Assessment of the compressive mechanical behavior of injection molded E-glass/polypropylene by mechanical testing and X-ray computed tomography

Nowadays, thermoplastic composite materials are considered among the most promising ones as they are gaining the interest of many industrial sectors due to their eco-friendly features such as their recyclability and their low-cost demand while being produced in high volumes. Among the most concerning issues regarding the injection molded, short fiber-reinforced composites are the fiber distribution, the fiber orientation, and their effect on the overall mechanical performance. In the present work, the effect of the injection molding on the compressive properties is investigated experimentally. In this context, compressive mechanical tests have been conducted in a range between subzero and elevated temperatures using specimens oriented parallel and perpendicular to the injection direction. In addition, X-ray computed tomography is implemented for characterizing some crucial features such as the fiber volume fraction, in local and global scale, and the orientation of the fibers through the thickness and length of the material. The results revealed a different compressive mechanical behavior between the two specimen categories in all the testing temperatures. In addition, the results obtained by the nondestructive testing revealed a significant variation of the fiber content locally and a notable difference between distinct zones through the thickness.