Synthesis and properties of crosslinking halloysite nanotubes/polyurethane-based solid-solid phase change materials

- Polyurethane-based phase change materials were synthesized by one step.
- Halloysite nanotubes and hexamethylene diisocyanate biuret both serve as crosslinker.
- Halloysite nanotubes can improve the energy storage density of the system.
- The composites possess well solid-solid phase change properties and excellent thermal stability.

Polyurethane-based solid-solid phase change materials were first synthesized using polyethylene glycol (PEG) and hexamethylene diisocyanate biuret (HDIB), and the influence of halloysite nanotubes (HNTs) on this system was investigated. HNTs can not only serve as crosslinking agent in synergy with HDIB, which reinforces the solid-solid phase change properties of the system that has no leakage even at the temperature that 40 °C higher above the melting temperature of PEG, but also greatly improve the latent heat of the system from 86.8 to 118.7 J/g, as a result of heterogeneous nucleation effect, which can make up partial latent heat loss caused by crosslinking. Also, HNTs endows the system with excellent thermal stability, where the temperature at 5% weight loss is increased by 53 °C. The synthesized PCMs have extensive applying prospects in thermal energy storage fields.

The crosslinking network, formed with HNTs and HDIB as crosslinking points, could prevent the dissolution of PEG when melting and endow the system with excellent form-stability.234