Processable Thermally Conductive Polyurethane Composite Fibers

Abstract

In recent decades there has been a significant focus upon the incorporation of electronic components into textiles and wearable garments for functionalities such as sensing, health, environment monitoring, and energy storage. [1][2][3][4][5][6][7] Owing to the rapid development of nanoscience and technology, it is now possible to build electronic functions inside of, or on the surface of, fibers and consequently incorporate them into a garment structure using well-established textile fabrication techniques. [1] As a result of the ever-increasing demand for wearable electronics, research has focused on the development of electrically conductive fibers for applications including strain sensing, energy storage, and electrical wiring. [8][9][10][11][12] Heat removal and heat management in microelectronics is now becoming important in light of the ever-growing demand for miniaturization and development of wearable electronics. [13] As a result, thermally conductive polymeric composite materials utilizing carbonous fillers such as reduced graphene oxide [14] or inorganic fillers such as boron nitride (BN) [15][16][17][18][19] have been investigated in a range of application including self-healing resins, electronic packaging, ultrahigh voltage electrical devices, and energy storage field. [14,[16][17][18][19][20] Alternatively, electrospun polyethylene fibers [21] and carbon fibers [22] have also been investigated as thermally conductive substrates.In this study, processable thermally conductive composite fibers have been produced utilizing a solvent-based polymerfiller solution mixing method from which fibers were produced via a wet-spinning (solvent/non-solvent) technique. [23] Non-cross-linked polyurethane (PU) was selected as it exhibits similar mechanical properties to that of rubber, whilst being thermally and solvent-processable. The combination of high elasticity along with high abrasion resistance makes PU very popular for a wide range of applications. [24] In addition, noncross-linked PU is readily soluble in organic solvents, from which composite structures with different fillers can be readily produced. [5,8,9,25] Boron nitride, also known as white graphite, is an isoelectronic with carbon and has a wide range of attractive properties such as high thermal conductivity, low coefficient of thermal expansion, high electrical resistivity over a wide temperature range, high temperature stability, high mechanical strength and hardness, and chemically and thermally stable Thermally Conductive FibersThe demand for wearable electronics has resulted in an increasing interest in the development of functional fibers, with a specific focus upon the development of electrically conductive fibers incorporable into garments. However, the production of thermally conductive fibers for heat dissipation has been largely neglected. Owing to the very rapid development of miniaturized wearable electronics, there is an increasing need for the development of thermally conductive fibers as heat sinks and thermal management processes....

Advanced Textiles for Personal Thermal Management and Energy

“…Compared with the surface coating method, the composite fibers provide a more durable alternative for human body conductive cooling. [59][60][61] Gao et al reported a personal thermal regulated textile using thermally conductive and highly aligned boron nitride (BN)/poly (vinyl alcohol) (PVA) composite (a-BN/PVA) fibers to improve the thermal transport properties of textiles for personal cooling (Figure 6A). 59 The enhanced thermal conductivity of a BN/PVA composite fibers can transport the heat generated by human body to the outer surface of textile more efficiently, thus realizing conductive cooling effect and personal energy management (Figure 6B).…”

Thermally drawn biodegradable fibers with tailored topography for biomedical applications

“…According to the DSC and TGA spectra shown in Figure 2a,b, the PCL melting point was approximately 55°C while the decomposition of PCL started at 300°C. The viscosities of different molecular weights of PCL shown in Figure 2c decreased with the shear rate due to the phenomenon known as shear thinning 14,32 . DMA analysis was utilized to further investigate the properties of different PCL samples.…”

“…Malikmammadov et al reported the fabrication of wet‐spun composite tricalcium phosphate/PCL fibers as a good candidate for bone tissue engineering applications 13 . In the wet spinning method, fiber morphology and cross‐section shape greatly depend on the mass transfer rate difference between the solvent and coagulant 14 . However, the requirement for a non‐solvent can make this method costly 15 .…”

Improving thermal conductivities of textile materials by nanohybrid approaches

“…Thermally conductive and electrically insulating BN nanopowder (BNNP)/PU composite fibers were wet-spinned by Wallace and coworkers ( Farajikhah et al., 2019 ). The addition of BNNP resulted in a decrease in specific heat capacity and increase in thermal diffusivity and thermal conductivity, which improved around 160% with a low loading of 5 wt % BNNP, reaching 0.262 W m −1 K −1 .…”