A comparative evaluation of mechanically reinforced and heat-resistant organic powder/polyurethane elastomer hybrid composites

Polyurethane elastomers are widely utilized in various engineering applications due to their favorable properties. However, their high surface energy and internal heat generation limit their potential use under high dynamic or temperature conditions. To overcome these limitations, we prepared polyurethane elastomer (PUE) composites and blended them to reinforce with polytetrafluoroethylene (PTFE), polyethylene wax (PEW), or melamine cyanurate (MCA). The composites were characterized using several techniques, including electronic universal material testing machine, scanning electron microscope, differential scanning calorimetry, and thermal gravimetric analyzer. Our results indicated that the optimal mass ratio of curing agent to polyurethane prepolymer was 12.5%, which yielded a PUE with a shore hardness of 92 HA, tensile strength of 17.2 MPa, and elongation-at-break of 329%. In addition, we observed that the incorporation of 0.5% (by wt) multifunctional friction reducer into the composite produced an excellent antistatic performance. The MCA-reinforced PUE composite exhibited remarkable tensile and thermal behavior, with an 11.6% increase in tensile strength and a 101.2% increase in elongation-at-break compared to pristine PUE. Moreover, the glass transition temperature and thermal stability of MCA/PUE composite were enhanced to - 26.7celcius and 280celcius, respectively, compared to the unmodified counterpart. However, the incorporation of PTFE or PEW only marginally influenced the tensile and thermal behavior of the PUE composites. These findings indicated that the improved tensile and thermal properties of the polyurethane composite reinforced with MCA can be attributed to the superior interface compatibility between MCA and the polyurethane matrix as well as the increased cross-linking density. Therefore, this work demonstrates the potential for expanding the use of PUE in high-performance automobile tires or rubber-covered rollers.