The J -integral method was introduced to investigate the fracture process of PP/CaCO 3 composites. The results showed that the resistance of PP/CaCO 3 composites to crack initiation and propagation was greatly improved with the addition of CaCO 3 filler. Large scale plasticity was caused in PP/CaCO 3 composites, from which a large amount of energy was absorbed by the PP matrix. The reason for the increase in the fracture toughness of PP/CaCO 3 composites was attributed to the partial micro-drawing ahead of the crack tip in the PP matrix, which was formed by the stress concentration caused by the filler particles in the PP matrix and/or by the interfacial debonding between filler particles and the PP matrix. It was indicated that the presence of CaCO 3 filler could augment the ductility of composites locally, resulting in higher fracture energy in the crack initiation and propagation of the PP/CaCO 3 composites in a certain CaCO 3 content range.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44729/1/10853_2004_Article_BF00357345.pd
