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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Nous termoestables epoxídics modificats amb estructures dendrítiques de tipus hiperramificat i estrella

Morell Bel, Mireia 19 December 2011 (has links)
Aquest treball s'emmarca en el camp dels materials termoestables amb aplicacions com a recobriments o encapsulants per microelectrònica i pretén l'obtenció de materials amb una millor durabilitat i que puguin ser degradats un cop finalitzada la seva vida útil, permetent la recuperació del dispositiu electrònic. L'estratègia escollida s’ha basat en la modificació de la reïna comercial diglicidilèter de bisfenol A (DGEBA) amb estructures dendrítiques de tipus hiperramificat i estrella. Aquesta estratègia permet la introducció de grups ester, tèrmicament làbils així com reduir l'encongiment que es produeix durant el curat. A més, la incorporació d’aquest tipus d’estructures augmenta el volum lliure de la xarxa polimèrica fent augmentar la tenacitat del material sense empitjorar el processat de la mescla reactiva ni les propietats termomecàniques del material. / This work is related to the field of thermosetting materials as coatings or encapsulates for microelectronic devices. The main objective of this project deals with the improvement of durability of a commercial epoxy resin (diglycidylether of bisphenol A, DGEBA) and its capability to be degraded after its working life which let the recuperation of the electronic material, which fulfills the environmental requirements. The approach selected has been the modification of DGEBA by means of dendritic polymer structures such as hyperbranched and multiarm star polymers. This strategy leads to introduce ester groups into the epoxy network which are thermally labile and the reduction of the shrinkage during the curing process. In addition, the free of the epoxy network is increased by the incorporation of these kinds of macromolecular structures which helps increasing toughness without worsening the processability of the reactive formulation and the thermomechanical properties of the resulting thermoset.
2

Regulation of intellectual property rights and trade

Berger, Stefan 16 September 2010 (has links)
This thesis consists of three essays on the regulation of Intellectual Property Rights (IPRs) and trade in open economies. The rst chapter investigates the di erences in Intellectual Property Rights between countries. The analysis of a cross-country panel reveals that the protection of IPRs is higher in countries that are (i) richer, (ii) more productive in R&D and (iii) more open to trade. It is then shown that the rst two facts can be explained in a model where innovations are a global public good and where demand for innovations is non-homothetic in income. The second chapter addresses the third observation. If trade is driven by large di erences in productivities across countries and sectors then having strong IPR protection can become more bene cial for the individual country, since a part of the associated costs are passed onto the trading partners. The third chapter aims to explain why and when countries link agreements on trade with agreements that regulate the provision of global public goods. It shows that a linkage is particularly attractive if countries are di erent in size.

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