Effect of hybrid cross‐linked polyphosphazene microspheres on ablative and mechanical properties of ethylene propylene diene monomer

Abstract

Polymeric ablative materials (PAMs) are widely used in spacecraft currently for thermal insulation. However, it is challenging to find a single filler that can improve both ablative and mechanical properties of PAMs. In this study, a new type of hybrid cross‐linked polyphosphazene microspheres (PHC) is added to ethylene propylene diene monomer (EPDM) composites as a filler for the first time and its influence on the ablation, mechanical, and thermal properties of EPDM is investigated. The results show that the addition of 3 phr PHC increases the ablation performance by about 10% and enhances the mechanical properties by 20% approximately. In addition, the ablation mechanism is studied in accordance with SEM, FTIR, and Raman spectroscopy. On the one hand, PHC has the effect of catalyzing carbonization, thus increasing the rate of residual carbon; on the other hand, PHC changes the morphology of the char layer, forming a cross‐linked structure containing P─O─Si bonds on the surface. The findings regarding catalyzing carbonization and the special char layer structure could guide the design of ablative materials.

Effects of Fluorinated Side Groups on the Insulation Performances of Polyphosphazenes with Organic Fiber Reinforcement

“…Drawing on the improving ablation resistance techniques of traditional organic rubber insulation materials, the ablation performance of the traditional EHSM can be effectively improved by the flame-retardant modification of the structure and addition of flame retardants . Like ammonium polyphosphate, boron compounds, and polyhedral oligomeric siloxanes, these flame-retardant fillers could promote the carbonization of organic cracking fragments by retarding oxidation and enhance the strength and density of the charred layer via ceramic reactions, which would help to improve the ablation performance of insulating materials. − Unfortunately, most flame retardants could not promote the promotion of the interaction between the charred layer and the nether virgin insulation materials, implying the flaming gas scouring could make the charred layer peel out from the substrate easily which may lead to further erosion of the substrate and thermal protection failure in severe cases. , Therefore, structural modification of elastomers is a more ideal method to obtain the expected flame-retardant properties.…”

Enhancing the Anti-Migration Performance and Mechanical Properties of EPDM Insulation through Functionalized GO

“…Due to the specific location and special functions of the internal insulation layer, there are strict requirements for the internal insulation materials, not only in terms of thermal properties and ablation resistance but also in terms of mechanical properties, compatibility, process performance, and anti-aging properties [ 4 ]. Ethylene propylene diene monomer (EPDM) is widely used as the combustion chamber of SRM owing to its outstanding age-resistant, ablate-resistant, thermal shock-resistant, and low-density properties [ 5 , 6 , 7 ].…”

Preparation and anti‐migration performance of ethylene propylene diene terpolymer composites modified with GO‐SiO2 hybrid nanomaterials

“…1 An inhibitor coating is an indispensable part of solid rocket motors and is a layer of heat-insulating/ablation-resistant material placed between the shell and solid propellant. [2][3][4] It plays an important role in controlling the combustion area of the propellant charge and helps thermally insulate the engine casing. The inhibitor coating needs to have sufficient bonding performance, mechanical properties, low density, and ablation resistance, while also having anti-plasticizer migration resistance to protect the engine case.…”

“…The inhibitor coating needs to have sufficient bonding performance, mechanical properties, low density, and ablation resistance, while also having anti-plasticizer migration resistance to protect the engine case. 4 Ethylene propylene diene terpolymer (EPDM) rubber is a widely used synthetic rubber, and vulcanized EPDM shows a low density, excellent Zhehong Lu and Yubing Hu are contributed equally to this work. mechanical properties, oxidation resistance, and good thermal stability.…”

“…mechanical properties, oxidation resistance, and good thermal stability. [3][4][5] Therefore, EPDM has become an ideal matrix for inhibitor coatings. 6 Plasticizers increase the flexibility of inhibitor coatings and improve the mechanical properties of propellants.…”