Relationship between microstructure and dielectric/thermal management properties of biomass ramie fiber and its applications in recyclable wave-transparent composites

Industrial fiber crops are increasingly utilized in functional composites as substitutes for conventional fibers, aiming to address the limited microwave transmittance (MWT) and thermal conductivity (λ) of commercial glass fiber-reinforced composites (D-GFRC), which significantly reduce the service life of communication equipment shells and result in substantial waste pollution. Ramie fiber-reinforced composite (RFRC) possesses good dielectric/thermal management properties attributed to distinctive microstructure. However, the uncontrollable microstructure and unclear structure-property relationship of ramie fiber hinder its application in communication composites. Herein, the microstructures of ramie fiber, including aggregation and micro/nanopores structures, were successfully manipulated by coupling physical fields (temperature and force fields) with the guidance of molecular simulation. Subsequently, a clear relationship between microstructure and dielectric/thermal management properties was established. Moreover, leveraging this relationship, the performance of RFRC was optimized through coupled physical fields. Specifically, the MWT of RFRC reaches an impressive 95.9 %, and the λ is enhanced by 140 % compared to that of D-GFRC. Importantly, RFRC waste can be completely transformed into functional particles, thereby achieving a closed-loop utilization. This research strategy offers valuable insights into the regulation of microstructures and the development of recyclable wave-transparent composites derived from industrial crops. [Display omitted] •Molecular simulation reveals the effect of physical fields on microstructures of the ramie model.•The aggregation structures and micro-nano pores are controlled via coupled physical fields.•The relationship between microstructures and multiple functions of the ramie is established.•Recyclable ramie-reinforced composite has good dielectric properties and thermal management.•The waste of ramie-reinforced composite can be 100 % converted into multifunctional particles.