Application Note:It is possible to triple both the modulus and strength of polypropylene resin by adding only 15 volume % carbon nanofibers.
Graph top left: Tensile strength versus modulus for 15 volume % composites using different types of CNF in polypropylene. The open circle shows the properties of polypropylene. The data shows that it is possible to triple both the modulus and strength of the polypropylene resin by adding only 15 volume % carbon nanofibers.
Graph bottom left: Loss factor vs. fiber volume fraction for CNF/polypropylene composites at room temperature. Shows the variation of the loss factor of the graphitized fiber, air-etched, and clean fiber/polypropylene composites versus fiber volume fraction. As fiber volume fraction increases, the loss factor decreases compared to the unreinforced polypropylene. The slope of the damping versus fiber volume fraction curves increases as adhesion between the fiber and the matrix increases.
Graph right: Tensile strength and modulus of composites fabricated from 15 vol% CNF produced with different gaseous feedstock residence times. Fibers grown under conditions of lower feedstock residence time are more graphitic and adhere more poorly to polypropylene.
More graphitic fibers adhere poorly to the polypropylene matrix compared to less graphitic fibers. Fiber matrix adhesion may be improved by moderately oxidizing the fibers in air or carbon dioxide. This oxidation seem to become more effective as it increases the product of the external surface area and the surface energy of the fibers; however, excessive etching can be destructive.
Better fiber-matrix adhesion increases the mechanical properties of the CNF/polypropylene composites.
To improve the modulus and strength of polypropylene resin, PPI recommends the following products XXX