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Summary Polymers have a great interest for the study and design of new materials. Among these materials are epoxy resins, that have good properties, such as low shrinkage during cure, good adhesion, high water and chemical resistance, etc. They have also fast and easy cure in a broad range of temperatures. TTT diagrams are very helpful to design new epoxy materials as they allow the search for very important final properties, such as thermal stability, conversion or glass transition temperature of a material cured through a selected curing cycle. In this work the dependence of the thermal stability on the selected curing cycle for a DGEBA/1,2 DCH system was studied.

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Journal of Thermal Analysis and Calorimetry
Authors: Maria Villanueva, I. Fraga, J. Rodríguez-Añón, J. Proupín-Castiñeiras, and J. Martín

Abstract  

The diffusive, calorimetric and thermal degradation behavior of different epoxy-amine systems was investigated during water sorption at different temperatures (23, 40 and 70°C). Experimental results showed that the water absorption at these temperatures fitted well to Fick’s law. Influence of water immersion during different periods of time on the glass transition temperatures was studied by differential scanning calorimetry. Thermal degradation of saturated samples was studied by thermogravimetric analysis. Dependence on the selected curing cycle was also checked.

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Journal of Thermal Analysis and Calorimetry
Authors: M. Villanueva, J. Martín-Iglesias, J. Rodríguez-Añón, and J. Proupín-Castiñeiras

Abstract  

The thermal degradation of the epoxy system diglycidyl ether of bisphenol A (DGEBA n=0) and m-xylylenediamine (mXDA) containing different concentrations of polyhedral oligomeric silsesquioxanes (POSS) nanoparticles was studied by thermogravimetric analysis in order to determine the influence of both, the POSS concentration and the curing cycle on the degradation process and to compare it with the results for the non modified system. Glass transition temperatures for the same systems were also determined by differential scanning calorimetry. Different behaviors have been observed, depending on the POSS concentration and on the curing selection.

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Journal of Thermal Analysis and Calorimetry
Authors: L. Núñez-Regueira, M. Villanueva, and I. Fraga-Rivas

Abstract  

The study of the degradation of a polymer is important because it can determine the upper temperature limit, the mechanism of a solid-state process, and the life-time for this system. Since the behavior of thermosets is affected by the selection of the curing cycle, it is important to investigate the changes which take place during the thermal degradation of these materials when a change on the sequence of time and temperature is introduced during the curing reaction. In this work, the thermal degradation of two epoxy systems diglycidyl ether of bisphenol A (BADGE n=0)/1, 2 diamine cyclohexane (DCH) cured through different sequences of time and temperature was studied by thermogravimetric analysis in order to determine the reaction mechanism of the degradation processes, and also to check the influence of the curing cycle on this mechanism. Values obtained using different kinetic methods were compared to the value obtained by Kissinger’s method (differential method which do not require a knowledge of the n-order reaction mechanism), and to that obtained through Flynn–Wall–Ozawa method in a previous work.

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section. During a partial cure cycle, the resist collapses under the surface tension of the flowing material and forms a curved shape which can be used as a template for advanced shapes (e.g., curved metal contacts for compliant interconnects) ( Fig. 13

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in analytical grad. Sample preparation and curing cycle selection To prepare the composites a specific level of nanoalumina was added into epoxy matrix before adding the curing agent at stoichiometric ratio. In a

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) tape, manufactured by Cytec Engineered Materials (USA) was used in this study. This thermoplastic toughened epoxy resin prepreg is formulated for autoclave or press molding. The manufacturer recommended cure cycle for 977-2 UD is isothermal cure at 177

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Journal of Thermal Analysis and Calorimetry
Authors: C. Gracia-Fernández, J. Tarrío-Saavedra, J. López-Beceiro, S. Gómez-Barreiro, S. Naya, and R. Artiaga

. Olivier , P , Cottu , JP , Ferret , B . Effects of cure cycle pressure and voids on some mechanical properties of carbon/epoxy laminates . Composites . 1995 ; 26 : 509 – 515 . 10.1016/0010-4361(95)96808-J . 8

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, Cottu JP , Marinez JJ , et al. Optimisation of cure cycle parameters for a carbon epoxy laminate . 2nd international conference on deformation and fracture composites, Manchester; 1993. p. 29 – 31 . 24

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fragile solid. This result indicates that the reactivity of the secondary amine towards the oxirane group of ECC is very low below 120 °C, and remains low even at 190 °C, leading to a long curing cycle. Since it is not possible to cure at higher

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