The mechanical and thermal behaviors of glass bead filled polypropylene

Notch Izod impact strength of poly(propylene) (PP)/glass bead blends was studied as a function of temperature. The results indicated that the toughness for various blends could undergo a brittle‐ductile transition (BDT) with increasing temperature. The BDT temperature (T_BD) decreased with increasing glass bead content. Introducing the interparticle distance (ID) concept into the study, it was found that the critical interparticle distance (ID_c) reduced with increasing test temperature correspondingly. The static tensile tests showed that the Young's modulus of the blends decreased slightly first and thereafter increased with increasing glass bead content. However, the yield stress decreased considerably with the increase in glass bead content. Dynamic mechanical analysis (DMA) measurements revealed that the heat‐deflection temperature of the PP could be much improved by the incorporation of glass beads. Moreover, the glass transition temperature (T_g) increased obviously with increasing glass beads content. Differential scanning calorimetry (DSC) results implied that the addition of glass beads could change the crystallinity as well as the melting temperature of the PP slightly. Thermogravimetric analysis (TGA) measurements implied that the decomposition temperature of the blend could be much improved by the incorporation of glass beads. Copyright © 2004 John Wiley & Sons, Ltd.