Effect of Silica Nanoparticles on Reinforcement of Poly(phenylene ether) Based Thermoplastic Elastomer

2008 ◽  
Vol 8 (4) ◽  
pp. 2114-2126
Author(s):  
Samik Gupta ◽  
Parnasree Maiti ◽  
Kumar Krishnamoorthy ◽  
Raja Krishnamurthy ◽  
Ashok Menon ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Sol Gel ◽  
Soxhlet Extraction ◽  
Thermoplastic Elastomer ◽  
Ethylene Vinyl Acetate ◽  
Spectroscopic Studies ◽  
Extensive Study ◽  
Silica Sol ◽  
Twin Screw Extrusion ◽  
Twin Screw

Reinforcement of a novel poly(phenylene ether) (PPE) based thermoplastic elastomer (TPE), i.e., styrene-ethylene-butylene-styrene (SEBS)/ethylene vinyl acetate (EVA) and PPE-polystyrene (PS), was studied to develop a reinforced thermoplastic elastomer or thermoplastic vulcanizate (TPV). An effort was made to reinforce selectively the elastomeric dispersed phase of EVA by silica nanoparticles and silica sol–gel precursors, like alkoxy orthosilanes, using twin-screw extrusion and injection molding processes. Improvement of tensile strength and percent elongation at break was observed both with silica nanoparticles and tetraethoxy orthosilane (TEOS). Addition of TEOS transformed the dispersed EVA lamellar morphology into semispherical domains as a consequence of possible crosslinking. Soxhlet extraction was done on the silica and TEOS reinforced materials. The insoluble residues collected from both the silica and TEOS reinforced samples were analyzed in detail using both morphological and spectroscopic studies. This extensive study also provided an in-depth conceptual understanding of the PPE based TPE behavior upon reinforcement with silica nanoparticles and silica sol–gel precursors and the effect of reinforcement on recycling behavior.

scholarly journals Determination of growth kinetics and size dependent structural, morphological, optical characteristics of sol-gel derived silica nanoparticles in silica matrix

2019 ◽  
Vol 37 (1) ◽  
pp. 16-24
Author(s):  
Bengü Özuğur Uysal ◽  
Fatma Z. Tepehan
Keyword(s):  
Thin Films ◽  
Silica Nanoparticles ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Silica Film ◽  
Silica Sol ◽  
Nano Silica ◽  
Silica Films ◽  
Annealing Temperatures ◽  
Silica Thin Films

AbstractNanocomposite silica thin films made using the sol-gel method were studied. The nano-silica films were prepared using a mixture of tetraethyl orthosilicate (TEOS), deionized water, ethanol, and ammonia solution. To control the growth of the particles inside the film, the nanocomposite silica film was prepared using a mixture of the nano-silica sol and the silica sol. The change in the particle size with the heat treatment temperature ranging from 450 °C to 1100 °C was investigated. X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), NKD (refractive index-N, extinction coefficient-K, and thickness-D) and ultraviolet-visible (UV-Vis) spectrophotometry were used for characterization purposes. The XRD studies showed that the nano-silica thin films were amorphous at all annealing temperatures except for 1100 °C. The_-cristobalite crystal structure formed at the annealing temperature of 1100 °C. Optical parameters, such as refractive indices and extinction coefficients, were obtained using the NKD analyzer with respect to the annealing temperature of the films. The activation energy and enthalpy of the nanocomposite silica film were evaluated as 22.3 kJ/mol and 14.7 kJ/mol, respectively. The cut-off wavelength values were calculated by means of extrapolation of the absorbance spectra estimated using the UV-Vis spectroscopy measurements. A red shift in the absorption threshold of the nanocomposite silica films indicated that the size of the silica nanoparticles increased with an increase of the annealing temperatures from 450 °C to 900 °C, and this confirms the quantum confinement effect in the nanoparticles.

Spectroscopic studies of chromium-doped silica sol–gel glasses

2001 ◽  
Vol 288 (1-3) ◽  
pp. 56-65 ◽  
Author(s):  
W. Stręk ◽  
P.J. Dereń ◽  
E. Łukowiak ◽  
J. Hanuza ◽  
H. Drulis ◽  
...  
Keyword(s):  
Sol Gel ◽  
Spectroscopic Studies ◽  
Silica Sol ◽  
Gel Glasses

scholarly journals Biodegradation and Antimicrobial Properties of Zinc Oxide–Polymer Composite Materials for Urinary Stent Applications

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1002
Author(s):  
Chaitra Venkatesh ◽  
Marco Laurenti ◽  
Marina Bandeira ◽  
Eduardo Lanzagorta ◽  
Lorenzo Lucherini ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Sol Gel ◽  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
Mechanical And Thermal Properties ◽  
Twin Screw Extrusion ◽  
Functional Coating ◽  
Twin Screw ◽  
Artificial Urine ◽  
Bacteria Adhesion

Research advancements in the field of urinary stents have mainly been in the selection of materials and coatings to address commonly faced problems of encrustation and bacterial adhesion. In this study, polylactic acid (PLA) and polypropylene (PP) were evaluated with zinc oxide (ZnO) coating to assess its ability to reduce or eliminate the problems of encrustation and bacteria adhesion. PLA and PP films were prepared via twin screw extrusion. ZnO microparticles were prepared using sol-gel hydrothermal synthesis. The as-prepared ZnO microparticles were combined in the form of a functional coating and deposited on both polymer substrates using a doctor blade technique. The ZnO-coated PP and PLA samples as well as their uncoated counterparts were characterized from the physicochemical standpoints, antibacterial and biodegradation properties. The results demonstrated that both the polymers preserved their mechanical and thermal properties after coating with ZnO, which showed a better adhesion on PLA than on PP. Moreover, the ZnO coating successfully enhanced the antibacterial properties with respect to bare PP/PLA substrates. All the samples were investigated after immersion in simulated body fluid and artificial urine. The ZnO layer was completely degraded following 21 days immersion in artificial urine irrespective of the substrate, with encrustations more evident in PP and ZnO-coated PP films than PLA and ZnO-coated PLA films. Overall, the addition of ZnO coating on PLA displayed better adhesion, antibacterial activity and delayed the deposition of encrustations in comparison to PP substrates.

scholarly journals Continuous and Scalable Synthesis of a Porous Organic Cage by Twin Screw Extrusion (TSE)

2020 ◽  
Author(s):  
Benjamin Egleston ◽  
Michael C. Brand ◽  
Francesca Greenwell ◽  
Michael E. Briggs ◽  
Stuart L. James ◽  
...  
Keyword(s):  
Solid State ◽  
Large Scale ◽  
Crystal Packing ◽  
Reaction Times ◽  
Soxhlet Extraction ◽  
Twin Screw Extrusion ◽  
Technical Grade ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Scalable Synthesis

The continuous and scalable synthesis of a porous organic cage (<b>CC3</b>), obtained through a 10-component imine polycondensation between triformylbenzene and a vicinal diamine, was achieved using twin screw extrusion (TSE). Compared to both batch and flow syntheses, the use of TSE enabled the large scale synthesis of <b>CC3</b> using minimal solvent and in short reaction times, with liquid-assisted grinding (LAG) also promoting window-to-window crystal packing to form a 3-D diamondoid pore network in the solid state. A new kinetically trapped [3+5] product was also observed alongside the formation of the targeted [4+6] cage species. Post-synthetic purification by Soxhlet extraction of the as-extruded ‘technical grade’ mixture of <b>CC3</b> and [3+5] species rendered the material porous.

scholarly journals Continuous and Scalable Synthesis of a Porous Organic Cage by Twin Screw Extrusion (TSE)

2020 ◽  
Author(s):  
Benjamin Egleston ◽  
Michael C. Brand ◽  
Francesca Greenwell ◽  
Michael E. Briggs ◽  
Stuart L. James ◽  
...  
Keyword(s):  
Solid State ◽  
Large Scale ◽  
Crystal Packing ◽  
Reaction Times ◽  
Soxhlet Extraction ◽  
Twin Screw Extrusion ◽  
Technical Grade ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Scalable Synthesis

The continuous and scalable synthesis of a porous organic cage (<b>CC3</b>), obtained through a 10-component imine polycondensation between triformylbenzene and a vicinal diamine, was achieved using twin screw extrusion (TSE). Compared to both batch and flow syntheses, the use of TSE enabled the large scale synthesis of <b>CC3</b> using minimal solvent and in short reaction times, with liquid-assisted grinding (LAG) also promoting window-to-window crystal packing to form a 3-D diamondoid pore network in the solid state. A new kinetically trapped [3+5] product was also observed alongside the formation of the targeted [4+6] cage species. Post-synthetic purification by Soxhlet extraction of the as-extruded ‘technical grade’ mixture of <b>CC3</b> and [3+5] species rendered the material porous.

scholarly journals A simple approach to prepare fluorescent molecularly imprinted nanoparticles

RSC Advances ◽  
2021 ◽  
Vol 11 (13) ◽  
pp. 7732-7737
Author(s):  
Fenying Wang ◽  
Dan Wang ◽  
Tingting Wang ◽  
Yu Jin ◽  
Baoping Ling ◽  
...  
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Sol Gel ◽  
Silica Sol ◽  
Simple Approach ◽  
Imprinted Polymer ◽  
Molecularly Imprinted ◽  
Low Toxicity ◽  
Good Biocompatibility ◽  
Molecularly Imprinted Nanoparticles

Fluorescent molecularly imprinted polymer (FMIP) gains great attention in many fields due to their low cost, good biocompatibility and low toxicity. Here, a high-performance FMIP was prepared based on the autocatalytic silica sol–gel reaction.

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