Date of Award

December 2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Alena Kubatova

Second Advisor

Evguenii Kozliak

Abstract

Silicone sealants are essential components in various applications, but their long-term performance can be compromised by aging and weathering. This study investigated the thermal degradation behavior of poly dimethyl silicone sealants to gain insights into the underlying mechanisms of failure. A combined approach using Evolved Gas Analysis (EGA) and Thermal Desorption-Pyrolysis Gas Chromatography-Mass Spectrometry (TD-Pyr-GC-MS) was employed to analyze the degradation products and identify the factors influencing the degradation process.Aged and weathered sealants exhibited distinct thermal degradation profiles compared to fresh samples. The evolution of siloxane degradation products occurred at lower temperatures in aged sealants, indicating accelerated degradation. TD-Pyr-GC-MS analysis revealed changes in siloxane speciation, suggesting alterations in material structure and intermolecular interactions. Statistical analysis confirmed that there were significant differences in the thermal degradation behavior between the control samples (L0) and the aged samples (L2 and L3). However, not much significant differences were observed between the control and slightly aged samples (L1), except at higher temperatures. This research provides a comprehensive understanding of the thermal degradation mechanisms of silicone sealants. By combinin1g EGA and TD-Pyr-GC-MS, we can effectively characterize the degradation products and identify factors contributing to sealant failure. These findings have significant implications for the development of more durable and long-lasting silicone sealants.

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