Absorption-stripping with aqueous, concentrated piperazine (PZ) is a viable retrofit technology for post-combustion CO2 capture from coal-fired power plants. The rate of thermal degradation and oxidation of PZ was investigated over a range of temperature, CO2 loading, and PZ concentration. At 135 to 175 °C, degradation is first order in PZ with an activation energy of 183.5 kJ/mole. At 150 °C, the first order rate constant, k1, for thermal degradation of 8 m PZ with 0.3 mol CO2/mol alkalinity is 6.12 × 10-9 s-1. After 20 weeks of degradation at 165 °C, 74% and 63%, respectively, of the nitrogen and carbon lost in the form of PZ and CO2 was recovered in quantifiable degradation products. N-formylpiperazine, ammonium, and N-(2-aminoethyl) piperazine account for 57% and 45% of nitrogen and carbon lost, respectively. Thermal degradation of PZ likely proceeds through SN2 substitution reactions. In the suspected first step of the mechanism, 1-[2-[(2-aminoethyl) amino]ethyl] PZ is formed from a ring opening SN2 reaction of PZ with H+PZ. Formate was found to be generated during thermal degradation from CO2 or CO2-containing molecules. An analysis of k1 values was applied to a variety of amines screened for thermal stability in order to predict a maximum recommended stripper temperature. Morpholine, piperidine, PZ, and PZ derivatives were found to be the most stable with an allowable stripper temperature above 160 °C. Long-chain alkyl amines or alkanolamines such as N-(2-hydroxyethyl)ethylenediamine and diethanolamine were found to be the most unstable with an allowable stripper temperature below 120 °C. Iron (Fe2+) and stainless steel metals (Fe2+, Ni2+, and Cr3+) were found to be only weak catalysts for oxidation of PZ, while oxidation was rapidly catalyzed by copper (Cu2+). In a system with Fe2+ or SSM, 5 kPa O2 in the inlet flue gas, a 55 °C absorber, and one-third residence time with O2, the maximum loss rate of PZ is expected to 0.23 mol PZ/kg solvent in one year of operation. Under the same conditions but with Cu2+ present, the loss rate of PZ is predicted to be 1.23 mole PZ/kg solvent in one year of operation. Inhibitor A was found to be effective at decreasing PZ loss catalyzed by Cu2+. Ethylenediamine, carboxylate ions, and amides were the only identified oxidation products. Total organic carbon analysis and overall mass balances indicate a large concentration of unidentified oxidation products. / text

Piezoelectric materials have numerous applications like high temperature accelerometers, pressure, flow and NDT transducers, acoustic emission, ultrasonic cleaning, welding, high voltage generators, medical therapy etc. The commonly used piezoelectric material, PZT continues to dominate the commercial market for piezoelectric actuators applications. The primary limitations of PZT are the lower Curie temperature TC <390oC and rapid thermal degradation avobe 200oC. Continuing efforts are focused on the development of piezoelectric materials suitable for high temperature applications >200oC. These materials will be very useful for making sensors for space exploration, oil and geothermal well drilling tools, oil & gas pipeline health monitoring and automotive smart brakes. Recently material based on (1-x)Bi(Me)O3-xPbTiO3 developed with TC~460oC, and d33~500 pC/N compared to TC~390oC and d33~220 pC/N of pure PZT. Enhanced room temperature properties and higher transition temperature makes this material interesting for further investigation as a high temperature piezoelectric material. Reliability of technological piezoelectric devices is a major concern for their applications. Many piezoelectric materials undergo a process of aging, associated with a spontaneous decrease of electromechanical properties. In the current work thermal degradation and aging behavior of high temperature piezoelectric material BSPT was evaluated and compared with the commonly used PZT.

No description available.

ABSTRACT CHARACTERIZATION OF CONDUCTING POLYMERS OF ESTER LINKAGE CONTAINING THIOPHENE DERIVATIVES VIA MASS SPECTROSCOPY Aslan, Evren M.Sc., Department of Chemistry Supervisor: Prof. Dr. Levent Toppare Co-Supervisor: Prof.Dr. Jale Hacaloglu December 2004, 86 pages In order to investigate the thermal and structural characteristics of terepthalic acid bis-(2-thiophen-3-yl-ethyl)ester (TATE), decanedioic acid bis-(2-thiophen-3-yl- ethyl) ester (DATE) and octanoic acid 2-thiophen-3-yl-ethyl ester (OTE), their corresponding homopolymers, copolymers with thiophene and polythiophene, pyrolysis mass spectrometry technique was utilized. The results were discussed in detail considering the effects of spacer group in between ester linkages. Thermal Gravimetry Analysis was used to investigate the weight loss for polymers and monomers. Conductivities of samples were measured by four-probe technique. It was found that when the ester linkages contain hydrocarbon chains, the growth of polymer occurred through both 2 and 5 positions. On the other hand, when the ester linkages contain more rigid groups such as phenyl, steric hindrance inhibited the growth of the polymer through 2- position and polymerization proceeded via coupling of thiophene moieties mainly at 5-position yielding a polymer with lower conductivity. Though the structure of P(OTE) is inherently different than P(DATE) and P(TATE) extent of network structure is also quite low for this polymer compared to PTh. Similar thermal characterizations were recorded indicating that thermal units were not significantly affected by the presence of TATE, DATE or OTE for all copolymer samples.

Orientador: Lúcia Helena Innocentini Mei / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-16T13:24:11Z (GMT). No. of bitstreams: 1 Carvalho_JoseWilsonCamilher_D.pdf: 2648911 bytes, checksum: a24c06cac0abecd9825f4e073f262762 (MD5) Previous issue date: 2010 / Resumo: É apresentada a preparação e a caracterização de nanocompósitos, produzidos a partir da vermiculita e poliolefinas funcionalizadas como matriz polimérica. As poliolefinas foram representadas pelo polietileno de baixa densidade (PEBD) e o polietileno de baixa densidade linear (PEBDL), utilizadas com e sem o anidrido maleico. A vermiculita de origem nacional foi escolhida como fase inorgânica na preparação dos nanocompósitos, devido a sua abundância e o seu baixo custo associado. A interação das matrizes poliolefínicas com a vermiculita foi facilitada pela utilização de agentes de acoplamento, baseados em compostos de amônio, cujos efeitos sobre as propriedades de barreira, ao oxigênio, à umidade, e de retardância de chama dos compostos obtidos são relatados. Foi utilizada como ferramenta de análise a Espectroscopia de Infravermelho com transformada de Fourier (FTIR), para o acompanhamento e caracterização do processo de síntese das organo-vermiculitas. A Difração de Raio X (DRX) foi utilizada tanto para a análise do minério de vermiculita como recebido, quanto para a caracterização dos nanocompósitos utilizando as vermiculitas modificadas com os agentes de acoplamento. Os resultados foram confirmados com a utilização da Microscopia Eletrônica de Transmissão (MET) e a Microscopia Eletrônica de Varredura (MEV), com auxílio da técnica de feixe de íons (FIB). Essas técnicas confirmaram a obtenção de compostos esfoliados, evidenciando a eficiência dos agentes de acoplamento no processo de obtenção dos nanocompósitos, previamente analisados via DRX. A estrutura esfoliada dos compostos obtidos permitiu que fossem conduzidos testes sobre a sua capacidade de barreira ao oxigênio e a umidade, cujos resultados promissores mostraram a possibilidade de serem utilizados como materiais de embalagem. Da mesma forma, a característica esfoliada destes materiais possibilitou o desenvolvimento de testes para o atendimento da área de fios e cabos como isolamento e cobertura de cabos. Com este objetivo, foram analisados os requisitos de retardância de chama e ao aumento da temperatura de degradação, fundamental à preservação da integridade dos cabos durante o ataque das chamas. Este trabalho apresentou de maneira pioneira o processo de produção e utilização da vermiculita nacional, na obtenção de nanocompósitos, desde minério bruto até o produto final e a sua aplicação em casos reais / Abstract: The preparation and characterization of nanocomposites made from vermiculite and functionalized polyolefins as a polymeric matrix is presented. Polyolefins are represented by low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE), used with and without maleic anhydride. Vermiculite from a national origin was chosen as an inorganic phase in the nanocomposite preparation, due to its abundance and low cost. The interaction of the polyolefin matrixes with the vermiculite was facilitated using coupling agents. The coupling agents used were represented by the ammonium compounds and their effects were reported in the barrier properties to oxygen, humidity and in flame retardance in the produced compounds. As a nanocomposite analysis tool, Fourrier transformed infrared spectroscopy (FTIR) techniques were used, mainly in following and characterizing the organo-vermiculite process. X-ray diffraction (XRD) was used from the analysis of the vermiculite as received to the nanocomposite characterization using coupling agents. These results were confirmed using the transmission electronic microscopy (TEM) and scanning electronic microscopy (SEM), using focused ion beam (FIB), as well. These techniques confirmed the obtainment of exfoliated compounds that reinforced the coupling agents in the nanocomposite obtainment process, previously analyzed by XRD. The exfolied structure of the compounds obtained allowed for barrier-capacity tests. The nanocomposites tested as an oxygen and humidity barrier showed the possibility of being used as packaging materials due to the promising results presented. Likewise, the exfoliated characteristic of these materials enabled the development of tests to meet the needs of the wire and cable area as insulation and cable jacketing. Within this objective, there was the need to focus on the flame retardance requirements and the increase of the degradation temperature, crucial to preserve cable integrity during the flame attack. This work presents, in a pioneering manner, a revision of the production process and utilization of national vermiculite in obtaining the nanocomposite, from its ore to the final product and its application in real cases / Doutorado / Ciencia e Tecnologia de Materiais / Doutor em Engenharia Química

Orientador: Inés Joekes / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-19T10:48:43Z (GMT). No. of bitstreams: 1 Richena_Marina_M.pdf: 1581549 bytes, checksum: cea715827b6e69afa186bff163d1c821 (MD5) Previous issue date: 2011 / Resumo: O cabelo branco se torna amarelo com o tempo, apesar de não possuir melanina, o pigmento responsável pela coloração. Este amarelecimento gera insatisfação nas pessoas. Neste trabalho estudamos em profundidade as mudanças de cor e as propriedades mecânicas do cabelo branco após exposição ao UV, Vis e IV, e os fatores que afetam o amarelecimento, incluindo descoloração com H2O2 e a presença de umidade, e tentamos identificar os cromóforos amarelos. Usamos cabelos brancos de dois tipos: cabelo padrão (blenda de várias cabeças), mais amarelado (valor da coordenada de azul-amarelo, b* = 20), e cabelo comum (cabelo de uma cabeça), menos amarelo (b* = 10). Os resultados mostram que a coloração inicial interfere no comportamento frente à exposição ao UV - Vis: após exposição numa lâmpada de mercúrio por cerca de 200 h, o cabelo padrâo desamarela (Db* = - 6), e o cabelo comum amarela (Db* = 2). Entretanto, quando o cabelo padrâo é descolorido com H2O2 (b* = 8), amarela após poucas horas de irradiação (Db* = 3). Expondo apenas ao Vis ocorre desamarelecimento, independentemente da coloração inicial, tanto no cabelo padrão (Db* = - 9), quanto no cabelo comum (Db* = - 3). Os resultados de variação de cor do cabelo branco exposto ao sol concordam com os resultados de exposição à lâmpada de mercúrio. Já a radiação IV na temperatura de 81°C amarela tanto o cabelo branco comum (Db* = 9), quanto o cabelo branco padrão (Db* = 3). O cabelo padrão irradiado em 100% de umidade relativa não mostra variação de cor após 88 h de irradiação. Além disso, o cabelo que foi irradiado, mas lavado com solução de lauril sulfato de sódio após cada período de irradiação, manteve o valor de Db*. O cabelo não lavado continuou menos amarelo após a armazenagem; entretanto, um amarelecimento (Db* > 1,5) foi observado após 1 ano. A única alteração significativa observada nas propriedades mecânicas foi a redução da tensão máxima em 17% depois de 480 h de exposição ao Vis da lâmpada. Medidas de absorbância no UV - Vis de soluções de cabelo branco com diferentes tonalidades de amarelo mostram absorção em toda a faixa do visível, comportamento decorrente do amarelecimento. Há ainda a formação de uma banda forte em 320 nm após irradiação UV. Contrariamente ao mostrado na literatura de lã, que também é uma estrutura formada por queratina, esta banda não está relacionada com a formação dos cromóforos amarelos. Demonstramos que o amarelecimento inicial do cabelo é um fator determinante na sua variação de cor após irradiação UV e que este amarelecimento é decorrente da ação do calor. Ademais, após a irradiação são formados radicais livres responsáveis pelas reações de degradação no escuro, em que a água tem um papel importante na desativação destes radicais / Abstract: White hair turns yellow after time, but it has no melanin, the pigment responsible for hair color. This yellowing upsets people. In this work we study in depth the color changes and mechanical properties in white hair after exposure to UV, Vis and IR, and the factors that effect the yellowing, including bleaching with H2O2 and the presence of moisture, and try to identify the yellow chromophores. We use two types of white hair, blended hair (blend of several heads), initially yellowish (value of color coordinate blue-yellow, b* = 20), and single head hair (hair of one head), lesser yellow initially (b * = 10). The results show that the initial color affects the behavior by exposuring to UV - Vis: after exposure to a mercury lamp for 200 h, the blended hair turns less yellow (Db * = - 6), and the single head hair turns yellowier (Db * = 2). However, when the blended hair is bleached with H2O2 (b * = 8), turns yellowier after a few hours of irradiation (Db * = 3). By exposing only the Vis turns less yellow independently of initial color, both in blended hair (Db * = - 9) and in the single head hair (Db * = - 3). The results of color changes in white hair after sun irradiation agree with the results of exposure to mercury lamp. The IR radiation at 81°C turns hair yellowier both single head white hair (Db * = 9) and blended white hair (Db * = 3). The blended hair irradiated at 100% relative humidity shows no color variation after 88 h of irradiation. Still, the hair that has been irradiated, but washed with a sodium lauryl sulfate solution after each irradiation period, kept the Db* value. The without washings hair continued less yellow after storage, however, a yellowing (Db* > 1.5) was observed after 1 year. The only significant change in mechanical properties was observed in the reduction of maximum stress by 17% after 480 h of exposure to Vis lamp. UV - Vis absorbance measurements in the white hair solutions with different shades of yellow show absorption in the visible range, these behavior is due to the yellowing, and the formation of a strong band at 320 nm after UV irradiation. Unlike shown in the wool literature, which is also a structure formed by keratin, this band is not related to the formation of yellow chromophores. We demonstrate that the initial hair yellowing is a determining factor in their color variation after UV radiation, and this yellowing is caused by heat action. Still, after irradiations are formed free radicals responsible for the degradation reactions in the dark, in which water plays an important role in the deactivation of these radicals / Mestrado / Físico-Química / Mestre em Química

Thermal oil oxidation is an important reason for the engine oil degradation in trucks. Having a comprehensive model that includes all the influential factors while it is feasible for being implemented in the ECUs, was aimed for this work. Therefore, the chemical investigating of the problem leaded to propose a first kinetic model and its thermal analysis caused modelling the oil thermal behaviour. The latter was developed for four compartments: Bearings, turbocharger, piston cooling and oil sump in the oil path through the lubrication system, because the highest oil temperature happens due to friction, combustion of fuels and exhaust gas transportation. Independency from the design parameters of the compartments and simplicity of models for the ECU implementation caused to investigate two various modelling hybrid approach: physical modelling and control theory approach. The first one was done for the bearings and piston cooling, and showed a high level of complexity leading to switch to the second approach. The latter was applied for all compartments while it satisfied requested requirements. To adjust and evaluate the models, an experimental campaign was devoted to acquiring the needed parameters with consideration of the project budget. Also using the previous simulation and experimental efforts at the company provided a possibility to develop flow rate sub-models used in the thermal modelling. The proposed model for all compartments, well predicted the oil thermal behaviour for both stationary and dynamic operating conditions. A comparison between the experimental data for the oil in the oil sump and turbo charger was done to show the reliability of the related models in both stationary and transient statuses. For the bearings, the simulation data for stationary condition were applied as a reference. The modelled oil temperature after piston cooling was compared to a set of experimental data that presented the probable temperature in some conditions close to stationary operating points.

This thesis explores new and existing cellulose nanocrystal (CNC) production methods and evaluates their effects on CNC properties, with emphasis on their thermal performance. CNCs produced from industrial and lab-scale processes possess a wide range of surface chemistries, surface charge contents, as well as structural and morphological properties which affect their performance in CNC-based applications. Despite the broad range of available CNC properties, some challenges persist, particularly in the incorporation of CNCs into hydrophobic matrices, high brine liquid formulations, and high temperature applications. Herein, sulfated and carboxylated CNCs produced from large-scale processes were thoroughly characterized and key differences in their thermal performance and self-assembly and rheological behaviors were identified. Furthermore, an optimization study on phosphoric acid hydrolysis parameters and a novel surface modification method which deposits cellulose phosphate oligosaccharides onto CNC surfaces were proposed. The optimization study revealed that CNCs with high colloidal stability could not be produced with phosphoric acid alone; however, the weak acid hydrolysis allowed for precise control over CNC length. The deposition of oligosaccharides onto CNCs, however, resulted in highly colloidally stable CNCs possessing both phosphate and sulfate functional groups. Furthermore, this surface modification method altered CNC surface charge content, water interactions, and the viscosity of their aqueous suspensions. In these studies, however, changes in CNC thermal performance were difficult to elucidate. As such, to further understand the effects of CNC properties on both their dried and aqueous form thermal performance, a systematic comparison of sulfated, phosphated, and carboxylated CNCs was performed. CNCs were produced with new acid blend hydrolyses (i.e., combining sulfuric and phosphoric acid) as well as existing organic acid hydrolyses and oxidation routes. The combined effects of surface chemistry and counterion profoundly affected the thermal performance of dried CNCs, whereby sulfated and carboxylated CNCs were less thermally stable with proton and sodium counterions, respectively. Additionally, dried CNCs with more surface charge groups, shorter cellulose chains, and higher specific surface areas were found to be less resistant to high temperatures. As such, the new CNCs produced with acid blends exhibited superior thermal performance in their dried form due to their lower charge contents and longer cellulose chains. In their aqueous suspension form, carboxylated CNCs far outperformed both sulfated and phosphated CNCs at high temperatures; their suspensions remained colloidally stable at temperatures up to 150°C for extended time periods. Overall, this thesis equips CNC users and researchers with knowledge and tools to expand the usage of CNCs in commercial applications, particularly those which require high temperatures such as melt-processed polymer composites and oil and gas extraction fluids. / Thesis / Doctor of Philosophy (PhD) / This thesis contributes to a broader effort in replacing non-renewable and emissions intensive materials with sustainable alternatives such as nanocellulose. Nanocelluloses are nanometer-sized (where one nanometer is one billionth of a meter) cellulose particles manufactured from wood, cotton, or other natural resources. Nanocelluloses are made within Canada on a tonne-per-day scale; this value-added wood product presents an opportunity to refresh the Canadian forest industry. While nanocelluloses have many potential applications, their usage is somewhat limited by their inability to resist heat. This thesis examines changes in nanocellulose properties at high temperatures and evaluates how nanocellulose production methods affect their particle properties and thermal performance. New production methods are explored that increase nanocellulose resistance to heat, alter their dimensions, and change their interactions with water. Overall, this work aims to expand the usage of nanocellulose in commercial products such as coatings, plastics, industrial fluids, food products, and cosmetics (to name a few) by helping researchers select the right kind of nanocellulose for their intended applications.

<p dir="ltr">The frequency and intensity of wildfires occurring at the wildland-urban interface is increasing, and public drinking water systems operating in these communities are at risk. Widespread volatile organic compound (VOC) and semi-VOC (SVOC) contaminations have been detected in water distribution systems, often at concentrations above regulatory limits. Uncertainty about the source and fate of these contaminants has hindered recovery efforts. It is hypothesized that one source of the contaminants is the thermal degradation of plastic components within water distribution systems. Plastics are commonly used for water conveyance due to their low cost and ease of installation. However, plastics are vulnerable to thermal degradation, and have been shown to release VOC/SVOCs into the air when thermally degraded. Further, certain plastics such as polyethylene, are vulnerable to organic compound permeation, which could result in the contamination of otherwise undamaged components. This dissertation is comprised of four studies aimed at evaluating if plastic components within water distribution systems may be a source of contamination post-wildfire.</p><p dir="ltr">First, the aqueous leaching from commercial drinking water pipes was evaluated following thermal degradation in air. In this work, eleven plastic drinking water pipes were exposed to elevated temperatures (200°C to 400°C), and subsequently submerged in water or in <i>n</i>-hexane to observe the extent of VOC leaching. Results indicated that thermally damaged drinking water pipes can be sources of VOC leaching, with ten of the eleven materials leaching benzene, a carcinogen, into water. As exposure temperature increased, there was an increase in VOC leaching from the polyethylene plastics. Conversely, in the vinyl plastics the significant mass loss associated with high exposure temperature was inversely proportional to the amount of leaching that was observed.</p><p dir="ltr">The second study determined how the direct contact of water during plastic thermal degradation impacts the formation and aqueous leaching. Experiments were carried out using a continuously stirred tank reactor (CSTR) to expose plastics to a range of temperature (100°C to 300°C) in the presence of water. Five polyethylene materials were tested, including three cross-linked polyethylene (PEX) pipes, one high-density polyethylene pipe (HDPE), and one HDPE resin. Following degradation, clean water was pumped through the reactor to evaluate the efficacy of flushing to remove contaminants from thermally damaged plastics. Again, material type and exposure temperature impacted the leaching profile. Flushing removed contaminants from the thermally damaged plastics, however the removal rate varied based on chemical properties. Exhumed materials from wildfire impacted water systems were extracted in water to assess similarities and leached up to twelve different compounds, seven of which were also detected in laboratory experiments.</p><p dir="ltr">The third study investigated the impact of polyethylene formulation on aqueous leaching following thermal degradation to further understand the underlaying phenomenon causing the formation and leaching of contaminants. The impact of resin density, antioxidant type (Irganox 1010^® or Irgafos 168^®), antioxidant dose (0 to 10 wt. %), and impact of carbon black (0 or 2 wt. %) was investigated by compounding 12 different composites and thermally degrading them in the CSTR reactor described previously. Results found that all variables tested impacted the observed leaching. The addition of antioxidants decreased the observed leaching of polyethylene degradation products but increased the leaching of a variety of antioxidant degradation products. Carbon black was found to interact with the antioxidants during compounding, leading their consumption, and as a result decreased their effectiveness in protecting the polymer chain.</p><p dir="ltr">Lastly, the susceptibility of plastic water supply connectors such as ice-maker lines, faucet connectors, and washing machines hoses was assessed. The vulnerability of rigid plastic materials within water systems has been well studied, however, water supply connectors tend to be made of flexible plastics such as plasticized PVC and low-density polyethylene, and limited data exists on the susceptibility of these materials to contamination. In this study, seven connectors were exposed to hydrocarbon contaminated water, and subsequently decontaminated by water flushing. Following an initial 24 h contamination period, water samples were collected at three consecutive periods of 72 h. Results found that all materials sorbed more than 90% hydrocarbon contaminants. All materials released contaminants into the water during decontamination, at times above health-based limits. The majority of sorbed mass remained in the plastics at the end of the decontamination periods.</p>

El propósito de la presente tesis doctoral es estudiar el efecto de la degradación térmica, biológica y fotolítica en la polilactida (PLA) para contribuir a la caracterización de este polímero biodegradable bajo diferentes condiciones o entornos. Este polímero procede de fuentes renovables y está considerado un excelente candidato para sustituir a otros materiales poliméricos con escasa degradabilidad. En este estudio se describen los mecanismos que regulan cada tipo de degradación y, lo que es más importante, cómo cada uno de ellos afecta a la variación de la masa molar del PLA. La monitorización del descenso de masa molar de polilactida se realizó tanto mediante Cromatografía de Permeación en Gel (GPC) como por Viscosimetría. Adicionalmente se utilizó la Espectroscopía Infrarroja con Transformada de Fourier (FTIR) para establecer los mecanismos que controlan la degradación y su efecto en la estructura química de la polilactida. Asimismo, se ha determinado el impacto de cada tipo de degradación en la morfología y en las propiedades térmicas y mecánicas del PLA. La Termogravimetría (TGA) permitió monitorizar los cambios en la estabilidad térmica del material debidos a los diferentes tipos degradación, ulilizando parámetros como la temperatura de máxima velocidad de degradación térmica o la energía de activación. El resultado de la bio y la foto degradación en la superficie del material fue evaluado mediante Microscopía Electrónica de Barrido (SEM), observándose únicamente cambios debidos a la degradación biológica. Las propiedades viscoelásticas y térmicas se analizaron mediante Análisis Dinámico-Mecánico-Térmico (DMTA), Calorimetría Diferencial de Barrido (DSC) y Microscopía Óptica (OM). Se ha obtenido que los parámetros más relevantes para discernir las diferencias entre los tres procesos de degradación son los relativos al fenómeno de cristalización. Los resultados muestran que cada degradación está controlada por un mecanismo que afecta de diferente forma a la / Santonja Blasco, L. (2012). Contribution to the study of thermal, biological and photo degradation of polylactide [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/16470