Thermal and dynamic mechanical properties of polyethylene glycol/quartz composites for phase change materials

Abstract

Polyethylene glycol (PEG)/quartz (denoted as BP/Q) composites have been investigated as candidates of phase change materials (PCMs) due to their thermomechanical properties around the glass transition temperature as well as thermal properties between 30 and 600 C. Quartz (q-SiO 2 ) powders were extracted from local sand in Tanah Laut, Pelaihari, South Kalimantan, Indonesia. The composites were prepared by dispersing q-SiO 2 powders in the PEG matrix followed by the wet mixing process. The thermal properties of the composites were characterized using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), while the thermomechanical properties were examined using a dynamic mechanical analyzer (DMA) in a three-point bending mode around the PEG glass transition temperature range (−100-50 C). The morphology and interface bonding were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). From the DSC measurement, the endothermic peak of the composites showed a shift of approximately 7-12 C toward higher temperatures than that of the pure polymer. The melting enthalpy values (ΔH m ) of the BP/Q composites covered the required PCM application range, that is, between 139 and 182 J/g. The TGA of the composites showed that thermal degradation occurs in the range of 250-450 C. We found that solid-solid PCMs (ssPCMs) were successfully fabricated with the addition of 10 and 20 wt% q-SiO 2 . From DMA characterization, the BP/Q 20 wt% composite exhibited the maximum E' and the minimum energy dissipation (E"). Its E' value was approximately 250 MPa more than that of the pure PEG. The glass transition (T g ) temperatures of PEG and BP/Q composites (5, 10, and 20 wt%) were around −24.5, −19.1, −17.1, and − 5.3 C, respectively. In addition, the E" and tan δ values decreased with q-SiO 2 filler content. Furthermore, the Cole-Cole plots of the BP/Q composites revealed a better interfacial bonding between the q-SiO 2 and the PEG matrix in the composites with higher silica content. A compact morphology was shown by the BP/Q 20 wt% composite due to high silica concentration.

Zirconia‐dispersedpolyethylene glycol composites with a lowtemperature‐degradationrate

“…Therefore, the significant drop at approximately 55–62°C can be attributed to the melting temperature T m of PEG in the composites. According to the literature, T m of PEG is approximately 43–62°C 27–29 . In this range, the PEG polymer chain in our composites undergoes slippage with one another, thereby causing a modulus decrease.…”

“…The modulus of PEG/n‐ZrO 2 in the region is compared with those of other samples for the same matrix, for example, PEG/quartz composites. PEG/quartz, which was also referred to as PEG/silica, had the highest storage modulus among various types of silica fillers and was a PCM candidate 28 . In this study, two types of quartz filler are introduced: nanoquartz and microquartz (the composites are denoted as P/nQ and P/mQ, respectively).…”

https://researchopenworld.com/analysis-and-comparison-of-mechanical-structural-properties-of-polymeric-compounds-reinforced-with-gtr-particles/#

“…There are necessary for a deep analysis of the compounds analyzed, through DSC, Differential Scanning Calorimetry, that allows the study of those processes in which enthalpic variation occurs, for example determination of specific calories, boiling points and fusion, purity of crystalline compounds, reaction enthalpy and determination of other first and second order transitions. The calorimetry applied to the composite materials is used as a tool to detect the possible changes in the crystallinity and microstructure of the matrix by adding a second component as a reinforcement [23][24]. By measuring the melting temperatures and enthalpy of the compounds, these changes can be analyzed through DSC analysis.…”

Mechanical and thermal properties of date palm/kenaf fiber‐reinforced epoxy hybrid composites

“…The tan delta's higher peak is due to the higher degree of molecule mobilization vice versa. [38] Previous research on neat epoxy and DPF-reinforced epoxy composites has shown the dynamic mechanical behavior of these composites. [13] The neat epoxy composite showed very high tan delta (0.7), and after addition of DPF fiber, the viscoelastic factor decreased (0.32).…”