Mechanical properties and morphologies of polypropylene with different sizes of glass bead particles

Abstract A commercial grade of isotactic polypropylene (PP) was used to study the mechanical properties and morphologies of the PP composites filled with four sizes of glass bead particles. The glass bead particles used were with average particle sizes of 15 μm (GB15), 10 μm (GB10), 5 μm (GB5), and 2.5 μm (GB2.5), respectively. It was clear that the glass bead size was an important factor on the determination of mechanical properties of the composites. As a whole, in view of the scatter in the data, under the condition of same filler content, the yield strength and impact strength of the composites filled with smaller glass bead particles was higher than those of the composites filled with bigger ones. And the flexural strength and modulus of the composites filled with GB10, GB5, or GB2.5 particles could be regarded as the same. The flexural strength and modulus of the composites filled with GB15 particles were higher than those of the composites filled with other three sizes of particles. Among four sizes of glass bead particles, GB2.5 had the best toughening effect to improve the impact strength of PP matrix. And the major toughening mechanism of the PP/GB2.5 composites was the pinning effect introduced by GB2.5. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers