TENSILE TEST OF POLY(VINYL CHLORIDE) FILLED WITH GROUND CALCIUM-CARBONATE PARTICLES

The fracture behavior of poly(vinyl chloride) filled with ground calci um carbonate particles during a tensile test was studied. The particle s were prepared by crushing natural raw crystalline limestone. For thi s purpose, 10-50 parts of the particles having two different mean size s (2 and 8 mu m) without further surface treatment were mixed with 100 parts of poly(vinyl chloride) and 3 parts of lead stearate as a stabi lizer using a mixing roll. A tensile test was carried out using a dumb bell specimen. As a result, the yield stress decreased with increase i n the particle content; however, there was no significant influence of particle size. From scanning electron microscopic observations of the specimen's surfaces during the tensile test, it was found that the pa rticle/matrix interfaces were delaminated and formed voids around the particles when the applied stress approached the yield stress, that is , the particles acted as voids and the matrix around the voids was pla stically deformed effectively. These observations appear to be the rea son for the decrease of yield stress by the incorporation of the parti cles. (C) 1998 John Wiley & Sons, Inc.