The fractured surfaces of PLA/willow-fiber (80/20) and (70/30) composites are shown in Figure3. SEM images revealed uniform distribution of fibers in both the composites. Many voids inside the matrix as well as spaces between willow-fiber and polymer matrix were observed. Voids inside the matrix might have been generated because of the removal of the willow-fiber at the time of cryogenic fracture of the samples. Both observations, voids inside the matrix and spaces between willow-fiber and PLA matrix suggest insufficient bonding between the surface of willow-fiber and PLA matrix