Multi-scale self-healing nanocomposite shielding material for aerospace

In the past two decades, the attention of researchers shifted from intellectual to experimental studies that are appliance-directed (Portale, Hermida-Merino, & Bras, 2016). The area of polymeric radiation shielding materials is highly underrated as it has great application potential. Polymer shielding materials offer advantages such as enhanced homogenous shielding, flexibility, and lower weight relative to metallic shielding materials (Håkansson, Amiet, Nahavandi, & Kaynak, 2007). Such improvement is essential for the protection of astronauts, spacecraft, and payloads from radiation damage in long-term space missions (Emmanuel & Raghavan, 2016; Pohl & Britt; Slaba et al., 2017). Poly(methyl) methacrylate (PMMA) is a thermoplastic polymer with exceptional mechanical properties. (PMMA) (C5O2H8)n is widely used in the automotive and aerospace industry. PMMA is used in aircraft windshields, radar screens, and telescope production (Hu et al., 2016). Polymer's functionality such as magnetic, optical, and mechanical properties can be enhanced through the incorporation of inorganic nanomaterials into the polymer matrix. Changes in properties of the polymer depend on filler type and preparation method of the nanocomposite (Chang et al., 2008). One of the main reasons for polymer degradation is chain scission under radiation energy (I. H. Kim, Cho, Bae, Park, & Chung, 2003). This deterioration creates both new radicals and the macromolecules. The living polymer produced with the ATRP method has a potential advantage as the living matrix might allow self–healing from the damage induced by ionizing, ultraviolet, and electromagnetic radiation. The living polymer can induce recombination between new radicals and the macromolecular on the end of the matrix chain (Ming Qiu Zhang & Rong, 2011b; Zhu, Rong, & Zhang, 2015). For this reason, PMMA living polymer synthesized by ATRP was chosen as the matrix material of reinforced nanocomposites. In this study, the content of GMA loaded microspheres (MK) and Halloysite clay nanotubes (HNTs), as well as Montmorillonite clay nanoplates (MMT) and Colemanite (CMT), were optimized in a living PMMA matrix to achieve maximum radiation-shielding capacity while keeping the mechanical properties and the self-healing capacity. For maximum efficiency, a multiphase autonomous self-healing approach was followed. First, the most promising nanocomposite compositions have been determined by applying the hardness, impact, flexural, and compression tests for mechanical shielding applications. Samples are tested for shielding gamma and neutron radiation for radiation shielding properties. Thus, it is determined how to produce a multiphase self-healing nanocomposite shielding material for aerospace.