HIGH WEIGHT MOLECULAR POLYMERS

Author: CRUZ TEJEDOR M. ANGELES.
Year: 2003.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS QUҍMICAS.
Place of preparation: INSTITUTO DE CIENCIA Y TECNOLOGҍA DE POLҍMEROS,CSIC.

Summary: The membranes have reached an important place within the operations sepaciÃÂ ³ n, and estÃÂ ¡n between systems engineering mÃÂ ¡s important. AdemÃÂ ¡s, nÃÂ eighth mere application and effectiveness of the semipermeable membranes are amplÃÂan each dÃÂa in ÃÂ ¡ significant areas such as purificaciÃÂ ³ No water, industry petroquÃÂmica, the food industry, bioingenierÃÂa, the nuclear industry or obtenciÃÂ charges and recuperaciÃÂ charges of industrial gases. The work is presented estÃÂ It led to the study of new membranes polimÃÂ © rich for separaciÃÂ ³ n gas, with better properties separaciÃÂ ³ n.Para have been synthesized new polÃÂmetros and copolÃÂmetros very stiff chain and high fracciÃÂ charges volume free, have using mixtures of polÃÂmetros commercial pilot and has tested the incorporaciÃÂ ³ n loads inorgÃÂ ¡nicas, carbon and orgÃÂ ¡nicas funcionalizadas.A from these materials have been prepared membranes that have been tested for separaciÃÂ ³ n gas interÃÂ © s industry. By ÃÂ fourth last, have been studied processes compactaciÃÂ ³ n, disminuciÃÂ charges of free volume, which seriously affect the properties of these membranes.

Author: RAMÍREZ GUILLEM ALEJANDRO.
Year: 2004.
University: ALICANTE [www.ua.es].
Place of defense: UNIVERSIDAD DE ALICANTE.
Place of preparation: UNIVERSIDAD DE ALICANTE.

Summary: The thermoplastic adhesives termofusibles are solid at room temperature and liquid when applied. Once melted, apply on the materials that we want to unite and cooling, which happens quickly and without changes in the chemical structure of adhesive joints are obtained high cohesion and very resistant to separation. Although the use of adhesives termofusibles is very old, this technology continues to be dynamic and is constantly growing (in volume, mass manufacture, applications and applications), due in large part to the absence of solvents in its formulation. Although the adhesives termofusibles have great relevance in the industrial world, there are not many studies that relate their formulation and compatibility of its components with their property, mainly the adhesive properties. Adhesives termofusibles are mixtures of three or more ingredients, so the knowledge of compatibility or the miscibility between components of the adhesive mixture is imperative to relate it to their properties viscoelásticas, thermal and adhesive. Compatibility can be defined as the ability of two materials remain fixed on a permanent basis in the absence of segregation phases. The three components used in the manufacture of adhesives termofusibles are the EVA copolymer, hydrocarbon resins (which provide pégajosidad) and waxes, which act as a solvent adhesive cast, control the time and they have opened up a significant influence on the compatibility the mixtures EVA-resina. In this paper, we have used two different content of EVA copolymers of vinyl acetate, eight hydrocarbon resins of different polarity and four different types of waxes, varying amounts of each, to evaluate the effect of the formulation in the properties adhesives termofusibles. As developments in this work were used mainly resins based diciclopentadieno because there are no jobs dedicated to the study of the compatibility between hydrocarbon resins of different polarity and EVA copolymers. In addition, we studied the chemical structure of both natural waxes or synthetic waxes and assessed the effect of adding different waxes to EVA copolymer as the effect of adding these waxes to copolymer EVA-resina hydrocarbon mixtures. The hot tack "is a measure of fa-tack adhesive thermal cut at a temperature close to the minimum temperature of use of adhesive, so their quantification is necessary. One of the main objectives of this work was to develop a new experimental system for the measurement of hot tack "adhesive termofusibles, because there is no literature on virtually references on methods for measurement. Were prepared binary mixtures EVA-resina and EVA-cera, and mixtures temarias EVA-resina-cera through a system of agitation hot. Subsequently both raw materials as binary mixtures and temarias were characterized by their mechanical properties, thermal, rheological, adhesive and compatibility. Finally, we conducted the action 'hot tack "mixes adhesive, and the results related to the properties of these mixtures, especially with compatibility. The polarity and the crystallinity of the different components of mixtures exert a very significant effect on compatibility. The more polar resins compatible with domains of vinyl acetate of EVA, while resins less polar do with domains etilénicos the same, so a low EVA copolymer of vinyl acetate better compatibility with a resin Nature apolar (alifática or cicloalifática) while.

Author: AYALA ALCAIDE VANESA.
Year: 2004.
University: AUTÓNOMA DE MADRID [www.uam.es].
Place of defense: FACULTAD DE CIENCIAS DE LA UNIVERSIDAD AUTÓNOMA DE MADRID.
Place of preparation: INSTITUTO DE CIENCIA Y TECNOLOGÍA ADE POLÍMEROS CSIC..

Summary: The water filtration membranes have gained great importance in the last decade, both for desalination of sea water (reverse osmosis) for separation of solutes larger dissolved in aqueous solutions (micro and ultrafiltration). In these fields, polymeric materials, and within them, the aromatic polyamides have been shown as the best alternative for the manufacture of membranes due to a combination of proper price, ease of synthesis and structural versatility, which could not be reached by any other material. The materials for membrane water treatment must present very high hidrofília necessary to ensure high flows and low ensuciamientos by deposition of solute in the active layer. Therefore, the main objective of this study was to obtain new poliarnidas aromatic that values high water absorption and allow its use in de.separación through membranes. In order to achieve this goal have been obtained with different types of monomers functional groups characterized by their high hidrofília, such as amide group, the group benzimidazole, groups ethers fenal and sulphonic. From these monomers and other business have been synthesized different aromatic polyamides that values high water absorption. Correlations have been established between the structure of the monomers and their chemical reactivity and between the structure of the polymers obtained and their thermal properties, mechanical and solubility and has been guaranteed by X-ray diffraction, which are amorphous polymers, a necessary condition for good permeability of the membrane. We have prepared polymer films successfully in most cases, which has revealed that the materials obtained show good mechanical properties and can withstand high pressures necessary for membrane processes. From films has been studied the water absorption of this material, determining the influence of different functional groups in the uptake and transport of the parameters of water through films. It has also studied the influence of water absorbed in relajaciones and mobility of the polymer chains through studies of dielectric spectroscopy. They have also used methods of investment phase for the preparation of porous asymmetric membranes suitable for ultrafiltration processes. These membranes have been characterized in separation processes of polymers of different molecular weights pattern, determining water flow and molecular weight cut-off of the membranes. Finally, it has become a study on the fouling of the membrane ultrafiltration thanks to a new technique called resonance plasmón surface. This technique gives us information on the accession of different proteins to the surface of the membrane, knowing the possible fouling of the same and its useful life.