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The goal of the work is to study possibilities for the modification of interface in immiscible polymer blends, which determine to a large degree of the blend properties. For this purpose novel coupling agents (named SCA) containing 2-oxazoline, 2-oxazinone, and hydrosilane reactive sites have been prepared. In blends of amino- functional and carboxylic acid terminated polymers the oxazoline and oxazinone units of the SCA react selectively with one of the polymers and, therefore, the SCA should locate at the interface. The remaining hydrosilane sites can now be used for further modification, e.g. for crosslinking. In the thesis we discussed the effect of the SCA on the morphology and thermal and rheological properties of blends based on carboxylic acid terminated polystyrene (PS) and amino-terminated polyamide 12 (PA) or poly(methyl methacrylate) (PMMA). The morphology of the blends and the location of the SCA strongly depends on the processing conditions. The crosslinkability of the interface could be proven by changes in the solubility behavior of the blends.

Poly(3-hydroxybuttersäure-co-3-hydroxyvaleriansäure), PHBV, ist ein Copolyester, der auf biologischem Weg durch Bakterien herstellbar und ein steifes sowie relativ festes Polymer ist. Seine Biokompatibilität und biologische Abbaubarkeit weckt das Interesse für diverse Anwendungen in Pharmazie und Medizin. PHBV reagiert mit Abbau empfindlich auf zugleich thermische und mechanische Belastungen, was ein Problem für die Verarbeitung darstellt. Produkte aus PHBV aus einmal geschmolzenem und verarbeitetem Pulver sind hochkristallin. Daher ist das Material spröde. Ferner wirkt sich die hohe Kristallinität sowie eine große Änderung der Dichte beim Abkühlen der Schmelze nachteilig auf die Spinnbarkeit des Materials aus. Nach dem Passieren der Spinndüse ziehen sich die Spinnfäden zusammen, was die Gefahr eines Fadenrisses beim Spinnen erhöht. Aufgrund der relativ hohen Kristallinität des Materials und einer verzögerten Kristallisationskinetik bei gesponnenen Polymerfäden kommt es zur Nachkristallisation in einem erheblichen Ausmaß, die Fäden verkleben nach dem Aufwickeln auf den Galetten und reißen beim Abwickeln. Zur Behebung der Nachteile wurden Verarbeitungsbedingungen vor allem bei Schmelzspinnprozessen mit der Kolbenspinnanlage und bei Mischungsprozessen optimiert. Die Polymermischungen und ?verbundstoffe enthalten kugelförmige Mikropartikel verschiedener Morphologie, die zuvor synthetisiert und charakterisiert wurden. Vor allem mit Vinylgruppen modifizierte Silikat-Submikropartikel mindern die Sprödigkeit von PHBV.

M. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences) Vaal University of Technology. / The polymer and their blended fibres provide good surface and intermolecular chemistry that bring additional functionalities and structural changes that can be adapted for new usages. Natural polymers are known to possess desirable qualities in terms of biocompatibility and biodegradability. The natural polymers are chosen due to their abundance but have difficulties in the preparations hence the addition of a synthetic polymer is vital. An important property of the polymer blended fibres is its miscibility which affects the mechanical properties, the morphology and degradation. Metal oxide nanoparticles embedded into polymer blended fibres enhances the performances of the polymer blended fibre permeability, selectivity, strength, and hydrophilicity. This study reports on the synthesis and characterization of zein, collagen nanofibres, zein/PVA fibre blends, iron oxide, manganese oxide nanoparticles, Fe2O3/zein /PVA and Mn2O3/zein/PVA fibre nanocomposite blends. The zein nanofibres and zein/PVA fibre blends were electrospun using electrospinning technique. Parameters such as the concentration and voltage were investigated. These parameters had an effect on the fibre morphology. The electrospun zein nanofibres and zein/PVA fibre blends were characterized using scanning electron microscopy (SEM), UV-Visible spectroscopy, Photoluminescence (PL), X-ray diffraction (XRD), Fourier transformer infrared (FTIR) spectroscopy and Thermal gravimetric analysis (TGA). The SEM results illustrated that an increase in the concentration of zein nanofibres improved the morphology of the fibres into ribbon like shape and had an effect on the average diameter size. The addition of PVA into zein nanofibres enhanced electrospinnabilty and the mechanical strength of zein was dependent on the presence of PVA. The optical properties, XRD, FTIR and thermal studies confirmed that zein/PVA (80/20) blend weight ratio was miscible and the other blend weight ratios remained immiscible, this was due to stronger interaction of hydrophilic performance of zein and PVA through hydrogen bonding. Therefore, fibre blend weight ratios of zein/PVA (90/10, 80/20, 70/30, 60/40 and 50/50) were successfully fabricated. The optimisation of collagen nanofibres favoured electrospraying instead of electrospinning hence collagen nanofibres could not be fabricated. Iron oxide nanoparticles was synthesized using hydrothermal method and manganese oxide nanoparticles was synthesized through co-precipitation method. The TEM results revealed well defined shapes of metal oxide nanoparticles illustrating that the increment of temperature had an influence on the crystallinity and particle size of 𝛼-Fe2O3 , 𝛼-MnO2 and 𝛼-Mn2O3 nanoparticles. The XRD confirmed the crystalline pattern of the metal oxide nanoparticles were of rhombohedral 𝛼-Fe2O3 structures (JCPDS 00-033-0664), cryptomelane phase 𝛼-MnO2 (JCPDS No. 29-1020) and orthorhombic crystalline phase of 𝛼-Mn2O3 (JCPDS No. 04-007-088). The metal oxide nanoparticles were thermally stable. Three different concentrations (4.25 wt%, 4.75 wt% and 5.25 wt %) of 𝛼-Fe2O3 and 𝛼- Mn2O3 were embedded onto zein/PVA (80/20) fibre blends and electrospun. The SEM, optical properties, XRD and TGA confirmed that the embedment of metal oxide nanoparticles enhanced the zein/PVA fibre blends performance, mechanical strength and resistance to wear therefore 5.25 wt% of 𝛼-Fe2O3/zein/PVA and 𝛼-Mn2O3/zein/PVA were explored further for the adsorption of chrysoidine G removal from wastewater. The adsorption studies of zein/PVA (80/20), 𝛼-Fe2O3/zein/PVA and 𝛼-Mn2O3/zein/PVA were carried out in a batch system on the effects of contact time, pH, initial concentration and adsorbent dosage. All the nanoadsorbents could rapidly reach adsorption equilibrium within 30 min at room temperature. The maximum removal efficiency of chrysoidine G of zein/PVA, 𝛼-Mn2O3/zein/PVA was higher than 𝛼-Fe2O3/zein/PVA. The dye adsorption equilibrium data were well-fit with Langmuir isotherm rather than Freundlich isotherm. The comparison of kinetic models revealed that the overall adsorption process was described well by pseudo second-order kinetics. The polymeric materials were cost effective hence regeneration studies were implemented for three cycles. These nanoadsorbents are easily available and are expected to be economical.

Les dispositifs optoélectroniques sont devenus un élément essentiel de la technologie moderne visant à exploiter des applications de niche pour l'électronique flexible à base de composés organiques. Jusqu'à présent, les films minces préparés à partir de composés polymères conjugués ont été les principaux concurrents pour les dispositifs optoélectroniques organiques. Avec l'apparition de nouvelles méthodes de mise en œuvre et de nouveaux besoins électroniques, les méthodes de fabrication additive des matériaux optoélectroniques suscitent de plus en plus d'intérêt. Malgré l'intérêt croissant et la variété des méthodes de mise en œuvre tridimensionnelles, on comprend encore mal l'impact de la technique de mise en œuvre sur l'organisation moléculaire des échantillons. Ici, une étude est présentée impliquant l’impression 3D assistée par évaporation de solvant et le poly(3-hexylthiophène) (P3HT) qui est bien décrit dans la littérature, et, dans ce cas-ci, mélangé à diverses matrices thermoplastiques. Dans un premier temps, les matrices thermoplastiques employées, i.e. le polystyrène (PS), le polypropylène carbonate (PPC), le polyméthacrylate de méthyle (PMMA) et le polyoxyéthylène (PEO) sont évaluées en fonction de leurs propriétés rhéologiques et de leur imprimabilité en 3D, qui ne sont que très peu affectées par l'introduction du P3HT. Par la suite, le P3HT à régiorégularité élevée et faible est mélangé dans chacune des matrices thermoplastiques. L'organisation moléculaire des deux composantes dans les architectures imprimées a été évaluée par des techniques de spectroscopie UV-visible et de fluorescence. Les phases en présence ont été analysées à l'aide d’analyse calorimétrique différentielle à balayage, de microscopie optique polarisée et de diffraction des rayons X, ce qui a également permis d'analyser l'état d'agrégation du P3HT par rapport à celui retrouvé dans les films minces. Il est intéressant de noter que les propriétés optiques montrent peu ou pas de différence entre les architectures 3D et les films minces, ce qui indique vraisemblablement que l'efficacité d'un dispositif optoélectronique imprimé en 3D ne serait pas affectée par l’impression 3D assistée par évaporation de solvant. Cette étude pourrait permettre de mieux comprendre comment il serait possible de mettre au point des dispositifs optoélectroniques, y compris des photoconducteurs, des photovoltaïques organiques, des transistors à effet de champ organiques, etc. à l’aide de techniques de fabrication additive, ce qui ouvrira la voie à une nouvelle ère en électronique organique imprimée en trois dimensions. / Optoelectronic devices have become a staple in modern day technology which aims to transition to flexible electronics that are developed from organic compounds. To date, 2-dimensional films of conjugated polymer compounds have been the main contender for organic optoelectronic devices. As new processing methods and electronic needs become present in the modern day, a focus on 3-dimensional processing methods of optoelectronic materials have become increasingly of interest. With the increasing interest and variety of 3-dimensional processing methods, there is little understanding of how the processing technique molecularly affects the final product. Herein is presented a study on the extrusion-based, direct-ink writing of the well understood poly(3-hexylthiophene-2,5-diyl) (P3HT) blended into a variety of thermoplastic matrices. Initially the pristine thermoplastics of polystyrene (PS), poly(propylene carbonate) (PPC), poly(methyl methacrylate) (PMMA), and poly(ethylene oxide) (PEO) were evaluated based on their rheological and printable properties which are negligibly affected by the introduction of P3HT. Subsequently, after the blending of both high and low regioregular P3HT into each of the thermoplastic matrices, the printed architectures were further analyzed by X-Ray diffraction, UV-vis, and fluorescence techniques to assess the aggregation state of P3HT in comparison to 2-dimensional processed films. Interestingly, the electronic properties show little to no difference between 3-dimensional architectures and 2-dimensional films, which presumably indicates that the efficiency would not be affected by the direct-ink writing technique. This study could contribute to the beginning of producing optoelectronic devices, including photoconductors, organic photovoltaic and organic field effect transistors, in 3-dimensions resulting in a new age of electronics.

Kommersiella tunga transporter står för en stor del av utsläppen av växthusgaser. För att minska det globala fotavtrycket hos kommersiella fordon är det vanligt att använda biodrivmedel som ”drop in” bränslen. De avancerade motorer som för närvarande finns på marknaden är känsliga för olösliga föroreningarna, vilka benämns ”mjuka partiklar” av Scania. Dessa partiklar bildas som ett resultat av att biodieseln åldras, p.g.a. oxidationsinstabilitet, och en växelverkan med metalltillsatser i bränslet. Mjuka partiklar orsakar interna dieselinjektoravlagringar (IDID) och ett snabbt åldrande av bränslefilters genom igensättning. Avsikten med denna studie var att analysera det sistnämnda problemet genom att undersöka bränslefiltrets filtreringseffektivitet av oönskade mjuka partiklar. Ett protokoll över utförandet av feltreringstesterna utvecklades och skalades upp från en småskalig filterrestrigg vid KTH (Fas 1) till en fullskalig filtertestrigg på Scania (fas 2). Den experimentella uppställningen var ett försök att reproducera fältscenarier för filtrering i verkliga lastbilar. Tyngdpunkten i fas 1 riktades mot accelererade tester i den småskaliga testriggen med höga koncentrationer av tvålmjuka partiklar av zinkneodekanoat och syntetiskt producerade mjuka kalciumpartiklar. Separationseffektiviteten hos bränslefilter undersöktes med hjälp av GC-MS-analys. ICP mätningar gjordes för att upptäcka Zn2+ och Ca2+-joner i tvålämnena. Dessa tvålämnen identifierades tidigare på igensatta bränslefiltren och värden från dessa konventionella bränslefilter jämfördes med resultat från en absorptionsfiltreringsprocess med hjälp av ler(silikat)filter. Syftet med jämförelsen var att studera en alternativ bränslefiltreringsteknik för fordonstillämpningar. Mätningar med SEM-EDS gav rimliga förklaringar angående effektivitetsvärden för Zn-och Ca-tvålämnen för olika filtren, som används i försöken. Adsorptionsfiltret av lera hade 99 % filtreringseffektivitet och är en intressant lösning för framtida studier. Fas 2 fokuserade på en uppskalning av försöksprotokoll för filtreringstester med biobränslen och inkluderade sex olika riggförsök. Resultaten visade på tillförlitliga och exakta värden av tryckvariationer och filtereffektiviteten med en maximal effektivitet på 63,3 % för huvudfiltret och 75 % för förfiltret, som ett resultat av GC-MS-analysen. De uppmätta tryckvariationerna visar att förfiltret fångar in en majoritet (över 70 %) av de mjuka partiklarna, vilket resulterar i en ökning av tryckfallet över tiden. Med hänsyn till resultaten så rekommenderas försöksförfarandet för fortsatta framtida studier. / Commercial heavy duty transportation accounts for a major share of greenhouse gas emissions. In order to reduce the global footprint, commercial vehicles are widely known to use biodiesel as drop in fuels. The advanced engines, currently on the market, are sensitive to the insoluble contaminants, termed as soft particles in Scania. They are formed because of aging of biodiesel and the interaction with metal additives in the fuel. This is a common problem associated with the fuel due to high oxidation instability. Soft particles are responsible for causing Internal Diesel Injector Deposits (IDIDs) and premature fuel filter clogging. This report deals with the analysis of the latter problem. The purpose of the project is to investigate the fuel filter efficiencies against desired soft particles. A protocol of experiments was developed and scaled up from a small-scale filter rig at KTH (Phase 1) to a full-scale filter test rig at Scania (Phase 2) at ambient temperatures. The experimental campaign in this project is an attempt to replicate on field scenarios of filtration in real trucks. In Phase 1, the emphasis of the accelerated tests (higher concentrations) was on using soap soft particles, zinc neodecanoate and synthetically produced calcium soft particles for the small-scale filter rig. Separation efficiencies of fuel filters were examined using GC-MS analysis. Whereas ICP measurements were done to detect Zn2+ and Ca2+ ion in these soaps. These soaps were successfully identified to be present on the clogged fuel filters. Values from conventional fuel filters were compared with results from absorption filtration process using clay (silicate) filters. The purpose of the comparison was to study an alternate fuel filtration technique for vehicle application. Furthermore, SEM-EDS provided reasonable explanations about the efficiency values of the filters against Zn and Ca soaps used in the operation. The adsorption clay filter as had 99% of filtration efficiency proving an interesting solution for future investigations. Phase 2 started with an initiation of the scaling up or the protocol for test fuels, including six different rig operations. The maximum efficiencies of the filters (63.3% for main filters and 75% for pre filters) were noted as a result of quantification of the GC-MS results of the samples obtained from the rig. The pressure variations recorded proved, that the pre filters were trapping majority (over 70%) of the soft particles showing a rise in pressure drops over time. According to the results, the full-scale filter rig gave reliable and accurate values of pressure variations and filter efficiencies. Thus, it is suggested to use in the future investigations.

In response to the growing concerns surrounding pollution and sustainability, this research explores the possibility of recycling post-consumer polyester (PET) and nylon (PA6) waste for textile applications. By blending the polymers and analyzing the recyclability and thermomechanical properties of PET/PA6 blends, this study aims to contribute to the development of sustainable materials for textile applications. Virgin PET and PA6 polymers were utilized, with blending ratios ranging from 35% PET to 65% PET to assess the impact of composition on the material’s performance. Compounding and injection molding techniques were employed to prepare samples for characterization. Mechanical testing revealed that the blending of PET and PA6 increased tensile and flexural strengths, with higher PET content leading to increased stiffness. However, impact testing indicated a decrease in toughness with the incorporation of PET, which is attributed to increased crystallinity. Thermal analysis demonstrated that the blends retained sufficient thermal stability for industrial processing, despite slight reductions in degradation temperatures. Differential scanning calorimetry explained the crystallization behavior of the blends, revealing nuanced changes in PET's crystallization temperature. The dynamic mechanical analysis highlighted enhanced elastic modulus and improved rigidity and adhesion. These findings may have significant implications for polymer blend research and applications. Understanding the mechanical and thermal behavior of PET/PA6 blends is crucial for optimizing their performance in textiles and various other sectors. The study contributes to the development of sustainable materials with improved mechanical properties, offering potential solutions to environmental challenges and promoting the adoption of recyclable polymers in society. Future research should focus on optimizing blend compositions with compatibilizers to enhance impact strength and fully integrate these materials into textile production processes.

No / We have probed the coupling between flow and concentration fluctuations in polymer blends using small-angle neutron scattering. We utilized a recirculating cell with a slot die, enabling us to measure the behavior at the entrance, within and at the exit of a contraction-expansion flow. While, as expected, anisotropy was observed in all nonquiescent experiments, the correlation lengths associated with the concentration fluctuations are found to be "stretched" more in the direction perpendicular to the flow at all positions along the centerline of the flow, except at the slot die exit. To gain insight into the observations, we present calculations of the scattering based on a multiscale approach, which bridges the gap between macroscopic Newtonian fluid dynamics and the convection of nanoscale concentration fluctuations. However, we find that this model contains insufficient physics to correctly describe our observations. Consequently, we argue that the deformation of the correlation length is primarily due to the coupling between weakly non-Newtonian stresses and thermodynamics

Tesis por compendio / [ES] El objetivo de esta tesis doctoral radica en el estudio y desarrollo de materiales basados en ácido poliláctico (PLA), con la finalidad de mejorar sus propiedades para su aplicabilidad en diversos sectores industriales. Este estudio se enfoca en la modificación de la fragilidad y rigidez inherentes al PLA mediante la incorporación de diferentes materiales, como plastificantes derivados de aceites vegetales epoxidado y maleinizado del aceite de linaza denominado MLO. Además, se investiga la creación de mezclas binarias con polímeros de mayor ductilidad, como el policarbonato (PC) y el estireno-b-(etileno-ran-butileno)-b-estireno (SEBS), se explora la inclusión de oligómeros de ácido láctico (OLA) y monoterpenos como estrategias para mejorar las propiedades del PLA. Estas investigaciones buscan proporcionar soluciones avanzadas y sostenibles para diversas aplicaciones industriales que demandan materiales con características mejoradas. En el contexto actual de la industria de los polímeros, la búsqueda de materiales sostenibles y respetuosos con el medio ambiente ha adquirido un protagonismo destacado. Esta creciente conciencia ambiental ha impulsado una profunda investigación y desarrollo de soluciones innovadoras que cumplan con los estándares de sostenibilidad y, al mismo tiempo, ofrezcan propiedades y rendimientos excepcionales. Dentro de este marco, la presente investigación se sumerge en el estudio y evaluación de alternativas prometedoras con las que mejorar la fragilidad y rigidez inherentes al PLA mediante la incorporación de diferentes materiales, como plastificantes, oligómeros, compatibilizantes u otros polímeros en mezclas binarias. El primer ámbito de estudio de esta investigación se centra en la incorporación de MLO como un agente compatibilizador en mezclas compuestas por PLA y SEBS. Los resultados de este estudio arrojan evidencia sólida de que el MLO supera de manera significativa a los tradicionales compatibilizadores derivados del petróleo. Se logra un incremento notable en la resistencia al impacto de estas mezclas, lo que es esencial en aplicaciones de envasado que requieren una protección adecuada de los productos contenidos. Además, se destaca que la adición de MLO conlleva una ligera disminución de la temperatura de transición vítrea (Tg) en la fase rica en PLA. Este efecto puede ser beneficioso en términos de flexibilidad, lo que resulta especialmente relevante en el envasado de productos que necesitan adaptabilidad y resistencia a condiciones variables. El segundo plano de investigación se enfoca en la comparación exhaustiva entre compatibilizadores de origen natural y aquellos de procedencia petroquímica en mezclas de PLA y PC. Este análisis confirma que los compatibilizadores naturales, incluyendo MLO y el aceite de linaza epoxidado (ELO), presentan ventajas notables en términos de resistencia al impacto sin comprometer la estabilidad térmica. Este hallazgo subraya la viabilidad y sostenibilidad de los compatibilizadores biobasados en aplicaciones específicas del envasado. Además, se aborda en el concepto de extrusión reactiva (REX) como una estrategia efectiva para potenciar la tenacidad de las mezclas de PLA. Tanto la inclusión de OLA y MLO durante el proceso de REX producen resultados altamente prometedores. Esto incluye un notable aumento en la resistencia al impacto, un atributo crítico en aplicaciones de envasado donde la integridad del producto es esencial. Es importante destacar que la adición de MLO, en particular, resulta en una transparencia sobresaliente, un factor que potencia aún más su idoneidad para aplicaciones de envasado de alimentos. Por último, se profundiza en el estudio de los monoterpenoides no esterificados y su impacto en el PLA. Estos compuestos, entre los que se destacan la carvona, el citral, el citronelal y el eucaliptol, han demostrado ser capaces de mejorar significativamente la ductilidad del PLA sin afectar de manera sustancial su transparencia. Este hallazgo adquiere / [CA] L'objectiu d'aquesta tesi doctoral radica en l'estudi i desenvolupament de materials basats en àcid polilàctic (PLA), amb la finalitat de millorar les seues propietats per a la seua aplicabilitat en diversos sectors industrials. Aquest estudi s'enfoca en la modificació de la fragilitat i rigidesa inherents al PLA mitjançant la incorporació de diferents materials, com a plastificants derivats d'olis vegetals epoxidats i maleinizats de l'oli de llinosa denominat MLO. A més, s'investiga la creació de mescles binàries amb polímers de major ductilitat, com el policarbonat (PC) i el estiré-b-(etilé-ran-butilé)-b-estiré (SEBS), s'explora la inclusió de oligomers d'àcid làctic (OLA) i monoterpens com a estratègies per a millorar les propietats del PLA. Aquestes investigacions busquen proporcionar solucions avançades i sostenibles per a diverses aplicacions industrials que demanden materials amb característiques millorades. En el context actual de la indústria dels polímers, la cerca de materials sostenibles i respectuosos amb el medi ambient ha adquirit un protagonisme destacat. Aquesta creixent consciència ambiental ha impulsat una profunda recerca i desenvolupament de solucions innovadores que complisquen amb els estàndards de sostenibilitat i, al mateix temps, oferisquen propietats i rendiment excepcionals. Dins d'aquest marc, la present investigació se submergeix en l'estudi i avaluació d'alternatives prometedores amb les quals millorar la fragilitat i rigidesa inherents al PLA mitjançant la incorporació de diferents materials, com a plastificants, oligómers, compatibilitzants o altres polímers en mescles binàries. El primer àmbit d'estudi d'aquesta investigació se centra en la incorporació de MLO com un agent compatibilitzador en mescles compostes per àcid poliláctic (PLA) i poliestiré-b-(etilé-ran-*butilé)-b-estiré (*SEBS). Els resultats d'aquest estudi llancen evidència sòlida que MLO supera de manera significativa als tradicionals compatibilitzadors derivats del petroli. S'aconsegueix un increment notable en la resistència a l'impacte d'aquestes mescles, la qual cosa és essencial en aplicacions d'envasament que requereixen una protecció adequada dels productes continguts. A més, es destaca que l'addició del MLO comporta una lleugera disminució de la temperatura de transició vítria (Tg) en la fase rica en PLA. Aquest efecte pot ser beneficiós en termes de flexibilitat, la qual cosa resulta especialment rellevant en l'envasament de productes que necessiten adaptabilitat i resistència a condicions variables. El segon pla d'investigació s'enfoca en la comparació exhaustiva entre compatibilitzadors d'origen natural i aquells de procedència petroquímica en mescles de PLA i policarbonat (PC). Aquesta anàlisi confirma que els compatibilizadors naturals, incloent el MLO i l'oli de llinosa epoxidat (ELO), presenten avantatges notables en termes de resistència a l'impacte sense comprometre l'estabilitat tèrmica. Aquesta troballa subratlla la viabilitat i sostenibilitat dels compatibilizadors de base biològica en aplicacions específiques de l'envasament. A més, s'aprofundeix en el concepte d'extrusió reactiva com una estratègia efectiva per a potenciar la tenacitat de les mescles de PLA. Tant la inclusió de oligómers d'àcid làctic (OLA) com l'aplicació de peròxid de dicumil (DCP) i MLO durant el procés d'extrusió reactiva produeixen resultats altament prometedors. Això inclou un notable augment en la resistència a l'impacte, un atribut crític en aplicacions d'envasament on la integritat del producte és essencial. És important destacar que l'addició de MLO, en particular, resulta en una transparència excel·lent, un factor que potencia encara més la seua idoneïtat per a aplicacions d'envasament d'aliments. Finalment, s'aprofundeix en l'estudi dels monoterpenoides no esterificats i el seu impacte en la PLA. Aquests compostos, entre els quals es destaquen la carvona, el citral, el citronelal i el eucaliptol, han demostrat ser capaços de millo / [EN] The objective of this doctoral thesis is the study and development of materials based on polylactic acid (PLA), with the aim of improving its properties for its applicability in various industrial sectors. This study focuses on the modification of the inherent brittleness and stiffness of PLA by incorporating different materials, such as plasticizers derived from epoxidized vegetable oils and maleinized linseed oil called MLO. In addition, the creation of binary blends with higher ductility polymers such as polycarbonate (PC) and polystyrene-b-(ethylene-ran-butylene)-b-styrene (SEBS) is investigated, the inclusion of lactic acid oligomers (OLA) and monoterpenes are explored as strategies to improve the properties of PLA. This research aims to provide advanced and sustainable solutions for various industrial applications that demand materials with improved characteristics. In the current context of the polymer industry, the search for sustainable and environmentally friendly materials has taken on an outstanding role. This growing environmental awareness has prompted in-depth research and development in the search for innovative solutions that meet sustainability standards and, at the same time, offer exceptional properties and performance. Within this framework, the present research is immersed in the study and evaluation of promising alternatives to improve the inherent brittleness and stiffness of PLA by incorporating different materials, such as plasticizers, oligomers, compatibilizers or other polymers in binary blends. The first area of study of this research focuses on the incorporation of MLO as a compatibilizing agent in blends composed of polylactic acid (PLA) and styrene-b-(ethylene-ran-butylene)-b-styrene (SEBS). The results of this study provide strong evidence that MLO significantly outperforms traditional petroleum-derived compatibilizers. A noticeable increase in the impact resistance of these blends is achieved, which is essential in packaging applications that require adequate protection of the contained products. Furthermore, it is noted that the addition of MLO leads to a slight decrease in the glass transition temperature (Tg) in the PLA-rich phase. This effect can be beneficial in terms of flexibility, which is particularly relevant in packaging products that need adaptability and resistance to variable conditions. The second research plane focuses on the comprehensive comparison between compatibilizers of natural origin and those of petrochemical origin in PLA and polycarbonate (PC) blends. This analysis confirms that natural compatibilizers, including MLO and epoxidized linseed oil (ELO), present notable advantages in terms of impact resistance without compromising thermal stability. This finding underlines the viability and sustainability of biobased compatibilizers in specific packaging applications. Furthermore, the concept of reactive extrusion as an effective strategy to enhance the toughness of PLA blends is further explored. Both the inclusion of lactic acid oligomers (OLA) and the application of dicumyl peroxide (DCP) and MLO during the reactive extrusion process produce highly promising results. This includes a marked increase in impact resistance, a critical attribute in packaging applications where product integrity is essential. Importantly, the addition of MLO, in particular, results in outstanding transparency, a factor that further enhances its suitability for food packaging applications. Finally, the study of non-ester monoterpenoids and their impact on PLA is further explored. These compounds, including carvone, citral, citronellal and eucalyptol, have been shown to significantly improve the ductility of PLA without substantially affecting its transparency. This finding is particularly relevant in the context of packaging applications, where flexibility and resistance to deformation are critical aspects. Thus, these non-ester monoterpenoids present themselves as a promising option for th / Me gustaría realizar especial mención a los proyectos concedidos al grupo de investigación en el que he realizado la tesis doctoral. Por un lado, los proyectos del Ministerio de ciencia e innovación MAT2017–84909–C2–2–R y PID2020–116496RB–C22. Igualmente agradecer a la Generalitat Valenciana por los proyectos AICO/2021/025 y CIGE/2021/094 / Tejada Oliveros, R. (2023). Optimización de las propiedades de tenacidad e impacto de formulaciones de ácido poliláctico (PLA), mediante mezclas con polímeros flexibles y optimización de los sistemas de compatibilización [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/201561 / Compendio

Ziel der vorliegenden Arbeit war es, die Zusammenhänge zwischen der molekularen Architektur, Morphologie und den mechanischen bzw. bruchmechanischen Eigenschaften in S-SB-S-Triblockcopolymeren und deren Blends und in PI-PS-Multipfropfcopolymeren herauszuarbeiten und damit einerseits einen Beitrag für das Verständnis der Struktur-Eigenschaftsbeziehungen in Block- und Pfropfcopolymeren zu leisten und andererseits Möglichkeiten zur Entwicklung neuer Materialien aufzuzeigen, welche besondere Eigenschaftskombinationen aufweisen und damit ein bedeutendes Interesse für industrielle Anwendungen hervorrufen. Für die Untersuchungen wurde dabei der PS-Außenblockanteil und das S/B-Verhältnis im SB-Mittelblock in S-SB-S-Triblockcopolymeren, die Thermoplast/Thermoplastisches Elastomer (TP/TPE) -Zusammensetzung in S-SB-S-Triblockcopolymer-Blends sowie die Funktionalität und die Anzahl der Verknüpfungspunkte in PI-PS-Multipfropfcopolymeren variiert. Zur Charakterisierung der Phasenmischbarkeit und der Morphologie wurden die dynamisch mechanische Analyse (DMA), die Transmissionselektronenmikroskopie (TEM) und die Röntgenkleinwinkelstreuung (SAXS) angewandt. Die mechanischen Eigenschaften wurden mit dem einachsigen Zugversuch untersucht. Bruchmechanische Untersuchungen erfolgten unter Anwendung der „Essential Work of Fracture“- (EWF-) Methode, welche als Konzept der „Post-Yield“-Bruchmechanik innerhalb der Fließbruchmechanik für duktile nanostrukturierte polymere Materialien sehr gut anwendbar ist und Aussagen zur Bruchzähigkeit der Materialien liefert. Zur näheren Charakterisierung des zeitaufgelösten Deformationsverhaltens sowie der Rissausbreitungskinetik wurden die Dehnungsfeldanalyse, eine Bruchflächenanalyse mittels Rasterelektronenmikroskopie (REM) sowie das Risswiderstandskurven-Konzept angewandt. Die Untersuchungen der S-SB-S-Triblockcopolymersysteme und der PI-PS-Multipfropfcopolymere konnten den signifikanten Einfluss der molekularen Architektur, der Blockzusammensetzung und des PS-Gehaltes auf das Phasenverhalten, die Morphologie und die Eigenschaften klar herausstellen. Durch die Variation dieser Parameter kann das Eigenschaftsspektrum von thermoplastisch zu elastomer eingestellt und somit sowohl TPs oder TPEs mit hoher Steifigkeit und Zähigkeit als auch TPEs mit superelastischem Charakter erzeugt werden. Daraus eröffnet sich ein breiter Anwendungsbereich dieser Materialien, welche aufgrund ihrer Transparenz und physiologischen Verträglichkeit auch interessante optische und gesundheitliche Vorteile mitbringen. Es konnte gezeigt werden, dass durch die systematische Variation der Architektur die gezielte Einstellung gewünschter Eigenschaftsprofile möglich ist. Die Arbeit leistet somit einen Beitrag zur Entwicklung anwendungsorientierter Materialkonzepte, welche ingenieurwissenschaftlich interessant sind. / The aim of this thesis was to study the relation between molecular architecture, morphology and (fracture) mechanical properties of S-SB-S triblock copolymers and PI-PS multigraft copolymers. Hence, this work should contribute to the understanding of structure-property-relationship in block and multigraft copolymers and thus offer possibilities for the development of novel materials with special properties interesting for industrial application. Within this study in the case of S-SB-S triblock copolymers the PS outer block content and the S/B ratio of the middle block, in the case of S-SB-S triblock copolymer blends the thermoplast/thermoplastic elastomer (TP/TPE) composition and in case of PI-PS multigraft copolymers the functionality and number of branch points were varied. For the characterisation of morphology and phase miscibility dynamic mechanical analysis (DMA), transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS) were applied. Uniaxial tensile tests were carried out to investigate the mechanical properties. The fracture mechanical behaviour was studied using essential work of fracture (EWF) concept based on the post yield fracture mechanic principles, which is suitable to characterise fracture toughness of ductile nanostructured materials. The time resolved analysis of deformation and fracture behaviour was characterised qualitatively by strain field analysis, scanning electron microscopy (SEM) of the fractured surfaces and quantitatively by evaluation of the crack propagation kinetics and construction of R-curves. This study clearly highlights the significant influence of molecular architecture block composition and PS content on the phase behaviour, morphology and properties of S-SB-S triblock copolymers and PI-PS multigraft copolymers. By varying these parameters the property profile can be adjusted diversifying from thermoplastic to elastomeric and both TP or TPE materials with high stiffness and toughness and TPEs with super-elastic characteristics can be designed. Hence, fundamentally it offers a broad scope of application of these materials, in which physiological compatibility and transparency are added advantages. Thus, conceptually it could be shown, that by systematic variation of the architecture desired property profiles can be adjusted. Therefore the present work contributes to the development of application-oriented material concepts, which are interesting in engineering terms.