COMPOUND POLYMER

Author: SIERRA MUÑETON JUAN DIEGO.
Year: 2004.
University: PAÍS VASCO [www.ehu.es].
Place of defense: FACULTAD DE CIENCIA Y TECNOLOGIA.
Place of preparation: CIENCIA Y TECNOLOGIA.

Summary: The present investigation was forumló one-dimensional mathematical model that allows simulate spinning fibers from molten material, based on the basic equations of transport phenomena, namely: continuity equation, equation of time and energy equation. The above equation must be complemented by constitutive equations and a model for crystallization kinetics. Particularly in this investigation were used rheological two models: a Newtonian and another viscoelástico (Phan Thien and Tanner in several ways). As for the model to describe the crystallization kinetics exemplifies a model Nakamura, whose constant speed can be estimated with correlations proposed by Ziabicki and Lauritzen and Hoffman. It also makes use of some correlations to calculate the coefficient of drag with the air, the ratio of convection heat; dependence of viscosity with temperature and the degree of crystallization, and surface tension. To solve the coupled system of differential equations that constitute the model of the spinning of fibers, a numerical discretizando the implementation of the system in finite difference equations and using the shooting and two solution algorithms, a method Runge-Kutta of order 6 and a method Crank-Nicholson. In the spirit of making a validation of the model and implemented to evaluate the properties and morphology that is obtained in the fibers biconstituidas made from blends of polypropylene and polyamide 6, a test in a line of spinning laboratory and an extensive morphological characterization mechanics and fibers. A characterization reológica of individual polymers and blends, allowed estimating the model parameters for rheological models and also see some interesting anomalies in the form and dynamic viscosity of the mixture. The results of the validation indicate that the simulation program adequately reproduce the experimental results and simulations of spinning by other researchers. The model reproduces quite well the experimental data in diameter fiber obtained in this investigation, particularly if using a model viscoelástico George and the correlation coefficient for the convection of heat. The predictions are correct final effort with the experimental measurements.

Author: LARRAÑAGA ANTIA MAIDER.
Year: 2004.
University: PAÍS VASCO [www.ehu.es].
Place of defense: ESCUELA UNIVERSITARIA POLITÉCNICA DE SAN SEBASTIÁN.
Place of preparation: E.U. POLITÉCNICA DONOSTIA-SAN SEBASTIAN.

Summary: The morphologies and control structures of nanoscale is having considerable attention in several technologies. Due to the miniaturization of electronics, optoelectronic and magnetic has become very important to obtain molds at the nano-scale. One way of obtaining structures nanoseparadas is the use of block copolymers. Moreover epoxy resins are among the polymeric materials are widely used at present. Notably modified epoxy systems with block copolymers, where he was principal objective is to obtain structures nanoseparadas improving or maintaining the mechanical properties. This work has two main objectives. On the one hand, show that the generation of structures nanoseparadas is a function not only of the building blocks of copolymers but also various physicochemical aspects involved in the process of curing epoxy resin. Thus, the effect has been studied in different morphologies and mechanical properties of the kinetic and thermodynamic aspects of the systems diglicidileter of bisphenol A (DGEBA) / diamino diphenyl methane (DDM) modified copolymers tribloqueo PEO-PPO-PEO, which differ the molar ratio PEO: PPO, both varying percentages copolymer as curing conditions. . For the analysis of this system has taken into account the behavior of the thermoplastic epoxy-modified poly (methyl methacrylate).

Author: Subiela Valls Josep Ramon.
Year: 2005.
University: VALENCIA [www.uv.es].
Place of defense: Facultat de Química.
Place of preparation: Facultat de Química.

Summary: The innovation in the industry and the production of new materials brings with it the need to develop new techniques and measurement methods to characterize the properties of these products. These techniques and methods must meet a number of requirements. They must be simple and easy to use, without requiring purchase much theoretical knowledge to use. Flexibility is another characteristic desired, ie the technique should be used for various types of testing or they are adapted to new needs is not complicated. Of course the results must be quantitative, reproducible and reliable. And all this must be accomplished with a price content of instrumental and assembly technology. In the field of measurement of electrical properties of materials can be found in various market instruments with which measurements: bridge impedances, conductímetros, multimeters, teams unloading potential team impedanciasâ | A computer analysis impedances complete rises quite the budget because it is composed of a series of high price components: a potenciostato and signal generator, a frequency analyzer and a personal computer with specific software for impedances. Furthermore, the study and analysis of the results, as well as the manipulation of the technical set-up and use of the software is fairly complicated. Therefore, despite being a very versatile and powerful technique to characterize when electrical properties of the material, is not a suitable tool for use in industry, but for research at universities and research centers. The teams download applied potential high potential for a sample to break the dielectric, obtaining the value at which the sample becomes conductive. This may give an idea of how much or little driver who is the material, but does not provide direct information about the value of the conductivity of the sample. Moreover, although these teams are not particularly expensive, it does require special electrical wiring and are not versatile. The continuous flow meters used to measure the resistance of the samples. In highly conductive materials with the potential difference applied is sufficient to characterize the resistance of the sample, but in low conductivity materials with the use of alternating current is recommended by most allow better characterization of the material because of their behavior as dielectric. The conductivity operates with alternating current low amplitude, with potential for up to 6V (depending on model), but the frequency of the flow can not be changed and not very high (3.8 kHz). Instead, the bridge allows impedances vary the frequency of the alternating current reaching 100 kHz (also depending on the model), current amplitude in several volts, and the applied potential (through an external potenciostato) all of a a simple, fast and intuitive. It also provides more complete information on the electrical properties of the material under consideration, not limited only to show resistance values, but also to characterize the capacitive component of the material. Its configuration possibilities (potential amplitude and frequency) allow you to characterize many types of samples, materials with resistance from virtually zero to a few hundred megaohms (M). As a final advantage of the price bridge is impedances along with the multimeter and the conductivity, the lowest of the tools mentioned above. After eval 8 uar the e23 different solutions market has been selected impedances of the bridge and its applicability has been studied as a technique for characterizing systems "composite" drivers in the industry. Systems employees have been a "composite" in liquid phase, a "composite" in binary solid phase and a "composite" in ternary solid phase. The "composite" in liquid phase has consisted of a painting of aluminum which has been scattered three different formulations of aluminum paint on a commercial basis. By impedances of the bridge has been obtained information on the conductivity and the process of electrical conduction in each of the formulations at various concentrations. Furthermore, the results obtained with the bridge impedances have helped develop a quantitative method for determining the amount of loading and a method for distinguishing between different formulations of aluminum. With a "composite" binary solid, consisting of zinc powder scattered on EVA copolymer (etilenvinilacetato) in amounts from 10 to 75% by weight zinc has been applied bridge impedances as a technique for the determination of the percolation threshold , to develop a methodology that ensures good contact between the samples and the connection terminals bridge impedances. The electrical properties are compared with the mechanical properties of materials (obtained in Section Departmental the College of Engineering from Bucharest, the Department of Mechanical Engineering and Materials of the Polytechnic University of Valencia). It has also been proposed use of a commercial scanner connected to a PC as a method of obtaining images from the surface of samples for optical characterization, comparing their results with those obtained by diffraction RX. Lastly, he has studied how it affects the electrical and mechanical properties chemical degradation of the material, which has been simulated corrosion of the material through an acid attack. Once developed the method of measurement, the impedances bridge has been used to characterize three systems "composite" ternary based on the dispersion of metal burdens on the basis of polypropylene + graphite at the same time has been improved contact between connectors with the samples. Charges have been metallic aluminum powder, powdered zinc and nickel powder in proportion 50% PP, 40% graphite and 10% metal (percentage by weight). The electrical characterization of materials has been extended to the use of other techniques such as electrochemical cyclic voltammetry, cronopotenciometría and cronoamperometría, which has developed a manual assembly and use equipment with simple, low cost. It has also been proposed as a method for sanding of the surface reclamation and reuse of the electrodes based on these materials.

Author: OCHOA MENDOZA ALMUDENA.
Year: 2005.
University: POLITÉCNICA DE MADRID [www.upm.es].
Place of defense: E.T.S. ING. INDUSTRIALES.
Place of preparation: E.T.S. ING. INDUSTRIALES.

Summary: The headline goal of this research work is to improve the properties of composite materials matrix Polyolefin (polyethylene and polypropylene) reinforced with fibers of natural origin (mainly forest origin), by identifying the influence of its membership (formulation) and their processing conditions (referred to the process of collection, processing and recycling) on its overall structure and the study of its recyclability. The thesis is divided into three distinct blocks: R BLOCK: In this initial phase is studied the effect of mechanical recycling by injection into the rheological properties of composite materials matrix polyethylene or polypropylene reinforced with different percentages of reinforcing fibers kraft pulp residualesdel process. We studied the rheological properties of the original materials (not recycled) materials and subjected to five cycles of mechanical recycling by injection. Finally, as compared rheological properties have evolved from the original materials (not recycled) to be recycled and analyzes the data statistically to treat and remove equations rheological behavior. The purpose of this block is to select what is most appropriate thermoplastic matrix to formulate some definitive composite materials presenting better results compared to recycling. BLOCK II: Once selected, the matrix of thermoplastic composite material definitive must choose the most appropriate formulation of the remaining components of the composite material. Therefore, we have to find out what percentage of reinforcement is the most appropriate considering that in some cases use a fixed amount of agent coupling (1.5%) and others will not be added to the formulations coupling agent. To achieve the objective looks at the rheological properties of composite materials reinforced with polypropylene fibers of cellulose with different percentages of reinforcement in its formulation, percentages ranging from 30, 40 and 50 percent by weight of total composite material. BLOCK III: Once selected matrix (Selection Block I), the percentage of reinforcement, the use or absence of coupling agent and the optimal processing conditions (Selection BLOCK II), we arrive at a formulation of composite material in according to the results obtained previously. At this point, what is of interest is to study the properties of the material compound (not recycled), and its behavior mechanical recycling by injection. To ensure the full study on the most appropriate design, chosen as a percentage of cellulose fibers that examines treatment of fibers provides better results in property values compared to recycling, so that this studied the properties of two materials like design, reinforced with fibers of cellulose bleached pulp for crude elected, but in one case with bleached cellulose fibers undergone treatment and refining in the other case were used unrefined bleached fibers. The purpose of employment or not this treatment is included in the study the influence of the chemical composition of the fiber on the quality of the composite material.

Author: EXPÓSITO ESPINOSA MARIA TERESA.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS QUÍMICAS.
Place of preparation: FACULTAD DE CIENCIAS QUÍMICAS.

Summary: The development of polymers is a major advancement in the materials industry everyday use. The preparation of these materials are required, particularly in the case of polyolefins, the use of catalytic systems that have evolved gradually along with the need for the development of new polymeric materials. The design of new catalysts whose catalytic properties are better, is a great challenge because of the need by the industry, to obtain new materials with certain properties, whether chemical, mechanical or electronic, and to facilitate the processability or compatibility with various additives. Moreover, the development of new catalysts for active together has enabled the control of the structure of copolymers based olefínica with the aim that it is homogeneous. This is very important since it allows the systematic study of the relationship between molecular architecture and physicochemical properties of the polymer from a more basic. In memory of this thesis presents the results of the study of the synthesis of copolymers of ethylene / styrene using various kinds of metallocene catalysts, geometry forced and post-metaloceno (all of them active only). It has studied the effect of the chemical structure of the catalyst on parameters such as the catalytic activity, the content comonómero incorporated into the copolymer and the chemical structure of the copolymer. It also has studied the relationship structure molecular-propiedades physical, such as the impact of content comonómero on the merger processes, glass transition, as well as on mechanical and rheological properties. Finally, as a possible solution to the problem presented by polyolefins obtained by catalytic active only in relation to their processability, has done a study that concluded the presence of small amounts of high molecular weight polyethylene lead to eliminate the distortions in the trial.

Author: MENKIKUTE FIERRO GORKA.
Year: 2005.
University: PAÍS VASCO [www.ehu.es].
Place of defense: FACULTAD DE QUÍMICAS.
Place of preparation: FACULTAD DE QUÍMICAS.

Summary: The thesis deals with the relationship structure properties of poliuiretanos segmented. It segmented polyurethane synthesized using MDI and TDI as diisocyanates, Polipropilenglicol and Politetrametilenglicol molecular weight 2000 and 425 g / mol as polyols and extendedores chain Butanodiol, Butilen diamina and Ethylene diamina. With these materials were obtained polyurethanes in the same chemical composition and different percentage of segment rigid. Since blocks segment rigid and flexible are only partially miscible a study of the interaction between these two segments. The size of the blocks is determined by the molecular weight of polyol and percentage of segment rigid. The survey results indicated that the block size segment rigid as flexible influence of the interaction between them and miscibility and thus affect the properties of polyurethane end. In recent years there has been an increasing use of laminated silicate as a reinforcement of polymeric materials, which studied the effect of these materials on polyurethane matrix. Characterization of the structure revealed that the clay is intercalaban in the polymer matrix, causing an increase in the Young modulus, the greater the lower was the form of the matrix. It is well known that aromatic polyurethanes are very sensitive to ultraviolet radiation, so it seemed appropriate to establish a relationship between the stability of these materials with the percentage of segment rigid and molecular weight of polyol. The results indicated that the resistance fotooxidativa increases with the percentage of segment rigid and decrease the molecular weight of the polyol. However, in the case of systems poly (urea-uretanos) s stability is virtually independent of the percentage of segment rigid. Finally, the Termogravimetría (TGA) showed that the MDI-based polyurethanes have a mechanism of mass loss in three stages regardless of size block segment rigid besides leaving residue, while those based on TDI, the mechanism depends on the size of block segment rigid.

Author: JUANES GARCIA FRANCISCO JAVIER.
Year: 2005.
University: PAÍS VASCO [www.ehu.es].
Place of defense: ESCUELA UNIV. DE INGENIERÍA TÉCNICA INDUSTRIAL.
Place of preparation: E.T.S.I.I Y TELECOMUNICACIONES DE BILBAO.

Summary: In the Doctoral Thesis arises, first, a study of mechanical behavior of a system composed based on epoxy resin tetrafuncional TGDDM cured with amine, -PDA and charged with various proportions of calcium carbonate particles of various sizes on the order micrometer. This study provides a preliminary phase characterization using analytical techniques chemoreológico and FT-IR of reactive systems and a later stage of implementation and interpretation of standardized testing of composite materials late in flexion, understanding, impact and fracture analysis termodinámicomecánico. Second is facing the adhesive function of these materials from the point of view of the accession structural. Taking the most significant compositions of the above study examines the influence of the consolidation of the charges in the adhesive properties of the resin allowing establish optimal conditions according to the particle size and percentage incorporated. The study is complemented by an analysis of degradation in films like adhesive material together with adhesive visual inspection of adherents for determining the type of break in simulated conditions of high humidity saline. Thirdly and finally analyzes simulated on standardized tests conducted in the first phase with composite materials, modeling various test tubes, razonadamente choosing the most appropriate finite elements, as well as the criteria for mesh generation. It establishes restrictions on movement and loads acomodándolas as close as possible to actual behavior. Finally set different proposals vary any of the above parameters seeking greater approximation to the actual data.

Author: ARBELAIZ GARMENDIA AITOR.
Year: 2005.
University: PAÍS VASCO [www.ehu.es].
Place of defense: ESCUELA UNIVERSITARIA POLITÉCNICA DE DONOSTIA.
Place of preparation: ESCUELA TÉCNICA SUPERIOR DE INGENIERÍA DE BILBAO.

Summary: The main objective of the research work carried out in this thesis has been studying the viability of composites based on natural fibers and biodegradable thermoplastic matrices. The nature hidrofílica of natural fibers and the hydrophobic matrices leads to poor compatibility. In order to improve compatibility between fiber and flax hydrophobic matrices have been made several changes on the surface d read fiber and the matrix. It has studied the impact of changes in the properties of fiber in the interface fiber / matrix, as well as the properties of composites. Since the properties of the composites based on polypropylene and policaprolactona depend on the crystallization, has studied the crystallization process of the composite in general, as well as the interface fiber / matrix.

Author: RAMIRO MANJARRES JORGE.
Year: 2005.
University: PAÍS VASCO [www.ehu.es].
Place of defense: FACULTAD DE QUIMICAS.
Place of preparation: UNVIERSIDAD DEL PAÍS VASCO.

Summary: This paper aims to be a contribution to the understanding and development of polymer blends, focusing on the study of systems composed of the poly (ether imide), one of the few generic engineering resins or high performance introduced in the market since the decade of the 80. The poly (ether imide) introduced major drawbacks as a limited processability and a relatively high cost. Therefore, this polymer has been mixed in this work with a range of engineering polymers and high performance (poly (trimetilén terftalato), polycarbonate, polyamide polysulphones and amorphous), in order to reduce the cost and sometimes improve processability polymer base, trying to maintain an excellent balance of properties that this polymer presents. The study of different mixtures has been addressed since you view the behavior of phases and the miscibility, including analysis of their morphology in the development and deepening of the relationship between structure generated during processing and the resulting mechanical properties.

Author: CANJURA URRUTIA ORLANDO.
Year: 2005.
University: PAÍS VASCO [www.ehu.es].
Place of defense: CIENCIA Y TECNOLOGÍA.
Place of preparation: CIENCIA Y TECNOLOGÍA.

Summary: There were various hydrogels synthesized using comonómeros monoitaconato Butyl (n-, iso, sec and terc-) and acrylamide in order to study the influence of isomería the first one in the properties and swelling kinetics, release medication and various network parameters of the material. In the latter we find modules Yopung and compression, as well as the molecular weight between interleavings, and the density of intersecting effective, and the parameters of interaction polímero-disolvente. In all these parameters, the effect of isomería of comonómero monoitaconato butyl, has been very important. It has been found that depending on the isomer used all their properties vary quite sharply from the isomer iso to terc-. It has also studied the kinetics of the swelling, indicating that follows a first order kinetics. It has been found that apparent diffusion mechanism water is a no-Fickiano or anomalous. There have also been compared in hydrogels synthesized mechanisms for the dissemination of two drugs: theophylline and aminophylline, found significant differences in the processes of liberation.

Author: VERA MAIQUEZ MONTSERRAT.
Year: 2006.
University: POLITÉCNICA DE CATALUÑA [www.upc.edu].
Place of defense: Aula d'Audiovisuals del Dept. d'Enginyeria Química.
Place of preparation: ETSEIB, PAVELLÓ G Campus SUD.

Summary: The general goal of the present work is the development of new poly(ester amide)s with potential applications in the biomedical field. In this thesis the preparation and characterization of two new families of biodegradable poly(ester amide)s are studied. In this way, a new synthesis method based on a thermal polycondensation with formation of a metal halide salt as a driving force has been developed. The first studied family of polymers is constituted by alternating poly(ester amide)s derived from glycolic acid and ù-amino acids. The second group includes sequential poly(ester amide)s constituted by glycolic acid, diamines and dicarboxylic acid units. Lysine was also considered as a possible diamine, since it may bring functionalized lateral groups that enhances the potential applicability of the resulting polymer. An alternative synthesis route for the second series has also been applied according to the procedure previously described in the literature. The synthesis results have been compared as well as some properties of the final polymers. It is worth to indicate that the new methodology based on the thermal polycondensation is easier, cheaper and avoids the use of toxic solvents. Furthermore, polymerization yields are high and final polymers show film and fibre forming properties. A particular feature of this new methodology is that a composite formed by a mixture of polymer and inorganic salt crystals is directly obtained from the synthesis process. Those crystals may be subsequently washed out, leaving a porous material with potential interest for applications in tissue engineering. All the products obtained through the different synthetic routes have been identified by means of nuclear magnetic resonance and infrared spectroscopy. Furthermore, the kinetics of the thermal polycondensation reaction and the thermal properties of the final products have been studied employing differential scanning calorimetry and thermogravimetric analysis. Hydrolytic degradation studies have been performed at different temperatures and pH conditions. Enzymatic degradation has also been evaluated by using different kinds of enzymes. Scanning electron microscopy has allowed discard autocatalytic phenomena in the degradation process of the studied samples.