Zirconia‐dispersedpolyethylene glycol composites with a lowtemperature‐degradationrate

Abstract

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.

Thermomechanical and optical characteristics of nanoquartz‐ and nanozircon‐filled poly(methyl methacrylate) composites

“…Increasing the filler content of both silica and zircon leads to an increase in the storage modulus of the composites, as observed in other dispersed-filler polymer composites. [18][19][20] This is primarily due to the high stiffness of the filler compared with that of the polymer and the presence of a hydrogen-bond interaction as interface bonding between the matrix and filler, which improves the storage modulus of the polymer. In composite studies, to compare the influence of two different fillers, the volume fraction of the filler becomes an important factor and needs to be considered more than the weight fraction.…”

“…Assuming that the rate of fast decline in the second region is the transition area, T ost is the line intersection of the slope extension before the transition area and the transition area, whereas T end is the line intersection of the slope extension between the transition area and after the transition area. 18 Therefore, region I covers 40 C-T ost , region II covers T ost -T end , and region III covers T end -100 C. First, we are concerned with the first region.…”

“…The DMA allows the modeling study of such deterioration by acquiring the thermomechanical characteristics (e.g., storage modulus) as a function of the applied temperature. Modeling of the deterioration rates of dispersed‐filler polymer‐based composites has been reported previously 18,19 . The implementation of the model in this study provides an understanding of how the composites undergo thermomechanical weakening so that the potential operating temperature range can be determined.…”

“…Modeling of the deterioration rates of dispersed-filler polymer-based composites has been reported previously. 18,19 The implementation of the model in this study provides an understanding of how the composites undergo thermomechanical weakening so that the potential operating temperature range can be determined.…”

“…T A B L E 2 Storage moduli at 40 C and the glass transition temperature of PMMA and the composites. Parameters C and k 2 of the model18 for the composites.…”