Nanofibers as a Vehicle for the Synthetic Attactant TRIMEDLURE to be Used for Ceratitis capitata Wied: (Diptera, Tethritidae) Capture
Pages 40-47
R. Bisotto-de-Oliveira, B. C. De Jorge, I Roggia, J. Sant'Ana and C.N. Pereira

DOI: http://dx.doi.org/10.6000/1929-5995.2014.03.01.6

Published: 02 April 2014

Abstract: The Mediterranean fruit fly (medfly), Ceratitis capitata (Wied.) is considered a serious pest of citrus fruits in the southeast of Brazil because of the direct economic impact they have on fruit production and quarantine restrictions for fruit exports. Monitoring and detection of the medfly, using food bait and synthetic attractants, is a key step towards signalling the need for management and control. The aim of this study has been to verify the attractiveness of innovative nanofiber formulations with Trimedlure (TML) for the male of C. capitata in laboratory and field cage tests.

Material and Methods:The nanofibers were produced by solution or emulsion electrospinning, containing TML and polymers, such as polycaprolactone, PEG-polycaprolactone, ethyl cellulose and polyvinyl acetate-PVP.

Results: At the laboratory the electrophysiological responses were accessed by the eletroanntenogram technique and in the field by the cage test. The bioactivity of C. capitata antennae was highest when stimulated with all TML nanofiber treatments rather than their controls. There were no differences among the TML nanofiber treatments. In the field cages the same number of medflies were found on the adhesive traps baited with one of each of the TML nanofibers.

Upon Synthesis of Poly(N-isopropylacrylamide-co-2-dimethyl-aminoethyl methacrylate-co-itaconic acid) Copolymers as Matrix Ensuring Intramolecular Strategies for Further Coupling Applications
Pages 48-56
Aurica P. Chiriac, Loredana E. Nita, Iordana Neamtu, Vera Balan and Alina Diaconu

DOI: http://dx.doi.org/10.6000/1929-5995.2014.03.01.7

Published: 02 April 2014

Abstract: The study presents a set of copolymers synthesis based on N-isopropylacrylamide, 2-dimethylaminoethyl methacrylate and itaconic acid comonomers found in different gravimetric ratio, acquired through polymerization in water in the presence of ammonium persulfate as radical initiator. The purpose was to prepare polymeric structure with dual sensitivity to temperature and pH respectively, and able as well to ensure intramolecular strategies for coupling applications of inorganic or bioactive compounds. The polymers composition was confirmed by FTIR and ¹H-NMR spectra. The thermal stability of the polymeric compounds was evaluated, and SEM investigations of the polymer morphology are also presented. The polymers dispersions were characterized from the viewpoint of their hydrodynamic radius, zeta potential and conductivity.

Application of Disordered Organic Semiconductor Theory to Low Temperature Curing of Epoxy Resins
Pages 1-9
Edward A. Aitken

DOI: http://dx.doi.org/10.6000/1929-5995.2014.03.01.1

Published: 02 April 2014

Abstract: The steep autocatalytic feature in a highly accurate DSC study of the heat rate from curing an epoxy resin with piperidine at 27.5 Deg C could not be explained using chemical kinetic power laws usually applied to curing epoxy resin products at higher temperatures. The theory of disordered conjugated organic semiconductors developed in the last decade has been applied to the observed heat rate data. Four heat rate sources have been identified to completely account for the experimental data. Two of the four sources generating 80% of the heat are consistent with mobility change of ion pairs indicating that the low temperature cure follows an organic semiconductor mechanism. It was shown that autocatalysis did not begin until about one fiftieth of the epoxy rings were opened (ignition). After ignition the heat rates of two propagation mechanisms grow exponentially. One charge transport mechanism generates a small heat rate but grows immediately after ignition due to an increase in ion pairs by the dopant (piperidine). The second mechanism appears later but becomes dominant, peaking at 50% completion, where the heat rate is about 50 times higher than the start of the first mechanism. The rate increase is attributed to localized energy sites that lower the LUMO level closer to the HOMO level of the monomer increasing the mobility (heat rate).

Application of Disordered Organic Semiconductor Theory to Low Temperature Curing of Epoxy Resins
Pages 1-9
Edward A. Aitken

DOI: http://dx.doi.org/10.6000/1929-5995.2014.03.01.1

Published: 02 April 2014

Abstract: The steep autocatalytic feature in a highly accurate DSC study of the heat rate from curing an epoxy resin with piperidine at 27.5 Deg C could not be explained using chemical kinetic power laws usually applied to curing epoxy resin products at higher temperatures. The theory of disordered conjugated organic semiconductors developed in the last decade has been applied to the observed heat rate data. Four heat rate sources have been identified to completely account for the experimental data. Two of the four sources generating 80% of the heat are consistent with mobility change of ion pairs indicating that the low temperature cure follows an organic semiconductor mechanism. It was shown that autocatalysis did not begin until about one fiftieth of the epoxy rings were opened (ignition). After ignition the heat rates of two propagation mechanisms grow exponentially. One charge transport mechanism generates a small heat rate but grows immediately after ignition due to an increase in ion pairs by the dopant (piperidine). The second mechanism appears later but becomes dominant, peaking at 50% completion, where the heat rate is about 50 times higher than the start of the first mechanism. The rate increase is attributed to localized energy sites that lower the LUMO level closer to the HOMO level of the monomer increasing the mobility (heat rate).

Bisphenol, Diethylstilbestrol, Polycarbonate and the Thermomechanical Properties of Epoxy–Silica Nanostructured Composites

Pages 183-193
Francisco Torrens and Gloria Castellano

DOI: http://dx.doi.org/10.6000/1929-5995.2013.02.04.1

Published: 31 December 2013

Abstract: The report has a double character: it deals with the synthesis and preparation of a series of polymers based on bisphenol-A (BPA) monomer; a series of physical and thermomechanical properties are examined for one type (diglycidyl ether of BPA, DGEBA with nanosilica) of the prepared materials. The reactions involved in diepoxy curing with a diamine, functional group modelling for cross-linked polymers, formation of a polymer DGEBA, BPA polyaddition to DGEBA forming a polyether, DGEBA curing with Jeffamine and cross-linking to form a resin are analyzed. Nanocomposites of silica, coated with cross-linked epoxy–amine, are synthesized and examined by ²⁹Si-magic-angle-spinning nuclear magnetic resonance and Fourier-transform infrared spectroscopies, thermogravimetric and dynamic mechanical analyses, differential scanning calorimetry and scanning electron microscopy. Epoxy matrix is filled with nanosilica to design materials with defined properties. A low weight percentage of filler results in matrix improvement.