Tensile behaviour of isotactic polypropylene modified by specific nucleation and active fillers

Commercial-grade polypropylene was modified with a specific nucleation agent based on an amide of dicarboxylic acid, which promotes crystallization predominantly in the β-phase. The resulting material was used as a matrix for composites containing 10%, 20%, and 30% (by weight) of different calcium carbonate fillers. These fillers differed in particle size and surface treatment. The β-phase content, morphology and tensile mechanical properties were investigated. A distinct β-nucleation activity was found with surface-treated fillers; nevertheless, to obtain stiff and reasonably ductile composite materials, a matrix containing a critical nucleant concentration (0.03 wt%) was necessary.