Thermal, morphological, and electrical characterization of microwave processed natural fiber composites

Experiments to investigate the effectiveness of microwave curing of natural fiber reinforced composites have been performed. Hemp, flax, kenaf, henequen and glass (15 wt.%) reinforced epoxy composed of diglycidyl ether of bisphenol-A (DGEBA) and diaminodiphenyl sulfone (DDS) composites were studied. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), environmental scanning electron microscopy (ESEM), and swept frequency diagnostic method were used to investigate material properties. Samples were processed using both microwave and thermal curing. Glass and flax composites reached a higher final extent of cure with microwave curing than with thermal curing. Glass, flax, and hemp cured faster in the microwave than their convection oven counterparts. Natural fibers and their composites degraded at lower temperatures than glass and glass fiber composites. ESEM micrographs, used to investigate fiber morphology, indicated a lack of bonding at the interfaces between the fibers, natural and glass, and matrix.