Boron nitride nanotubes embedded nylon-6 nanofibers composites for space applications

Abstract

In this article, the enhancement of thermal and mechanical properties, and the moisture resistance of nylon-6 nanofiber fabrics for the space application such as the astronaut suits by compounding boron nitride nanotubes (BNNT) is investigated. For the proposed application, BNNT are first surface modified through the wrapping of nanotubes with Sodium Dodecyl Sulfate (SDS) for enabling the dispersion of BNNT in nylon-6 matrix, then the nylon-6 nanofiber fabrics compounded with SDS modified 2.5 wt% (BNNT2.5), 5.0 wt% (BNNT5.0), 7.5 wt% (BNNT7.5), 10.0 wt% (BNNT10.0) of BNNT are fabricated through electrospinning. Among these samples, BNNT5.0 shows the ultimate performance with its mechanical performance by having the tensile strength of 12.41 MPa and 35 % elongation performance which is 340 % higher tensile strength than neat nylon-6 sample and 152 % higher tensile strength than neat nylon-6 sample having SDS additive (Neat). BNNT5.0 also shows higher water contact angle (86.56°) than Neat (71.38°) proving the enhanced moisture resistance. In terms of thermal performance, BNNT5.0 shows 32 % enhanced thermal conductivity (0.434 W/mK) compared to Neat (0.296 W/mK), and a superior thermal stability showing shrinking resistance at elevated temperatures as high as 200 °C while Neat melts down at same temperature. Finally, BNNT5.0 also shows rapid cooling performance which two times higher than Neat according to the infrared imaging for cooling from 60 °C to room temperature. Consequently, we expect BNNT may provide lighter and robust feasibility for the conventional nylon-6 nanofibers to be used for the astronaut suits.