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Full-Text Articles in Physical Sciences and Mathematics
Does Organic Modification Of Layered Double Hydroxides Improve The Fire Performance Of Pmma?, Calistor Nyambo, Dan Chen, Shengpei Shu, Charles A. Wilkie
Does Organic Modification Of Layered Double Hydroxides Improve The Fire Performance Of Pmma?, Calistor Nyambo, Dan Chen, Shengpei Shu, Charles A. Wilkie
Chemistry Faculty Research and Publications
The effect of modified layered double hydroxides (LDHs) on fire properties of poly(methyl methacrylate) is investigated. Organically-modified LDHs were prepared via rehydration of calcined hydrotalcite in a palmitate solution. Composites consisting of the organo-LDHs, unmodified hydrotalcite and calcined oxides were prepared with poly(methyl methacrylate) using melt blending. Thermal and fire properties of the (nano)composites were studied. The thermogravimetric analyses of the composites show an increase in thermal stability. Fire performance, evaluated using cone calorimetry, show that organically-modified LDHs composites give the best reductions in peak heat release rate, PHRR, i.e., 51% at 10% weight loading. Dispersion of the LDHs was …
Variation Of Anions In Layered Double Hydroxides: Effects On Dispersion And Fire Properties, Linjiang Wang, Shengpei Shu, Dan Chen, Charles A. Wilkie
Variation Of Anions In Layered Double Hydroxides: Effects On Dispersion And Fire Properties, Linjiang Wang, Shengpei Shu, Dan Chen, Charles A. Wilkie
Chemistry Faculty Research and Publications
Layered double hydroxides (LDHs) are interesting materials for nanocomposite formation because one can vary the identity of the metals, the anions and the stoichiometry to see the effect of these on the ability of the nano-material to disperse in a polymer and to see what effect dispersion has on the properties of the polymer. In this study, the anions 2-ethylhexyl sulfate (SEHS), bis(2-ethylhexyl) phosphate (HDEHP) and dodecyl benzenesulfonate (SDBS) have been utilized as the charge balancing anions to synthesize organo-LDHs. Nanocomposites of poly(methyl methacrylate) (PMMA) and polystyrene (PS) with organo-LDHs were prepared both by melt blending and bulk polymerization. X-ray …
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 …
The Role Of The Trivalent Metal In An Ldh: Synthesis, Characterization And Fire Properties Of Thermally Stable Pmma/Ldh Systems, Charles Manzi-Nshuti, Dongyan Wang, Jeanne Hossenlopp, Charles A. Wilkie
The Role Of The Trivalent Metal In An Ldh: Synthesis, Characterization And Fire Properties Of Thermally Stable Pmma/Ldh Systems, Charles Manzi-Nshuti, Dongyan Wang, Jeanne Hossenlopp, Charles A. Wilkie
Chemistry Faculty Research and Publications
Two layered double hydroxides (LDHs), calcium aluminum undecenoate (Ca3Al) and calcium iron undecenoate (Ca3Fe), have been prepared by the co-precipitation method. XRD analysis of these LDHs reveals that they are layered materials and FT-IR and TGA confirmed the presence of the undecenoate anions in the material produced. The PMMA composites were prepared by bulk polymerization and the samples were characterized by XRD, TEM, TGA and cone calorimetry. Both additives greatly enhance the thermal stability of PMMA, while the calcium aluminum LDH gives better results when the fire properties were examined using the cone calorimeter.