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In this study the feasibility of applying two kinds of mudar (Calotropis gigantea) fibers, namely bark fibers and seed fibers, as an alternative raw material for fiber-reinforced composite (FRC) is investigated. The chemical analysis of the bark and seed fibers indicates that their main components are holocellulose 76 and 69%, cellulose 57 and 49%, lignin 18 and 23%, and alkali soluble substances 17 and 15%, respectively. There are statistically significant differences in the bark and seed fiber dimensions. The bark fibers are long, with a thin wall relative to their diameter, and are therefore lightweight. The seed and bark fibers are very similar to hard- and soft-woods, in terms of chemical compositions and fiber dimensions, respectively. The mechanical properties of the mudar bark fibers are: tensile strength 381 MPa, strain at break 2.1% and Young's modulus 9.7 GPa. In general, both types of fibers have enough potential for replacing or supplementing other fibrous raw materials as reinforcing agent. [ABSTRACT FROM AUTHOR]

In this paper, the flexural modulus and wear resistance of silicon carbide and alumina whisker-reinforced epoxy composites are reported. The composites were fab ricated from epoxy resins and whiskers which were produced in a plasma furnace. The resulting silicon carbide and alumina whisker-reinforced epoxy composites have low den sities, high flexural moduli and good wear resistance. The specific stiffnesses of these two composites with 16-18% weight fraction of whiskers were 1.59 and 1.50 (GPa/g/mm3) respectively. These values were 46 and 37 percent higher than that of the unreinforced epoxy resins. The silicon carbide and alumina whiskers which have low densities, high strength, high length to diameter ratios, and large surface area, are effective reinforcing agents for epoxy composites. Also, the factors that determine the flexural modulus of the composite are discussed. [ABSTRACT FROM PUBLISHER]