Synthesis and thermomechanical characterization of PEG/cristobalite composites

Fadly

et al. 2018

The effect of silica polymorphs on the thermomechanical properties of 0, 5, 10, and 20 wt % silica particles-reinforced-based poly(ethylene glycol) (PEG) composites have been studied as a function of temperature using dynamic mechanical analysis (DMA). The silica polymorphs exhibited quartz (Q), cristobalite (C), and amorphous (A) phases, which were obtained by processing natural silica sand. The DMA thermomechanical properties were determined in tensile (E) and shear (G) modes. The maximum storage moduli (E 0 and G 0 ) were achieved by samples with 20 wt % silica for all type of fillers. These values increased approximately 12 times for PEG/Q, 10 times for PEG/A, and 11 times for PEG/C composites compared to the pure PEG. Furthermore, the Poisson's ratio values of the composites were filler phase dependent, that is, 0.39-0.47 for PEG/Q, 0.15-0.18 for PEG/A, and somewhat anomalous for PEG/C composites.

Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 56%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Dynamic tensile and shear storage moduli of PEG/silica‐polymorph composites

Fadly

et al. 2018

Zirconia‐dispersedpolyethylene glycol composites with a lowtemperature‐degradationrate

Muwwaqor

et al. 2020

The effect of tetragonal‐zirconia nanoparticle inclusion on the temperature‐dependent storage modulus, or the temperature‐degradation rate, of polyethylene glycol (PEG)‐based composites was investigated using shear‐mode dynamic mechanical analysis (DMA) at temperatures ranging from room temperature up to 75°C. We carried out further investigations in the rubbery area in terms of the characteristic of the degradation rate with temperature and compared it with silica‐quartz‐filled PEG composites, which exhibited a potential as phase‐change materials (PCMs). The investigation began by plotting the shear storage modulus (G′) of the composites and observing the slopes of the curves in the range of the rubbery area, which were assumed to follow a straight‐line equation. Then, we completed the investigation by developing and introducing a temperature‐dependent storage modulus model in the rubbery area for describing the storage modulus of such filler‐dispersed PEG/inorganic composites, to yield the degradation rates of the composites. The new model includes parameters k1 and C that are associated with the degradation rate and the amount of a filler, respectively. The model shows a satisfactory agreement with the experimental data of G′ in the rubbery area, being parameter k1 is associated with a linear degradation rate.

Filler‐size‐dependent dynamic mechanical properties of polyethylene glycol/zircon composites

Nurmalasari

et al. 2021

The thermomechanical properties of polyethylene glycol (PEG) composites filled with various zircon sizes were studied. The zircon powders were derived from natural (well-known as puya) sand collected from Kereng Pangi, Central Kalimantan, Indonesia. The effects of the zircon size and content were examined to understand the thermomechanical properties of the composites using dynamic mechanical analysis in shear mode. Pure zircon powders with micron to nanometer sizes were prepared. The microzircon powders were prepared by heating zircon at 500, 1000, and 1200 C. Moreover, the nanozircon powders were prepared by a wet milling method with milling times of 5, 10, and 15 hours. Furthermore, the composites were prepared by a wet mixing method. According to elemental analysis of scanning electron microscopy/energy dispersive X-Ray spectroscopy (SEM/EDX) data, it was found that the various zircon sizes caused different distribution effects, that is, in general, the smaller the size was, the better the distribution. Filler size variation also affected the thermomechanical properties of the composites. The addition of microzircon heated at 1200 C had the lowest storage moduli (G'), that is, 154.90 MPa and 155.55 MPa for 5 wt.% and 10 wt.%, respectively. Moreover, the maximum value of G' was obtained for the composite with the addition of nanozircon milled for 10 h (Z10h), that is, 679.27 MPa and 706.37 MPa for 5 and 10 wt.%, respectively. The addition of nanozircon slightly reduced roomtemperature G', presumably due to the agglomerated filler, as confirmed by the SEM/EDX data. Moreover, a decrease in zircon size caused an increase in the melting temperature (T m ) of the matrix. In contrast, 15 h of milling had a minor effect on T m and G', whereas the loss modulus (G") decreased with the addition of nanozircon. The effects of filler size on the thermomechanical properties of PEG/zircon composites are discussed in detail. K E Y W O R D Snano-and micron-sized filler, PEG, thermomechanical properties, zircon