Fatigue life of coir fiber reinforced PP composites: Effect of compatibilizer and coir fiber contents

Abstract

The fatigue behavior of polypropylene/coir fiber composites was investigated. Composites were prepared according to an experimental statistical design, in which the independent variables coir fiber and compatibilizer content were varied. The compatibilizer used was maleic anhydride grafted polypropylene (PP‐g‐MA). Compatibilizer free composites were also prepared. Composites were prepared in a corotating twin‐screw extruder and the mechanical behavior of polypropylene/coir fiber composites were assessed through monotonic (tensile) and cyclic (fatigue) tests. Fatigue load controlled tests were conducted under tension–tension loads at a frequency of 6 Hz. The fracture mechanism was accompanied by surface fracture analyses using scanning electron microscopy (SEM). The results indicated the need for using compatibilizer in the composites; however, increase in compatibilizer content did not affect composite fatigue lifetime. Coir content was the variable with the strongest effect on composite properties; increasing this variable caused significant increase in fatigue life. POLYM. ENG. SCI., 53:2159–2165, 2013. © 2013 Society of Plastics Engineers

Evaluation of interactions between compatibilizers and photostabilizers in coir fiber reinforced polypropylene composites

“…As it can be seen by comparing the samples of Group 2 and Group 3 in Table , adding the compatibilizer (PPMAH) to the PP/CF composites increases the adhesion between the phases of PP and coir fibers, and consequently, it increases tensile strength due to the adequate load transfer between phases, since it is a maleic anhydride grafted polypropylene, whose anhydride phase may react and/or interact with the hydroxyls of the fiber surface. These results show the importance of incorporating compatibilizers in incompatible systems, using PP as the matrix, as it has been extensively shown in the literature.…”

“…The addition of a compatibilizer favors the processing and improves the dispersion of fibers in the polymer matrix, in addition to reducing composite water absorption and increasing tensile strength, bending strength and the mechanical properties in the long term, such as fatigue . However, increasing the concentration of compatibilizers is not sufficient to increase the mechanical properties, reaching a percentage limit, depending on the matrix and the reinforcement .…”