Investigation on Foamed PP/Nano-CaCO Composites in a Combined in-Mold Decoration and Microcellular Injection Molding Process.

A combined in-mold decoration and microcellular injection molding (IMD/MIM) method has been used in this paper. The foamed PP/nano-CaCO composites were prepared to investigate their mechanical properties, cellular structure, and surface quality. The content of nano-CaCO varied from 0 to 10 wt %. The results showed that nano-CaCO acted as a reinforcing phase and nucleating agent, which help to improve the mechanical properties of foamed composites. The cellular structure and mechanical properties were optimum when the nano-CaCO content was 6 wt %. In the vertical section, the cell size and density of transition layer on the film side was bigger than that on the non-film side. In the parallel section, the cell ratio of length to diameter of transition layer on the film side was smaller than that on the non-film side, and the cell tile angle was larger than that on the non-film side. With nano-CaCO content increasing, the surface quality showed a trend of decreasing first and then increasing.