Structure–Property Relationship in Injection-Molded Polypropylene/Clay Composite Foams

Polypropylene (PP)/organically modified montmorillonite (OMMT) composite foams were fabricated by a two-step injection foaming technique. The structure–mechanical property relationship in the composite foams was investigated. The OMMT favors the tensile and impact properties of the composite foams by optimizing the cell structure and the polymer matrix structure. The microcells in the polymer matrix played a positive part in the toughening of PP/OMMT composite foams, but lowered the reinforcing effect of OMMT as expected from the mixture rule. The enhanced mechanical properties for the composite foams were obtained by incorporating well-dispersed OMMT into PP matrix.