Effects of filler size and heat treatment on the crystallization behavior of glass bead-filled polypropylene

The effects of glass bead (GB) size and annealing temperature on the formation of beta-crystals of glass bead-filled polypropylene (PP) are studied in this articles. Differential scanning calorimetry (DSC) measurements indicated that the amount of beta-form. in PP crystals was a function of the glass bead content and size. For a fixed glass bead content, it was found that the smaller the diameter of the glass bead, the higher was the content of beta-crystals formed in the PP. On the other hand, wide-angle X-ray diffraction (WAXD) measurements revealed that the annealing temperature was also a major factor that affected the crystallization behavior of glass bead-filled PP. It seemed that the blends with different glass bead contents had their own optimal annealing temperatures for beta-crystal formation. As an example, when the glass bead content was 48 wt%, the optimal annealing temperature for beta-crystal formation was about 108 degreesC, whereas it shifted to 100 degreesC for 14 wt% glass bead-filled polypropylene. (C) 2004 Wiley Periodicals, Inc.