Glass transition of polystyrene (PS) studied by Raman spectroscopic investigation of its phenyl functional groups

Menezes, Durval Bertoldo; Reyer, Andreas; Marletta, Alexandre; Musso, Maurizio

doi:10.1088/2053-1591/4/1/015303

Cited by 30 publications

(23 citation statements)

References 39 publications

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“…The C-H in-plane bending modes were at 1028.1, 1149.6, and 1187.0 cm −1 . The C-C stretching mode was at 1441.9 cm −1 , and the C-C quadrant stretching mode was at 1592 cm −1 [22][23][24]. However, the samples exhibited the high Raman fluorescence and the PS peaks disappeared upon the further increase in the annealing temperature to 500 ∘ C. This result indicated the PS degradation, which correspondings to a low carbon content in the EDS analysis.…”

Section: Resultsmentioning

confidence: 94%

Superhydrophobicity/Superhydrophilicity Transformation of Transparent PS-PMMA-SiO2 Nanocomposite Films

et al. 2018

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A transparent superhydrophobic nanocoating with high water contact angle (>150∘ ) was successfully prepared by a simple dip coating method. The coating solutions were prepared by the dissolution of polystyrene (PS) and poly(methyl methacrylate) (PMMA) in toluene. Fumed silica (SiO2) was then added to increase the roughness of the coating. The annealing treatment conditions were investigated to optimize the water contact angle. The heat treatment conditions and other factors were studied systematically to optimize the transmission and the contact angle of water on the films. The results have shown that the films increase with the annealing temperature. The superhydrophobicity of films is observed only in PS-consisted films after the annealing at 200 ∘C. The superhydrophobic/superhydrophilic transformation was achieved at the annealing temperature higher than 200 ∘C due to the decay of the polymer into hydrophilic monomers.

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Section: Resultsmentioning

confidence: 94%

Superhydrophobicity/Superhydrophilicity Transformation of Transparent PS-PMMA-SiO2 Nanocomposite Films

et al. 2018

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“…For the "grey" EPS C (black lines in Figure 6a,b), in both Raman spectra, a significant decrease in Raman spectral intensity was observed. Such suppression of phonon spectra is usually associated with structural deformation of the molecules or molecule chains, which results in transitions to more disordered structural forms of polymer matrix [59]. The suppression effect was observed for both optical and acoustic phonons for the polystyrene matrix with GMP.…”

Section: Micro-raman Spectra Of Tested Productsmentioning

confidence: 99%

Change in Conductive–Radiative Heat Transfer Mechanism Forced by Graphite Microfiller in Expanded Polystyrene Thermal Insulation—Experimental and Simulated Investigations

2020

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This article introduces an innovative approach to the investigation of the conductive–radiative heat transfer mechanism in expanded polystyrene (EPS) thermal insulation at negligible convection. Closed-cell EPS foam (bulk density 14–17 kg·m−3) in the form of panels (of thickness 0.02–0.18 m) was tested with 1–15 µm graphite microparticles (GMP) at two different industrial concentrations (up to 4.3% of the EPS mass). A heat flow meter (HFM) was found to be precise enough to observe all thermal effects under study: the dependence of the total thermal conductivity on thickness, density, and GMP content, as well as the thermal resistance relative gain. An alternative explanation of the total thermal conductivity “thickness effect” is proposed. The conductive–radiative components of the total thermal conductivity were separated, by comparing measured (with and without Al-foil) and simulated (i.e., calculated based on data reported in the literature) results. This helps to elucidate why a small addition of GMP (below 4.3%) forces such an evident drop in total thermal conductivity, down to 0.03 W·m−1·K−1. As proposed, a physical cause is related to the change in mechanism of the heat transfer by conduction and radiation. The main accomplishment is discovering that the change forced by GMP in the polymer matrix thermal conduction may dominate the radiation change. Hence, the matrix conduction component change is considered to be the major cause of the observed drop in total thermal conductivity of EPS insulation. At the microscopic level of the molecules or chains (e.g., in polymers), significant differences observed in the intensity of Raman spectra and in the glass transition temperature increase on differential scanning calorimetry(DSC) thermograms, when comparing EPS foam with and without GMP, complementarily support the above statement. An additional practical achievement is finding the maximum thickness at which one may reduce the “grey” EPS insulating layer, with respect to “dotted” EPS at a required level of thermal resistance. In the case of the thickest (0.30 m) panels for a passive building, above 18% of thickness reduction is found to be possible.

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“…The fusion of the matrix material F68 was analyzed by differential scanning calorimetry (DSC 41 ) and Raman spectroscopy as a function of temperature. 40 These studies contrast with the 1 H-NMR 35 , 37 − 39 correlations that explain the hydrophobicity indices for the systems and components involved. The determination of the CMC of F68 was performed by high-resolution eliposometry 37 , 42 for films on the hydrophilic substrate.…”

Section: Introductionmentioning

confidence: 98%

Morphological and Semi-empirical Study of the Pluronic F68/Imogolite/Sudan III Intersurfaces Composite for the Controlled Temperature Release of Hydrophobic Drugs

2020

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Some PluronicF68 (F68) triblock copolymer properties demonstrate surprising applications in selective drug administration, such as the transportation of hydrophobic anti-inflammatories through epithelial barriers. Nuclear magnetic resonance ( 1 H-NMR) spectroscopy was carried out for micelle precursor dispersions and F68 films modified with a synthetic imogolite (IMO) biocompatible hydrogel. Theoretical calculations and morphological assessment for the process of morphogenesis of dendritic crystallization were performed by molecular docking and atomic force microscopy (AFM) of the Sudan III-IMO-F68 composite, which was more hydrophobic than Sudan III-F68 and carried out the prolonged release of the Sudan III “drug” captured by a water–octanol interface determined by standard absorbance. Surface fusions were measured and compared to the unmodified matrix. However, despite the superior properties of the composite, the critical micelle concentration (CMC) was practically unmodified because solitary IMO strands attached to Sudan III formed Sudan III-IMO. These strands unraveled in a stable manner by expanding like a “spiderweb” in hydrophilic interfaces according to NMR analysis of the hydrogen one H 1 polarization of Sudan III and F68 methyl, whose correlation relates hydrophobicity of Sudan III-IMO-F68 with dendrite properties from F68 concentrations. CMC and surface fusions equivalent to F68 surface properties, calculated by differential scanning calorimetry and dynamic Raman spectroscopy, were determined by AFM and high-resolution ellipsometry. Our results show highly specialized pharmacological applications since micelle surfaces expand, triggering maximum deliveries of “Drugs” from its interior to the physiological environment. The implanted sensor prototype determined equilibria reached Sudan III according to temperature (32–50 °C) and time it took to cross the membrane model 1-octanol (48 h). The findings suggest that the targested design of a F68-IMO-“Drug” would function as a microdevice for the prolonged release of hydrophobic drugs. In addition, the said microdevice could regenerate the damaged tissue in the central nervous system or other organs of the body. This is due to the fact that it could perform both tasks simultaneously, given the properties and characteristics acquired by the compatible material depending on the temperature of the physiological environment.

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Glass transition of polystyrene (PS) studied by Raman spectroscopic investigation of its phenyl functional groups

Cited by 30 publications

References 39 publications

Superhydrophobicity/Superhydrophilicity Transformation of Transparent PS-PMMA-SiO2 Nanocomposite Films

Superhydrophobicity/Superhydrophilicity Transformation of Transparent PS-PMMA-SiO2 Nanocomposite Films

Change in Conductive–Radiative Heat Transfer Mechanism Forced by Graphite Microfiller in Expanded Polystyrene Thermal Insulation—Experimental and Simulated Investigations

Morphological and Semi-empirical Study of the Pluronic F68/Imogolite/Sudan III Intersurfaces Composite for the Controlled Temperature Release of Hydrophobic Drugs

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