Electrospun nanofibrous membranes embedded with aerogel for advanced thermal and transport properties

Abstract

The primary purpose of cold weather clothing is to shield the wearer from the extremities of the external environment. The thermal properties of nanofibers and their potential applications have tremendous scope and application in this area. The objective of this study was to investigate the mechanisms of heat transfer through fibrous insulation where the fiber diameter was less than 1 μm. Electrospinning process was used to produce flexible polyurethane and polyvinylidene fluoride nanofibers embedded with silica aerogel. The thermal and transport behavior of the samples was evaluated, and results were statistically analyzed. Presence of aerogel particles were confirmed through microscopic examination. Thermal behavior was investigated by using thermogravimetric analysis and differential scanning calorimetry. The results showed that the polyvinylidene fluoride nanofibrous membranes embedded with aerogel obtained a good thermal stability with lower weight loss than polyurethane nanofibrous membranes. The glass transition and melting point was not affected by the aerogel content in the layers, validating that polymers are not miscible. The increase in duration of electrospinning led to higher web thickness, which resulted in considerable decrease in air permeability. Considerable improvement of thermal insulation was observed by increasing the number and the weight per unit area of both nanofibrous membranes. The results confirmed increase in thermal insulation by embedding silica aerogel in nanofibrous membranes. With reference to the results, it could be concluded that nanofibers embedded with aerogel are good for thermal insulation in cold weather conditions. Thermal insulation battings incorporating nanofibers could possibly decrease the weight and bulk of current thermal protective clothing.

Transport Properties of Electro-Sprayed Polytetrafluoroethylene Fibrous Layer Filled with Aerogels/Phase Change Materials

“…Silica aerogel, as a gel composed of a porous solid where the dispersed phase is air, exhibits lower thermal conductivity than air under the same condition [ 6 ] and thus has the potential for low-weight composites presenting extraordinary thermal and multifunctional properties [ 7 ]. The lightweight silica aerogel particles have been coated on cotton woven fabric [ 8 ] and wool-Aramid blended fabric [ 9 ], incorporated with polyester nonwovens by thermal bonding [ 10 ], encapsulated in a multi-layered composites [ 11 ], embedded in nanofibrous structure by electrospinning [ 12 ], successfully achieving significantly lower thermal conductivity of the overall structures. PCMs, functioning by absorbing external incoming heat flux due to phase change and acting as thermal buffering of sudden heat changes, were used for several years mainly for thermal regulating purposes.…”

Preparation of Electrosprayed, Microporous Particle Filled Layers

“…A polymer network becomes more solid. It leads to a higher spinning performance of a solution [22,23]. Non-conductive carbon microparticles were milled from pitch-based carbon fiber yarn.…”

Preparation of photochromic isotactic polypropylene filaments: influence of drawing ratio on their optical, thermal and mechanical properties

“…The thermal behavior of the photochromic miPP filaments was analyzed by differential scanning calorimetry (DSC; Perkin Elmer) according to ASTM standard D3418-08. 11 The miPP filaments were heated at a rate of 10 C min À1 from 25 C to 200 C (melting) and from 200 C to 25 C (cooling), under nitrogen atmosphere (20 mL.min À1 ). From the DSC measurements, various thermal properties, such as melting peak temperature (T m ), melting enthalpy (ÁH m ) and melting entropy (ÁS m ), were calculated.…”