Effect of cross-head speed and temperature on the mechanical properties of polypropylene and glass fiber reinforced polypropylene pipes

Recently, glass fiber reinforced polypropylene is commonly used in scientific and industrial applications such as marine, aerospace, automotive, and construction industries among other materials because of their low cost, lightweight, easy processing, and high reliability. For those promising characteristics, researches have been undertaken for understanding the thermal and mechanical behaviors of polypropylene. The main objective of this study is to investigate the mechanical properties of polypropylene (PP) and glass fiber reinforced polypropylene (GFPP) pipes, which are used in water distribution networks and compressed air systems. Tensile tests were performed at different cross-head speeds at room temperature while, flexural tests were conducted at different cross-head speeds with five distinct temperatures 23, 35, 50, 70, and 90 degrees C. The exper-imental results show that both materials are sensitive to cross-head speed, temperature, and holding time. Additionally, the percentage of elongation at break and toughness of GFPP are lower than that of PP. However, the elastic modulus and yield stress of GFPP are higher than that of PP at the same cross-head speed. On the other hand, the bending energy and the dissipated energy of GFPP are higher than that of PP under all cross-head speeds and testing temperatures. PP gains 20.4% and GFPP gains 15.2% bending energy with raising cross-head speed from 5 to 50 mm/min. Also, a decrease in flexural modulus for both materials occurs with raising temperature from 23 to 50 degrees C. (C) 2021 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria UniversityTHE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University.