A Comprehensive Review on the Thermal Stability Assessment of Polymers and Composites for Aeronautics and Space Applications

Abstract

This review article provides an exhaustive survey on experimental investigations regarding the thermal stability assessment of polymers and polymer-based composites intended for applications in the aeronautical and space fields. This review aims to: (1) come up with a systematic and critical overview of the state-of-the-art knowledge and research on the thermal stability of various polymers and composites, such as polyimides, epoxy composites, and carbon-filled composites; (2) identify the key factors, mechanisms, methods, and challenges that affect the thermal stability of polymers and composites, such as the temperature, radiation, oxygen, and degradation; (3) highlight the current and potential applications, benefits, limitations, and opportunities of polymers and composites with high thermal stability, such as thermal control, structural reinforcement, protection, and energy conversion; (4) give a glimpse of future research directions by providing indications for improving the thermal stability of polymers and composites, such as novel materials, hybrid composites, smart materials, and advanced processing methods. In this context, thermal analysis plays a crucial role in the development of polyimide-based materials for the radiation shielding of space solar cells or spacecraft components. The main strategies that have been explored to improve the processability, optical transparency, and radiation resistance of polyimide-based materials without compromising their thermal stability are highlighted. The combination of different types of polyimides, such as linear and hyperbranched, as well as the incorporation of bulky pendant groups, are reported as routes for improving the mechanical behavior and optical transparency while retaining the thermal stability and radiation shielding properties. Furthermore, the thermal stability of polymer/carbon nanocomposites is discussed with particular reference to the role of the filler in radiation monitoring systems and electromagnetic interference shielding in the space environment. Finally, the thermal stability of epoxy-based composites and how it is influenced by the type and content of epoxy resin, curing agent, degree of cross-linking, and the addition of fillers or modifiers are critically reviewed. Some studies have reported that incorporating mesoporous silica micro-filler or microencapsulated phase change materials (MPCM) into epoxy resin can enhance its thermal stability and mechanical properties. The mesoporous silica composite exhibited the highest glass transition temperature and activation energy for thermal degradation among all the epoxy-silica nano/micro-composites. Indeed, an average activation energy value of 148.86 kJ/mol was recorded for the thermal degradation of unfilled epoxy resin. The maximum activation energy range was instead recorded for composites loaded with mesoporous microsilica. The EMC-5p50 sample showed the highest mean value of 217.6 kJ/mol. This remarkable enhancement was ascribed to the polymer invading the silica pores and forging formidable interfacial bonds.

Characterization of eco‐friendly composites for automotive applications prepared by the compression molding method

“…When the thermosetting polymer resin reaches a specific level of thermal energy, its amorphous stiff structure transforms into a flexible structure, resembling rubber. 79,80 This transformation enables the polymer molecules to move unrestrictedly among one another. The glass transition temperature refers to this specific point of transition.…”

“…At temperatures above the glass transition temperature (Tg) but below the melting temperature (Tm), the polymer resin is in a flexible state resembling rubber. 79,80 Under relatively low stresses, the material can undergo significant deformations. 79 The three test specimens generated in this study did not undergo an endothermic phase; even when exposed to a temperature of 550 C, they did not undergo the process of melting.…”

Recent Advances and Challenges in Polymer-Based Materials for Space Radiation Shielding

“…PDMS shows advantageous properties such as flexibility, suitable thermal stability, chemical inertness, and low cost [39][40][41][42]. These properties have been extensively exploited for the development of membranes, enclosures, microfluidic structures, and sensors [43][44][45][46][47].…”

Nanostructured Poly-l-lactide and Polyglycerol Adipate Carriers for the Encapsulation of Usnic Acid: A Promising Approach for Hepatoprotection

“…The size and zeta potential of the obtained particles as well as the stability of the colloidal suspension over time were studied with dynamic light scattering. In order to investigate the compatibility of PLLA and PGA in the 50/50 blend, the thermal properties of the systems were also investigated using differential scanning calorimetry, which is a renowned technique to study the compatibility and stability of polymers, plastic waste, and hybrid organic-inorganic materials [31][32][33][34]. A qualitative degradation assay of NPs was performed using a lipase from porcine pancreas as the degradative enzyme.…”