Sofia F. Rocha and Beatriz Delgado graduate with a M.Sc.
Congratulations to Sofia and Beatriz who graduated, in Nov-Dec. 2018, with the following M.Sc. theses:
"Polymer coating of capsules for controlled release", by Sofia F. Rocha. Supervised by Ana C. Marques and Jorge Oliveira, in collaboration with University College Cork
Abstract: The objective of this thesis is the microencapsulation and protection of highly reactive isocyanate based cross-linkers to be used in onecomponent adhesive formulations for the footwear industry, aiming to eliminate the hazards related to isocyanate handling by product manufacturers. The methodology employed in this work is microencapsulation resourcing to microemulsion combined with interfacial polymerization for the synthesis of microcapsules containing unreacted isocyanate as core material in a polyurethane (PU)/ polyurea (PUA) or PU/PUA-silica hybrid shell. Several studies were performed in order to determine the effect of changing active hydrogen source and concentration, synthesis temperature and duration, on the microcapsules encapsulation yield. Peeling strength tests were performed at different temperatures to evaluate the microcapsules core release and its effect on the adhesive strength of the glue base used in footwear industries. The synthesis process was scaled-up and the differences in terms of the resulting microcapsules morphology, encapsulation yield and size distribution were analysed. To increase the microcapsules shelf-life, top spray fluidized-bed coating techniques were employed to reduce the registered loss of core material over time due to the permeability of the microcapsules shell to moisture in the air. The Taguchi method for Design of Experiments (DoE) was executed. The selected microcapsules were subjected to coating and the critical operation parameters were determined based on the responses defined for the system as size distribution, bulk and tapped density and encapsulation yield.
"Preparation and characterization of composite systems Pluronic F127/water/polycaprolactone microspheres", by Beatriz Delgado. Supervised by Teresa Cidade and Ana C. Marques
Abstract: In this dissertation, a composite system composed of Pluronic F127 / water / microspheres of poly (e-caprolactone) (PCL) was developed with the aim of developing an injectable system for tissue repair capable of presenting two different rates of drug release (drug and growth factor, for example, or any other combination). In the first step, PCL microspheres containing an aqueous solution of methylene blue (in substitution of the drug, for release studies) were prepared by the double emulsion method (water W1/ oil O / water W2), combined with solvent evaporation. In parallel, the Pluronic F127/water system was characterized. In the second step the composite system was produced. Its rheological behavior and methylene blue release, at a pH of 7.4 and at 37 C were evaluated. To perform the analysis of the release profiles, mathematical models adapted to this system were used. The composite system Pluronic F127/water/PCL microspheres, developed in this work, is herein shown to be promising as an injectable system with two different drug release rates, for tissue regeneration.