F. Stricker et al., MECHANICAL AND THERMAL-PROPERTIES OF SYNDIOTACTIC POLYPROPENE FILLED WITH GLASS-BEADS AND TALCUM, Polymer, 38(21), 1997, pp. 5347-5353
Glass bead-and talcum-reinforced polypropene composites based on syndi
otactic polypropene (s-PP) and isotactic polypropene (i-PP) were prepa
red to study mechanical and thermal properties and to identify influen
ce of PP type and stereoregularity. Composites based on s-PP gave high
er notched Izod impact strength than those based on i-PP, accompanied
by lower Young's modulus and yield stress. The experimental Young's mo
duli and yield stresses of composites based on highly stereoregular s-
PP and i-PP were in good agreement with theoretical predictions accord
ing to Kerner and Nicolais-Narkis, respectively. The higher relative Y
oung's modulus and yield stress of composites based on s-PP of low ste
reoregularity were attributed to strong interfacial adhesion and can b
e described by the theory of Jancar. Lap shear tests confirmed strong
glass polymer interactions. Investigations of crystallization show the
nucleating effect of glass beads and talcum in the case of i-PP as we
ll as s-PP. With increasing filler volume fraction, PP degree of cryst
allinity decreases. Dynamic mechanical analysis of glass bead-reinforc
ed s-PP composites show an unexpected relaxation occurring at 55 degre
es C. (C) 1997 Elsevier Science Ltd.