Thesis
Fire retardant polyurethane foams
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2026
- Thesis identifier
- T17571
- Person Identifier (Local)
- 201782872
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- This study investigates the thermal degradation mechanisms of thermally expandable graphites (TEGs) and their application in developing an effective fire-stop foam for the oil and gas industry. The research began by formulating a polyurethane foam with rapid curing properties and flexibility, achieving a material that met these initial objectives. As the study progressed, the incorporation of thermally expandable graphite (TEG) introduced new complexities, requiring a detailed investigation into the thermal degradation pathways of the foams and the fire retardant. A significant part of the research was to understand the thermal degradation pathways of TEG and monitor products for any that may be toxic or affect the stability of the polymer. Two commercially available thermally expandable graphites with different intercalated acids were analysed using thermal volatilisation analysis—sub-ambient distillation (TVA-SAD), mass spectrometry (MS), and Fourier transform infrared spectroscopy (FTIR). The results confirmed the presence of three principal thermal events related to the expansion of sulfuric acid intercalated expandable graphite (EG-S) and nitric acid intercalated expandable graphite (EG-N). Isothermal analyses provided a deeper understanding of the processes and decomposition products released from each stage. For both graphites, desorption of migrating gases and volatilisation of water occurred in the first instance. EG-S released CO2, CO, and water upon expansion and released a significant volume of SO2 subsequently. EG-N expansion was shown to proceed with releasing NO2, NO, CO and water. Additionally, the release of non condensable species and carbonyl-derived fragments suggested that the exfoliation process occurred due to multiple degradation processes. The study also examined the thermal degradation of polyurethane foams modified with TEGs (PUEG-N and PUEG-S) compared to the base foam. It was found that incorporating TEGs into the base foam significantly altered its degradation pathway. For the PUEG-S, the sulfuric acid played a catalytic role in the degradation process, resulting in the formation of different products compared to the base foam. The degradation route of the PUEG-N foam also changed compared to the base foam, attributed to oxidation reactions by nitric acid which enhanced polyol degradation and limited the occurrence of the six-membered ring transition state. In addition, the oxidative degradation behaviour of the foams was analysed in detail, providing insights into its decomposition pathways under both inert and oxidative conditions. The study demonstrated that the degradation mechanisms were highly environment-dependent, with the six-membered ring transition state dominating under nitrogen but not under air. The addition of fire retardants, particularly EG-S and EG-N, altered these pathways, suppressing certain degradation mechanisms and leading to different degradation products. Overall, the research highlighted the complex interplay between expandable graphite, their intercalated acids, and polyurethane foam degradation, emphasising the importance of considering environmental factors and degradation behaviour of fire retardants in the design and optimisation of fire-resistant materials, particularly in high risk industrial applications. This comprehensive understanding of the degradation behaviour of polyurethane foams provides a foundation for future advancements in fire protection technologies.
- Advisor / supervisor
- Liggat, John A.
- O’Keeffe, Luke
- Resource Type
- DOI
- Date Created
- 2025
- Embargo Note
Relations
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File | 2026-08-04 | Embargo |