Sintering behavior of ceramic ethylene‐propylene‐diene rubber/pyrophyllite/zinc borate composites

Abstract

Ceramic polymer materials have great future applications in the field of fireproof materials. However, ceramic polyolefins have shortcomings such as few available inorganic fillers, high sintering temperature, and low flexural strength. Therefore, achieving rapid sintering of ceramic ethylene‐propylene‐diene rubber (EPDM) is an urgent problem that needs to be solved. Herein, we prepared ceramic EPDM materials using pyrophyllite as aggregate and zinc borate as flux. The materials were prepared using a mixer and sintered in a muffle furnace at 850 and 1000°C. The flexural strength of the sinter residue was tested by a material testing machine. The microstructure changes during the ceramification process were characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TG), derivative thermogravimetric analysis (DTG), differential thermal analysis (DTA), and x‐ray diffraction (XRD). The results indicated that the EPDM filled with pyrophyllite and zinc borate had a flexural strength of 2.6 MPa after sintering at 850°C. After sintering at 1000°C, its flexural strength further increased up to 12.3 MPa. The SEM results indicated that as the temperature increased, the zinc borate melted and filled in the space among pyrophyllite particles, and the zinc borate and the pyrophyllite were sintered into a dense whole. The TG, DTG and DTA testing results indicated that the melting and decomposition behaviors of the pyrophyllite‐zinc borate mixture changed compared with pure pyrophyllite and zinc borate. The XRD results indicated that during the sintering process, the crystalline structure of the zinc borate and the pyrophyllite gradually transformed into a quartz‐based crystalline structure. It is promising that the ceramic polyolefin materials are prepared by the pyrophyllite/zinc borate combination.