NIST only participates in the February and August reviews.
The conversation surrounding the facilitation of a circular economy for textiles has, to date, largely focused on the growing waste problem associated with consumer textiles, such as apparel and home furnishings. While this is clearly a major area of concern, economically, the valorization of textiles associated with these industries is not self-sustaining, since virgin feedstocks of materials like polyester and cotton are so inexpensive. Thus, scaling such industries will likely involve subsidies or policies such as extended producer responsibility. One textile field that has not been the subject of as much attention is the potential for recycling and reclamation of fiber-reinforced composite materials. These materials are commonly used in high performance applications, such as aerospace or transportation. Some fiber reinforced composites are also used in protective applications such as ballistic resistant helmets or body armor. Given the high cost of the materials (e.g., aramid or carbon fibers) used in these applications, pathways by which these fibers can be reclaimed and repurposed have the potential to be economically self-sustaining. One major goal of this research is to identify methodologies for fully removing the thermoset matrix material (usually epoxy polymer matrices) from the fibers, which has remained an obstacle to realizing the reuse potential of these materials. Specifically, this opportunity seeks to leverage unique capabilities within NIST, namely a deep expertise in fiber characterization at low and high strain rates, and a strong understanding of composite materials with our more recently obtained knowledge surrounding textile circularity. As a first step, we propose to identify and evaluate different methodologies for removal of matrix materials from fiber reinforced composites containing both carbon fiber and aramid fiber materials. Many research institutions and companies are actively working on developing innovative technologies to efficiently and selectively remove the thermoset matrix such as advanced solyvolysis or pyrolysis or by using novel catalysts. Goals for this opporunity would fall under this last research effort, to evaluate the effect of matrix removal processes on the properties of fibers obtained through these recycling processes. Once a methodology could be identified to remove the matrix most efficiently, with the least damage to the fibers, options for repurposing of these fibers could be explored through this project opportunity, potentially with new, more easily reclaimed matrix materials instead of thermosetting epoxies.
References:
(1) Khan, F., et al. Advances of composite materials in automobile applications – A Review, Journal of Engineering Research, 2024, https://doi.org/10.1016/j.jer.2024.02.017.
(2) Yuan, Y., et al. Multiply fully recyclable carbon fibre reinforced heat-resistant covalent thermosetting advanced composites, Nature, 2016, doi: 10.1038
(3) Liu, T. et al. Progress in chemical recycling of carbon fiber reinforced epoxy composites. Macromol. Rapid. Commun, 2022, 43, 22005318.
composites; high strength materials; mechanical properties; fracture; chemical recycling; advanced manufacturing; ballistic resistant materials; single fiber properties