• Energy Research

PEG was modified with epoxy to form a film which demonstrated dual function of thermal energy storage and vibration damping.

PEG was modified with epoxy to form a film which demonstrated dual function of thermal energy storage and vibration damping.

Abstract Poly(ethylene glycol) (PEG) is known to be very effective phase change material (PCM), which has been processed by various techniques. Efforts for development of better processing technique are always on, to make the process product and performance superior. Microwave technology based process development for the preparation of form stable phase change composites was attempted, with the motivation of establishing a green technique, which will be energy and time efficient and require minimum amount of solvent. The process could easily be scaled for large scale production of PCM blends. The microwave-assisted blending of PEG and cellulose acetate (CA) was carried out in various ratios resulting in the formation of biodegradable form-stable PCM. PEG acted as the latent heat storage material and cellulose acetate as the supporting material. As a result of microwave treatment, a high loading capacity of 96.5 wt% PEG was achieved without any leakage during the transition process. The blending was confirmed by Fourier-transform infrared spectroscopy (FTIR) analysis which showed no chemical bonds between PEG and CA. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicated that maximum enthalpy of 155 J/g was attained and the material was found to have good thermal stability. The surface properties of these materials were studied by using contact angle for various weight percentages of PEG. The X-ray diffraction (XRD) investigation revealed that the crystallinity of the PEG-CA blend increased with increasing concentration of PEG. The morphology was studied with field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) suggesting a homogeneous network formation of the blend.

Abstract Poly(ethylene glycol) (PEG) is known to be very effective phase change material (PCM), which has been processed by various techniques. Efforts for development of better processing technique are always on, to make the process product and performance superior. Microwave technology based process development for the preparation of form stable phase change composites was attempted, with the motivation of establishing a green technique, which will be energy and time efficient and require minimum amount of solvent. The process could easily be scaled for large scale production of PCM blends. The microwave-assisted blending of PEG and cellulose acetate (CA) was carried out in various ratios resulting in the formation of biodegradable form-stable PCM. PEG acted as the latent heat storage material and cellulose acetate as the supporting material. As a result of microwave treatment, a high loading capacity of 96.5 wt% PEG was achieved without any leakage during the transition process. The blending was confirmed by Fourier-transform infrared spectroscopy (FTIR) analysis which showed no chemical bonds between PEG and CA. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicated that maximum enthalpy of 155 J/g was attained and the material was found to have good thermal stability. The surface properties of these materials were studied by using contact angle for various weight percentages of PEG. The X-ray diffraction (XRD) investigation revealed that the crystallinity of the PEG-CA blend increased with increasing concentration of PEG. The morphology was studied with field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) suggesting a homogeneous network formation of the blend.

Abstract In this study, we have reported the synthesis of copolymers of poly(ethylene glycol) acrylate (PEGA) with methyl methacrylate (MMA) in various ratios which can be utilized as polymeric phase change materials (PCMs). The monomer reactivity ratio of PEGA copolymers was determined by Fineman-Ross method. The values of r1 (PEGA) and r2 (MMA) were found to be 0.8164 and 0.3371 respectively. The thermal analysis performed by DSC indicated high fusion enthalpy of 168 J·g−1 at 55 °C for the feed ratio of 40:60 of PEGA:MMA (Copolymer mole fraction of 76:24). The crystallization behaviour shows the presence of spherulites but of smaller size compared to PEG and with reduced crystallization ability. The results point out the capabilities of PEGA to function as an effective PCM which can be utilized for numerous thermal energy storage applications.

Abstract In this study, we have reported the synthesis of copolymers of poly(ethylene glycol) acrylate (PEGA) with methyl methacrylate (MMA) in various ratios which can be utilized as polymeric phase change materials (PCMs). The monomer reactivity ratio of PEGA copolymers was determined by Fineman-Ross method. The values of r1 (PEGA) and r2 (MMA) were found to be 0.8164 and 0.3371 respectively. The thermal analysis performed by DSC indicated high fusion enthalpy of 168 J·g−1 at 55 °C for the feed ratio of 40:60 of PEGA:MMA (Copolymer mole fraction of 76:24). The crystallization behaviour shows the presence of spherulites but of smaller size compared to PEG and with reduced crystallization ability. The results point out the capabilities of PEGA to function as an effective PCM which can be utilized for numerous thermal energy storage applications.

Abstract With an aim to prepare phase change material (PCM) as self-sustaining film from poly(ethylene glycol) (PEG) having reduced hydrophilicity, cross-linking of PEG and hydroxy-terminated poly(dimethyl siloxane) (HTPDMS) was done by using tetraethyl orthosilicate (TEOS) as a cross-linking agent. Following the confirmation of the crosslinked polymer using FTIR and 13C-solid state NMR, the crystallization properties were studied using X-ray diffraction and polarized optical microscopy. DSC analysis indicated an increase in enthalpy with increasing concentration of PEG. The enthalpy of fusion and crystallization was observed to reach a maximum of 125 and 104 J g−1 respectively. Contact angle of 89.5° has been achieved for polymer with highest concentration of HTPDMS. The material with lowest PEG concentration was film forming in nature. This material can be extensively used as a thermal energy storage material particularly, in smart packaging.

Abstract With an aim to prepare phase change material (PCM) as self-sustaining film from poly(ethylene glycol) (PEG) having reduced hydrophilicity, cross-linking of PEG and hydroxy-terminated poly(dimethyl siloxane) (HTPDMS) was done by using tetraethyl orthosilicate (TEOS) as a cross-linking agent. Following the confirmation of the crosslinked polymer using FTIR and 13C-solid state NMR, the crystallization properties were studied using X-ray diffraction and polarized optical microscopy. DSC analysis indicated an increase in enthalpy with increasing concentration of PEG. The enthalpy of fusion and crystallization was observed to reach a maximum of 125 and 104 J g−1 respectively. Contact angle of 89.5° has been achieved for polymer with highest concentration of HTPDMS. The material with lowest PEG concentration was film forming in nature. This material can be extensively used as a thermal energy storage material particularly, in smart packaging.

Abstract A series of semi-interpenetrating polymer networks (IPN) of poly(2-hydroxyethyl methacrylate) (poly(HEMA)) and crosslinked polyethylene glycol (PEG) were prepared by simultaneous IPN polymerisation technique. Tetraethyl orthosilicate (TEOS) was used for crosslinking. The prepared semi-IPNs were characterized by Fourier transform infrared spectroscopy (FTIR), 13C-nuclear magnetic resonance (13C-NMR), X-ray diffraction (XRD), polarized optical microscopy (POM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), swelling studies and contact angle measurements. The river like pattern of fractured cross section of the SEM micrograph of IPNs indicated no phase separation and also siloxane moiety placement on matrix-air interface. The semi-IPN samples are found to possess crystalline spherulites and the crystallinity reduces as the percentage of poly(HEMA) increases as demonstrated by XRD and POM. Maximum melting enthalpy obtained from DSC thermogram was around 145 J/g. The contact angle studies show that the relative hydrophobicity of the semi-IPNs increases with increase in content of HEMA in the semi-IPNs. These materials show satisfactory latent heat storage capacity and good thermal reliability for application as phase change material (PCM).

Abstract A series of semi-interpenetrating polymer networks (IPN) of poly(2-hydroxyethyl methacrylate) (poly(HEMA)) and crosslinked polyethylene glycol (PEG) were prepared by simultaneous IPN polymerisation technique. Tetraethyl orthosilicate (TEOS) was used for crosslinking. The prepared semi-IPNs were characterized by Fourier transform infrared spectroscopy (FTIR), 13C-nuclear magnetic resonance (13C-NMR), X-ray diffraction (XRD), polarized optical microscopy (POM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), swelling studies and contact angle measurements. The river like pattern of fractured cross section of the SEM micrograph of IPNs indicated no phase separation and also siloxane moiety placement on matrix-air interface. The semi-IPN samples are found to possess crystalline spherulites and the crystallinity reduces as the percentage of poly(HEMA) increases as demonstrated by XRD and POM. Maximum melting enthalpy obtained from DSC thermogram was around 145 J/g. The contact angle studies show that the relative hydrophobicity of the semi-IPNs increases with increase in content of HEMA in the semi-IPNs. These materials show satisfactory latent heat storage capacity and good thermal reliability for application as phase change material (PCM).