http://hdl.handle.net/10016/14126 2013-05-20T09:27:55Z http://hdl.handle.net/10016/16983 Title: Improvement of Ti Processing through Colloidal Techniques Author(s): Garcia Das Neves, Roberto; Escribano, J.A.; Ferrari, Begoña; Gordo Odériz, Elena; Sanchez Herencia, Antonio Javier Abstract: The colloid-chemistry control of metallic powders in aqueous slurries is proposed as a way to prepare Ti powders with small particle size for a better pressing behavior through the spray dry process. The chemical-physic behavior of titanium powders with two different particle size distributions dispersed in water has been studied by measuring the zeta potential as a function of pH, and dispersant concentration. The employment of poly-acrylic dispersants allowed the fabrication of stable slurries with solid contents up to 50 vol% that have been sprayed under different conditions to form agglomerates ranging between 50 and 200 µm. Conditions were selected to achieve spherical agglomerates formed by a broad distribution of particle sizes that shown excellent flowability. Agglomerates were pressed in a uniaxial die to measure the compressibility, showing an improvement in pressing behavior with respect to powders with bigger particle size. The sintering behavior is also improved, as values of 96 % of the theoretical density were obtained for compacts sintered in vacuum at 1100 ºC for 30 minutes. 2012-07-31T22:00:00Z http://hdl.handle.net/10016/16905 Title: Preparation of cycloaliphatic epoxy hybrids with non-conventional amine-curing agent Author(s): González-González, María; Cabanelas Valcárcel, Juan Carlos; Pozuelo de Diego, Javier; Baselga Llido, Juan Abstract: Cycloaliphatic epoxy resin has been successfully thermally cured using a polyamino siloxane oligomer as hardener. The curing reaction was followed by infrared spectroscopy in the near range, and thermal transitions were measured by dynamic mechanical thermal analysis. The use of accelerants and a plasticizer (dodecylphenol), and different curing schedules were explored. Cured materials showed high Tg values (around 125&-164 °C), and the analysis of laser scanning confocal microscopy images showed that they are homogeneous in the microscale. 2011-01-31T23:00:00Z http://hdl.handle.net/10016/16823 Title: Crosslinking of epoxy-polysiloxane system by reactive blending Author(s): González-González, María; Kadlec, Peter; Stepanek, Peter; Strachota, Adam; Matejka, Libor Abstract: (PAMS) containing pendant amino groups and diglycidyl ether of Bisphenol A (DGEBA). The initially immiscible blend is compatibilized during the reaction and crosslinked. Network formation, dynamics of the system and evolution of morphology were determined by dynamic mechanical analysis and light scattering techniques. The grafting epoxy-amine reaction involves a high extent of cyclization resulting in a high fraction of the sol in the networks. Dynamic light scattering data analysis reveals fast and slow relaxation modes of reacting species in the pregel and one single mode in the post-gel state. The network with a stoichiometric composition shows the most homogeneous morphology with a single glass transition temperature. On the contrary, the networks with excess of PAMS are strongly phase-separated exhibiting the unreacted PAMS-rich phase, PAMS phase partly grafted with epoxide and PAMS-DGEBA crosslinked phase. 2004-07-20T22:00:00Z http://hdl.handle.net/10016/14129 Title: Applications of FTIR on Epoxy Resins - Identification, Monitoring the Curing Process, Phase Separation and Water Uptake Author(s): González-González, María; Cabanelas, Juan Carlos; Baselga, Juan 2012-03-31T22:00:00Z