Low-Temperature Curable Epoxy–Silica Composites for Intricate Ablative Structures

Autor: Dona Mathew, N. Sreenivas, B. Satheesh Kumar, Temina Mary Robert, K. S. Santhosh Kumar, K. Sunitha
Rok vydání: 2021
Předmět:
Zdroj: Transactions of the Indian National Academy of Engineering. 6:105-110
ISSN: 2662-5423
2662-5415
Popis: Room-temperature-curable, easy to fabricate, low-cost epoxy novolac composites, reinforced with silica fiber were investigated as ablative thermal protection systems for moderate thermal environments. These composites possessing good mechanical and thermo-mechanical properties were prepared by blending epoxy novolac resin with the reinforcement and varying proportions of glass microballoons (1, 3, 5, and 10% by wt). The composites were cured using polyamidoimidazoline. Complete curing of the epoxy groups was ensured from Fourier transform infra-red spectroscopy (FTIR) and Differential scanning calorimetry (DSC), while the extent of cure was monitored by rheometry. The composites exhibited inter laminar shear strength > 23 MPa and flexural strength > 120 MPa. The thermal and thermo-oxidative stability were monitored by thermo-gravimetric analysis (TGA). The composites were found to be self-extinguishing with Limiting Oxygen Indices (LOI) in the range of 40–46%. Coefficient of thermal expansion (CTE) and specific heat were in the range of 4.8–7.0 × 10–6/°C and 0.6–0.64 cal/g/°C respectively. The composites exhibited heat of ablation in the range of 1.4–1.7 × 107 J/kg which renders them potential candidates for ablative applications capable of withstanding moderate heat flux applications.
Databáze: OpenAIRE
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