ELASTOMERS

Author: NAVARRO BAÑÓN MARÍA VIRTUDES.
Year: 2005.
University: ALICANTE [www.ua.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: LABORATORIO DE ADHESIÓN Y ADHESIVOS, UNIVERSIDAD DE ALICANTE.

Summary: Addressing halogenation usually used in the footwear industry to improve the properties of materials accession to tread rubber polyurethane adhesives. This treatment is based on the implementation of a dissolution of an organic compound of chlorine giver (usually trichloroisocyanuric acid, ICT) in an organic solvent type cetónico or ester (eg methylethylketone, MEK, or ethyl acetate, EA) on the surface material rubber changing the chemistry and morphology of the rubber surface energy and improving, therefore, the properties of his accession versus polyurethane adhesives. However, the substantial toxicity of organic solvents and existing legislation which obliges reduce the emission of VOCs (volatile organic compounds) into the atmosphere has led recently to the need for aqueous polyurethane dispersions used as adhesives for training unions corte-suela in footwear. However, it was still employ solutions clorantes containing organic solvents to make the surface treatment of rubber soles. Therefore, the primary objective that was raised at the time of conducting this study was to obtain eliminate the presence of organic solvents in the completion of treatment halogenation of SBS rubber soles in footwear. It prepared solutions clorantes based ethanol or water of different chlorinated compounds, organic and inorganic, and determined the stability of these solutions, changes introduced in a rubber surface thermoplastic styrene-butadiene - styrene (SBS) is not cured and its impact in the properties of accession. The results showed that aqueous solutions of chloramine T in water acidified with concentrated sulfuric acid, CT/H2O (H +), changes in the chemical, energy and surface morphology rubber SBS and its commitment to improving polyurethane adhesive in an aqueous base, producing values accession similar to those obtained with the system clorante currently used in the shoe industry. Moreover, it also studied the influence of the development of SBS rubbers in the effective treatment of chlorination with CT/H2O (H +). The results showed that treatment in an aqueous base is less aggressive treatment with TCI / MEK, and therefore its effectiveness is influenced by the design of the rubber on which it is applied. The presence of inorganic loads in the formulation of SBS rubbers decreases the degree of surface chemical modification introduced, but the presence of oil on the surfaces of rubber does not seem to influence the superficial changes made, for a value of accession considerably alto.Se analyzed the influence of the nature of the aqueous polyurethane dispersion in the properties of a rubber SBS accession treaty with the system clorante aqueous selected and treated with TCI / MEK. In addition we studied how modifying the properties of adherence to add isocyanate to the aqueous polyurethane dispersion. The results showed that the nature of the aqueous polyurethane dispersion does not affect the values obtained accession probably due to the interaction between the treaty and rubber polyurethane adhesive is sufficiently favorable as to the rheological properties of adhesive are not prevailing accession. Moreover, the addition of isocyanate agent reticulante the aqueous polyurethane dispersion improves the rheological properties of adhesive but this improvement nor inf 8 luye in 399 values obtained for accession joints prepared with rubber treated each system clorantes . In order to determine the mechanism by which there is an improvement of the properties of rubber accession SBS when it is subjected ...

Author: SUAREZ MUÑOZ INMACULADA.
Year: 2005.
University: REY JUAN CARLOS [www.urjc.es].
Place of defense: ESCUELA SUPERIOR DE CIENCIAS EXPERIMENTALES Y TECNOLOGÍA.
Place of preparation: ESCUELA SUPERIOR DE CIENCIAS EXPERIMENTALES Y TECNOLOGÍA.

Summary: This thesis has been developed in the laboratories of the department of environmental chemistry and technology of the King Juan Carlos University in collaboration with the company REPSOL-YPF and financed through a project awarded by the Ministry of Education and Science. The investigation has been to develop a method that allows heterogeneizar system catalytic MAO / Metaloceno, which promotes the use of these catalysts on an industrial scale. This would have investigated various methods among those selected as the best in terms of productivity and morphology of the same polymer obtained anchoring metallocene called by the conventional method. Secondly has developed a polymerization system that has a controlling relationship comonomeros in food in order to obtain copolymers ethylene / propylene with a specific composition and a more homogeneous distribution of comonomero along the chain copolymer . This facility operates on a laboratory scale and discontinuous regime. Finally copolymers were obtained in the full range of compositions using a catalytic system under homogeneous and heterogeneous. The thermal and structural characterization of these copolymers revealed that the method of impregnating selected centers did not change significantly active catalyst.

Author: SAÉZ MARTÍNEZ VIRGINIA.
Year: 2006.
University: PAÍS VASCO [www.ehu.es].
Place of defense: FACULTAD DE CIENCIA Y TECNOLOGÍA.
Place of preparation: FACULTAD DE CINCIA Y TECNOLOGÍA.

Summary: Within the polymers can be chemically modified in order to provide specific properties are hydrogels. These systems are very advantageous compared with more conventional materials, as its absorption capacity of different media can be altered chemically modifying their structure. Although the internal structure is very similar to that of hydrogels, dimensionally the microgeles can be regarded as colloidal particles that typically means presenting diameters between 50 nm and 5 um. These polymers presented by both properties intermediate between their fellow microscopic, hydrogels, and dissolutions coloidades. The microgeles are being used increasingly as systems controlled release of drugs. These may contain reactive groups which like ligands can get the union of these conveyors systems to specific locations or specific types of cells through the presence of surface receptors of these ligands. The microgeles are able to offer a fast response to external stimuli. This sensitivity is due to the presence of functional groups in the polymer chains, which often must be made to those of post-polimerización,. It is known that the areas have a tumor pH more acidic than that of healthy tissues and blood, in this case required microgeles with weakly basic groups that ionicen to vapors acid pH and capable of releasing active substances in areas tumor . Based on these assumptions, this report has preceded the synthesis, characterization and funcionalización chemistry microgeles copolymers size of the nano. The goal is to create a synthetic "intelligent" which is capable of being easily modified for use in various therapies, in this case, has been chosen as the basis therapy against cancer. To do so, after the monomer synthesis based on the NPA whose functional groups are easily replaceable, has been the chemical modification of microgeles with various groups pH-sensibles based pyridine derivatives to facilitate the controlled release of drugs and located in anticancer areas tumor. In addition to this, there have been coupled to the structure of folic acid molecule as a ligand head toward areas tumor, as it is known that tumors presented excess receptors foltao on its surface, which provides the mechanism for capturing "nanoingenio" them.

Author: TRICAS ROSELL NURIA.
Year: 2006.
University: RAMÓN LLULL [www.url.edu].
Place of defense: ESCUELA TECNICA SUPERIOR IQS.
Place of preparation: ESCUELA TECNICA SUPERIOR IQS.

Summary: The present works deals with plasma modification of carbon black (CB). Although this type of treatment is widely used on flat surfaces handling problems should be overcome in order to treat powders as CB. In this study CB has been modified both by means of low-pressure and atmospheric pressure non-equilibrium plasmas. In order to accomplish this objective three different plasma reactors have been set-up; two at low pressure and one at atmospheric pressure working conditions. Low pressure plasma reactors utilised in this work consist in a down-stream and a fluidised bed system working at Radio Frequency generation power (RF 13,56 MHz). Both reactors have been optimized to treat powder materials. For the down-stream reactor, position of the reactive gas inlet, and treatment conditions such as generator power and time have been studied for oxygen, nitrogen and ammonia treatments. For the fluidized bed reactor the distance of the powder sample to the plasma generation zone, particle size and support porosity have been taken into account. Concerning atmospheric plasma, a device has been set up in order to adapt a commercial plasma torch (Openair® from Plasmatreat GmbH), for powder modification. An adaptable reactor, a method to introduce the powder in the plasma zone as well as a collecting system had been developed in order to obtain a quasi-continuous modification treatment. Three types of CBs, N134, XPB 171 and Vulcan XC-72 have been modified in both the down-stream and the atmospheric plasma system. Graphitization and extraction of N134 were also carried out before plasma modification in order to study the effect of both impurities and surface structure of the CB during plasma modification. Surface oxidation and nitrogen enrichment were the two main studied treatments in both systems which allowed comparing their performances. Unmodified and Modified CBs have been characterised from several points of view. Specific surface area, XRD, WAXS and STM have been used in order to study morphological and surface structure changes. On the other hand, pH measurements, acid/base titration and XPS were employed in order to study the surface chemistry composition changes that had taken place during plasma modification. Some of the modified CB grades were selected in order to be tested in final applications such as rubber reinforcement and oxygen reduction non-noble metal catalyst for PEMFC. In the first case, the effect of atmospheric plasma treatment on the vulcanization kinetics and mechanism has been evaluated both by rheometre curves and the model compounding approach. Studies about the polymer-filler interaction have been also carried out by calculating bound rubber and adsorption from polymer solution. Last but not least, plasma modification capacity to enhance the oxygen reduction activity to obtain non-noble metal catalysts for PEMFC has been evaluated after the correspondent preparation. Oxygen reduction activity has been studied by means of cyclic voltammetry. The main CB properties which could play an important role in such applications have been analyzed.