Carbon fibre reinforced polymer (CFRP) composite materials exhibit high specificstrength and stiffness therefore they can be a lightweight alternative to metalliccomponents for the front section of an aero-engine. Despite the benefit of CFRP composite materials for aero-engine applications, there arealso new challenges due to their inherent properties compared to conventionalaerospace metallic structures, such as a lower erosion resistance, poor thermalresistance, and poor electrical conductivity. In aero-engines, some components can be subjected to harsh erosive environmentsduring operation, therefore the erosion resistance of CFRP composite materials need tobe investigated. CFRP composites are not able to withstand as high temperatures astraditional metallic components and their ability to resist fire events need to beenhanced. On the other side, the poor electrical conductivity of CFRP composites canalso be critical when the aircraft is struck by lightning. Therefore, improving theconductivity of CFRP composite is of large interest. This thesis work is focusing on investigating innovative coating solutions to overcomethese three independent challenges in order to enhance CFRP composite applicationsinto the front section of an aero-engine. Coating systems for lightning strike protection have been investigated and developed.A fire protection has been identified and tested; the tests showed promising results forfire application. Furthermore, investigations on erosion resistant coatings indicated thepossible improvement of replacing the currently used erosion resistant coating by othercoatings presented in this thesis work.

Sporopollenin is considered a resistant material and might be applicable in flame retardant material. The use of renewable material in fields mainly dominated by toxic materials, such as bromides in flame retardant materials, could greatly improve the sustainability in those fields. A renewable porous film could be of interest in applications were cellophane is used today. The aim of this report is to investigate some basic properties of films made from nanofibrillated cellulose (NFC) and Lycopodium spores with a specific focus on flame retardant and mechanical properties. These properties were investigated using machines such as SEM, a universal electromechanical tester, TGA and vertical flame testing. During the production of the films an ultra turrax, rotavapor and rapid köthen was used. The films containing spores did not improved properties such as flame retardancy and mechanical properties when compared to the original NFC film. Density was lowered by almost half in some cases compared to the original NFC-film. Mechanical properties of the alkali-treated spores showed a significant increase compared to the untreated spores. An increased spore-ratio shows a decreased Young’s modulus. Further research on flame retardancy could be done using xyloglucan or another more flame retardant organic compound as a matrix. A foaming agent inside the sporopollenin could also contribute to flame retardancy. The mechanical properties could be compared to cellophane in order to see any future possibility of application. If possible pure sporopollenin should be used instead of whole spores. / Degree Project in Polymeric Materials, First Cycle

Indoor photovoltaics is an emerging technology that could power the Internet of Things (IoT)devices with low energy requirements. The conventional silicon-based photovoltaics is notsuitable for indoor lighting conditions, opening the door for organic photovoltaics (OPV).When fabricating OPV devices, a transparent and conductive electrode is needed. Indium tinoxide is a common transparent for research, but it is expensive and difficult to use in roll-toroll (R2R) production. PEDOT:PSS is a cheap conductive polymer compatible with R2Rprocessing, but its relatively low conductivity limits cell size and geometric fill factor. Addingsilver nanowires to the PEDOT:PSS solution could improve conductivity but raises the risk ofshort-circuiting the devices. In this thesis, organic photovoltaic devices have been fabricatedusing electrodes based on a commercially available solution of PEDOT:PSS dispersed withsilver nanowires to test its viability. Devices utilizing the novel electrode demonstrated aforward current density of 2,905 mA/cm2, dark current density of -1,25E-05 mA/cm2, shortcircuit current density of 0,037 mA/cm2, open-circuit voltage of 0,630 V, and fill factor of76,6%. Performance for devices with the a reference electrode of pure PEDOT:PSS was aforward current density of 0,94 mA/cm2, dark current density of -2,35E-05 mA/cm2, shortcircuit current density of 0,0341 mA/cm2, open-circuit voltage of 0,630 V, and fill factor of76%. However, the resistance in the novel electrode appears to degrade faster than in thereference electrode, even in an inert atmosphere, which motivates further studies ondegradation mode and methods to prevent it.

The report contains an account of a development project done during 10 weeks of the spring semester at Luleå University of Technology 2021. The project is done as a final thesis for the program Bachelor of Science with a focus in industrial design. The development project resulted in a prototype lamp. The functioning prototype is an embodied union of the perspectives environment and living environment. Through smart lighting of the home, the living environment, a room can become more flexible and adaptable. It is easier to install new lighting than it is to move a wall. The lamp is created to improve lighting and spaciousness. A light source's use of contrasts and illumination in all directions can make a room feel more comfortable to be in and larger than it is. The environmental perspective is based on materials science. When designing new products, a factor that controls the product's climate footprint and environmental impact is the choice of material. Greater and greater value is placed in the environmental impact of products and consumers have actively begun to influence their buying behaviors based on striving for a better relationship with the environment, this work has taken advantage of. A biocomposite has therefore been created consisting of a matrix material of potato plastic combined with fiber reinforcement made from dried fruit residues from juice production. Especially potatoes and carrots. This gives a result of a 100% bio-based material. The work has followed an iterative process and used creative methods to stimulate innovation and solutions. A great focus has been placed on the prototype's material and the production of samples of biocomposites. Which has given rise to a lamp whose aesthetics are governed by the material. The lamp has a function of giving off two completely different looks when it is on and off. In an off position, the hardness of the material is emphasized, and when it is lit, it comes to life. Like a sun hanging from the ceiling, the lamp extends the days into the night. / Rapporten innehåller en redogörelse av ett utvecklingsprojekt gjort under 10 veckor av vårterminen på Luleå Tekniska Universitet 2021. Projektet är gjort som ett avslutande examensarbete för programmet Teknologiekandidat med inriktning Teknisk design. Utvecklingsprojektet resulterade i en prototyp-lampa. Den fungerande protypen är en förkroppsligad förening av perspektiven miljö och livsmiljö. Genom smart ljussättning av hemmet, livsmiljön kan ett rum bli mer flexibelt och anpassningsbart. Det är lättar att installera ny belysning än vad det är att flytta en vägg. Lampan är skapt för att förbättra ljussättning och rumslighet. En ljuskällas användning av kontraster och upplysning åt alla håll kan få ett rum att upplevas bekvämare att vara i och större än det är. Miljöperspektivet grundat sig i materiallära. Vid utformning av nya produkter är en faktor som styr produktens klimatavtryck och miljöpåverkan valet av materialet. Ett större och större värde läggs i produkters miljöpåverkan och konsumenter har aktivt börjat påverka sina köpbeteenden utifrån att sträva efter ett bättre förhållande med miljön detta har arbetet tagit vara på. En biokomposit har därför skapats bestående av ett matrismaterial av potatisplast kombinerat med fiberarmering gjort av torkade fruktrester från juiceproduktion. Framförallt potatis och morot. Detta ger ett resultat av ett 100 % biobaserat material. Arbetet har följt en iterativ process och använt kreativa metoder för att stimulera innovation och lösningar. Ett stort fokus har lagts på protypens material och framtagning av prover på biokompositer. Vilket har get ett resultat av en lampa vars estetik styrs av materialet. Lampan har en funktion av att ge ifrån sig två helt skilda utseenden när den är tänd och släckt. I ett släckt läge framhävs materialets hårdhet med när det sedan tänds kommer den till liv. Likt en sol hängande från taket förlänger lampan dagarna in i natten.

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The research field of composite materials is particularly fascinating due to the design freedom they offer and the infinite number of constituent combinations, including those that are already explored, and many more that are yet to be tried. One composite material that holds great potential contains carbon in its fiber shape. Carbon fibers possess unique properties that excel in mechanical aspects, as well as interesting electrical and thermal properties that are yet to be fully explored. These fibers are readily available on the market and can be introduced as reinforcement in various lengths and orientations, yielding diverse results depending on the intended effect. Although carbon fiber reinforced polymer composites (CFRP) are present on the market for quite some time, specifically in high-performance applications, they are predominantly used when their performance outweighs their cost. Meanwhile, carbon fiber composite waste is starting to cumulate in noticeable amounts. This waste originates from both, production scrap and end-of-life scenarios, as components introduced in service life in the past 30 years are being decommissioned and discarded. Unfortunately, the prevalent solution for handling this waste is landfilling, due to its ease, affordability, and accessibility. Consequently, substantial amounts of composite waste are accumulating worldwide. Furthermore, it has finally come to our attention that our planet's resources are finite. Our exploitation of these resources has been largely devoid of consideration for the needs of future generations. As a result, recently, sustainability has emerged as a key enabler for a circular economy, driven by increasing environmental concerns and demands from customers and users for market transformation. The implementation of sustainable practices is now underway, albeit at a gradual pace.   In summary, we find ourselves facing a trifold predicament: a splendid material being underutilized due to production costs, the cumulative generation of CFRP waste resulting from a lack of foresight and suitable alternatives, and the urgent need to transition towards a circular economy due to resource depletion. This research work aims to address all three challenges by developing an integrated solution.   The current work demonstrates that it is possible to recycle carbon fiber model composites through a two-step pyrolysis treatment, a fully mature recycling technology. The study has been done in two stages which are presented in two journal papers included in the thesis. The primary objective of the first paper is to identify and optimize process parameters that maximize the retention of mechanical properties in the recovered fibers. The overall results achieved show good retention value; with over 90% retention on stiffness and 90% on strength. Encouraging results from initial experimental work, have spurred the research focus towards further investigation. Thus, the second paper reports on repetitive manufacturing and recycling cycles of two sets of identical model composites by using the two most effective recycling treatments identified through the parameter optimization. The mechanical performance and structural changes of the recycled fibers are characterized and analyzed. Although further analysis is required, current mechanical behavior shows recovered fibers suitable for secondary applications after two recycling cycles, with an abrupt decay in fiber properties after the third cycle.   With the waste challenge under control, through successful recycling of composite waste, it is time to find concrete applications for this research. Having recycled carbon fibers (rCF) with comparable performance to virgin carbon fibers (vCF) opens up opportunities for rCF mats and other intermediate products to compete in previously inaccessible markets.

Microvascular composites are materials with an inner hollow network which allows thecirculation of fluids. This functionalizes the composite materials, giving them furtherapplications such as self-healing or active cooling. Some of the already existingmicrovascular composites are made with fiber reinforced epoxy resin with cavitiescreated by removal of a sacrificial low temperature resistant polymer insert. Currentresearch is focused on the obtention of microvascular composites that can withstandhigher service temperatures than epoxy, using polyimide as the high-temperature resinmatrix. The aim of this project is to find a suitable sacrificial material that will withstandthe higher curing temperatures of the polyimide while allowing its easy removal fromthe matrix. Three different candidate sacrificial materials were studied for this purpose:PEEK, PPS, and PC. Preliminary DSC test showed that the melting temperature of the PEEK was close to therange of the chosen resin. PPS melting temperature and PC glass transition temperaturewere below this range of curing temperatures. TGA test revealed that the degradationsuffered by the different materials at the curing temperature of the polyimide wasconsiderably low. A small-scale test mimicking the actual microvascular compositemanufacturing conditions was designed to study the actual behavior of the differentmaterials when heated. It was seen that both the PEEK and the PPS could not flowwithout applying extra pressure for the desired range of temperatures. Furthermore, ascaled model test revealed that there was no visible interaction between the differentmaterials tested and the polyimide resin. The initial study showed that PEEK and PPS arenot readily viable to use due to the apparent difficulties to remove them from thecomposite by just applying heat. PC was also considered not viable for this applicationsince it softened too much a too low temperature.

Composite materials like carbon fiber-reinforced polymers (CFRPs) present highly appealing material properties, as they can combine high strength with low weight. In aerospace applications, these properties help to realize lightweight designs that can reduce fuel consumption. Within the aerospace industry, the use of these types of materials has increased drastically with the introduction of a new generation of commercial aircraft. This increased use of CFRP drives a need to develop more rational manufacturing methods. For aerospace applications, CFRP products are commonly manufactured from a material called prepreg, which consists of carbon fibers impregnated with uncured polymer resin. There are two dominant manufacturing technologies for automated manufacturing using prepreg, automated tape layup and automated fiber placement. These two technologies are not suitable for all types of products, either due to technical limitations or a combination of high investment costs and low productivity. Automation alternatives to the two dominant technologies have been attempted, but have so far had limited impact. Due to the lack of automation alternatives, manual manufacturing methods are commonly employed for the manufacturing of complex-shaped products in low to medium manufacturing volumes. The research presented in this thesis aims to explore how automated manufacturing systems for the manufacturing of complex CFRP products made from prepreg can be designed so that they meet the needs and requirements of the aerospace industry, and are suitable for low to medium production volumes. In order to explore the area, a demonstrator-centered research approach has been employed. A number of demonstrators, in the form of automated manufacturing cells, have been designed and tested with industrial and research partners. The demonstrators have been used to identify key methods and technologies that enable this type of manufacturing, and to analyze some of these methods and technologies in detail. The demonstrators have also been used to map challenges that affect the development of enabling methods and technologies. Automated manufacturing of products with complex shapes can be simplified by dividing the process into two steps. Thin layers of prepreg are laid up on top of each other to form flat laminates that are formed to the desired shape in subsequent forming operations. The key methods and technologies required to automate such a system are methods and technologies for automated prepreg layup, the automated removal of backing paper and the forming of complex shapes. The main challenges are the low structural rigidity and tacky nature of prepreg materials, the extensive quality requirements in the aerospace industry and the need for the systems to handle a wide array of prepreg shapes. The demonstrators show that it is possible to automate the manufacturing of complexshaped products using automated layup and forming of prepreg laminates. Tests using the demonstrators indicate that it is possible to meet the quality requirements that apply to manual manufacturing of similar products. / Polymera kolfiberkompositer erbjuder en eftertraktad kombination av låg vikt och högstyrka som kan bidra till lättviktskonstruktioner som t.ex. kan leda till bränslebesparingarför passagerarflygplan. Inom flygindustrin har användningen av denna materialtyp ökatkraftigt med introduktionen av en ny generation flygplan som till mer än hälften består avkompositmaterial. Den ökade användningen av polymera fiberkompositer medför ett ökatbehov av rationella produktionsmetoder. Inom flygindustrin tillverkas ofta polymera kolfiberkompositprodukter av så kallatprepreg-material som består av kolfibrer impregnerade med en plast. Det finns tvåhuvudalternativ för automatisk tillverkning av prepreg-baserade produkter, automatisktejpläggning eller automatisk fiberplacering. De två alternativen har tekniskabegränsningar och är förknippade med mycket höga investeringskostnader vilket gör attdet finns produkter som de inte kan tillverka eller som inte är kostnadseffektiva atttillverka med dessa två metoder. Andra automatiska alternativ har utvecklats, men har intenått någon större industriell implementering. Bristen på automatiseradetillverkningsalternativ leder till att produkter med komplex form, och som tillverkas i småoch medelstora volymer ofta tillverkas manuellt. Forskningen som presenteras i denna avhandling syftar till att undersöka hur automatiskatillverkningsceller för tillverkning av polymera kolfiberkompositprodukter med komplexform kan utformas så att de uppfyller de krav som gäller för tillverkningen av produkterför flygindustrin och är lämpliga för låga och medelhöga tillverkningsvolymer. Endemonstratorcentrerad forskningsmetod har använt för att utforska området och ett flertaldemonstratorer har byggts och testats tillsammans med partners från industrin och andraforskningsorganisationer. Demonstratorerna, som är kompletta tillverkningsceller, haranvänts för att identifiera metoder och utrustning som är nödvändiga att utveckla för attautomatisera denna typ av tillverkning och för att undersöka några metoder och tillhörandeutrustning mer i detalj. Demonstratorerna har också använts för att kartlägga faktorer sompåverkar hur metoder och utrustning utformas. Automatisk tillverkning av produkter med komplex form kan förenklas genom att delaupp tillverkningen i två steg. Först läggs prepreg-ark ihop till ett laminat som formas tillproduktens form i ett efterföljande steg. För att automatisera denna typ av tillverkningbehöver nyckelmetoder och nyckelutrustning för hopläggning av laminat, borttagning avskyddspapper samt formning av laminat till komplexa former utvecklas. Viktiga faktorersom påverkar utformningen av tillverkningscellerna är prepreg-materialens låga styvhetoch klibbiga yta, de höga kvalitetskrav som gäller för tillverkning avflygplanskomponenter samt att systemen måste hantera en stor mängd olikformadeprepreg-ark. Demonstratorerna visar att det är möjligt att automatisera tillverkningen avpolymera kolfiberprodukter med komplex form genom automatisk uppläggning ochformning av plana laminat. Tester med demonstratorerna pekar på att det är möjligt atttillverka produkterna i enlighet med de kvalitetskrav som finns för manuell tillverkningav liknande produkter.

Biobased all-cellulose composites (ACCs), in which the matrix and the reinforcement are made out of the same material, have gained a noticeable increased attention in recent years. Their successful application would solve the commonly faced challenges with natural fiber composites regarding their chemical antipathy between the hydrophilic fiber and the usually hydrophobic polymer matrix, while still keeping the advantages of being environmental friendly. Moreover, the use of man-made continuous regenerated cellulose fibers for this purpose could result in unidirectional all-cellulose composites with excellent mechanical properties. In this study, a new processing technique for unidirectional all-cellulose composites, reinforced with continuous regenerated cellulose nanocomposite fibers, has been developed, where the fibers are wound directly after the coagulation bath and then welded together while still being swelled in order to form all-cellulose composite sheets without the need of adding any additional solvent or chemicals. Scanning electron microscopy and tensile testing were used to investigate and compare the microstructure and mechanical properties, of a reference material without nanoreinforced fibers and two variants reinforced with 2 % cellulose nanocrystals (CNCs) and 2 % halloysite nanotubes (HNTs). Analysis revealed that transparent all-cellulose composites with a high compaction degree and minimal warpage during shrinkage, showing high mechanical properties could be made. However, the addition of nanoreinforcements did not lead to any improvements.

Glass fibre composites are common materials used in high voltage applications as insulating materials that provide good structural integrity. The aim of this thesis is to develop a method of studying the failure in such materials by measuring the dielectric strength on micro- and meso- scale samples, consisting of single fibre filaments and fibre bundles respectively embedded in epoxy resin. To do this, a body of relevant knowledge has been amassed, which is complemented with finite element analysis giving detailed insight into the electric field distribution in the microstructure of fibre composites. A method of producing virtually defect free single fibre samples has been developed where a filament is hung down tubes and cast in epoxy resin. A similar method was developed for producing bundle samples, however this needs some slight correction in order to prevent exothermic reactions. The dielectric strength of these samples are measured by applying a continuously increasing voltage until discharge is recorded. To evaluate the method micro- and meso- scale samples were prepared of three different fibres and their dielectric strengths measured. This evaluation showed that the method can be used to measure a definitive lower bound in the dielectric strength of fibre composites. However, the method can not definitively determine the location of the discharge, which is necessary to verify conclusions about the materials properties. To progress the method, the dielectric strength of neat epoxy samples of the same dimensions as the fibre composite samples should be investigated. Increasing the tolerance of the measurement setup should also be investigated as this could help by increasing the power of the discharge leading to more severe damage in the material.