Internal friction studies of particulate filled polypropylene

Internal friction of injection-molded polypropylene with various fractions of magnetite, barite, copper, talc, strontium ferrite and glass fibers was measured in the temperature range 170–425 K with frequencies of 0.1–100 Hz. Peaks of the α- and α′-relaxation were found while no peak of the β-relaxation was detected. At high temperatures a drastic increase of the loss factor superposes the α′-peak. The crystallinity of the filled polypropylene varies in the range from 23% to 35%. The samples consist of α- and β-crystallites depending on the material and amount of filler.