Investigation on mechanical and thermal properties of giant milkweed (Calotropis persica) fibers -plastics composites

The suitability of using Iranian grown giant milkweed fibers (GFs) as a new raw material for thermoplastic composites was investigated. The polypropylene (PP) was used as the matrix polymer and the maleated polypropylene, Epolene G- 3003TM, was used as coupling agent. In the sample preparation, four levels of fiber loading (10, 20, 30, and 40 wt%) and three levels of coupling agent content (0, 1.5, and 3 wt%) were applied and the mechanical properties of composites are analyzed. GF/PP composites were prepared by a melt compounding process in a twin-screw extruder followed by injection molding. The results showed that with the addition of coupling agent, both tensile and flexural properties improved considerably compared with control specimens (without coupling agent). As expected, notched Izod impact strength was significantly decreased as the mixing ratio of fiber increased. The results of the present study revealed that composites with good strength properties could be successfully developed using GF as the reinforcing agent. The Heat Deflection Temperature (HDT) is determined following the test procedure outlined in ASTM. High HDT in this study showed that coupling agent at3 wt% and fiber loadiny either 30 or 40 wt% were superior compared with other treatments