Parameters regulating interfacial and mechanical properties of short glassfiber reinforced polypropylene

The performance of thermoplastic composites is known to depend on the intri nsic properties of the two composite components, the quality of the fiber-m atrix interface, and the crystalline properties of their matrix. The object ive of this work is to characterize the effect of the addition of modified polypropylene (PP) and silane coupling agent on the mechanical and interfac ial properties of short fiber reinforced PP composites. Differential scanni ng calorimetry (DSC), single fiber composite fragmentation tests (SFC), and mechanical testing are used to understand the different parameters regulat ing the interfacial properties of composites. No influence of the modified PP on the level of crystallinity is observed. Some differences in the size of the spherulites are observed for acrylic acid grafted PP (PP-g-AA). Thos e samples also show lower mechanical properties in spite of good interfacia l interactions. Maleic anhydride grafted PP (PP-g-MAh) leads to better mech anical performances than PP-g-AA. A high MAh content PP-g-MAh grade with lo w viscosity is the best polymeric additive used in the present work. (C) 20 00 John Wiley & Sons, Inc.