Polyethylene glycol infused acid-etched halloysite nanotubes for melt-spun polyamide-based composite phase change fibers

Abstract

The unique tubular structure and morphology of inorganic nanotubes makes them very useful supporting materials for thermal energy storage. Lending these properties in the form of composites together with traditional organic phase change materials (PCMs) can solve the existing energy storage and thermal stability problems in PCMs. Here, the acid-etching halloysite nanotubes (A-HNTs) are prepared and employed as inorganic supporting materials to encapsulate polyethylene glycol (PEG). The N2 physisorption results indicated that the specific surface area and pore volume of A-HNTs increased from 45.4m2/g, 0.243cm3/g to 253.4 m2/g and 0.621 cm3/g before and after acid etching leading to an effective PEG load increase from 50 mass% to 70 mass% of composite PCMs. This increasing encapsulation capacity of PEG had a beneficial effect on the phase change performances and the latent heat of the prepared PEG/A-HNTs composite PCMs which reached 112 J/g (as compared to 70.64 J/g of PEG/HNTs). The temperature- regulating time of heat storage and release process were >500 s and 491 s respectively. Further, the DSC thermograms with 100 thermal cycles and TGA results demonstrated that the PEG/A-HNTs composites had an excellent thermal reliability and stability for preparing phase-change fibers by high-temperature melt spinning. The thermal enthalpy, thermal regulating time and relative temperature difference of resultant PA6/PEG/A-HNTs reached 13.57 J/g, 206 s and 3.2 °C, respectively.