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Unsized single-end rovings are oxygen plasma pretreated and organosilicon plasma coated using plasma nanotechnology to optimize the interphase in glass-fiber-reinforced polyester composites and to determine the achievable range of their shear strength for potential applications. This surface modification of the fibers allows us to vary the shear strength of the composite in the range of 23.1 to 45.2 MPa at reduced financial costs of the process, while the commercial sizing corresponds to 39.2 MPa. The shear strength variability is controlled by the adhesion of the interlayer (plasma nanocoating) due to the variable density of chemical bonds at the interlayer/glass interface. The optimized technological conditions can be used for continuous surface modification of rovings in commercial online fiber-processing systems.

Unsized single-end rovings are oxygen plasma pretreated and organosilicon plasma coated using plasma nanotechnology to optimize the interphase in glass-fiber-reinforced polyester composites and to determine the achievable range of their shear strength for potential applications. This surface modification of the fibers allows us to vary the shear strength of the composite in the range of 23.1 to 45.2 MPa at reduced financial costs of the process, while the commercial sizing corresponds to 39.2 MPa. The shear strength variability is controlled by the adhesion of the interlayer (plasma nanocoating) due to the variable density of chemical bonds at the interlayer/glass interface. The optimized technological conditions can be used for continuous surface modification of rovings in commercial online fiber-processing systems.

Unsized single-end rovings are oxygen plasma pretreated and organosilicon plasma coated using plasma nanotechnology to optimize the interphase in glass-fiber-reinforced polyester composites and to determine the achievable range of their shear strength for potential applications. This surface modification of the fibers allows us to vary the shear strength of the composite in the range of 23.1 to 45.2 MPa at reduced financial costs of the process, while the commercial sizing corresponds to 39.2 MPa. The shear strength variability is controlled by the adhesion of the interlayer (plasma nanocoating) due to the variable density of chemical bonds at the interlayer/glass interface. The optimized technological conditions can be used for continuous surface modification of rovings in commercial online fiber-processing systems.

This experimental study investigated how defects, in particular fiber misalignment, affect the mechanical behavior of glass fiber composites (GFRP) under compressive loading. GFRP cross-plies with three different types of fiber misalignment, namely a fold, a wave, and an in-plane undulation, were fabricated using the resin transfer molding process. The compressive tests were performed at four different temperatures, in order to investigate the role of a change in the matrix properties on the strength of the composite. The experiments showed that the defects, especially at lower temperatures, had a significant impact on the mechanical properties of the composite, exceeding the proportion of the defects inside the composite. With increasing temperature, the damage mechanism changed from fiber-dominated to matrix-dominated and, in doing so, decreased the significance of fiber misalignment for the mechanical behavior.

Given the time-consuming and complex nature associated with the aging of composites, a novel fabric pre-aging method was developed and evaluated for static and fatigue testing. It allows for investigating sizing and interphase-related aging effects. This fast method is independent of the diffusion processes and the composites’ thickness. Moreover, the new methodology offers enhanced analysis of the sizing, interphase, and fiber-related degradation of composites without aging them by conventional accelerated procedures or under severe maritime environments. For validation purposes, fiber bundle, longitudinal, and transverse tensile tests were performed with five different glass fiber inputs. Significant differences in the durability of composites were found for pre-aging and classical aging, respectively. The impacts of degradation of the single constituents on the fatigue life are identified by cyclic testing of untreated, pre-aged, and wet-aged composites. Here, it is evident that the interphase strength is likewise essential for the tension-tension fatigue performance of unidirectional composites, as is the fiber strength itself. In summary, the presented method provides industry and academia with an additional opportunity to examine the durability of different fibers, sizings, and composites for design purposes following a reasonable methodology., Given the time-consuming and complex nature associated with the aging of composites, a novel fabric pre-aging method was developed and evaluated for static and fatigue testing. It allows for investigating sizing and interphase-related aging effects. This fast method is independent of the diffusion processes and the composites’ thickness. Moreover, the new methodology offers enhanced analysis of the sizing, interphase, and fiber-related degradation of composites without aging them by conventional accelerated procedures or under severe maritime environments. For validation purposes, fiber bundle, longitudinal, and transverse tensile tests were performed with five different glass fiber inputs. Significant differences in the durability of composites were found for pre-aging and classical aging, respectively. The impacts of degradation of the single constituents on the fatigue life are identified by cyclic testing of untreated, pre-aged, and wet-aged composites. Here, it is evident that the interphase strength is likewise essential for the tension-tension fatigue performance of unidirectional composites, as is the fiber strength itself. In summary, the presented method provides industry and academia with an additional opportunity to examine the durability of different fibers, sizings, and composites for design purposes following a reasonable methodology.

The growing demand for polymer composites and their widespread use is inevitably accompanied by the need to know their degradation behavior over a sufficiently long period of time. This study focuses on commercial glass fiber rovings, which were stored in the indoor environment for up to 11 years. Fibers with different storage times, from fresh up to the oldest, were used to produce unidirectional fiber-reinforced polyester composites that were characterized to determine their shear and flexural properties dependent on fiber storage time. A significant decrease in shear strength was observed throughout the aging of the fibers, down to a decrease of 33% for the oldest fibers. An important finding, however, was that the significant decrease in shear strength was only partially reflected in the flexural strength, which corresponded to a decrease of 18% for the oldest fibers at consistent flexural modulus., Rostoucí poptávka po polymerních kompozitech a jejich široké použití je nevyhnutelně doprovázeno potřebou znát jejich degradační chování po dostatečně dlouhou dobu. Tato studie se zaměřuje na komerční pramence ze skleněných vláken, které byly skladovány ve vnitřním prostředí po dobu až 11 let. Vlákna s různou dobou skladování, od čerstvých po nejstarší, byla použita k výrobě jednosměrných polyesterových kompozitů vyztužených vlákny, které byly charakterizovány stanovením jejich smykových a ohybových vlastností v závislosti na době skladování vlákna. V průběhu stárnutí vláken byl pozorován významný pokles pevnosti ve smyku až do poklesu o 33 % u nejstarších vláken. Důležitým zjištěním však bylo, že výrazný pokles pevnosti ve smyku se jen částečně projevil v pevnosti v ohybu, což odpovídalo poklesu o 18 % u nejstarších vláken při konzistentním modulu v ohybu.

The growing demand for polymer composites and their widespread use is inevitably accompanied by the need to know their degradation behavior over a sufficiently long period of time. This study focuses on commercial glass fiber rovings, which were stored in the indoor environment for up to 11 years. Fibers with different storage times, from fresh up to the oldest, were used to produce unidirectional fiber-reinforced polyester composites that were characterized to determine their shear and flexural properties dependent on fiber storage time. A significant decrease in shear strength was observed throughout the aging of the fibers, down to a decrease of 33% for the oldest fibers. An important finding, however, was that the significant decrease in shear strength was only partially reflected in the flexural strength, which corresponded to a decrease of 18% for the oldest fibers at consistent flexural modulus., Rostoucí poptávka po polymerních kompozitech a jejich široké použití je nevyhnutelně doprovázeno potřebou znát jejich degradační chování po dostatečně dlouhou dobu. Tato studie se zaměřuje na komerční pramence ze skleněných vláken, které byly skladovány ve vnitřním prostředí po dobu až 11 let. Vlákna s různou dobou skladování, od čerstvých po nejstarší, byla použita k výrobě jednosměrných polyesterových kompozitů vyztužených vlákny, které byly charakterizovány stanovením jejich smykových a ohybových vlastností v závislosti na době skladování vlákna. V průběhu stárnutí vláken byl pozorován významný pokles pevnosti ve smyku až do poklesu o 33 % u nejstarších vláken. Důležitým zjištěním však bylo, že výrazný pokles pevnosti ve smyku se jen částečně projevil v pevnosti v ohybu, což odpovídalo poklesu o 18 % u nejstarších vláken při konzistentním modulu v ohybu.

The growing demand for polymer composites and their widespread use is inevitably accompanied by the need to know their degradation behavior over a sufficiently long period of time. This study focuses on commercial glass fiber rovings, which were stored in the indoor environment for up to 11 years. Fibers with different storage times, from fresh up to the oldest, were used to produce unidirectional fiber-reinforced polyester composites that were characterized to determine their shear and flexural properties dependent on fiber storage time. A significant decrease in shear strength was observed throughout the aging of the fibers, down to a decrease of 33% for the oldest fibers. An important finding, however, was that the significant decrease in shear strength was only partially reflected in the flexural strength, which corresponded to a decrease of 18% for the oldest fibers at consistent flexural modulus., Rostoucí poptávka po polymerních kompozitech a jejich široké použití je nevyhnutelně doprovázeno potřebou znát jejich degradační chování po dostatečně dlouhou dobu. Tato studie se zaměřuje na komerční pramence ze skleněných vláken, které byly skladovány ve vnitřním prostředí po dobu až 11 let. Vlákna s různou dobou skladování, od čerstvých po nejstarší, byla použita k výrobě jednosměrných polyesterových kompozitů vyztužených vlákny, které byly charakterizovány stanovením jejich smykových a ohybových vlastností v závislosti na době skladování vlákna. V průběhu stárnutí vláken byl pozorován významný pokles pevnosti ve smyku až do poklesu o 33 % u nejstarších vláken. Důležitým zjištěním však bylo, že výrazný pokles pevnosti ve smyku se jen částečně projevil v pevnosti v ohybu, což odpovídalo poklesu o 18 % u nejstarších vláken při konzistentním modulu v ohybu.

The alkali-activation of aluminosilicate materials produces a geopolymer binder that promises to be a sustainable replacement to cement in concrete. Yet, such concrete has experienced brittle behavior and poor resistance to cracking. As a means of improving its performance, this research assesses the feasibility of utilizing glass fibers in slag-fly ash blended geopolymer concrete for structural applications. A blend of slag and fly ash served as the binding material. Two types of glass fibers were used individually or as a hybrid combination. Type A and B glass fibers had similar properties but different lengths of 24 and 43 mm, respectively. The workability of geopolymer concrete was evaluated through slump, compaction factor, and vebe time. Its mechanical properties were characterized by compressive and splitting tensile strength, modulus of elasticity, flexural performance, and shear performance. The durability properties were assessed using water absorption, sorptivity, abrasion resistance, and ultrasonic pulse velocity. Glass fiber-reinforced geopolymer concrete beams were cast and tested to examine their shear behavior. Results highlighted the ability of glass fibers to improve the mechanical and durability properties of geopolymer concrete while maintaining acceptable workability. A hybrid combination of glass fibers of 1%, by volume, provided superior results. Analytical models were established to predict the mechanical and durability characteristics of glass fiber-reinforced geopolymer concrete. The addition of glass fibers to geopolymer concrete beams played a similar role to that of steel stirrups. The inclusion of a hybrid combination of glass fibers was more effective in improving the shear strength than the use of a single type of glass fibers at the same volume fraction. A new refined analytical model was proposed to predict the shear capacity of geopolymer concrete beams reinforced with glass fibers.

El següent treball planteja una de les possibles aplicacions que podria tenir la implementació d'un “digital twin”, en aquest cas, en un procés industrial de pultrusión d'un perfil de fibra de vidre. Però podria adquirir-se en qualsevol altra mena de procés industrial. Aquesta eina (un “digital twin”) permet originar una rèplica digital d'un producte, servei o, en aquest cas, un procés. Després, mitjançant una sèrie de sensors físics que capten i envien informació en temps real, permeten monitorar diversos subprocessos dins del procés principal, podent així tenir una visió més àmplia i un control a distància d'aquest. Per a ensenyar aquesta tècnica i els seus molts usos, en aquest projecte s'ha optat per realitzar un digital twin d'un procés de fabricació d'un perfil recte de fibra de vidre mitjançant pultrusión. En aquest, es detalla pas a pas, des del disseny en 3D del procés mitjançant un programa de CAD, com la programació i la posterior implementació de les diferents plataformes complementàries necessàries per a dur a terme aquest procés, com MQTT, IOT, Grafana i NODE-XARXA. Aquests seran els intermediaris per a poder captar i transmetre la informació captada pels sensors i tenir-la ben expressada i monitorada en el nostre digital twin. D'aquesta manera s'espera mostrar de manera clara i senzilla les múltiples possibilitats, aplicacions i oportunitats que té aquesta eina., El siguiente trabajo plantea una de las posibles aplicaciones que podría tener la implementación de un “digital twin”, en este caso, en un proceso industrial de pultrusión de un perfil de fibra de vidrio. Pero podría adquirirse en cualquier otro tipo de proceso industrial. Esta herramienta ( “digital twin”) permite reproducir una réplica digital de un producto, servicio o, en este caso, un proceso. Después, mediante una serie de sensores físicos que captan i envían información en tiempo real, permite monitorizar varios subprocesos dentro del proceso principal, pudiendo así tener una visión más amplia y un control a distancia del mismo. Para enseñar esta técnica y sus muchos usos, en este proyecto se ha optado por realizar un digital twin de un proceso de fabricación de un perfil recto de fibra de vidrio mediante pultrusión. En este, se detalla paso a paso, desde el diseño en 3D del proceso mediante un programa de CAD, como la programación y la posterior implementación de las diferentes plataformas complementarias necesarias para llevar a cabo este proceso, como MQTT, IOT, Grafana y NODE-RED. Estos serán los intermediarios para poder captar y transmitir la información captada por los sensores y tenerla bien expresada y monitorizada en nuestro digital twin. De esta forma se espera mostrar de forma clara y sencilla las múltiples posibilidades, aplicaciones i oportunidades que tiene esta herramienta., The following paper proposes one of the possible applications that could have the implementation of a "digital twin", in this case, in an industrial process of pultrusion of a fiberglass profile. But it could be acquired in any other type of industrial process. This tool (a "digital twin") allows to originate a digital replica of a product, service or, in this case, a process. Then, by means of a series of physical sensors that capture and send information in real time, they allow to monitor several threads within the main process, thus being able to have a wider vision and a remote control of the same. To teach this technique and its many uses, in this project has chosen to make a digital twin of a process of manufacturing a straight profile of fiberglass by pultrusion. In this, we detail step by step, from the 3D design of the process through a CAD program, such as the programming and subsequent implementation of the different complementary platforms necessary to carry out this process, such as MQTT, IOT, Grafana and NODE-RED. These will be the intermediaries to capture and transmit the information captured by the sensors and have it well expressed and monitored in our digital twin. In this way it is expected to show clearly and easily the multiple possibilities, applications and opportunities that this tool has.

Projecte sorgit de la preocupació per la preservació del medi ambient i la contribució a reduir les emissions de CO2 produïdes en la fabricació, utilització i posterior reciclat dels materials compostos reforçats amb fibra de vidre. Es decideix plantejar objectivament la vertadera viabilitat de substituir les fibres de vidre per una fibra natural que garanteixi un comportament mecànic similar a l’obtingut utilitzant fibres de vidre com a reforç en materials compostos. Es fabriquen uns compostos només diferenciats pel tipus de reforç i caracteritzats a partir d'assajos de tracció i flexió. Gràcies als resultats dels assajos s'avaluen les diferències entre compostos i es determina el potencial de les fibres naturals. Posteriorment, s'avalua a través de simulacions i anàlisis d'esforços, si és factible aplicar aquests compostos en la fabricació de la cúpula de la moto elèctrica de l'equip de competició UPC Vilanova E3 Team. Per acabar, es detallen totes les consideracions de reciclabilitat i sostenibilitat que objectivament cal tenir en compte en tractar amb aquests materials., Proyecto surgido de la preocupación por la preservación del medio ambiente y la contribución a reducir las emisiones de CO₂ producidas en la fabricación, utilización y posterior reciclado de los materiales compuestos reforzados con fibra de vidrio. En este trabajo se plantea objetivamente la verdadera viabilidad de sustituir las fibras de vidrio por una fibra natural que garantice un comportamiento mecánico similar al obtenido utilizando fibras de vidrio como refuerzo en materiales compuestos. Se fabrican unos compuestos solo diferenciados por el tipo de refuerzo y caracterizados a partir de ensayos de tracción y flexión. A partir de los resultados de los ensayos se evalúan las diferencias entre compuestos y se determina el potencial de las fibras naturales. Posteriormente, se evalúa mediante simulaciones y análisis de esfuerzos si es factible aplicar estos compuestos en la fabricación de la cúpula de la moto eléctrica del equipo de competición UPC Vilanova E3 Team. Para finalizar, se detallan todas las consideraciones de reciclaje y sostenibilidad que objetivamente se deben tener en cuenta al tratar con estos materiales., This project stems from concern for preserving the environment and contributing to reduce carbon emissions produced in the manufacture, use and recycling of fibre-reinforced composite materials. It is decided to objectively establish the proper feasibility of replacing glass fibres with a natural fibre that ensures similar mechanical behaviour to that of glass fibres. The manufacture of composites is differentiated only by the type of reinforcement and is characterised by tensile and flexural testing. The results of the tests allow us to evaluate the differences between compounds and the potential of natural fibres is determined. In addition, simulations and effort analysis were conducted to evaluate whether these compounds were feasible for use in the manufacture of electric motorcycle domes for the UPC Vilanova E3 Team competition team. To conclude, all considerations of recyclability and sustainability that must be objectively taken into account are made.

Sandwich panels represent a lightweight solution with additional properties as insulation compared to traditional solutions used for building enclosures. In this study, a technology based on vegetal FRCM (fabric reinforced cementitious matrix) provides an economical, sustainable and competitive solution. The research introduces a composite design made of different vegetal fabrics (hemp and sisal) and mortar as skins of the sandwich and a core of extruded polystyrene. Both composite skins were connected with different types of connectors including vegetal designs. An experimental campaign of sandwich panels included four-point bending tests and a later development of numerical models capable of reproducing the experimental results. The results obtained show that the use of vegetal fabrics and connectors were as competitive for the development of effective composite action as synthetic fabrics (glass fiber)., This study has been partially carried out within the project ‘‘Desarrollo de paneles industriales prefabricados tipo sándwich con materiales compuestos de matriz cementicia (FRCM) y con digitalizacion ´ BIM incorporada. PANELPLUS’’, funded by the Spanish Ministry of Science, Innovation and University through the Torres Quevedo program. The materials support of Sika AG and Mapei Spain S.A. is acknowledged. Authors want to thanks the research project SEVERUS (RTI2018- 099589-B-I00) of the Spanish Research Agency. The contribution of PhD. Lluis Gil is also acknowledged. Second author is a Serra Húnter Fellow., Peer Reviewed, Postprint (author's final draft)

The application of glass fiber reinforced composites has grown rapidly due to their high strength-to-weight ratio, low cost, and chemical resistance. However, the increasing demand for fiber reinforced composites results in the generation of more composite wastes. Mechanical recycling is a cost-effective and environmentally-friendly recycling method, but the loss in the quality of recycled glass or carbon fiber composite hinders the wide-spread use of this recycling method. It is important to develop novel composite materials with higher recyclability. Thermotropic liquid crystalline polymers (TLCPs) are high-performance engineering thermoplastics, which have comparable mechanical performance to that of glass fiber. The TLCP reinforced composites, called in situ composites, can form the reinforcing TLCP fibrils during processing avoiding the fiber breakage problem. The first part of this dissertation is to study the influence of mechanical recycling on the properties of injection molded TLCP and glass fiber (GF) reinforced polypropylene (PP). The processing temperature of the injection molding process was optimized using a differential scanning calorimeter (DSC) and a rheometer to minimize the thermal degradation of PP. The TLCP and GF reinforced PP materials were mechanically recycled up to three times by repeated injection molding and grinding. The mechanical recycling had almost no influence on the mechanical, thermal, and thermo-mechanical properties of TLCP/PP because of the regeneration of TLCP fibrils during the mold filling process. On the other hand, glass fiber/PP composites decreased 30% in tensile strength and 5% in tensile modulus after three reprocessing cycles. The micro-mechanical modeling demonstrated the deterioration in mechanical properties of GF/PP was mainly attributed to the fiber breakage that occurred during compounding and grinding. The second part of this dissertation is concerned with the development of recyclable and light weight hybrid

Microplastic pollution of water and ecosystem is attracting continued attention worldwide. Due to their small sizes (≤5 mm) microplastic particles can be discharged to the environment from treated wastewater effluents. As microplastics have polluted most of our aquatic ecosystems, often finding its way into drinking water, there is urgent need to find new solutions for tackling the menace of microplastic pollution. In this work, sustainable green photocatalytic removal of microplastics from water activated by visible light is proposed as a tool for the removal of microplastics from water. We propose a novel strategy for the elimination of microplastics using glass fiber substrates to trap low density microplastic particles such as polypropylene (PP) which in parallel support the photocatalyst material. Photocatalytic degradation of PP microplastics spherical particles suspended in water by visible light irradiation of zinc oxide nanorods (ZnO NRs) immobilized onto glass fibers substrates in a flow through system is demonstrated. Upon irradiation of PP microplastics for two weeks under visible light reduced led to a reduction of the average particle volume by 65%. The major photodegradation by-products were identified using GC/MS and found to be molecules that are considered to be mostly nontoxic in the literature., QC 20210720

The automotive industry is always focusing on advanced composites to improve the strength-to-weight ratio. To meet this need, many unique composite materials have been developed or fabricated in the automotive industry. Both synthetic and natural polymers are being used in the production of composite materials for automotive applications. The use of synthetic polymers derived from petroleum sources is hazardous to the environment. The majority of the motorcycle's body frame parts are composed of an ABS (Acrylonitrile Butadiene Styrene) engineering thermoplastic. ABS is a petroleum-based plastic that is non-biodegradable, is not a renewable resource, and is not environmental friendly. Because of the environmentally hazardous properties of ABS plastic, researchers are leaning toward biodegradable plastic in order to save the environment. This might have been achieved with biodegradable materials such as poly(lactic acid) (PLA) and natural fiber composites. PLA is an excellent choice for replacing ABS since it is a bio-degradable type of plastic that is made from plant-based materials such as corn starch or sugarcane. PLA is a biobased, biodegradable, biocompatible, compostable, and non-toxic polymer with low material and manufacturing costs as well as desired mechanical properties. Sugar palm [Arenga pinnata (Wurmb.) Merr] fiber has been chosen to mixed with PLA and glass fiber, because of its availability, particularly in Southeast Asia, and its proven performance. Therefore, this research describes the development and characterization of hybrid and non-hybrid composites of sugar palm and glass fiber reinforced poly(lactic acid) for Modenas Kriss 110 motorcycle battery housing part. To evaluate the impact of different wt.% of fiber loading, treatment and hybridization, hybrid and non-hybrid sugar palm/glass fiber (SPF/GF) reinforced PLA composites were developed using a Brabender Plastograph, followed by a compression molding method. Initially the effect of various f

[ES] En el ámbito de los materiales compuestos o composites para la construcción, el cemento reforzado con fibras de vidrio (GRC, del inglés glass fiber reinforced cement) es el más extensamente utilizado, por sus excelentes propiedades mecánicas (resistencia a flexión y tenacidad). Sin embargo, la durabilidad de estos composites se ha demostrado crítica, y es necesario proponer alternativas. Las fibras usadas, de carácter álcali-resistente (fibras AR, formadas por agrupación de filamentos), son atacadas por el medio agresivo que impone el cemento hidratado. Una alternativa interesante, desde el punto de vista tecnológico, es la incorporación de materiales cementantes suplementarios de carácter puzolánico. El objetivo del presente trabajo es estudiar la influencia de las diferentes adiciones activas en morteros de GRC, observando el comportamiento de los elementos constitutivos del material en condiciones normales de curado, y también al ser sometidos a procesos de envejecimiento controlado. Asimismo, se analiza el comportamiento de los nuevos composites sometidos a diferentes medios agresivos, evaluando la durabilidad y la mejora de los compuestos por medio de la determinación de sus propiedades mecánicas, químicas y físicas. Se han elaborado probetas de GRC a través del procedimiento de premezcla (premix) y se han determinado sus propiedades mecánicas (resistencia a flexión, tenacidad y módulo de elasticidad). Adicionalmente, se han cuantificado las ganancias de resistencia al comparar composites GRC basados en cemento Portland (especímenes control) con otros en los que se ha sustituido hasta el 60% de dicho cemento por adiciones puzolánicas. Al objeto de mejorar la reactividad de las puzolanas, en algunos casos se ha implementado un aumento de su finura a través de la molienda (cenizas volantes molidas, CVm) o de procesos de sonicación (humo de sílice sonicado, HSS). Los especímenes de GRC han sido sometidos a un proceso de envejecimiento (tratamiento en agua a 5, [CAT] En l'àmbit dels materials compostos o compòsits per a la construcció, el ciment reforçat amb fibres de vidre (GRC, de l'anglès glass fiber reinforced cement) és el més extensament utilitzat, per les seves excel·lents propietats mecàniques (resistència a flexió i tenacitat). No obstant això, la durabilitat d'aquests compòsits s'ha demostrat crítica, i cal proposar alternatives. Les fibres usades, de caràcter àlcali-resistent (fibres AR, formades per agrupació de filaments), són atacades pel medi agressiu que imposa el ciment hidratat. Una alternativa interessant des del punt de vista tecnològic és la incorporació de materials cimentants suplementaris de caràcter putzolànic. L'objectiu d'aquest treball és estudiar la influència de les diferents addicions actives en morters de GRC, observant el comportament dels elements constitutius del material en condicions normals de curat, i també quan son sotmesos a processos d'envelliment controlat. Així mateix, s'analitza el comportament dels nous compòsits sotmesos a diferents mitjans agressius, avaluant la durabilitat i la millora dels compostos mitjançant la determinació de les seves propietats mecàniques, químiques i físiques. S'han elaborat provetes de GRC a través del procediment de mescla prèvia (premix) i s'ha determinat les seves propietats mecàniques (resistència a flexió, tenacitat, mòdul d'elasticitat). Addicionalment s'han quantificat els guanys de resistència al comparar compòsits GRC basats en ciment Portland (espècimens control) amb altres en què s'ha substituït fins al 60% d'aquest ciment per materials putzolànics. A l'objecte de millorar la reactivitat de les putzolanes, en alguns casos s'ha implementat un augment de la seva finor a través de la mòlta (cendres volants mòltes, CVm) o de processos de sonicació (fum de sílice sonicat, HSS). Els espècimens de GRC han estat sotmesos a un procés d'envelliment (tractament en aigua a 55ºC durant un període prolongat) i s'ha observat l'empitjorament molt signific, [EN] In the field of composite materials for construction, glass fiber reinforced cement (GRC) is the most widely used, due to its excellent mechanical properties (resistance to bending and toughness). However, the durability of these composites has been demonstrated to be critical and alternatives need to be proposed. The used fibers, alkali-resistant (AR fibers, formed by grouping of filaments), are attacked by the aggressive medium imposed by the hydrated cement. An interesting alternative, from a technological point of view, is the incorporation of supplementary cementitious materials of pozzolanic behaviour. The purpose of this research is to study the influence of the different mineral additions in GRC mortars, observing the behaviour of the constituent elements of the material under normal curing conditions and controlled aging processes. Likewise, the behaviour of new composites subjected to different aggressive environments is analyzed, evaluating the durability and improvement of the compounds by determining their mechanical, chemical and physical properties. GRC specimens have been produced through the premix procedure and their mechanical properties (flexural strength, toughness, and modulus of elasticity) have been determined. Additionally, resistance gains have been quantified when comparing GRC composites based on Portland cement (control specimens) with others in which up to 60% of that cement has been replaced by pozzolanic additions. In order to improve the reactivity of pozzolans, in some cases an increase in its fineness has been implemented through grinding (ground fly ash, CVm) or sonication processes (sonicated silica fume, HSS). The GRC specimens have been subjected to an aging process (treatment in water at 55ºC for an extended period) and worsening of the flexural strength and toughness of those who only have Portland cement as cementitious component has been observed. GRC composites containing high amounts of pozzolan (60% CVm) or mixtures

By combining the concepts of in situ thermotropic liquid crystalline polymer (TLCP) composites and conventional fiber composites, a recyclable and high-performance in situ hybrid polypropylene-based composite was successfully developed. The recycled hybrid composite was prepared by injection molding and grinding processes. Rheological and thermal analyses were utilized to optimize the processing temperature of the injection molding process to reduce the melt viscosity and minimize the degradation of polypropylene. The ideal temperature for blending the hybrid composite was found to be 305 °C. The influence of mechanical recycling on the different combinations of TLCP and glass fiber composites was analyzed. When the weight fraction ratio of TLCP to glass fiber was 2 to 1, the hybrid composite exhibited better processability, improved tensile performance, lower mechanical anisotropy, and greater recyclability compared to the polypropylene reinforced by either glass fiber or TLCP alone.

By combining the concepts of in situ thermotropic liquid crystalline polymer (TLCP) composites and conventional fiber composites, a recyclable and high-performance in situ hybrid polypropylene-based composite was successfully developed. The recycled hybrid composite was prepared by injection molding and grinding processes. Rheological and thermal analyses were utilized to optimize the processing temperature of the injection molding process to reduce the melt viscosity and minimize the degradation of polypropylene. The ideal temperature for blending the hybrid composite was found to be 305 °C. The influence of mechanical recycling on the different combinations of TLCP and glass fiber composites was analyzed. When the weight fraction ratio of TLCP to glass fiber was 2 to 1, the hybrid composite exhibited better processability, improved tensile performance, lower mechanical anisotropy, and greater recyclability compared to the polypropylene reinforced by either glass fiber or TLCP alone.

L’idea de realitzar aquest treball sorgeix de la necessitat de millorar l’adhesió entre fibres de vidre (GF, glass fiber) i la resina epoxi, al ser modificades superficialment i poder millorar les propietats tribològiques. Actualment, hi ha una mancança considerable d’informació sobre quin és el millor tractament per tal de millorar l’adhesió interfacial i d’aquesta manera millorar el seu comportament a fricció. En aquest sentit, per estudiar l’efectivitat d’aquests tractaments superficials es desitjava realitzar assajos tribològics (assajos de ratllat i desgast) per tal d’avaluar el coeficient de fricció i la tassa de desgast, respectivament. Però degut a la pandèmia causada per el COVID-19, es va veure truncat i el treball final de màster és va convertir en un treball: experimental i teòric. (1) Experimentalment, només es va poder determinar el temps de gelificació i realitzar uns compostos a petita escala, per determinar la relació òptima de resina-fibra, per el mètode de la bossa al buit (BV) o el procés d’infusió al buit (VIP, vacuum infusion process). Els resultat va mostrar que per a major temps d’agitació el temps de gelificació disminueix. Lo mateixa tendència s’observa quan s’incrementa la quantitat de solució de NH4OH ja que aquest accelera la velocitat de gelificació. Mentre que per a realitzar un compost amb unes dimensions de 3 x 3 cm amb 3 capes de fibra de vidre (aprox. 300 mg) resulta necessari injectar aprox. 900 mg de resina, és a dir, es requereix un 25% en pes de fibra. (2) Pel que fa al treball bibliogràfic, s’ha realitzat un treball exhaustiu on s’ha avaluat si la modificació superficial de les fibres ajuda a millorar les propietats mecàniques. En aquest sentit, es va trobar que l’addició de fibres en resines termoestables, específicament epoxídics, augmenta les propietats mecàniques, en comparació amb la resina pura. Però la modificació superficial del reforç, efectivament, augmenta encara molt més les seves propietats finals. En aquest senti, La idea de realizar el presente trabajo surge de la necesidad de mejorar la adhesión entre fibras de vidrio (GF, glass fiber) y resina epoxi, al ser modificada superficialmente y poder mejorar las propiedades tribológicas. Actualmente, no existe ningún artículo donde se explique cuál es el mejor tratamiento para mejorar la adhesión interfacial i de esta manera mejorar su comportamiento a fricción. En este sentido, con el objetivo de estudiar la efectividad de estos tratamientos superficiales se iba a realizar un estudio de estos compuestos en condiciones tribológicas (frente a la fricción y desgaste) con el objetivo final de poder evaluar el coeficiente de fricción y la tasa de desgaste, respectivamente. Pero debido a la pandemia causada por el COVID-19, se tomó la decisión de hacer un trabajo final de máster mixto: experimental y teórico. (1) Experimentalmente, solo se pudo determinar el tiempo de gelificación y realizar unos compuestos a pequeña escala, para determinar la relación óptima de resina-fibra, por el método de la bolsa de vacío (BV) o el proceso de infusión al vacío (VIP, vacuum infusion process). Los resultados mostraron que a mayor tiempo de agitación el tiempo de gelificación disminuye. La misma tendencia se observa cuando se incrementa la cantidad de solución de NH4OH ya que este actúa como catalizador acelerando la velocidad de gelificación. Mientras que para realizar un compuesto de 3 x 3 cm con 3 capas de fibra de vidrio (aprox. 300 mg) resulta necesario inyectar aprox. 900 mg de resina, es decir, se requiere un 25% en peso de fibra. (2) Por lo que hace referencia al trabajo bibliográfico, se ha realizado un trabajo exhaustivo donde se observó que la modificación superficial de las fibras ayuda a mejorar las propiedades mecánicas. En este sentido, se encontró que la adición de fibras en resinas termoestables, específicamente epoxi, aumenta las propiedades mecánicas, en comparación con la resina pura. Pero la modificación superficial del refuerzo, The idea to conduct this research work arises from the need to improve the adhesion between glass fibers (GF) and epoxy resin, by means of superficially modifying and be able to enhance their tribological properties. Nowadays, scarce information related to this topic is available in the literature. In this sense, in order to study the effectiveness of these coatings, tribological tests were desired to conduct (scratch and wear tests) in order to evaluate the friction coefficient and the wear rate, respectively. However, due to the pandemic caused by COVID-19, this research work was adapted to mixed Master’s thesis: experimental and theoretical. (1) Experimentally, it was only possible to determine the gelification time and performsome small specimens (laboratory scale), to determine the optimum resin-fiber ratio, by the bag of empty method or the vacuum infusion process (VIP). The preliminary results showed that the longer the stirring time, the gelling time decreased. Similar trend was observed when the amount of NH4OH solution increases due to this chemical agent acts as a catalyst and accelerates the gelling rate. In this context, some specimens were built (3 x 3 cm composite with 3 layers of fiberglass). These specimens present around 300 mg of GF and around 900 mg of resin, which means around 25 weight % of fiber is required. (2) Regarding the bibliographic study, exhaustive work was carried out on the evaluation of the different superficial modification techniques which leads to enance the mechanical properties. In this sense, it was found that the addition of fibers in thermosetting resins, specifically epoxy, increases the mechanical integrity in comparison with the pure resin. But the surface modification of the reinforcement effectively increases their final mechanical properties. Within this context, the silane treatment is turned out to be the most used treatment due to the compatibility of silica with the glass structure, allowing to increase the adhesi

Goal of the thesis: The main goal of the thesis was to create a simulation model that captures the thermal behaviour of the bushing used in the production of glass fibres. In particular, the bushing at the RWTH Aachen Institut für Textiltechnik was examined. The study investigates on the temperature distribution in working conditions in order to better understand the thermal behaviour and ultimately to enable the design of new innovative bushings. Approach: The study of the temperature distribution of the bushing was done using the finite elements method. So as to build a simulation model, the thermal parameters of the materials of the system were determined. Inventor and Autodesk CFD were the softwares used to build the geometry and the thermal model respectively. Key results: The simulation model design could not be fully validated. Further improvements are required in the glass modelling.

All reinforcements for polymer-matrix composites must be coated with a suitable material in the form of thin film to improve compatibility and interfacial adhesion between the reinforcement and the polymer matrix. In this study, plasma nanotechnology was used to synthetize such functional nanocoatings using pure tetravinylsilane (TVS) and its mixtures with oxygen gas (O2) as precursors. The plasma-coated glass fibers (GFs) were unidirectionally embedded in a polyester resin to produce short composite beams that were analyzed by a short-beam-shear test to determine the shear strength characterizing the functionality of the nanocoatings in a GF/polyester composite. The developed plasma nanocoatings allowed controlling the shear strength between 26.2 – 44.1 MPa depending on deposition conditions, i.e., the RF power and the oxygen fraction in the TVS/O2 mixture. This range of shear strength appears to be sufficiently broad to be used in the design of composites., Všechny výztuže pro polymerní kompozitymusí být potaženy vhodným materiálem ve formě tenké vrstvy, aby se zlepšila kompatibilita a adheze mezi výztuží a polymerní matricí. V této studii byla použita plazmová nanotechnologie k syntetizaci takových funkčních nanopovlaků za použití čistého tetravinylsilanu (TVS) a jeho směsí s plynným kyslíkem (O2) jako prekurzorů. Plazmová skleněná vlákna (GF) byla jednosměrně zabudována do polyesterové pryskyřice za vzniku krátkých kompozitních paprsků, které byly analyzovány zkouškou střihem s krátkým paprskem, aby se stanovila pevnost ve smyku charakterizující funkčnost nanokovin v kompozitu GF / polyester. Vyvinuté plazmové nanokovory umožnily regulovat smykovou pevnost mezi 26,2 - 44,1 MPa v závislosti na podmínkách nanášení, tj. Na vysokofrekvenčním výkonu a kyslíkové frakci ve směsi TVS / O2. Tento rozsah smykové pevnosti se zdá být dostatečně široký, aby mohl být použit při konstrukci kompozitů.

Polyurethane shape memory polymer (SMP) are comparatively low in modulus. Hence, there is a need for incorporation of chopped strand mat glass fibers as reinforcing materials for the development of SMP composites (SMPC). In this study, glass fibers in different volume fractions which are 0%, 5%, 10%, 15% and 30% were used. The aim is to obtain the optimum volume fractions of glass fibers in SMPC based on the dynamic mechanical properties. The dynamic mechanical analysis (DMA) was carried out to determine the dynamic mechanical properties of the composite material. The dynamic parameters which reliance to temperature such as storage modulus (E’), loss modulus (E”), damping factor (tan δ), glass transition temperature (Tg) values and others will gives the data regarding the adhesion of fiber-matrix of the composite material. The result shows that upon the addition of reinforcing fibers, an improvement in storage modulus was obtained. The tan δ peak value were decrease when the fiber volume fractions were increased, which confirming the reinforcing effectiveness of glass fibers in SMPC. It was also observed that the (Tg) increase upon the addition of reinforcing glass fibers. Summarizing, 15SMPC was chosen as the optimum volume fractions of glass fibers in SMPC. The parameter of the damping vibration demonstrates main significance for civil applications for building reliability and performance enhancement. Besides, it can foresee the impacts of temperature and time towards the polymer viscoelastic performance under various conditions. This study will provide several information to determine its functional application in future research.

The design, analysis and structural testing of a new wing for a flutter wind tunnel model is considered. The aircraft configuration represents a modern light weight fighter configuration with external stores. A first test in the Transonic Dynamics Tunnel (TDT) at NASA Langley was performed in 2016 and the upcoming second test is planned for 2020. During the first test program, a large amount of static aeroelastic data was acquired both in air and heavy gas (R134a) and also some dynamic data. Flutter testing was also performed but only two flutter conditions were achieved before model damage. For the second test, a new wing structural design is being developed in order to allow flutter testing also without under-wing external stores and without significant mass balancing. However, in order to maintain sufficient structural strength, design optimization is required. The new design is to maintain the same strength as the first design tested but with much lower flutter dynamic pressure in transonic conditions. The strength requirements are considered using structural testing in combination with linear elastic finite element analysis. The design process has demonstrated that changing the composite layup will have a very significant influence on the predicted flutter dynamic pressure without loss of strength. By using a mix of glass-fiber weave with a few layers of uni-directional glass-fiber and tailoring of the fiber orientation, a sufficiently large reduction in flutter dynamic pressure can be obtained., QC 20200622

Thermoplastic resin transfer molding (T-RTM) is attracting much attention due to the need for recyclable alternatives to thermoset materials. In this work, we have prepared polyamide-6 (PA6) and PA6/fiber composites by T-RTM of caprolactam. Glass and carbon fibers were employed in a fixed amount of 60 and 47 wt.%, respectively. Neat PA6 and PA6 matrices (of PA6-GF and PA6-CF) of approximately 200 kg/mol were obtained with conversion ratios exceeding 95%. Both carbon fibers (CF) and glass fibers (GF) were able to nucleate PA6, with efficiencies of 44% and 26%, respectively. The alpha crystal polymorph of PA6 was present in all samples. The lamellar spacing, lamellar thickness and crystallinity degree did not show significant variations in the samples with or without fibers as result of the slow cooling process applied during T-RTM. The overall isothermal crystallization rate decreased in the order: PA6-CF > PA6-GF > neat PA6, as a consequence of the different nucleation efficiencies. The overall crystallization kinetics data were successfully described by the Avrami equation. The lamellar stack morphology observed by atomic force microscopy (AFM) is consistent with 2D superstructural aggregates (n = 2) for all samples. Finally, the reinforcement effect of fibers was larger than one order of magnitude in the values of elastic modulus and tensile strength.

All reinforcements for polymer-matrix composites must be coated with a suitable material in the form of thin film to improve compatibility and interfacial adhesion between the reinforcement and the polymer matrix. In this study, plasma nanotechnology was used to synthetize such functional nanocoatings using pure tetravinylsilane (TVS) and its mixtures with oxygen gas (O2) as precursors. The plasma-coated glass fibers (GFs) were unidirectionally embedded in a polyester resin to produce short composite beams that were analyzed by a short-beam-shear test to determine the shear strength characterizing the functionality of the nanocoatings in a GF/polyester composite. The developed plasma nanocoatings allowed controlling the shear strength between 26.2 – 44.1 MPa depending on deposition conditions, i.e., the RF power and the oxygen fraction in the TVS/O2 mixture. This range of shear strength appears to be sufficiently broad to be used in the design of composites., Všechny výztuže pro polymerní kompozitymusí být potaženy vhodným materiálem ve formě tenké vrstvy, aby se zlepšila kompatibilita a adheze mezi výztuží a polymerní matricí. V této studii byla použita plazmová nanotechnologie k syntetizaci takových funkčních nanopovlaků za použití čistého tetravinylsilanu (TVS) a jeho směsí s plynným kyslíkem (O2) jako prekurzorů. Plazmová skleněná vlákna (GF) byla jednosměrně zabudována do polyesterové pryskyřice za vzniku krátkých kompozitních paprsků, které byly analyzovány zkouškou střihem s krátkým paprskem, aby se stanovila pevnost ve smyku charakterizující funkčnost nanokovin v kompozitu GF / polyester. Vyvinuté plazmové nanokovory umožnily regulovat smykovou pevnost mezi 26,2 - 44,1 MPa v závislosti na podmínkách nanášení, tj. Na vysokofrekvenčním výkonu a kyslíkové frakci ve směsi TVS / O2. Tento rozsah smykové pevnosti se zdá být dostatečně široký, aby mohl být použit při konstrukci kompozitů.

This research is aimed at developing optimized process parameters to fabricate pineapple leaf fibre (PALF)-vinyl-ester-based hybrid biocomposites utilising the industrial robotic arm integrated with fibre spray up mechanism. The optimized process parameters are developed through a series of testing using different variable process parameters controlled by the integrated spray gun-robotic arm system. In the preliminary study, material characterization of pineapple leaf fibre (PALF) of 273 tex, was conducted, which include physical, morphological, mechanical, and thermal testing and analysis. PALF yarn fibre with different robot linear travel speed (0.15, 0.23, 0.30, 0.38, and 0.45) m/s reinforced vinyl ester composites are fabricated and characterized based on mechanical (tensile and flexural), thermal (TGA and DMA) and surface morphology. For each mechanical result, coefficient of variance (COV) is calculated to measure the variability of the mean distribution. The optimum robot linear travel speed obtained is 0.23 m/s, which produced composite with density of 1.12 g/cm3 and fibre volume fraction of 27.4%. The COV for 0.23 m/s robot speed sample is 9.51%, with the highest tensile strength of 28.70 MPa. The analysis of spray angle showed optimum spray angle of 70°, whereby spray distribution of the chopped fibre showed highest degree of uniformity (COV 5.84%), as well as high mechanical strength. Linear spray pattern produced more uniform fibre and resin distribution as compared to circular and cross, whereby a lot of overlap fibre distribution occurred, which affect thickness consistency throughout the sample. Thermal analysis showed that linear pattern resulted in the highest Onset Oxidation Temperature (OOT) at 397.56°C, while circular pattern recorded the maximum char residue at 5.78%. The length of pineapple yarn consists of 3 different combination, namely as L1 (130 - 150) mm, L2 (530 - 550) mm and L3 (130 – 550) mm. The mechanical analysis depicted that L1 res

All reinforcements for polymer-matrix composites must be coated with a suitable material in the form of thin film to improve compatibility and interfacial adhesion between the reinforcement and the polymer matrix. In this study, plasma nanotechnology was used to synthetize such functional nanocoatings using pure tetravinylsilane (TVS) and its mixtures with oxygen gas (O2) as precursors. The plasma-coated glass fibers (GFs) were unidirectionally embedded in a polyester resin to produce short composite beams that were analyzed by a short-beam-shear test to determine the shear strength characterizing the functionality of the nanocoatings in a GF/polyester composite. The developed plasma nanocoatings allowed controlling the shear strength between 26.2 – 44.1 MPa depending on deposition conditions, i.e., the RF power and the oxygen fraction in the TVS/O2 mixture. This range of shear strength appears to be sufficiently broad to be used in the design of composites., Všechny výztuže pro polymerní kompozitymusí být potaženy vhodným materiálem ve formě tenké vrstvy, aby se zlepšila kompatibilita a adheze mezi výztuží a polymerní matricí. V této studii byla použita plazmová nanotechnologie k syntetizaci takových funkčních nanopovlaků za použití čistého tetravinylsilanu (TVS) a jeho směsí s plynným kyslíkem (O2) jako prekurzorů. Plazmová skleněná vlákna (GF) byla jednosměrně zabudována do polyesterové pryskyřice za vzniku krátkých kompozitních paprsků, které byly analyzovány zkouškou střihem s krátkým paprskem, aby se stanovila pevnost ve smyku charakterizující funkčnost nanokovin v kompozitu GF / polyester. Vyvinuté plazmové nanokovory umožnily regulovat smykovou pevnost mezi 26,2 - 44,1 MPa v závislosti na podmínkách nanášení, tj. Na vysokofrekvenčním výkonu a kyslíkové frakci ve směsi TVS / O2. Tento rozsah smykové pevnosti se zdá být dostatečně široký, aby mohl být použit při konstrukci kompozitů.

All reinforcements for polymer-matrix composites must be coated with a suitable material in the form of thin film to improve compatibility and interfacial adhesion between the reinforcement and the polymer matrix. In this study, plasma nanotechnology was used to synthetize such functional nanocoatings using pure tetravinylsilane (TVS) and its mixtures with oxygen gas (O2) as precursors. The plasma-coated glass fibers (GFs) were unidirectionally embedded in a polyester resin to produce short composite beams that were analyzed by a short-beam-shear test to determine the shear strength characterizing the functionality of the nanocoatings in a GF/polyester composite. The developed plasma nanocoatings allowed controlling the shear strength between 26.2 – 44.1 MPa depending on deposition conditions, i.e., the RF power and the oxygen fraction in the TVS/O2 mixture. This range of shear strength appears to be sufficiently broad to be used in the design of composites., Všechny výztuže pro polymerní kompozitymusí být potaženy vhodným materiálem ve formě tenké vrstvy, aby se zlepšila kompatibilita a adheze mezi výztuží a polymerní matricí. V této studii byla použita plazmová nanotechnologie k syntetizaci takových funkčních nanopovlaků za použití čistého tetravinylsilanu (TVS) a jeho směsí s plynným kyslíkem (O2) jako prekurzorů. Plazmová skleněná vlákna (GF) byla jednosměrně zabudována do polyesterové pryskyřice za vzniku krátkých kompozitních paprsků, které byly analyzovány zkouškou střihem s krátkým paprskem, aby se stanovila pevnost ve smyku charakterizující funkčnost nanokovin v kompozitu GF / polyester. Vyvinuté plazmové nanokovory umožnily regulovat smykovou pevnost mezi 26,2 - 44,1 MPa v závislosti na podmínkách nanášení, tj. Na vysokofrekvenčním výkonu a kyslíkové frakci ve směsi TVS / O2. Tento rozsah smykové pevnosti se zdá být dostatečně široký, aby mohl být použit při konstrukci kompozitů.

La construction d’une base de données des différentes matières de moules utilisées dans le monde verrier est effectuée sur demande de Baccarat afin de pouvoir mieux maîtriser les facteurs susceptibles de dégrader les moules et de dégrader la production d’articles en cristal.Une première partie constituée d’un travail essentiellement bibliographique a permis d’acquérir les connaissances de bases relatives à la formation du cristal, et à ses principales propriétés, ainsi que les caractéristiques recherchées pour des moules performants. Il est ainsi nécessaire d’avoir des moules résistants à l’usure à des températures élevées, mais aussi possédant de bonnes propriétés thermiques et notamment de conductivité afin de permettre une homogénéisation de la température. Les matériaux utilisés pour les moules doivent être facilement usinables afin de réduire les coûts de fabrication, et doivent permettre de démouler facilement les articles en cristal, ce qui est déterminé par leur état de surface. Ces axes de recherche sont motivés par l’existence d’un problème de collage du cristal aux parois du moule constaté par les ouvriers de Baccarat.Dans le but d’implémenter un mode de production semi-automatisé de gobelets en cristal, il a également été nécessaire d’effectuer des recherches sur les machines types IS, ainsi que sur les caractéristiques de moules utilisés dans ce type de machines.Enfin, il a été décidé en accord avec l’industriel de mener des tests expérimentaux afin de caractériser le comportement des moules lors des cycles de montée en température et de refroidissement subis par les moules. Les tests de dureté mis en place pour trois matériaux d’intérêt ont permis de montrer que les trempes après montée en température influent peu sur la dureté des matériaux testés, mais il faut néanmoins tenir compte du fait que les cycles de montée en température suivis de trempes répétés peuvent conduire à la dégradation des matériaux. Les tests de dilatation thermique ont permis de, Outgoing

All reinforcements for polymer-matrix composites must be coated with a suitable material in the form of thin film to improve compatibility and interfacial adhesion between the reinforcement and the polymer matrix. In this study, plasma nanotechnology was used to synthetize such functional nanocoatings using pure tetravinylsilane (TVS) and its mixtures with oxygen gas (O2) as precursors. The plasma-coated glass fibers (GFs) were unidirectionally embedded in a polyester resin to produce short composite beams that were analyzed by a short-beam-shear test to determine the shear strength characterizing the functionality of the nanocoatings in a GF/polyester composite. The developed plasma nanocoatings allowed controlling the shear strength between 26.2 – 44.1 MPa depending on deposition conditions, i.e., the RF power and the oxygen fraction in the TVS/O2 mixture. This range of shear strength appears to be sufficiently broad to be used in the design of composites., Všechny výztuže pro polymerní kompozitymusí být potaženy vhodným materiálem ve formě tenké vrstvy, aby se zlepšila kompatibilita a adheze mezi výztuží a polymerní matricí. V této studii byla použita plazmová nanotechnologie k syntetizaci takových funkčních nanopovlaků za použití čistého tetravinylsilanu (TVS) a jeho směsí s plynným kyslíkem (O2) jako prekurzorů. Plazmová skleněná vlákna (GF) byla jednosměrně zabudována do polyesterové pryskyřice za vzniku krátkých kompozitních paprsků, které byly analyzovány zkouškou střihem s krátkým paprskem, aby se stanovila pevnost ve smyku charakterizující funkčnost nanokovin v kompozitu GF / polyester. Vyvinuté plazmové nanokovory umožnily regulovat smykovou pevnost mezi 26,2 - 44,1 MPa v závislosti na podmínkách nanášení, tj. Na vysokofrekvenčním výkonu a kyslíkové frakci ve směsi TVS / O2. Tento rozsah smykové pevnosti se zdá být dostatečně široký, aby mohl být použit při konstrukci kompozitů.

The selectivity in composite damage sensing using the electrical resistance approach is investigated by deliberately placing multiwall carbon nanotubes dispersed within the matrix or deposited onto the fiber surface. To this aim, unidirectional glass fiber/carbon nanotube/vinyl ester specimens with fibers oriented along (0°) and transverse (90°) to the loading direction are subjected to quasi-static tension up to failure. The electrical resistance changes in the composite are correlated to the mechanical strain and acoustic emission events. Using this approach, it is shown that the electrical signal is able to discern between fiber and matrix (or fiber/matrix interface) damage. The electrical resistance of composites with multiwall carbon nanotubes located within the matrix is capable of tracking matrix-dominated damage but is poorly sensitive to fiber breakage. In contrast, the composites with multiwall carbon nanotube–modified fibers exhibit outstanding sensitivity to fiber- and fiber/matrix interface damage.

An entangled multiwalled carbon nanotube film (Buckypaper) embedded in a polyurethane membrane was integrated into a glass fiber reinforced epoxy composite by means of a vacuum infusion to become a part of the composite and to give it a strain self-sensing functionality. In order to increase the strain sensing, pristine nanotubes were either oxidized by KMnO4 or Ag particles were attached to their surfaces. Moreover, the design of the carbon nanotube/polyurethane sensor allowed a formation of a film of micro-sized cracks, which increased its reversible electrical resistance and resulted in an enhancement of the strain sensing. Prestaining of the sensor with Ag-decorated nanotubes increased its sensitivity to strain, which was quantified by a gauge factor, more than hundredfold in comparison with the sensor with pristine nanotubes. The tests revealed that the integrated strain sensing exhibited a long-term electromechanical stability, which was linked to the level of strain in the host glass fiber/epoxy composite. © 2017 Elsevier Ltd

Additive manufacturing is used in several industrial sectors where polymers and metals are established materials. Different academic studies prove that additive manufacturing methods can be applied on glass materials using powder or fiber based material sources. In terms of quartz glass, with melting temperatures around 2200°C, laser sources are used to achieve the necessary intensities. In the present study, additive manufacturing of quartz glass is achieved by melting a quartz glass fiber with a CO2 laser source. A combined laser head focusses the laser radiation onto the glass fiber in order to melt the fiber. A three axis system is used to move the printing stage and glass substrate. The experimental investigations show that CO2-laser glass deposition printing allows for the creation of arbitrary 3D quartz glass structures. This method is envisioned to replace conventional manual glass manufacturing processes for production of complex hollow glass structures which are present in the medical sector.

Soil stabilization is a universal approach commonly used in counter-balancing of soil ground under structures. This method of soil improvement utilizes binders such as cement and/or lime to enhance the mechanical properties of soil for construction purposes. However, the production of these binders has been known to increase the levels of carbon dioxide (CO2) in the environment. Therefore, in an attempt to stabilize soil conditions, the search for sustainable materials which are essentially harmless to surrounding soils when treated and at the same time are cost-efficient, is justified. Olivine, with a chemical composition of [(Mg,Fe)2SiO4] can be considered as a sustainable material which has the natural capability of capturing CO2 in the environment and creating carbonated minerals. The high amount of magnesium oxide (MgO) and aluminum oxide (Al2O3), as well as an adequate amount of silicon dioxide (SiO2) form the chemical composition of olivine, making olivine a good choice for use in soil improvement activities in terms of its pozzolanic reaction and hydration. The present study was undertaken to emphasize some problems on the utilization of olivine as a newly proposed sustainable material for soil improvement programs. The study highlights the applicability of glass fiber with an alkali activated soil-olivine mixture, with and without carbonation, which helps in determining the Unconfined Compressive Strength (UCS), Indirect Tensile Strength (ITS), and the Flexural Strength (FS). In the study, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy-Dispersive X- ray spectroscopy (EDX), and X-ray Diffraction (XRD) analyses were also executed on pure soil and alkali activated soil-olivine mixtures with and without carbonation. The first stage was to analyze the performance of the preliminary investigation in order to evaluate the effectiveness of olivine on some basic geotechnical characteristics of silty clay soil. The compacti

In this research, long sugar palm fibre was hybridised with long glass fibre produced by the hand lay-up method to improve the performance of the sugar palm composites. This study investigates the effect of glass fibre addition to the sugar palm-based composites and benzoylation effect to improve the mechanical properties of the composites. The study was divided into two stages, where the first stage results shows that the benzoylation treatment of the sugar palm fibre and the glass addition to the sugar palm composites has been demonstrated to significantly improve the physical, tensile, flexural and compressive properties of the sugar palm/glass fibre composites. The results obtained with regard to the physical and mechanical properties revealed that the EP/30TSPF/70GF composites exhibited the best physical and mechanical properties by increasing the tensile strength by 55.7%, flexural strength by 46.8% and compressive strength by 36.7% when comparing with EP/UTSPF composites. Similar results were acquired from the thermal testing using TGA, DSC and DMA. It was found that EP/TSPF/GF had better thermal properties compared to other composites. The second stage of the study investigated the impact properties and post-impact properties of the hybrid composites. The low velocity impact testing was applied to EP/30TSPF/70GF as it is the best formulation of the sugar palm/glass fibre composites, as concluded from the characterization results. After the impact test, ultrasonic scanning method (C-scan) was used to investigate the failure of the EP/30TSPF/70GF composite together with compression after impact testing (CAI). From the experimental studies, it could be concluded that the impact damage showed excellent correlation with the impact response. The damage area obtained from the ultrasonic C-scan images and CAI testing shows that the damage area increasing as the impact energy increasing and the compressive strength of the EP/30TSPF/70GF composite decreased as the imp

This research investigates the hybrid effects between kenaf and glass fibres reinforced in modified epoxy filled with nanoclay. Kenaf fibres were treated with 2M Sodium Hydroxide (NaOH) solution. Epoxy was modified with 1 wt% silicon powder. Nanoclay loading was sonicated at 1.0 wt%, 3.0 wt% and 5.0 wt% with respect to epoxy. Three layers of glass fibres and two layers of kenaf fibres were lay-up alternately, which constitute to 20 wt% of composite. Composites were then fabricated using hot compression moulding technique. Analysis from Fourier Transform Infrared Spectroscopy (FTIR) revealed the absence of hemicellulose, lignin and hydroxyl functional group on TK/Ep composite. Flexural test revealed improved flexural strength and flexural modulus among treated kenaf composites. Impact test was conducted at two different energy levels of 15 J and 30 J. It was observed that composite dispersed with nanoclay is capable of sustaining both the loads. Morphology study through Field Emission Scanning Electron Microscope (FESEM) revealed the roughness on the surface of the fractured treated kenaf fibre. Thermogravimetric Analysis (TGA) result shows that the highest initial decomposition temperature was achieved by GUK/Ep-Si/1% nanocomposite, with 2.386% higher than GTK/Ep-Si/1% nanocomposite. Dynamic Mechanical Analysis (DMA) result reveals that the glass transition temperature (Tg) of 3G2UK/Ep-Si/1% nanocomposite is 6% higher than GTK/Ep-Si/1% nanocomposite which indicates the lower free volume in GUK/Ep-Si/1%. Overall, it can be concluded that composite with treated kenaf has better mechanical properties while composites with untreated kenaf possesses better thermal properties.

El aligeramiento de peso es una de las principales estrategias llevadas a cabo por los fabricantes de automóvile s para reducir consumo de combustible y emisiones de gases de efecto invernadero. Debido a la creciente demanda creciente de plásticos y materiales compuestos para aplicaciones de automoción, algunas tecnolo gías como la espumación han sido adoptadas para reducir su peso. El presente trabajo tiene como objetivo compara la morfología y propiedades mecánicas de plásticos espumados obtenidos mediante dos tecnologías de espumación distintas: MuCell® y IQ Foam®. Pl acas macizas y espumadas de polipropileno reforzado con fibra de vidrio (PP/GF) fueron obtenidas mediante moldeo por inyección utilizando los procesos MuCell® y IQ Foam® en combinación con la tecnología de expansión de molde Core Back. La morfología de las placas espumadas resultantes se analizó mediante Microscopía Electrónica de Barrido (MEB) y Tomografía Computerizada (CT), y las propiedades mecánicas fueron evaluadas a través de ensayos de tracción, flexión e impacto. El análisis morfológico reveló la e xistencia de una estructura piel maciza/núcleo espumado en las placas espumadas. Las propiedades mecánicas disminuyen gradualmente con la densidad aparente del material microespumado. La densidad aparence se reduce conforme el espesor de la placa, aunque l a rigidez a flexión aumenta considerablemente. L a nueva tecnología IQ Foam® permite la fabricación de piezas espumadas y ligeras con propiedades resultantes comparables a las obtenidas mediante MuCell ® , presentando otras ventajas en cuanto a coste, sencill ez e independencia de máquina inyectora, Lightweight construction is one of the main strategies conducted by carmakers in order to reduce fue l consumption and greenhouse gas emissions. Since the demand of plastic and composite materials for automotive applications is continuously growing, lightening approaches like foaming techniques are b eing introduced with the aim of decreasing their weight. The present work aims to compare the morphology and mechanical properties of plastic foams obtained by two different foaming technologies: MuCell® and IQ Foam®. Solid and foamed plates of glass fiber reinforced - polypropylene (PP/GF) were injection molded by using MuCell® and IQ Foam® processes combined with the comple mentary tool technology Core Back expansion molding. The morphology analysis of the obtained plates was carried out through Scanning Electron Microscopy (SEM) and Computed Tomography (CT) techniques, and the mechanical properties were assessed by means of tensile, flexural and impact tests. The morphology analysis revealed the presence of solid skin - foamed core structure in the foamed samples. The mechanical properties decreased gradually with the apparent density of the microcellula r plates. By increasing the thickness of the part because of the expansion of the cavity, the apparent density decreased but the flexural stiffness was greatly enhanced. Foamed samples obtained by IQ Foam® technology exhibited lower cell density than that of the MuCell® ones, but consequently higher resistant area, and thus, slightly higher mechanical properties. The new IQ Foam® technology is able to produce foamed parts with properties comparable to that of the MuCell® process, offering additional benefits such as cost - effective ness, easy to use and machine - independence, Postprint (published version)

This paper aims to present a methodology to predict the anisotropic and non-linear behaviour of glass fibre reinforced plastics using finite element methods. A material model is implemented in order to remedy the need of multiple material definitions, and to control the local plastic behaviour as a function of the fibre orientation. Injection moulding simulations traditionally provide second order orientation tensors, which are considered together with a homogenization scheme to compute local material properties. However, in the present study, fourth order tensors are used in combination with traditional methods to provide more accurate material properties. The elastic and plastic response of the material model is optimized to fit experimental test data, until simulations and experiments overlap. The proposed material model can support design engineers in making more informed decisions, allowing them to create smarter products without the need of excessive safety factors, leading to reduced component weight and environmental impact.

[EN] An Ultra High Performance Fibre Glass Reinforced Concrete has been developed in order to see the addition of Glass fibers in the matrix of UHPC and analyze their effects. The UHPC offers great advantages in strength, durability and surface finish. The addition of glass fibers is to improve the properties of UHPC. For decades the concrete has evolved from traditional concrete, fiber concrete, Self-Compacting concrete and high performance concrete to become what is now known as Ultra High Resistance Concrete (HMAR) or Ultra High Performance Concrete (UHPC). Has developed an experimental investigation incorporating different types of fibers and with the objective of the glass fibers and taking as reference steel fibers. There have been more than fifty 300X150X20mm specimens which have been subjected to tensile bending tests with bending 4-point method. The experimental program was composed of two blocks in which different properties of samples with UHPRFC both fresh and hardened state were analyzed. The results showed that the Ultra High Performance Fibers Reinforced Concrete (UHPRFC) increases its performance by incorporating fibers. Glass fibers increase the strength and ductility of UHPC without changing the workability of the dough whereby a Self-Compacting concrete behavior remains. Moreover the durability of the glass fibers has been affected over time but still offered better performance than the UHPC without fibers. Steel fibers and synthetic fibers showed improved, first steel fibers consumption rose from very high so the strength and ductility of the samples even surpassing the samples with glass fibers, however synthetic looked more relegated all properties analyzed., [ES] Un Ultra High Performance Reinforced Glass-Fibre Concrete se ha desarrollado con el objetivo de ver la incorporación de fibras de vidrio en la matriz del UHPC y analizar sus efectos. El UHPC ofrece grandes ventajas tanto en la resistencia, durabilidad y superficie de acabado. Con la incorporación de las fibras de vidrio se busca mejorar las propiedades del UHPC. Desde varias décadas el hormigón ha ido evolucionando desde el hormigón tradicional, hormigón con fibras, hormigón autocompactante y hormigón de altas prestaciones hasta llegar a lo que actualmente se conoce como Hormigón de Muy Altas Resistencias (HMAR) o Ultra High Performance Concrete (UHPC). Se ha desarrollado una investigación experimental incorporando diferentes tipos de fibras y teniendo como objetivo las fibras de vidrio y tomando de referencias las fibras de acero. Se han realizado más de cincuenta espécimen de 300X150X20mm los cuales se han sometidos a ensayos de flexo traccion con el método de flexión a 4 puntos. El programa experimental se formó de 2 bloques en los cuales se analizaban diferentes propiedades de las muestras con UHPRFC tanto en estado fresco como endurecido. Los resultados obtenidos muestran que el Ultra High Performance Reinforced Fibers Concrete aumenta sus prestaciones con la incorporación de fibras. Las fibras de vidrio aumentan la resistencia y la ductilidad del UHPC sin alterar la trabajabilidad de la pasta con lo cual se mantiene un comportamiento de hormigón autocompactante. Por otra parte la durabilidad de las fibras de vidrio se ha visto afectada con el paso del tiempo pero todavía ofrecían mejores prestaciones que el UHPC sin fibras. Las fibras de acero y las fibras sintéticas mostraron mejoras, por una parte las fibras de acero incrementaban de manera muy elevada las resistencia y la ductilidad de las muestras incluso superando a las muestras con fibras de vidrio, sin embargo las sintéticas se veían más relegada en todas las propiedades analizadas.

This paper presents the test results of a durability study on a novel basalt fiber-reinforced polymer (BFRP) bar-anchor system. The BFRP bars were exposed to saline and alkaline solutions for 10 weeks before being anchored and tested under static and fatigue loading. Unconditioned basalt, glass, and carbon specimens were also tested and served as controls. Regardless of the fiber material, all the bar-anchor systems withstood their ultimate tensile loading with no sign of slippage or premature failure in the anchor zones. Conditioning of the BFRP bars in saline and alkaline solutions resulted in 7 and 9% decreases, respectively, in the systems’ tensile capacity. A decrease of 11% in the modulus of the alkali-conditioned BFRP specimens was also observed. The fatigue test results showed that the fatigue life of the bar-anchor system was primarily affected by the applied stress range. In addition, continuous immersion of the BFRP bar in the alkaline solution increased its tendency to fracture prematurely in the anchor zone. The fatigue limit of the BFRP bar-anchor system was determined to be 4% of its ultimate capacity, compared with 3 and 10% for the glass and carbon systems, respectively.

Presently, fiber reinforced materials are used for many industrial applications. Laser transmission welding (LTW) is a suitable method to join these materials. For multiple thermoplastics, the weld seam quality is affected by the amount of moisture content in the joining members. For LTW, heat is applied to the welding members and water in the composite changes phase from liquid to gas. Increasing the gas content can lead to detrimental cavities in the weld seam. Therefore, experiments were performed to investigate the influence of the laser focal geometry on the generation of cavities. Different focal geometries lead to different levels of process heat generation which affects the amount of vaporization. The experiments were conducted with endless glass fiber reinforced polyetherimide and endless carbon fiber reinforced polyetherimide. These samples were tested for their weld seam strength and the results were correlated to the moisture content and laser beam geometry. © 2016 The Authors.

The present study aims to investigate the effect of thermo-oxidative aging on the mechanical, chemical, physical properties of EHG250-68-37 E-glass fiberreinforced epoxy preimpregnated. To achieve the proposed research objectives, laminates of EHG-68-37 fiberglass/epoxy prepreg were exposed 800 h in isothermal condition and aircirculating oven at 82 °C. It is noteworthy that, before aging, specimens were dried to constant weight under vacuum at 70 °C in accordance with ASTM D 5229/D 5229M due to hydrophilic matrix. The variations of mechanical properties (the elastic moduli, tensile strength, strain break, and toughness) were quantified by conducting tensile tests on both aged and un-aged specimens based on ASTM D3039. Chemical changes in composites due to thermo-oxidative aging were analyzed by, Dynamic mechanical analysis (DMA), Differential Scanning Calorimetry (DSC), and Fourier Transform Infrared spectroscopy (FTIR). Physical degradation mechanisms resulting from sub-Tg aging were monitored by weight loss measurements as a function of time and Scanning Electron Microscope (SEM) to investigate superficial resin, cross sectional, and the cryofractured surface morphology. The showed the toughness, tensile strength and modulus of the composites were increased after pronounced aging conditions, 3.7%, 48%, and 59%, respectively. Whereas a decrease (0.22%) was observed in the strain break. DMA results revealed that the glass transition temperature and rubbery state modulus were increased as a result of the matrix densification. FTIR spectroscopy demonstrated the formation of carbonyl compounds around IR band 1735 cm-1 due to oxidation of the chemical structure of the aromatic ethers. SEM observations indicated the existence of minor superficial cracking, growth in size and number of voids, and poor fiber-matrix adhesion after aging. In addition, a minor mass change was observed from mass loss monitoring methods. The overall findings suggest that post-curing and oxidat

Este proyecto de grado tuvo como objetivo principal determinar las propiedades mecánicas que obtiene el concreto al adicionarle fibra de vidrio tipo AR, esto se logró mediante una serie de ensayos de resistencia a la compresión, a la tensión y módulo de elasticidad, realizando un trabajo comparativo con una mezcla de referencia, dichos ensayos fueron realizados en el laboratorio Construlab Ltda. y el laboratorio de Suelos, Concretos y Pavimentos de la Universidad EAFIT -- Se buscó trabajar con una mezcla de referencia la cual permitiera que al adicionarle la fibra de vidrio lograra una trabajabilidad de la mezcla aceptable, y que a la vez obtuviera valores de resistencia a la compresión, tensión y modulo elasticidad de las mezclas más comerciales en el medio de la construcción -- Los porcentajes de fibra que se usó durante la fase experimental fue de 0.5%, 1%, 1.5%, 2% y 2.5% del peso total de la mezcla realizada -- También se realizó un estudio conceptual recopilando toda la información existente en cuanto a adiciones y aditivos utilizados en el concreto, estudiando específicamente la fibra de vidrio, sus propiedades y la influencia que esta tiene en el concreto -- Durante el proyecto de grado se logró concluir que la fibra de vidrio como adición a las mezclas de concreto aporta de manera positiva en cuanto a los tres parámetros estudiados adicionándole un 1% de fibra de vidrio a la mezcla, si se usa menos cantidad de fibra que la indicada no afecta en nada a ningún parámetro de los estudiados a la mezcla de referencia, pero si se usa en exceso ya empieza a afectar la mezcla en varios aspectos, principalmente en la cuestión de resistencia a la compresión, módulo de elasticidad y trabajabilidad, pero de cierto modo también aporta de manera positiva en tensión, por ende se buscó objetar una mezcla con porcentaje de adición de fibra de vidrio balanceada la cual aportara de manera positiva a los parámetros analizados, en cuanto a resistencia a compresión logro una gana

Effects of cold climate exposure on structures made of composite materials are scarcely documented. As a result, even if exceptional wind conditions prevail in some cold regions, uncertainties related to composite materials durability at low temperatures may hinder development of wind energy projects in those regions. Therefore, as part of the Wind Energy Strategic Network (WESNet) of the Natural Sciences and Engineering Research Council (NSERC) of Canada, efforts were made to evaluate the effects of cold climate exposure on the mechanical properties of glass-epoxy composites. Tensile and compressive quasi-static tests as well as tensile (R = 0.1) and fully reversed (R =- 1) fatigue tests were performed on vacuum-infused [±45]2s glass-epoxy composites at -40°C and 23°C. Results for quasi-static tests show an increase of tensile, compressive and shear strengths and moduli at low temperatures. It is also demonstrated that for the stress range under scrutiny, fatigue performance is improved at -40°C for both the R = 0.1 and R =- 1 loading cases. Moreover, the failure mode for R =- 1 fatigue changed from compressive failure due to buckling of delaminated plies to tensile failure, suggesting a more efficient use of the material. However, if R =- 1 fatigue results at low temperature are extrapolated towards the very low stresses that are also part of wind turbine blades fatigue load spectrum, fatigue life may be degraded compared with that at ambient temperature. Finally, evidence of visco-elastic behaviour leading to changes in s - N curve slope parameter are reported.

In this study, the influence of the glass fiber (GF) content on the microstructure and flexural strength of bulk molding compounds (BMCs) is investigated. Three sets of BMCs with different weight fractions of GF (5/10/12.5 wt%) were commercially prepared and compression molded into test specimens. The microstructure of the composites was analysed by scanning electron microscopy and further quantitatively characterized by Voronoi analysis in order to define the degree of the fiber distribution homogeneity. The experimental results were compared to the modelled microstructures. The results revealed that the fiber distribution in the composite with 5 wt% of GF is considered as the most homogeneous. Through the obtained microstructural descriptors, the fiber weight content and their distribution were correlated to the flexural strength of BMCs. The flexural strength was the highest for the composite with 10 wt% of GF.