Evaluation of Experimental Parameters in the Microbond Test with Regard to Lyocell Fibers

Microbond technique is used to measure the interfacial shear strength (IFSS) of cellulose fiber-reinforced composites. Critical aspect ratios are provided for a variety of cellulose fiber-polymer matrix systems to avoid the fiber breakage during microbond test. The influence of fiber cross-section and droplet curing condition on the force-displacement curve and the corresponding change of IFSS are discussed for lyocell-polypropylene system. Finally, a relationship between the contact angle of a polymer drop on a fiber and IFSS is established for composite systems involving thermoset and thermoplastic matrices.