Kinetic study of the curing of mixtures of DGEBA and five‐membered cyclic carbonates with lanthanum triflate as cationic initiator

Mixtures of diglycidylether of bisphenol A (DGEBA) with 1,3‐benzodioxolane‐2‐one (CC) or 4‐phenoxymethyl‐1,3‐dioxolane‐2‐one (PGEC) were cured in the presence of lanthanum triflate. FTIR/ATR was used to study the evolution of carbonate and epoxide groups to follow the reactive processes that take place during curing. DSC was applied to study the thermal characteristics of the curing process and to determine the glass‐transition temperatures of the cured materials. The kinetics of the curing was studied isothermally by means of FTIR and the kinetic model was selected through the isokinetic relationships. DSC experiments were used to study the kinetics in nonisothermal conditions by means of isoconversional procedures and the Coats–Redfern and Criado methodologies. By TMA we could monitor the evolution of the shrinkage during isothermal curing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2875–2884, 2007     

Anionic copolymerization of diglycidyl ether of bisphenol A with Meldrum's acid derivatives initiated by 4‐(N,N‐dimethylamino) pyridine

The anionic copolymerization of diglycidyl ether of bisphenol A with 2,2,5,5‐tetramethyl‐4,6‐dioxo‐1,3‐dioxane or 6,6‐dimethyl‐(4,8‐dioxaspiro[2.5]octane‐5,7‐dione) with 4‐(N,N‐dimethylamino) pyridine as an initiator to form thermosets was studied with differential scanning calorimetry, and the kinetics were evaluated with isoconversional procedures. The evolution during the curing process of the epoxide, lactone, and linear ester bands was evaluated with Fourier transform infrared spectroscopy in the attenuated total reflection mode to clarify the reactions taking place. The shrinkage during curing, thermomechanical properties, and thermal degradability of the materials obtained by copolymerization with the different derivatives of Meldrum's acid were evaluated and related to the chemical structure of the final network. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Use of investigations in lower respiratory tract infection in the community: a European survey

A questionnaire survey was performed on the use of investigations and their impact on treatment of adult lower respiratory tract infection in the community. Data on the management of 2,056 such infections were obtained simultaneously from general practitioners in France, Germany, Italy, Spain and the UK. Diagnostic tests were only performed in 29% of cases. Chest radiographs were performed most frequently (22%), followed by peripheral blood white cell count (15%) and microbiological examination of sputum (7%), with major differences being found in the frequency of these tests both by clinical diagnosis and country. A change in initial antibiotic therapy was made in 12% of cases, with use of investigation being significantly linked to such changes. Second- and third-line antibiotics were significantly different to first-line therapy, with macrolides the most frequently prescribed second-line and quinolones the most frequently prescribed third-line antibiotics.