Enhancement of thermal properties of bio-based microcapsules intended for textile applications

Abstract

<jats:title>Abstract</jats:title><jats:p>The thermal properties of bio-based phase change material (PCM) microcapsules and their separate components, core and shell, were investigated considering the influence of used thermal enhancer. As a core, bio-based PCM, capric acid (CA), was used. Biodegradable material, such as polylactic acid (PLA), was used as a shell. To improve the thermal conductivity of PLA/CA microcapsules, the multiwall carbon nanotubes (MWCNTs) were used as a thermal enhancer. Composites of PCM with different concentrations of MWCNT as well as composites of PLA with these carbon compounds were prepared and investigated to assess how MWCNT influences the thermal conductivity of the core and the shell. The heat storage and release capacity, as well as the phase change temperatures of CA/MWCNT composites and manufactured PCM microcapsules, were determined using differential scanning calorimetry. To evaluate the thermal conductivity of prepared composites and to compare it with the conductivity of pure materials (without MWCNT), their thermal resistance was measured using the guarded-hotplate test method. To obtain the supplementary information and to assess the dynamic behavior of used PCM during the temperature changes, another technique, such as monitoring of a cold/hot plate with an IR camera, was used. The results of these measurements showed that introduced MWCNT increases the thermal conductivity of PCM used for the core and the conductivity of films prepared from PLA. Consequently, with reference to the results obtained, it could be stated that the introduction of MWCNT into PLA/CA microcapsules improved the thermal properties of these microcapsules. However, it was determined that too large concentration of MWCNT reduces an enthalpy of melting and crystallization of tested PCM and PCM microcapsules. Therefore, during the investigation, an optimal concentration of MWCNT additives has been determined.</jats:p>

Development of thermo‐regulating fabrics with enhanced heat dissipation via graphene‐modified n‐octadecane microcapsules

“…Hence, the optimum concentration was specified as a range between 0.5% and 1%. [58] As can be seen from these compiled studies, thermal conductivity and phase change enthalpies were not reported, in detail, in most previous studies. Therefore, in this study, the effect of graphene, a carbon-based thermal conductive material, on the thermal properties of PCM microcapsule-coated polyester woven fabrics was investigated.…”

“…[42] Although there are many studies on thermal conductivity enhancement of PCM microcapsules, there are limited number of studies investigating the thermal conductivity properties of PCM-microcapsule-coated fabrics. [48,56,58,59] Shemsadi et al developed a polyacrylamide (PAAm) membrane by coating PCM microcapsules (mPCMs) with graphene oxide (GO) and reduced graphene oxide (rGO) on polypropylene (PP) nonwovens with a micrometer adjustable film applicator. Thermal conductivity of the PAAm hydrogel-coated membranes (0.0024 W/m.K) was enhanced three times (0.0063 W/m.…”

Microencapsulation for Functional Textile Coatings with Emphasis on Biodegradability—A Systematic Review

“…The accumulated latent heat energy is released when the PCM re-solidifies, and the transition process is reversible. Typical organic PCMs are paraffin hydrocarbons or lipids with a melting point close to body temperature [37][38][39][40][41][42][43][44][45][46]. In addition to classical PCMs, photothermal energy conversion materials also perform similar functionalities.…”

“…3D polyester knitted fabric with enhanced thermal properties. [39] Ethyl cellulose. Immortelle essential oil.…”

Construction strategies and thermal energy storage applications of shape‐stabilized phase change materials

“…MEPCMs can be biodegradable by using biodegradable shell materials and core materials. Using capric acid as the biodegradable PCMs, degradable polylactic acid as the shell materials, Skurkytė-Papievienė et al 92 prepared the biodegradable MEPCMs, and added MWCNTs as the heat conduction enhancement fillers. Based on the experimental results, they found that the obtained MEPCMs are biodegradable and their thermal conductivity is enhanced.…”