Browsing Research articles (Dept of Chemistry) by Author "Ddamba, W.A.A."
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Ddamba, W.A.A.; Ngila, J.C.; Mokoena, T.T.; Motlhagodi, K. (South African Journal of Chemistry. <http://ejour.sabinet.co.za/images/ejour/chem/chem_v55_a1.pdf>., NaN, 2002)[more][less]
Abstract: The copolymerization of difurylmethane with maleic anhydride in the presence of azobisisobutyronitrile as an initiator has been investigated at 65 °C, 72 °C and 85 °C in different solvents. Reaction feeds containing 85 mol % and higher of difurylmethane yielded a soluble alternating copolymer in which the furan residue entrained in the polymer chain formed 2,5 linkages and had 3,4 unsaturation. The 1:1 difurylmethane– maleic anhydride adduct was readily prepared, and at the above temperatures and in the presence of the radical initiator partially underwent retro-Diels–Alder reaction. Copolymerization of the difurylmethane and maleic anhydride thus formed yielded the unsaturated alternating copolymer. Copolymers prepared from reaction feeds with proportions of difurylmethane lower than 85 mol % had higher cross-link density and exhibited higher thermodecomposition temperatures. URI: http://hdl.handle.net/10311/305 Files in this item: 1
Free radical.pdf (2.417Mb) -
Ddamba, W.A.A.; Mokate, O. (Journal of Solution Chemistry., NaN, 2006)[more][less]
Abstract: Densities (ρ) of the binary systems of {difurylmethane+(ethanol or propan-1- ol or butan-1-ol or pentan-1-ol or hexan-1-ol)} have been measured with an Anton Paar DMA 4500 vibrating-tube densimeter over the entire composition range at 298.15K and atmospheric pressure. Excess molar volumes (V E m ) of each binary system were determined and correlated by the Redlich-Kister equation. Limiting (Vi E,∞) and excess partial molar volumes (V E i ) of components of each binary system have been calculated to provide insight into the intermolecular interactions present and the packing efficiencies. The results have been discussed in terms of specific intermolecular interactions, dispersive forces and structural effects. URI: http://hdl.handle.net/10311/318 Files in this item: 1
Volumetric prop.pdf (3.737Mb) -
Ahmad, J.; Ddamba, W.A.A. (Chemic Publishing Co., http://www.asianjournalofchemistry.com/, NaN, 2006)[more][less]
Abstract: The expression for mechanical work obtained in the expansion of a gas commonly used in physical chemistry textbooks is critically examined. The mathematical form of the first law of thermodynamics is arrived at by a procedure that is consistent with the common definition of mechanical work. The treatment is extended to explain the concept of reversible and irreversible work. URI: http://hdl.handle.net/10311/225 Files in this item: 2
license.txt (1.998Kb)Work in thermodynamics.pdf (1.197Mb)
Now showing items 1-3 of 3