Smart behavior of elastomeric composites produced by injection molding

This work reports the preparation and characterization of composites based on ethylene vinyl acetate (EVA) and iron based powder produced by an injection molding machine specifically designed to host an electromagnet connected to a power supply which generates a magnetic field during the forming phases. The magnetic field allows the repositioning of the particles along the magnetic field lines leading to an anisotropic structural reinforcement. Thermogravimetric analyses show that the addition of iron powder to the EVA allows thermal stabilization, delaying the first degradation step ascribed to the loss of acetic acid. Mechanical characterizations show that the samples present a higher tensile modulus in the direction of the magnetic field with respect to the same property measured in the direction perpendicular to the magnetic field and considerably higher than the modulus of the samples obtained without the application of magnetic field. Furthermore, the samples obtained in the presence of magnetic field present sensitivity to the application of an external magnetic field. These results demonstrate that the application of a magnetic field during the injection molding process of EVA/Fe composite induced an alignment of the particles, which therefore induce peculiar properties to the samples. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46863.