Effect of elevated in-service temperature on the mechanical properties and microstructure of particulate-filled epoxy polymers

• Published in: Polymer degradation and stability Vol. 170; p. 108994
• Main Authors: Khotbehsara, Mojdeh Mehrinejad, Manalo, Allan, Aravinthan, Thiru, Reddy, Kakarla Raghava, Ferdous, Wahid, Wong, Hong, Nazari, Ali
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.12.2019; Elsevier BV
• Subjects: ambient temperature; civil engineering; Compressive strength; durability; epoxides; Epoxy resin; Epoxy resins; equations; Fillers; Flame retardants; Fly ash; Glass transition temperature; High temperature; In-service elevated temperature; Mechanical analysis; Mechanical properties; Microstructure; Particulate fillers; polymers; prediction; Prediction model; Room temperature; scanning electron microscopy; Temperature; Tensile strength; Thermal stability; Weight loss; Epoxy resin; Mechanical properties; Particulate fillers; Microstructure; In-service elevated temperature; Prediction model
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2019.108994

In civil engineering applications, epoxy-based polymers are subject to different environmental conditions including in-service temperature, which might accelerate their degradation and limit their application ranges. Recently, different particulate fillers were introduced to enhance the mechanical properties and reduce the cost of epoxy-based polymers. This paper addresses the effect of in-service elevated temperature (from room temperature to 80 °C) in particulate-filled epoxy based resin containing up to 60% by volume of fire retardant and fly ash fillers through a deep understanding of the microstructure and analysis of their mechanistic response. An improvement in the retention of mechanical properties at in-service elevated temperature was achieved by increasing the percentages of fillers. The retention of compressive and split tensile strength at 80 °C for the mix containing 60% fillers was 72% and 52%, respectively, which was significantly higher than the neat epoxy. Thermo-dynamic analysis showed an increase in glass transition temperature with the inclusion of fillers, while these mixes also experienced less weight loss compared to neat epoxy, indicating better thermal stability. Scanning electron microscopy images showed the formation of dense microstructures for particulate-filled epoxy based resin at elevated temperatures. This indicates that the particulate filled epoxy resin exhibits better engineering properties at in-service elevated temperatures, increasing their durability and therefore their suitability for civil engineering applications. A simplified prediction equation based on power function was proposed and showed a strong correlation to the experimental compressive and splitting tensile strength at different levels of in-service elevated temperature. •Degradation and stability of particulate-filled epoxy polymers at elevated temperature.•High strength retention of epoxy due to the high thermal stability of fillers.•Fillers make epoxy resin with a dense microstructure at elevated temperature.•FTIR analysis revealed no chemical changes in the epoxy at elevated temperature.•Strong correlation between predicted values and experimental results.