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Full-Text Articles in Chemistry
Material Properties Of Nanoclay Pvc Composites, Walid Awad, Gunter Beyer, Daphne Benderly, Wouter L. Ijdo, Ponusa Songtipya, Maria Del Mar Jimenez-Gasco, Evangelos Manias, Charles A. Wilkie
Material Properties Of Nanoclay Pvc Composites, Walid Awad, Gunter Beyer, Daphne Benderly, Wouter L. Ijdo, Ponusa Songtipya, Maria Del Mar Jimenez-Gasco, Evangelos Manias, Charles A. Wilkie
Chemistry Faculty Research and Publications
Nanocomposites of poly(vinyl chloride) have been prepared using both hectorite- and bentonite-based organically-modified clays. The organic modification used is tallow-triethanol-ammonium ion. The morphology of the systems was investigated using X-ray diffraction and transmission electron microscopy and these systems show that true nanocomposites, both intercalated and exfoliated systems, are produced. The mechanical properties have been evaluated and the modulus increases upon nanocomposite formation without a significant decrease in tensile strength or elongation at break. Thermal analysis studies using thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis were conducted. Thermal stability of the PVC systems was assessed using a standard thermal …
Nanostructured Layered Copper Hydroxy Dodecyl Sulfate: A Potential Fire Retardant For Poly(Vinyl Ester) (Pve), Everson Kandare, Grace Chigwada, Dongyan Wang, Charles A. Wilkie, Jeanne Hossenlopp
Nanostructured Layered Copper Hydroxy Dodecyl Sulfate: A Potential Fire Retardant For Poly(Vinyl Ester) (Pve), Everson Kandare, Grace Chigwada, Dongyan Wang, Charles A. Wilkie, Jeanne Hossenlopp
Chemistry Faculty Research and Publications
Composites of poly(vinyl ester) (PVE) with copper hydroxy dodecyl sulfate (CHDS) were prepared by thermal curing. The efficiency of the additive, CHDS, in reducing flammability is demonstrated via cone calorimetry and thermogravimetric analysis (TGA). The addition of 1-10% by mass of the CHDS additive resulted in significant increments in char formation (~4-11%) from thermogravimetric analysis (TGA). Incorporation of the CHDS into the polymer matrix at these low concentrations leads to substantial reductions in the total heat release (~20-30%) but no significant change in the peak heat release rate. The composite materials generally ignite more quickly, however, the flame extinguishes faster …
Fire Retardancy Of Vinyl Ester Nanocomposites: Synergy With Phosphorus-Based Fire Retardants, Grace Chigwada, Panchatapa Jash, David D. Jiang, Charles A. Wilkie
Fire Retardancy Of Vinyl Ester Nanocomposites: Synergy With Phosphorus-Based Fire Retardants, Grace Chigwada, Panchatapa Jash, David D. Jiang, Charles A. Wilkie
Chemistry Faculty Research and Publications
Vinyl ester (PVE) nanocomposites were prepared using both clay and polyhedral oligosilsesquioxanes (POSS) as the nano-dimensional material. From cone calorimetric data, it was shown that both POSS and clay affect the flammability of the nanocomposites to the same extent. To improve on the flame retardancy, the nanocomposites were combined with phosphorous-containing fire retardants (FRs) and the result compared to the benchmark halogen-containing system. The use of the cone calorimeter to investigate the fire properties of these nanocomposites showed a great reduction in peak heat release rate (PHRR) in the presence of phosphate and slight improvements in average mass loss rate …
Synergy Between Nanocomposite Formation And Low Levels Of Bromine On Fire Retardancy In Polystyrenes, Grace Chigwada, Panchatapa Jash, David D. Jiang, Charles A. Wilkie
Synergy Between Nanocomposite Formation And Low Levels Of Bromine On Fire Retardancy In Polystyrenes, Grace Chigwada, Panchatapa Jash, David D. Jiang, Charles A. Wilkie
Chemistry Faculty Research and Publications
An organically-modified clay has been prepared using ammonium salts which contain an oligomeric material consisting of vinylbenzyl chloride, styrene and dibromostyrene. The presence of dibromostyrene enhances the flame retardancy of polystyrene nanocomposites compared to both the virgin polymer and polystyrene nanocomposites prepared from non-halogen-containing organically-modified clays. The nanocomposites were prepared both by bulk polymerization and melt blending and they were evaluated by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis and cone calorimetry measurements. Bulk polymerization produced nanocomposites with reduced peak heat release rate, reduced total heat release and improved thermal stability. It is noteworthy that all these improvements were obtained …
Study On The Thermal Stability Of Polystyryl Surfactants And Its Modified Clay Nanocomposites, Shengpei Su, David D. Jiang, Charles A. Wilkie
Study On The Thermal Stability Of Polystyryl Surfactants And Its Modified Clay Nanocomposites, Shengpei Su, David D. Jiang, Charles A. Wilkie
Chemistry Faculty Research and Publications
Five oligomeric styrene surfactants, N,N,N-trimethylpolystyrylammonium, N,N-dimethyl-N-benzylpolystyrylammonium, N,N-dimethyl-N-hexadecylpolystyrylammonium, 1,2-dimethyl-3-polystyrylimidazolium, and triphenylpolystyrylphosphonium chlorides were synthesized and used to prepare organically modified clays. Both styrene and methyl methacrylate nanocomposites were prepared by melt blending and the type of nanocomposite was evaluated by X-ray diffraction and transmission electron microscopy. The thermal stability of the organically modified clays and the nanocomposites were studied by thermogravimetric analysis; these systems do give clays which have good thermal stability and may be useful for melt blending with polymers that must be processed at …
Synergy Between Conventional Phosphorus Fire Retardants And Organically-Modified Clays Can Lead To Fire Retardancy Of Styrenics, Grace Chigwada, Charles A. Wilkie
Synergy Between Conventional Phosphorus Fire Retardants And Organically-Modified Clays Can Lead To Fire Retardancy Of Styrenics, Grace Chigwada, Charles A. Wilkie
Chemistry Faculty Research and Publications
Polystyrene–clay nanocomposites combined with phosphorous-containing fire retardants have been prepared and used to explore the thermal stability and mechanical properties of the polymer formed. The amounts of fire retardants and clay used were varied to study the effect of each on thermal stability and mechanical properties of the polymer. The samples were prepared by bulk polymerization and analyzed by X-ray diffraction, thermogravimetric analysis, cone calorimetry, Fourier Transform infrared spectroscopy and the evaluation of mechanical properties. The thermal stability of the polymers is enhanced by the presence of the phosphorus-containing fire retardants.
Polystyrene/Graphite Nanocomposites: Effect On Thermal Stability, Fawn Marie Uhl, Charles A. Wilkie
Polystyrene/Graphite Nanocomposites: Effect On Thermal Stability, Fawn Marie Uhl, Charles A. Wilkie
Chemistry Faculty Research and Publications
Nanocomposites consisting of polymer and clay have been shown to exhibit a significant reduction in flammability and an increase in mechanical properties. This work examines the effect of thermal stability and mechanical properties of nanocomposites prepared from potassium graphite and styrene. Synthesis of nanocomposites was accomplished by using potassium graphite (KC8) as the initiator in the polymerization of styrene. A slight increase in thermal stability is observed but mechanical properties are decreased.
The Thermal Stability Of Cross-Linked Polymers: Methyl Methacrylate With Divinylbenzene And Styrene With Dimethacrylates, Fawn Marie Uhl, Galina F. Levchik, Sergei V. Levchik, Caroline Dick, John J. Liggat, C.E. Snape, Charles A. Wilkie
The Thermal Stability Of Cross-Linked Polymers: Methyl Methacrylate With Divinylbenzene And Styrene With Dimethacrylates, Fawn Marie Uhl, Galina F. Levchik, Sergei V. Levchik, Caroline Dick, John J. Liggat, C.E. Snape, Charles A. Wilkie
Chemistry Faculty Research and Publications
Cross-linking of polymers is frequently presumed to enhance the thermal stability of polymer systems. Methyl methacrylate has been reacted with divinylbenzene and styrene with various dimethacrylates. These systems have been characterized by gel content, swelling ratio, infrared spectroscopy, thermal analysis, TGA/FT-IR, and solid state NMR. Both systems show enhanced thermal stability and char formation. This is most pronounced in the cases of methyl methacrylate with divinylbenzene and styrene with bisphenol A dimethacrylate.
Photooxidation Of Polymeric-Inorganic Nanocomposites: Chemical, Thermal Stability And Fire Retardancy Investigations, Adams Tidjani, Charles A. Wilkie
Photooxidation Of Polymeric-Inorganic Nanocomposites: Chemical, Thermal Stability And Fire Retardancy Investigations, Adams Tidjani, Charles A. Wilkie
Chemistry Faculty Research and Publications
Nanocomposites of polypropylene-graft-maleic anhydride/clay and polypropylene/clay were prepared by melt blending using two different approaches. X-Ray diffraction results showed an intercalated structure. Samples of nanocomposites were exposed to UV light under atmospheric oxygen and their photo-oxidative stability was studied using FTIR and UV spectroscopy. The consequences of this photo-oxidation on the thermal stability and fire retardant performance of the nanocomposites were also addressed from thermogravimetry analysis and Cone calorimetry.
Polybutadiene Cross-Linked With Various Diols – Effect On Thermal Stability, Fawn Marie Uhl, Michael A. Mckinney, Charles A. Wilkie
Polybutadiene Cross-Linked With Various Diols – Effect On Thermal Stability, Fawn Marie Uhl, Michael A. Mckinney, Charles A. Wilkie
Chemistry Faculty Research and Publications
The relationship between cross-linking and thermal stability as related to polybutadiene is the focus of current research. Cross-linked polybutadienes have been prepared using various diols as the cross-linking agent. Cross-linked polymers have been characterized by gel content, swelling ratios, infrared spectroscopy, and thermal analysis. These polymers are not highly cross-linked, as seen by gel content and swelling ratios, and cross-linking does not have a large effect on the onset temperature of the degradation. Nonetheless, extensive formation of a non-volatile residue occurs.