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Structure - Property Relationships Of New Polystyrene Nanocomposites Prepared From Initiator-Containing Layered Double Hydroxides Of Zinc Aluminum And Magnesium Aluminum, Charles Manzi-Nshuti, Dan Chen, Shengpei Shu, Charles A. Wilkie
Structure - Property Relationships Of New Polystyrene Nanocomposites Prepared From Initiator-Containing Layered Double Hydroxides Of Zinc Aluminum And Magnesium Aluminum, Charles Manzi-Nshuti, Dan Chen, Shengpei Shu, Charles A. Wilkie
Chemistry Faculty Research and Publications
Polystyrene/layered double hydroxides (PS/LDHs) nanocomposites were prepared by free radical polymerization of styrene monomer in the presence of LDHs intercalated with 4,4′-azobis(4-cyanopentanoate) anions (LDH–ACPA). XRD and ATR-IR are used to confirm that the materials produced are layered and the presence of the azo-initiator anions in these LDHs. These LDHs were used successfully to polymerize styrene and both XRD and TEM images of the composites support the formation of a mixed exfoliated-intercalated nanocomposite for ZnAl–ACPA but a microcomposite for MgAl–ACPA. The magnesium-containing LDHs decreased the glass transition temperature (Tg) of the composites while ZnAl–ACPA did not affect T …
Fire Retardancy Of Bis[2-(Methacryloyloxy)Ethyl] Phosphate Modified Poly(Methyl Methacrylate) Nanocomposites Containing Layered Double Hydroxide And Montmorillonite, Linjiang Wang, Shengpei Shu, Dan Chen, Charles A. Wilkie
Fire Retardancy Of Bis[2-(Methacryloyloxy)Ethyl] Phosphate Modified Poly(Methyl Methacrylate) Nanocomposites Containing Layered Double Hydroxide And Montmorillonite, Linjiang Wang, Shengpei Shu, Dan Chen, Charles A. Wilkie
Chemistry Faculty Research and Publications
Copolymer nanocomposites were prepared by suspension copolymerization of bis[2-(methacryloyloxy)ethyl] phosphate and methyl methacrylate, together with bis(2-ethylhexyl) phosphate layered double hydroxide and a montmorillonite, Cloisite 93A. X-ray diffraction and transmission electron microscopy were used to characterize the morphology of nanocomposites and the dispersion of additives in the polymer. The thermal stability of the nanocomposites has been assessed by thermogravimetric analysis and cone calorimetry has been used to study the fire properties. Bis[2-(methacryloyloxy)ethyl] phosphate not only copolymerized with MMA, but also aids in the dispersion of additives in PMMA. The copolymer nanocomposites have better dispersion and higher degradation temperature and more char …
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 …
Variation Of Benzyl Anions In Mgal-Layered Double Hydroxides: Fire And Thermal Properties In Pmma, Calistor Nyambo, Dan Chen, Shengpei Shu, Charles A. Wilkie
Variation Of Benzyl Anions In Mgal-Layered Double Hydroxides: Fire And Thermal Properties In Pmma, Calistor Nyambo, Dan Chen, Shengpei Shu, Charles A. Wilkie
Chemistry Faculty Research and Publications
Magnesium aluminum layered double hydroxides (MgAl-LDHs) intercalated with a range of benzyl anions were prepared using the coprecipitation method. The benzyl anions differ in functionality (i.e. carboxylate, sulfonate, and phosphonate) and presence or absence of an amino substituent. Various methods for preparing LDHs (i.e. ion exchange, coprecipitation and rehydration of the calcined LDH methods) have been compared with the MgAl-benzene phosphonate and their effect on fire and thermal properties was studied. After characterization, the MgAl-LDHs were melt-blended with poly(methyl methacrylate) (PMMA) at loadings of 3 and 10% by weight to prepare composites. Characterization of the LDHs and the PMMA composites …
Layered Double Hydroxides Intercalated With Borate Anions: Fire And Thermal Properties In Ethylene Vinyl Acetate Copolymer, Calistor Nyambo, Charles A. Wilkie
Layered Double Hydroxides Intercalated With Borate Anions: Fire And Thermal Properties In Ethylene Vinyl Acetate Copolymer, Calistor Nyambo, Charles A. Wilkie
Chemistry Faculty Research and Publications
Fire and thermal properties of ethylene vinyl acetate (EVA) composites prepared by melt blending with layered double hydroxides (LDH) have been studied. Two types of LDHs intercalated with borate anion were prepared using the coprecipitation method and the metals Mg2+, Zn2+ and Al3+. Characterization of the LDHs and the EVA composites was performed using X-ray diffraction, thermogravimetric analysis, and cone calorimetry. Thermal analyses show that the addition of LDHs improves the thermal stability of EVA. Fire properties evaluated using the cone calorimeter were significantly improved in the EVA/LDH composites. The peak heat release rate was …
Fire Retardancy Of Melamine And Zinc Aluminum Layered Double Hydroxide In Poly(Methyl Methacrylate), Charles Manzi-Nshuti, Jeanne Hossenlopp, Charles Wilkie
Fire Retardancy Of Melamine And Zinc Aluminum Layered Double Hydroxide In Poly(Methyl Methacrylate), Charles Manzi-Nshuti, Jeanne Hossenlopp, Charles Wilkie
Chemistry Faculty Research and Publications
The thermal and fire properties of PMMA modified with various loadings of melamine or zinc aluminum undecenoate LDH were evaluated using TGA, DTA and cone calorimetry. The additives were characterized by X-ray diffraction, TGA, FT-IR and elemental analysis. While the two additives are very effective with this polymer, a higher loading of melamine (30%) is required to reach a good reduction in PHRR (47%) relative to the pure polymer, while with the LDH, 10% loading is enough to obtain a similar reduction. The combinations of these additives in PMMA reveal that the time to PHRR and the amount of smoke …
Styrenic Polymer Nanocomposites Based On An Oligomerically-Modified Clay With High Inorganic Content, Jinguo Zhang, David D. Jiang, Dongyan Wang, Charles A. Wilkie
Styrenic Polymer Nanocomposites Based On An Oligomerically-Modified Clay With High Inorganic Content, Jinguo Zhang, David D. Jiang, Dongyan Wang, Charles A. Wilkie
Chemistry Faculty Research and Publications
Clay was modified with an oligomeric surfactant containing styrene and lauryl acrylate units along with a small amount of vinylbenzyl chloride to permit the formation of an ammonium salt so that this can be attached to a clay. The oligomerically-modified clay contains 50% inorganic clay, and styrenic polymer nanocomposites, including those of polystyrene (PS), high-impact polystyrene (HIPS), styrene–acrylonitrile copolymer (SAN) and acrylonitrile–butadiene–styrene (ABS), were prepared by melt blending. The morphologies of the nanocomposites were evaluated by X-ray diffraction and transmission electron microscopy. Mixed intercalated/delaminated nanocomposites were formed for SAN and ABS while largely immiscible nanocomposites were formed for PS and …
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 …
Styrenic Nanocomposites Prepared Using A Novel Biphenyl-Containing Clay, Grace Chigwada, Dongyan Wang, David D. Jiang, Charles A. Wilkie
Styrenic Nanocomposites Prepared Using A Novel Biphenyl-Containing Clay, Grace Chigwada, Dongyan Wang, David D. Jiang, Charles A. Wilkie
Chemistry Faculty Research and Publications
Montmorillonite was organically modified using an ammonium salt containing 4-acetylbiphenyl. This clay (BPNC16 clay) was used to prepare polystyrene (PS), acrylonitrile butadiene styrene (ABS) and high impact polystyrene (HIPS) nanocomposites. Polystyrene nanocomposites were prepared both by in situ bulk polymerisation and melt blending processes, while the ABS and HIPS nanocomposites were prepared only by melt blending. X-ray diffraction and transmission electron microscopy were used to confirm nanocomposite formation. Thermogravimetric analysis was used to evaluate thermal stability and the flammability properties were evaluated using cone calorimetry. By thermogravimetry, BPNC16 clay was found to show high thermal stability, and by cone calorimetry, …
Polystyrene Nanocomposites Based On Quinolinium And Pyridinium Surfactants, Grace Chigwada, Dongyan Wang, Charles A. Wilkie
Polystyrene Nanocomposites Based On Quinolinium And Pyridinium Surfactants, Grace Chigwada, Dongyan Wang, Charles A. Wilkie
Chemistry Faculty Research and Publications
In this paper pyridine and quinoline-containing salts were employed to modify montmorillonite. TGA analysis shows that the quinolinium modified clay has a higher thermal stability than the pyridinium modified clay. Polystyrene nanocomposites were prepared by in situ bulk polymerisation and direct melt blending using both clays. The X-ray diffraction and transmission electron microscopy results show the formation of intercalated structures. The 50% degradation temperature of the nanocomposites is increased and so is the amount of char from TGA analysis compared to the virgin polymer. Cone calorimetric results indicate that clay reduces the peak heat release rate and average mass loss …
Flammability Of Styrenic Polymer Clay Nanocomposites Based On A Methyl Methacrylate Oligomerically-Modified Clay, Xiaoxia Zheng, David D. Jiang, Dongyan Wang, Charles A. Wilkie
Flammability Of Styrenic Polymer Clay Nanocomposites Based On A Methyl Methacrylate Oligomerically-Modified Clay, Xiaoxia Zheng, David D. Jiang, Dongyan Wang, Charles A. Wilkie
Chemistry Faculty Research and Publications
Nanocomposites of polystyrene, high impact polystyrene, acrylonitrile–butadiene–styrene terpolymer, polypropylene, and polyethylene were prepared using a methyl methacrylate oligomerically-modified clay by melt blending and the thermal stability and fire retardancy were studied. These nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis and cone calorimetry. The results show a mixed morphology, depending on the polymer.
Fire Properties Of Styrenic Polymer–Clay Nanocomposites Based On An Oligomerically-Modified Clay, Jinguo Zhang, David D. Jiang, Charles A. Wilkie
Fire Properties Of Styrenic Polymer–Clay Nanocomposites Based On An Oligomerically-Modified Clay, Jinguo Zhang, David D. Jiang, Charles A. Wilkie
Chemistry Faculty Research and Publications
An oligomerically-modified clay has been used to fabricate nanocomposites with styrenic polymers, such as polystyrene, high-impacted polystyrene, poly(styrene-co-acrylonitrile) and acrylonitrile–butadiene–styrene by melt blending. The clay dispersion was evaluated by X-ray diffraction and bright field transmission electron microscopy. All of the nanocomposites have a mixed delaminated/intercalated structure. The fire properties of nanocomposites were evaluated by cone calorimetry and the mechanical properties were also evaluated.
Thermal And Flame Properties Of Polyethylene And Polypropylene Nanocomposites Based On An Oligomerically–Modified Clay, Jinguo Zhang, David D. Jiang, Charles A. Wilkie
Thermal And Flame Properties Of Polyethylene And Polypropylene Nanocomposites Based On An Oligomerically–Modified Clay, Jinguo Zhang, David D. Jiang, Charles A. Wilkie
Chemistry Faculty Research and Publications
An oligomerically-modified clay was made using a surfactant which is the ammonium salt of an oligomer. The newly modified clay contains 37.5% inorganic clay and 62.5% oligomer. Polyethylene and polypropylene nanocomposites were made by melt blending the polymer with the oligomerically-modified clay in a Brabender mixer at various clay loadings. The structure of the nanocomposites was characterized by X-ray diffraction and transmission electron microscopy. Mechanical testing showed that the polyethylene nanocomposites had an enhanced Young's modulus and slightly decreased elongation, while the changes for polypropylene nanocomposites are small compared with the virgin polymers. The thermal stability and flame properties were …
Polystyrene Nanocomposites Based On An Oligomerically-Modified Clay Containing Maleic Anhydride, Xiaoxia Zheng, David D. Jiang, Charles A. Wilkie
Polystyrene Nanocomposites Based On An Oligomerically-Modified Clay Containing Maleic Anhydride, Xiaoxia Zheng, David D. Jiang, Charles A. Wilkie
Chemistry Faculty Research and Publications
An oligomerically-modified clay containing maleic anhydride was used to prepare polystyrene-clay nanocomposites by melt blending and the effect of this modified clay on the thermal stability and fire performance was studied. These nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis and cone calorimetry. The results show a mixed immiscible/intercalated/delaminated morphology. The maleic anhydride modified clay improved the compatibility between the clay and the polystyrene.
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 …
Effects Of Surfactants On The Thermal And Fire Properties Of Poly(Methyl Methacrylate)/Clay Nanocomposites, Panchatapa Jash, Charles A. Wilkie
Effects Of Surfactants On The Thermal And Fire Properties Of Poly(Methyl Methacrylate)/Clay Nanocomposites, Panchatapa Jash, Charles A. Wilkie
Chemistry Faculty Research and Publications
Nanocomposites of poly(methyl methacrylate) (PMMA) with layered silicates and with polyhedral oligosilsesquioxanes (POSS) were prepared by bulk polymerization. The thermal and fire stabilities of the various organically-modified clay and POSS nanocomposites were evaluated using both thermogravimetric analysis (TGA) and cone calorimetry. Thermogravimetric analysis is not a good criteria for evaluating nanocomposite formation but cone calorimetry can be. For montmorillonite systems, when more than 4% clay is present, the expected reduction in peak heat release rate is observed. For hectorite, a minimum of 6% clay concentration is required to achieve the same reduction in peak heat release rate. POSS has the …
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 …
Polystyrene Nanocomposites Based On Carbazole-Containing Surfactants, Grace Chigwada, David D. Jiang, Charles A. Wilkie
Polystyrene Nanocomposites Based On Carbazole-Containing Surfactants, Grace Chigwada, David D. Jiang, Charles A. Wilkie
Chemistry Faculty Research and Publications
New organically-modified clays containing a carbazole unit were prepared and the number of long alkyl chains on the surfactant was varied. The clay was used to prepare polystyrene nanocomposites by both bulk polymerization and melt blending. The dispersion of these clays in the polymer matrix was evaluated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The thermal stability of the clays and the nanocomposites were analyzed by thermogravimetric analysis (TGA) while the fire properties were evaluated by cone calorimetry. If more than two alkyl chains were present, the gallery spacing is apparently overcrowded, leading to poor dispersion. Bulk polymerization …
Poly(Methyl Methacrylate), Polypropylene And Polyethylene Nanocomposite Formation By Melt Blending Using Novel Polymerically-Modified Clays, Shengpei Su, David D. Jiang, Charles A. Wilkie
Poly(Methyl Methacrylate), Polypropylene And Polyethylene Nanocomposite Formation By Melt Blending Using Novel Polymerically-Modified Clays, Shengpei Su, David D. Jiang, Charles A. Wilkie
Chemistry Faculty Research and Publications
Two new organically-modified clays that contain an oligomeric styrene or methacrylate have been prepared and used to produce nanocomposites of poly(methyl methacryate), polypropylene and polyethylene. Intercalated nanocomposites and, in some cases, exfoliated or mixed intercalated/exfoliated nanocomposites of all of these polymers have been produced by melt blending in a Brabender mixer. The use of the styrene-containing clay permits the direct blending of the clay with polypropylene, without the usual need for maleation, to produce the nanocomposites. The systems have all been characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, cone calorimetry and the measurement of mechanical properties. These novel …
Novel Polymerically-Modified Clays Permit The Preparation Of Intercalated And Exfoliated Nanocomposites Of Styrene And Its Copolymers By Melt Blending, Shengpei Su, David D. Jiang, Charles A. Wilkie
Novel Polymerically-Modified Clays Permit The Preparation Of Intercalated And Exfoliated Nanocomposites Of Styrene And Its Copolymers By Melt Blending, Shengpei Su, David D. Jiang, Charles A. Wilkie
Chemistry Faculty Research and Publications
Two new organically-modified clays have been made and used to produce nanocomposites of polystyrene, high impact polystyrene and acrylonitrile–butadiene–styrene terploymer. At a minimum, intercalated nanocomposites of all of these polymers have been produced by melt blending in a Brabender mixer and, in some cases, exfoliated nanocomposites have been obtained. The systems have all been characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, cone calorimetry and the measurement of mechanical properties. These novel new clays open new opportunities for melt blending of polymers with clays to obtain nanocomposites with important properties.
Cross-Linking Of Polystyrene By Friedel-Crafts Chemistry: Reaction Of P-Hydroxymethylbenzyl Chloride With Polystyrene, Hongyang Yao, Michael A. Mckinney, Caroline Dick, John J. Liggat, C.E. Snape, Charles A. Wilkie
Cross-Linking Of Polystyrene By Friedel-Crafts Chemistry: Reaction Of P-Hydroxymethylbenzyl Chloride With Polystyrene, Hongyang Yao, Michael A. Mckinney, Caroline Dick, John J. Liggat, C.E. Snape, Charles A. Wilkie
Chemistry Faculty Research and Publications
p-Hydroxymethylbenzyl chloride was found to be an effective cross-linking agent for polystyrene. The reaction was found to occur by Friedel–Crafts alkylation between the benzyl alcohol/chloride functional groups in the additive and phenyl ring in polystyrene. The reaction was studied by TGA–IR to monitor the evolution of hydrogen chloride and water, and the structure of the resultant gel was analyzed by solid state NMR and elemental analysis. The potential application in flame-retardancy was evaluated using Cone calorimetry.
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.