The effect of size and concentration of nanoparticles on the glass transition temperature of polymer nanocomposites

Серенко, О. А.; Roldughin, V. I.; Аскадский, А.А.; Serkova, Elena S.; Страшнов, П. В.; Shifrina, Zinaida B.

doi:10.1039/c7ra08152a

Cited by 34 publications

(23 citation statements)

References 40 publications

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“…The intensity of these emissions is falling off and they also showed a blueshift as Ga content in the sample is increasing. The other emissions in visible region, defect level emissions, are resulting from charge carriers recombination in the defect levels within the band gap [ 42 ]. These emissions appeared over a wide visible region ranging from 530 to 640 nm, namely green, yellow, and orange-red emissions with clear weaker intensities than near band emissions as shown in Figure 6 .…”

Section: Resultsmentioning

confidence: 99%

“…These emissions appeared over a wide visible region ranging from 530 to 640 nm, namely green, yellow, and orange-red emissions with clear weaker intensities than near band emissions as shown in Figure 6 . The visible region emissions could be resulted from large varieties of defects since the defect formation as well as defect concentration in Ga doped ZnO are very complex [ 35 , 42 ]. The relative intensities of near band peaks to that of the defect levels are decreasing with Ga concentration in the samples, which means the electron–hole recombination occurs in the deep defect states rather than near band states [ 35 ].…”

Section: Resultsmentioning

confidence: 99%

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Ga-Doped ZnO Nanostructured Powder for Cool-Nanopigment in Environment Applications

2020

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Gallium (Ga) doped zinc oxide (ZnO) nanocrystals were successfully synthesized via a γ-radiation-assisted polymer-pyrolysis route. Ga doped ZnO samples with Ga and ZnO precursor salts with molar ratios of 0%, 3%, 5%, and 10% were produced. A γ-radiation dosage of 1.5 kGy was used for polymerization initiation during the sample preparation. The properties of the obtained nanocrystal samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV-visible absorption, NIR-VIS-UV diffused reflectance, and high-resolution transmission electron microscopy (HR-TEM) characterization techniques. XRD results revealed the formation of ZnO nanocrystals with wurtzite structure for both Ga-doped and undoped ZnO samples. Noticeable increasing in the line broadening of the XRD peaks as well as pronounced decreasing of crystallite size were observed with the increasing Ga ratio in the samples. Optical peaks around Ga:ZnO samples showed a blueshift in the optical absorption peaks with increasing Ga content. These results are in good agreement with the dependency of crystallites size as well as grain size on Ga ratio obtained from XRD and TEM images, which make them fit well for the powder cool-pigment applications. The doped samples showed high values of NIR reflectance (RNIR*) with percentage varied from 84.25% to 89.05% that enabled them to qualify for cool-nanopigment applications. Furthermore, such doped samples registered low values of visible reflectance (RVIS*) that enabled to reduce the glare from the reflected visible sunlight.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Ga-Doped ZnO Nanostructured Powder for Cool-Nanopigment in Environment Applications

2020

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“…In fact, T g values did not show a unique trend with increasing of the ZnO nanofiller in the polymer nanocomposites. This is due to the competition of many factors which affects the degree of freedom of the polymer chains [ 37 ]. In most cases of nanocomposites, there are two main competitive factors.…”

Section: Resultsmentioning

confidence: 99%

Thermal Degradation of Polystyrene (PS) Nanocomposites Loaded with Sol Gel-Synthesized ZnO Nanorods

2020

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Thermal degradation of polystyrene/ZnO (PS/ZnO) nanocomposites was investigated in this study. PS/ZnO polymer nanocomposites were prepared by using ZnO nanorods as nanofillers that were prepared via the sol-gel route. The as-prepared ZnO nanoparticles showed nanocrystallites in rod-like shapes with a non-uniform hexagonal cross-section and diameter varying from 40 to 75 nm. PS/ZnO nanocomposites with ZnO nanoparticles content ranging from 0–3 wt% are prepared via the common casting method. Even dispersion for ZnO nanoparticles within as-prepared PS/ZnO nanocomposites was verified through SEM/EDX measurements. Thermal degradation of the samples was checked by using the thermogravimetric (TG) analysis and differential scanning calorimetry (DSC) under non-isothermal conditions and a constant heating rate of 10 °C min. The thermal stability of the nanocomposite is elevated compared to that of pristine PS due to the addition of the ZnO nanoparticles. The homogeneity of the PS/ZnO nanocomposites is verified by systematic increases in thermal degradation with increasing ZnO content. The characterization degradation temperatures at different weight loss percentages of ZnO nanoparticles increase at high ZnO wt%. Static activation energy of decomposing is based on TGA data. Activation energies showed some enhancement after the addition of ZnO nanorods into the PS matrix. Enhancing the thermal stability of PS with ZnO addition within the investigated ZnO concentration range is verified by TG, DSC results.

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“…Figure presents the T g of PC and PC/SiO 2 nanocomposites for different nanofiller sizes and concentrations. It has been noted that the T g of PC gradually increases with increasing nano‐SiO 2 contents, due to the higher degree of filler–matrix interaction and the restriction of polymer chain movement caused by the nanoparticles . However, the T g is not significantly affected by the size of the nano‐SiO 2 particles.…”

Section: Resultsmentioning

confidence: 99%

“…Apart from mechanical properties, a degree of filler–matrix interaction also plays a significant role in thermal properties of polymer nanocomposites, particularly in T g for amorphous polymers. An appropriate filler–matrix interaction tends to increase the T g of the polymer resulting in an increase in the temperature range of material usage …”

Section: Introductionmentioning

confidence: 99%

Effects of nanoparticle size and concentration on optical, toughness, and thermal properties of polycarbonate

Nomai

Schlarb

2019

J of Applied Polymer Sci

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The influences of size and content of silicon dioxide (SiO 2 ) nanoparticles on the morphological, optical, toughness, and thermal properties of polycarbonate (PC) were investigated. The PC nanocomposites were prepared using a twin-screw extruder followed by injection molding. The scanning electron microscope (SEM) micrographs displayed an adequate level of nano-SiO 2 particle distribution within the PC matrix but still revealed some agglomerated particles. Upon increasing the content of nanoparticles, slightly larger agglomerates formed. These agglomerated particles caused a reduction in material transparency due to light loss via reflection and scattering. However, the incorporation of nano-SiO 2 into the PC matrix greatly improved toughness properties and slightly increased glass-transition temperature (T g ), in conjunction with filler content (up to 4 vol %). This was particularly in the case with the smaller sized nano-SiO 2 , which not only significantly improved toughness but also enhanced optical properties of the PC nanocomposites.

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The effect of size and concentration of nanoparticles on the glass transition temperature of polymer nanocomposites

Abstract: Here we use model nanocomposites based on polystyrene and polyphenylene dendrimers to show both theoretically and experimentally that inclusion of rigid nanoparticles of 2.3–5 nm size into the polymer leads to a negligible glass transition temperature (Tg) increase.

Cited by 34 publications

References 40 publications

Ga-Doped ZnO Nanostructured Powder for Cool-Nanopigment in Environment Applications

Ga-Doped ZnO Nanostructured Powder for Cool-Nanopigment in Environment Applications

Thermal Degradation of Polystyrene (PS) Nanocomposites Loaded with Sol Gel-Synthesized ZnO Nanorods

Effects of nanoparticle size and concentration on optical, toughness, and thermal properties of polycarbonate

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