Alkylated Nanofibrillated Cellulose/Carbon Nanotubes Aerogels Supported Form-Stable Phase Change Composites with Improved n-Alkanes Loading Capacity and Thermal Conductivity

Abstract

The exploitation of phase change materials (PCMs) with excellent shape stability, considerable latent heat storage capacity, and superior thermal conductivity is essential for their applications in heat storage and thermal regulation. Here, form-stable composite PCMs based on n-octacosane, nanofibrillated cellulose (NFC), and carbon nanotubes (CNTs) were successfully obtained by impregnating n-octacosane into the alkylated NFC/CNTs hybrid aerogels. The three-dimensional interconnected porous aerogels could adequately support the melted n-octacosane and prevent the leakage problem due to strong capillary force and surface tension. After treatment with alkylated modification, the affinity between NFC/CNTs aerogels and n-alkanes was significantly improved, resulting in excellent shape stability, improved thermal reliability, and high n-alkanes loading capacity for the as-prepared composite PCMs. The differential scanning calorimetry analysis showed that composite PCMs based on the alkylated NFC/CNTs aerogels exhibited an extremely high phase change enthalpy ranging from 250.9 to 252.9 J/g. Furthermore, the thermal conductivity and photothermal conversion and storage efficiency of the synthesized PCMs were effectively enhanced by the introduction of CNTs. Thus, the synthesized composite PCMs exhibit considerable potential for practical application in heat storage and thermal regulation.

Recent Progress on Nanocellulose Aerogels: Preparation, Modification, Composite Fabrication, Applications

“…After obtaining the precursor dispersion, many nanocellulose aerogels usually need to undergo a gelation process, which helps maintain and enhance the 3D network inside aerogels. [ 27 ] The gelation behavior of the nanocellulose is generally sorted into two major categories according to the nature of the gel: chemical crosslinking [ 28 ] and physical crosslinking [ 29 ] ( Figure ).…”

“…[ 86 ] They have provided several novel features to nanocellulose aerogels based on their excellent virtues, including large SSA, excellent electrical conductivity and heat conduction, and supermechanical strength. [ 27a,87 ]…”

“…In addition to effective thermal management, nanocellulose/inorganic composite aerogels have emerged in some additional areas (e.g., bone tissue engineering, [ 105 ] CO 2 adsorption, [ 27b ] self‐cleaning, [ 106 ] and oil–water separation [ 7b,107 ] ), with expectations that they will be further explored in the future.…”

Novel Hybrid Hypercrosslinked Polymer Assisted Highly Efficient Thermal Energy Storage

“…21 Therefore, a shapestabilized phase change material (SSPCM) which generally constituted by a working material and a supporting material has emerged as an important protocol for the use of solid-liquid phase change material. 22,23,24 The main methods for the preparation of shape stabilized PCMs are as follows: (1) Encapsulated PCMs into micro/nano capsules; 25,26 Such as, Kawaguchi et al 27 rstly reported a novel PCMs applications for high temperature(400-500˚C) by using Zn-30wt%Al alloy as wall material to encapsulate PCMs. The wall material of MEPCMs was composed of ZnO with a thickness of 500 nm and Al-oxide with a thickness of 300 nm.…”

“…(4) Grafting PCMs into the skeleton of the polymer through a covalent bond association way. 35,36 For instance, Du et al 26 successfully prepared a novel composite PCMs based on polyethylene glycol (PEG), nano brotic cellulose (NFC) and graphene by impregnating PEG into a PEGgrafted NFC/graphene-hybridized aerogel (GA/ NFC-G-PEG),Through grafting PEG to NFC, the a nity of PEG to NFC/graphene hybrid aerogel was improved, the PEG loading capacity of CNF-G-PEG/graphene aerogel was signi cantly improved, and PEG leakage was prevented. Though so many existed methods dedicated to developing a way for the solution of liquid leakage and poor thermal conductive performance, 37 the room for further improvement still existed.…”