Anisotropic polypropylene cellular polymers filled with nanoclays: Microstructure and properties

This work deals with the production and characterization of low-density rigid foams with anisotropic cellular structures based on polypropylene filled with nanoclays, which present a high potential to be employed for structural applications. The use of nanoclays and different external pressures during foaming allowed to modify several structural parameters such as anisotropy ratio, cell size, and open cell content which had a huge impact on their mechanical behavior. Moreover, nanoparticles catalyzed the thermal decomposition reaction of the blowing agent, which involved the formation of bimodal cellular structures. The mechanical anisotropy of these foams was characterized by measuring the compressive modulus in three different directions. The results indicate that mechanical properties can be significantly improved due to the introduction of nanoclays and to the structural modifications induced by their presence, especially when it comes to the anisotropy ratio parameter. POLYM. COMPOS., 40:E526–E539, 2019. © 2018 Society of Plastics Engineers.