Single fiber pull-out test of regenerated cellulose fibers in polypropylene: An energetic evaluation

This paper focuses on the energetic evaluation of the single fiber pull-out test (SFPT) using regenerated cellulose fibers (RCF) in a PP matrix with a varying MAPP content. Glass fibers were used for reference purposes. By means of the SFPT the interfacial shear strength (IFFS), the critical fiber length (lc), the consumed energy of a fiber pull-out and the consumed energy of a fiber rupture were determined. Results were related to the fiber length distribution in injection molded specimens. It was shown that theoretically more fiber ruptures appear in composites with RCF than with GF. But RCF composites offer a larger number of long fibers, slightly underneath the critical fiber length, consuming a high amount of energy by being pulled out at a composite failure. The consumed energy of a fiber pull-out per length was increased by using MAPP but simultaneously the critical fiber length was significantly reduced.