Mechanical Properties Associated with the Interface of a Co-injection Molded Structural TPO Foam

In this paper, we examined the influence of the morphology at the interface of a co-injection molded TPO foam part. Co-injection molding was selected as a possible method to manufacture a foamed part with 20% reduced weight while maintaining a Class A surface finish for a molded part. In the course of that investigation it was observed that mechanical properties could be dramatically affected by the core's cellular structure close to the interface of the A-B-A sandwich composite. Using this method, it was observed that mechanical properties of foam centered parts can decrease slightly as compared to solid core counterparts. SEM analysis shows that at room temperature, impact fractures have some plastic deformation, and occur within the cellular core structure.