Advanced characterization of 3D printed polyolefin elastomer-carbon black composites: cyclic mechanical behavior, thermophysical properties, and morphological analysis

Abstract

This study follows the effects of carbon black (CB) fillers with respect to the mechanical and thermal properties of polyolefin elastomer (POE) composites. Cyclic mechanical testing was conducted, highlighting the Mullins effect, which demonstrates a reduction in stiffness and stress upon subsequent loading cycles. Optimal mechanical performance was observed at 4% (by weight) CB, showing superior tensile strength and elongation. Thermal characterization by thermogravimetric analysis (TGA) revealed that the incorporation of CB significantly enhances the thermal stability of the POE matrix. The initial decomposition phase of pure POE ends at 323 °C, whereas the addition of 4% (by weight) CB shifts this to 352 °C. This shift is attributed to improved entanglement and restricted mobility of polymer chains due to CB fillers. Furthermore, the main decomposition phase showed a peak temperature increase from 463 to 476 °C with the addition of CB. Differential scanning calorimetry (DSC) analysis demonstrated that CB fillers affect the thermal transitions of POE, reducing the glass transition temperature (T_g) from − 50.50 to − 51.25 °C, decreasing the crystallization temperature (T_c) by 12 °C resulting in a 19% reduction crystallinity rate, and lowering the melting temperature (T_m) by 8.6 °C. Scanning electron microscopy (SEM) analysis confirmed a uniform dispersion of CB particles within the matrix and strong interfacial bonding, which mitigates common 3D-printing defects and enhances overall material durability. These findings underscore the potential of CB-reinforced POE composites for applications requiring enhanced mechanical and thermal properties.

Graphical abstract