Ceramifiable Silicone Rubber Composites with Enhanced Self-Supporting and Ceramifiable Properties

Abstract

Ceramifiable silicone rubber (SR) composites with excellent self-supporting properties and ceramifiable properties were prepared by incorporating silicate glass frits (SGFs) and sodium tripolyphosphate (STPP) into the SR. Ceramic residues were obtained by firing ceramifiable SR composites at 700, 850, and 1000 °C for 30 min. The bending angles of the composites were tested for evaluating the self-supporting property. To evaluate the ceramifiable properties of the ceramifiable SR composite, flexural strength, water absorption, and bulk density of its residues were tested. It was found that the addition of STPP improved the shape stability and the self-supporting property of the composites at high temperatures. The flexural strength of the ceramic residue of the composite with STPP firing above 850 °C is more than 5 MPa. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis showed that the relative content of the crystalline phase was enhanced by about 25% due to the addition of STPP. Furthermore, a possible mechanism for the formation of the crystalline phase was proposed. Scanning elector microscope (SEM) and energy dispersive spectrometry (EDS) analysis demonstrated that with the temperature increase, the inter-infiltration between these melts became easier, which implies that the bulk density of the ceramic residue was improved.

Effect of Inorganic Fillers on Electrical and Mechanical Properties of Ceramizable Silicone Rubber

“…Recently, ceramizable silicone rubbers (CSR) were developed as a novelty flameresistant insulating material, and are composed of a silicone rubber matrix, fluxing agent, inorganic filler, and vulcanizing agent, exhibiting excellent thermal, electrical, and mechanical properties [11][12][13][14]. During the high-temperature combustion process, CSR can transform into robust ceramic materials on the surface of power cables to prevent the development of flames [15][16][17].…”

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

“…After sintering, the flexural strength of silicone rubber is generally high. [17][18][19] What is more some special substances, including platinum, [20][21][22] iron oxide, 23 and boron, 24 can significantly promote ceramification of silicone rubber. In addition to silicone rubber, other special polymers containing boron and silicon are also easy to ceramification.…”

“…It can be easily to ceramification with some inorganic materials. After sintering, the flexural strength of silicone rubber is generally high 17–19 . What is more some special substances, including platinum, 20–22 iron oxide, 23 and boron, 24 can significantly promote ceramification of silicone rubber.…”

Study on mechanical properties and fire resistance of porous ceramic silicone rubber

“…10 The addition of the phosphorus-based flame-retardant sodium tripolyphosphate (STPP) to silicone rubber increases the relative content of the crystalline phase by about 25%, which can enhance the shape stability and self-supporting properties of the composites at high temperatures. 11 The porous ceramic silicone rubber (PCSR) composites in our study similarly incorporated GP, aluminum hydroxide and phosphorus-nitrogen flame retardants to enhance the composites' flame retardancy and the robustness of the carbon layer structure. However, few studies have been reported on the effect of matrix portion in porcelainised silicone rubber on mechanical and fire resistance properties, especially on tensile shear strength at different temperatures for a wide range of substrates.…”

“…The introduction of flame retardants is the most effective way to improve the flame retardancy of silicone rubber 10 . The addition of the phosphorus‐based flame‐retardant sodium tripolyphosphate (STPP) to silicone rubber increases the relative content of the crystalline phase by about 25%, which can enhance the shape stability and self‐supporting properties of the composites at high temperatures 11 . The porous ceramic silicone rubber (PCSR) composites in our study similarly incorporated GP, aluminum hydroxide and phosphorus‐nitrogen flame retardants to enhance the composites' flame retardancy and the robustness of the carbon layer structure.…”