Tesis por compendio / [ES] En esta tesis se obtuvieron fracciones celulósicas y extractos activos de paja de arroz mediante diferentes técnicas de extracción y purificación, utilizando agua como disolvente. Estas fracciones se incorporaron en películas de almidón y PLA, y en bicapas de almidón-PLA, para obtener materiales de envasado activos para extender la vida útil de diferentes alimentos. Los extractos obtenidos por combinación de ultrasonidos y calentamiento a reflujo (USHT) y con agua subcrítica (SWE) (a 160 °C (SWE-160) y 180 °C (SWE-180)) presentaron un alto contenido fenólico (37, 51 y 83 mg GAE.g-1 de extracto seco, respectivamente) y actividad antioxidante (6,3, 2,0 y 1,2 mg de extracto seco.mg-1 DPPH, respectivamente). Los extractos SWE fueron activos contra L. innocua y E. coli. Se aislaron fibras de celulosa (FC) del residuo insoluble de las diferentes extracciones. A pesar de las ligeras diferencias en el grado de purificación, los nuevos métodos dieron lugar a FCs con rendimientos más elevados que el método alcalino (35-39 % frente al 29 %), con cristalinidad (60-69 %), comportamiento térmico y relación de aspecto (20-60) similares. Se incorporaron fibras USHT al 1, 3 y 5 % (p/p) en películas termoprocesadas de almidón de maíz, y de almidón de maíz modificado térmicamente. La incorporación al 3 % dio lugar a películas con mejores propiedades funcionales. Los extractos activos (al 4, 6 y 8 % en peso) en la matriz de almidón, con o sin CF (3 %), dieron lugar a películas más extensibles y menos resistentes, con mayor capacidad de barrera al oxígeno. Las bolsas monodosis de aceite de girasol con estas películas activas y reforzadas redujeron eficazmente la oxidación. Las películas activas de PLA termoprocesado, con diferentes proporciones (2, 4 y 6 % p/p) del extracto USHT, presentaron color y propiedades mecánicas ligeramente peores, pero con mayor barrera al oxígeno. La cinética de liberación de los antioxidantes incorporados en simulantes alimentarios de diferente polaridad (A: productos acuosos; y D1: sistemas de aceite en agua), mostró que las películas con un 6% de extracto, tuvieron una capacidad antioxidante similar en simulantes con distinta polaridad. Se obtuvieron bicapas biodegradables laminando PLA, con y sin extracto USHT (6 %), y almidón termoplástico, con o sin FC USHT (3 %). Las bicapas mostraron mejor capacidad de barrera global que las monocapas. Sin embargo, la migración de compuestos entre capas dio lugar a películas menos rígidas y resistentes de lo esperado de la contribución del film de PLA. Las bicapas activas y reforzadas alargaron la vida útil de carne de cerdo refrigerada. Las películas de PLA con un 6 % (p/p) de los diferentes extractos (USHT, SWE-160 y SWE-180) presentaron menor resistencia mecánica y capacidad de barrera al vapor de agua, pero una mayor capacidad de barrera al oxígeno y a la luz UV. Además, estas películas, especialmente con el extracto SWE-180, alargaron la vida útil de la carne de cerdo refrigerada. Las FCs obtenidas con los diferentes métodos de purificación también se utilizaron para producir aerogeles de celulosa. Las diferencias composicionales afectaron a la microestructura de los aerogeles. La capacidad de absorción y de retención de agua de los aerogeles estuvo dentro de los rangos descritos para este tipo de materiales. Por tanto, fue posible obtener fracciones valorizadas de la paja de arroz, extractos activos y fibras celulósicas, útiles en el desarrollo de materiales biodegradables activos a base de almidón y PLA. Son necesarios más estudios para validar la seguridad alimentaria de los materiales, así como para el desarrollo de otras aplicaciones en el campo de la industria alimentaria o farmacéutica. / [CA] En aquesta tesi doctoral es van obtenir fraccions cel·lulòsiques i extractes actius de palla d' arròs mitjançant l'aplicació de diferents tècniques d'extracció i purificació, utilitzant aigua com a dissolvent. Aquestes fraccions es van incorporar a pel·lícules de midó i PLA, i bicapes de midó-PLA, per obtenir materials d'envasament actius útils per allargar la vida útil de diferents aliments. Els extractes combinant ultrasons i escalfament a reflux (USHT) i amb aigua subcrítica (SWE) (a 160 °C (SWE-160) i 180 °C (SWE-180)) van mostrar un alt contingut fenòlic (37, 51 i 83 mg GAE.g-1 d'extracte sec, respectivament) i activitat antioxidant (6,3, 2,0 i 1,2 mg d'extracte sec.mg-1 DPPH, respectivament). Els extractes SWE van mostrar activitat antibacteriana contra L. innocua i E. coli. Es van aïllar fibres de cel·lulosa (FC) de les fraccions insolubles de l'extracció. Malgrat les lleugeres diferències en el grau de purificació, els nous mètodes van donar lloc a FCs amb rendiments més elevats que el mètode alcalí (35-39 % enfront del 29 %), amb cristal·linitat (60-69 %), comportament tèrmic i relació d'aspecte (20-60) similars. Es van incorporar fibres USHT a l'1, 3 i 5 % (p/p) en pel·lícules de midó de dacsa, i de midó de dacsa modificat per tractament tèrmic. La incorporació al 3 % va donar lloc a pel·lícules amb les millors propietats funcionals. Els extractes actius (al 4, 6 i 8 % en pes) a la matriu de midó, amb o sense CF (3 %), proporcionaren pel·lícules més extensibles i menys resistents, però amb més capacitat de barrera a l'oxigen. Les bosses monodosi de l'oli de gira-sol amb aquestes pel·lícules actives i reforçades van reduir eficaçment l'oxidació. Les pel·lícules actives de PLA amb diferents proporcions (2, 4 i 6 % p/p) de l'extracte USHT, presentaren color i propietats mecániques lleugerament pitjors, però amb major capacitat de barrera a l'oxigen. La cinètica d'alliberament dels antioxidants incorporats, en simulants alimentaris de diferent polaritat (A: productes aquosos; i D1: sistemes d'oli en aigua), va mostrar que les pel·lícules amb un 6% d'extracte, tenien una capacitat antioxidant similar en simulants amb diferent polaritat. Es van obtenir bicapes biodegradables laminant PLA, amb i sense extracte USHT (6 %), i midó termoplàstic, amb o sense FC USHT (3 %). Les bicapes van mostrar millor capacitat de barrera global que les monocapes. No obstant això, la migració de compostos entre capes va donar lloc a pel·lícules menys rígides i resistents respecte a l'esperat de la contribució de la pel·lícula de PLA. Les bicapes actives i reforçades van allargar la vida útil de carn de porc refrigerada. Les pel·lícules de PLA amb un 6 % (p/p) dels diferents extractes (USHT, SWE-160 i SWE-180) van presentar menor resistència mecànica i capacitat de barrera al vapor d'aigua, però una major capacitat de barrera a l'oxigen i a la llum UV. A més, aquestes pel·lícules, especialment amb l'extracte SWE-180, van allargar la vida útil de la carn de porc refrigerada. Les FCs obtingudes amb els diferents mètodes de purificació també es van utilitzar per produir aerogels de cel·lulosa. Les diferències composicionals van afectar la microestructura dels aerogels. La capacitat d' absorció i de retenció d'aigua dels aerogels va estar dins dels rangs descrits per a aquest tipus de materials. Per tant, va ser possible obtenir fraccions valoritzades de la palla d' arròs, extractes actius i fibres cel·lulòsiques, útils en el desenvolupament de materials biodegradables actius a base de midó i PLA. Són necessaris més estudis per validar la seguretat alimentària dels materials, així com per al desenvolupament d' altres aplicacions en el camp de la indústria alimentària o farmacèutica. / [EN] This Doctoral thesis focused on obtaining cellulosic fractions and bioactive extracts from rice straw (RS) by applying different extraction and purification techniques, using water as a green solvent. These fractions were incorporated into starch and poly (lactic acid) (PLA)-based films, as well as into starch-PLA bilayers, to obtain active packaging materials useful for extending the shelf life of different food matrices. The extracts obtained by applying a combined ultrasound-reflux heating method (USHT) and subcritical water extraction (SWE) (at 160 °C (SWE-160) and 180 °C (SWE-180)) exhibited high phenolic content (37, 51, 83 mg GAE.g-1 dry extract, respectively) and antioxidant activity (6.3, 2.0, and 1.2 mg dry extract.mg-1 DPPH, respectively). The SWE extracts showed antibacterial activity against L. innocua and E. coli. Cellulose fibres (CF) were isolated from the extraction insoluble fractions and compared with those obtained from the traditional alkaline method. Despite slight differences in the degree of purification, the new methods gave rise to CFs with higher yields than the alkaline method (35-39% vs. 29%), with similar crystallinity (60-69%), thermal behaviour, and aspect ratios. USHT fibres were incorporated into corn starch (1, 3, and 5% wt.), and corn starch-modified by heat treatment, obtained by thermoprocessing. The incorporation of CF at 3% gave rise to films with the best functional properties. When active extracts were incorporated at different ratios (4, 6, and 8% wt.) into the starch matrix, with or without CF (3%), the films were more stretchable and less resistant, but with higher oxygen barrier capacity. Likewise, mono-dose bags of these active and reinforced films effectively reduced the oxidation of packed sunflower oil. Active, plasticised PLA films were produced, incorporating USHT extract (2, 4, and 6% wt.) by thermoprocessing, which exhibited colour and slightly worsened tensile behaviour, but with higher oxygen barrier capacity. The release kinetics of the incorporated antioxidant compounds in food simulants of different polarity (A: aqueous products; and D1: oil-in-water systems) showed that films containing 6% of extract delivered similar antioxidant capacity regardless of the food simulant polarity. Biodegradable bilayers were obtained by laminating plasticised PLA, with and without USHT extract (6%), and thermoplastic starch, with or without USHT CFs (3%). The bilayers exhibited improved overall barrier capacity with respect to the monolayers. However, the interlayer compound migration led to less stiff and resistant films with respect to that expected from the PLA film contribution. The active and reinforced bilayers were able to extend the shelf life of the packed pork meat during cold storage. PLA films with 6% wt. of the different extracts (USHT, SWE-160, and SWE-180) were produced, which exhibited lower mechanical resistance and water vapour barrier capacity, but improved oxygen barrier capacity and intense UV light-blocking effect. Furthermore, the active PLA films, especially with SWE-180 extract, extended the shelf life of cold storage pork meat. The CFs obtained with the different purification methods were also used to produce cellulose aerogels. The differences in the chemical composition of the CFs affected the aerogels' microstructure. The water absorption and retention capacity of the aerogels were within the previously reported ranges for this type of material. Thus, it was possible to obtain valorised fractions of rice straw, active extracts and cellulosic fibres, useful in developing active biodegradable materials based on starch and PLA. Further studies are needed to validate the food safety of the materials, as well as for developing other applications in the food or pharmaceutical industry. / The authors thank the Agencia Estatal de Investigación (Spain) for the financial support through projects PID2019-105207RB-I00/AEI/10.13039/501100011033 and Generalitat Valenciana [grant number GrisoliaP/2019/115]. / Vieira De Freitas, PA. (2022). Valorisation of rice straw by obtaining active compounds and cellulosic materials for the development of biodegradable food packaging systems [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/191380 / Compendio

For more than a century, plastics have become an increasingly important part of the human society. Thanks to the durability and the many varieties of plastic it has a wide range of applications, but unfortunately the traditional plastic made from fossil oil has its drawbacks. Neither the fact that fossil oil is used, nor that these plastics won’t degrade in nature, are in any way sustainable for the environment in the long run. But out of the shadow of these problems, new technologies for the manufacturing of bioplastics are born. This thesis aims towards mapping out properties of different plastics, fossil based as well as bio-based, and investigating the possibilities to manufacture plastic material from algae, so called blue plastics. Additionally, the thesis shed light on terms related to plastic production and bioplastics.  The result shows that there are multiple approaches to the manufacturing of blue plastics; several divergent polymers (e.g. starch, protein and alginate) can be extracted from algae for the production of plastic material, and there is a large number of algae strains and methods to use. Blue plastics are still not produced in large scale, and therefore suffer from high production costs, which makes it challenging to replace traditional plastics. Another obstacle is bad durability and mechanical properties of some algae-based materials. But the blue side of the spectrum of plastics is still a young field of study and new innovations are yet to be discovered. / I över ett sekel har plast blivit en allt viktigare del i det mänskliga samhället. Tack vare sin tålighet och mångsidighet har plast en mängd olika användningsområden, men tyvärr har den traditionella plasten även sina nackdelar. Varken det faktum att fossil olja används, eller det faktum att dessa plaster inte bryts ned i naturen, kan anses hållbart i längden. Men ur skuggan av dessa problem träder nya tekniker fram, som möjliggör tillverkning av bioplaster. Detta projekt syftar till att kartlägga egenskaperna hos olika plaster, fossilbaserade såväl som biobaserade, samt möjligheterna att tillverka plast med alger som råvara. Dessutom läggs fokus på att förklara vissa termer relaterade till plaster, bioplaster och dess livscykel.  Resultatet visar att det finns ett flertal tillvägagångssätt för tillverkningen av algbaserade plaster. Flera olika polymerer (t.ex. stärkelse, protein och alginat) kan extraheras från alger för vidare produktion av plastmaterial, och dessutom finns ett stort antal olika algarter och tillverkningsmetoder som kan användas. Idag produceras algplaster ännu inte i stor skala, något som innebär att produktionskostnaderna fortfarande är höga och att det således är svårt att konkurrera ekonomiskt med traditionella plaster. Ett annat hinder för algbaserade plaster är i vissa fall låg resistans och sämre mekaniska egenskaper jämfört med traditionella plaster. Men den algbaserade delen av plastspektrumet är fortfarande ung och outforskad, fortfarande finns nya upptäckter och möjligheter som väntar på att bli funna.

Annually, about 80,000 people die in the United Kingdom due to myocardial infarction, congestive heart failure, stroke, or from other diseases related to blood vessels. The current gold standard treatment for replacing the damaged blood vessel is by autograft procedure, during which the internal mammary artery (IMA) graft or saphenous vein graft (SVG) are usually employed. However, some limitations are associated with this type of treatment, such as lack of donor site and post-surgery problems that could negatively affect the patient’s health. Therefore, this present work aims to fabricate a synthetic blood vessel that mimics the natural arteries and to be used as an alternative method for blood vessel replacement. Polymeric materials intended to be used for this purpose must possess several characteristics including: (1) Polymers must be biocompatible; (2) Biodegradable with adequate degradation rate; (3) Must maintain its structural integrity throughout intended use; (4) Must have ideal mechanical properties; and (5) Must encourage and enhance the proliferation of the cells. The feasibility of using synthetic biodegradable polymers such as poly (ε- caprolactone) (PCL) and poly (lactide-co-glycolic acid) (PLGA) for fabricating tubular vascular grafts was extensively investigated in this work. Many fundamental experiments were performed to develop porous tissue- engineered polymeric membranes for vascular graft purposes through electrospinning technique to achieve the main aim. Electrospinning was selected since the scaffolds produced by this method usually resemble structural morphology similar to the extracellular matrix (ECM). Hence, four 6mm in diameter tubular shape vascular grafts PCL only, PLGA only, coaxial (core-PCL and shell-PLGA), and bilayer (inner layer-PCL and outer layer-PLGA) was designed and fabricated successfully. The structure and properties of each scaffold membrane were observed by scanning electron microscopy (SEM), and these scaffolds were fully characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), water contact angle measurements, mechanical tensile test, as well as cell culture studies were carried out by seeding human umbilical vein cells (HUVEC) and human vascular Fibroblast cells (HVF). Moreover, all polymeric grafts underwent degradation process, and the change in their morphological structure properties was studied over 12 weeks at room temperature. All scaffolds were also exposed to a controlled temperature of 37°C for four weeks, in phosphate-buffered saline solution (pH, 7.3). It was found that all scaffolds displayed exceptional fibre structure and excellent degradability with adequate steady weight-loss confirming the suitability of the fabricated scaffolds for tissue engineering applications. The coaxial and bilayer scaffolds degraded at a much slower (and steadier) rate than the singular PCL and PLGA tubular scaffolds. Coaxial grafts fabricated via coaxial needle showed an increase in their fibre diameter and pore size volume than other membranes, but also showed to have significant tensile strength, elongation at fracture, and Young’s modulus. To conclude, all scaffolds have demonstrated to be reliable to adhere and proliferate HUVEC, and HVF cells, but these cells were attracted to the PLGA membrane more than other fabricated membranes.

No description available.

No description available.

No description available.

With increasing population comes the concern for waste disposal. The absence of sanitary disposal methods has left most city residents with open landfills as their only source of waste disposal. The resulting leachate formed from the decomposition of these waste materials is highly polluting and finds its way to the underground water supply. The study investigated the effects of open landfill sites on the underground water quality by examining the physical and chemical properties of underground water in hand-dug wells around the Solous landfill sites in Igando, Alimosho Local Government Area of Lagos State. Solous landfill is the second largest landfill by landmass and volume of waste in Lagos State. Systematic random sampling was used for data gathering. Eighteen hand-dug wells were sampled at increasing distances from the landfill site. Physical, chemical and microbiological parameters were analysed at the Lagos State Environmental Protection Agency (LASEPA). Soil samples were also taken from both the A (0 – 30cm) and B (30 – 60cm) horizons of the water sampling points to determine the soil texture (silt, clay and loamy composition) and to show the impact of soil texture on ground water quality within the sampled area. The level of contamination of groundwater was also determined using the Contamination Index method. The results showed high degree of conformance with W.H.O standard with respect to the microbiological properties of the sampled groundwater. However, coliform tests indicated the potential presence of pathogens. Of the seven (7) physical parameters tested, conductivity was higher in one sample. The study of chemical properties from the eighteen wells showed five (5) parameters (dissolved oxygen, total alkalinity, iron, lead, nitrates and copper) above W.H.O limits in some samples. The water may therefore not be safe for human consumption and there is a serious need to monitor the groundwater quality in the area. The level of contamination of groundwater was also determined using the Contamination Index method. Areas of high and medium contamination were discovered. There was no area with low contamination level in the area sampled. Contamination levels were mapped to show the exact levels of contamination in the study area. The results of the soil analysis showed that the study area had soil that was mostly sandy in nature which may suggest an increase in parameters over time with significant health implications for the people who depend on surrounding wells for domestic use. The study also showed no significant variation in water quality with increasing distance from the dump site. Findings also indicated that the water around Solous 1 was of better quality for domestic use than groundwater around Solous 2 and 3 due to temporal reduction of contaminant concentration. There is therefore a need for adequate and proper planning, design and construction, and strategic management disposal of waste, as well as the implementation of a better sustainable environmental sanitation practice. / Environmental Sciences / M. Sc. (Environmental Science)

The thesis outlines possible medical applications of soft matter assemblies as nanotechnology based systems as well as their potential in the emerging field of nanomedicine. Nanomedicine can be defined as the investigation area encompassing the design of diagnostics and therapeutics at the nanoscale, including nanobots, nanobiosensors, nanoparticles and other nanodevices, for the remediation, prevention and diagnosis of a variety of illnesses. The ultimate goal of nanomedicine is to improve patient quality-of-life. Because nanomedicine includes the rational design of an enormous number of nanotechnology-based products focused on miscellaneous diseases, a variety of nanomaterials can be employed. Therefore, the thesis is driven by a focus on recent advances in the manufacture of soft matter-based nanomedicines specifically designed to improve cancer diagnostics and chemotherapy efficacy. It will in particular highlight liposomes, polymer-drug conjugates, drug- loaded block copolymer micelles and biodegradable polymeric nanoparticles, emphasizing the current investigations and potential novel approaches towards overcoming the remaining challenges in the field as well as a brief overview of formulations that are in clinical trials and marketed products. Based on vehicle-related and...

Inspiriert durch natürliche Grenzflächenproteine in Knochen wurden bifunktionale Biokonjugate für verschiedene Grenzflächenstabilisierungen genutzt. In einem kombinatorischen Ansatz wurden materialspezifische Peptid-block-Polyethylenglycol-Konjugate eingesetzt, um die Grenzflächen von Nanopartikeln in Lösung sowie in Polymerkompositen zu stabilisieren. Dazu wurden biokombinatorisch ausgewählte Peptid-Sequenzen mit einer Affinität für MgF2-Oberflächen in Form eines MgF2-bindenden Konjugats (MBC) synthetisiert, welches die materialaffine Bindung der monodispersen Peptid-Domäne mit der zusätzlichen Funktion des synthetischen Polymer-Blocks verbindet. Aus detaillierten Untersuchungen der Bindungseigenschaften von MBC und davon abgeleiteten Konjugaten mit variierten Peptidarchitekturen bzw. Polymer-Blocklängen bei verschiedenen Inkubationsbedingungen ging hervor, dass das sequenzspezifisch bindende MBC das Potenzial zur Stabilisierung von MgF2-Nanopartikeln hat. Das Konjugat verhinderte die Agglomeration der Partikel und ermöglichte im Gegensatz zu etablierten Stabilisatoren die vollständige Redispergierbarkeit sogar nach Eintrocknung. Die Stabilisierung in Lösung wurde auf die Kompatibilisierung von Partikeln in Polycaprolacton (PCL)-Kompositen übertragen, in denen das grenzflächenaktive MBC die Materialeigenschaften von bioabbaubaren PCL/MgF2-Kompositen optimierte. Die Grenzflächenstabilisierung führte zur gleichzeitigen Erhöhung der Steifigkeit und der Zähigkeit der Materialien bis in den Bereich natürlicher Knochen. Durch die gemeinsame Zugabe von MBC-kompatibilisiertem MgF2 und Hyxdroxylapatit zu PCL wurde ein bioaktives Material geschaffen, das nachweislich die osteogene Differenzierung von mesenchymalen Stammzellen und die Mineralisierung von neuem Knochengewebe unterstützte. Damit stellt es ein vielversprechendes Komposit für die Regeneration von Knochengewebe und weitere Anwendungen dar. / Inspired by natural interface proteins in bone, bifunctional bioconjugates were exploited for different interface stabilization applications. The interfaces of nanoparticles both in solution and in polymeric composites were stabilized by combinatorially selected, material specific peptide-polymer conjugates. Peptide sequences showing affinity to MgF2 particle surfaces were selected from a phage display library and translated into a MgF2-binding peptide-block-poly(ethylene glycol) conjugate (MBC). The MBC combined the material-affine binding of the monodisperse peptide domain with an additional function of a synthetic polymer block. Detailed studies of the binding properties of MBC and congeneric conjugates with other peptide architectures or different polymer block lengths, as well as varied incubation conditions revealed the potential of the sequence-specific MBC to stabilize MgF2 nanoparticles in solution. The conjugate inhibited the agglomeration of the particles. In contrast to established stabilizers, it enabled fully redispersable nanoparticles even after complete drying. The stabilization approach in solution was expanded to the compatibilization of the particles in polycaprolactone (PCL) composites. Inspired by the structure of highly specific interface proteins, MBC optimized the material properties of biodegradable PCL/MgF2 composites. Additionally, the interface stabilization simultaneously increased both the stiffness and the toughness of the composites up to the range of natural bone. The addition of hydroxyapatite alongside MBC-compatibilized MgF2 to PCL created a bioactive material that showed enhanced osteogenic differentiation of mesenchymal stem cells and the mineralization of new bone tissue. Therefore, a mechanically reinforced, osteoinductive material was prepared showing high potential in extensive in vitro studies for biomedical applications such as guided bone regeneration, yet not limited to that.

[pt] Ésteres de glicerol derivados de ácidos graxos são surfactantes não iônicos com aplicação como lubrificantes, agentes anti-estáticos, auxiliares de processamento, plastificantes, anti-espumas, agentes de dispersão e de outras aplicações que requerem atividade bifuncional. Os monoésteres de glicerol derivados de ácidos graxos naturais, tais como ácido octanóico (C menos 8), decanóico (C menos 10) e octadecanóico (C menos 18), foram sintetizados e caracterizados por técnicas de infravermelho e ressonância magnética nuclear de hidrogênio e carbono 13. Eles foram espalhados sobre uma subfase aquosa formando filmes de Langmuir em uma cuba de teflon. As propriedades interfaciais destes surfactantes foram investigadas na interface ar-água. Desta forma, foi também possível avaliar a isoterma de Langmuir Pi-A e as propriedades mecânicas das monocamadas através do módulo de compressão (Cs elevado a potencia negativa 1). As monocamadas mostraram um comportamento na fase de líquido expandido confirmado pelo módulo de compressão de 10 a 70 mN/m e na fase de líquido condensado confirmado pelo módulo de compressão de 70 a 175 mN/m. Por meio da espectroscopia de reflexão-absorção de infravermelho com fotomodulação (PM-IRRAS) e a microscopia no ângulo de Brewster (BAM) foi avaliada a organização dos filmes de Langmuir dos surfactantes. A elasticidade superficial dilatacional (E) dos filmes adsorvidos foram analisadas pelo método da gota pendente em um goniômetro. / [en] Fatty acid glycerol esters are non-ionic surfactants with application as lubricants, antistatic agents, processing aids, plasticizers, defoamers, dispersion aids and other applications requiring bifunctional activities. Monoesters of glycerol based on natural fatty acids such as octanoic acid (C less 8), decanoic acid (C less 10) and octadecanoic acid (C less 18), were synthesized and characterized by infrared and hydrogen nuclear magnetic resonance and carbon 13 nuclear magnetic resonance techniques. They were spread over the water subphase forming Langmuir films in a Teflon trough. The interfacial properties of these surfactants at the air/water interface have been investigated. Thus it was also possible to evaluate the Langmuir Pi-A isotherm and mechanical properties of the monolayers by calculating the compression modulus (Cs elevated to negative power 1). The monolayers showed a behavior in the expanded liquid phase, confirmed by the compression modulus between 10 and 70 mN/m and a behavior in the condensed liquid phase confirmed by the compression modulus between 70 and 175 mN/m. Through photomodulated-infrared reflection-absorption spectroscopy (PM-IRRAS) and Brewster angle microscopy (BAM) was evaluated organization of Langmuir films of surfactants. The surface dilatational elasticity (E) of the adsorbed films were analyzed by the pendant drop method with a goniometer apparatus.