transfer molding (RTM) were investigated as a function of fiber content, frequency, and temperature. Investigation proved that at all temperature range the storage modulus (E¹) value is maximum for the composites having fiber loading of 40 vol%. The loss modulus (E ¹¹) and damping peaks (tan δ) were lowered with increasing iber content. The height of the damping peaks depends upon the fiber content and the fiber/matrix adhesion. The extent of the reinforcement was estimated from the experimental storage modulus, and it has been found that the effect of reinforcement is maximum at 40 vol% fiber content. As the fiber content increases the T_g from tan δ curve showed a positive shift. The loss modulus, storage modulus, and damping peaks were evaluated as a function of frequency. The activation energy for the glass transition increases upon the fiber content. Cole-Cole analysis was made to understand the phase behavior of the fiber reinforced composites. Finally, attempts were made to correlate the experimental dynamic properties with theoretical predictions. POLYM. COMPOS., 30:768-775, 2009.