V textilním průmyslu je v dnešní době veliká konkurence. Každá novinka může znamenat velký zisk. Tato diplomová práce se bude zabývat aplikací termochromních přísad (látka reagující na teplotu změnou své barvy) do polymerní matrice, konkrétně polypropylenu, a jeho další zpracování u výrobce technického polotovaru - výroba vláken. Po výrobě vzorků bude provedeno jejich testování. Porovnají se vlastnosti polypropylenu s a bez termochromních přísad a zhodnotí se, nakolik tyto přísady ovlivňují vlastnosti polypropylenu. Ze získaných výsledků se stanoví možnost využití termochromních přísad v textilním průmyslu.

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Syntactic foams (SFs) are characterized by a unique combination of low density, high mechanical properties, and low thermal conductivity. Moreover, these properties can be tuned to specific applications. In contrast to traditional foams, where porosity is formed during the foaming process, porosity in syntactic foams can be obtained simply by incorporating pre-formed bubbles. Because of their high chemical stability and buoyancy, these type of foams found their first application in the marine industry. Nowadays, they are utilized in many other fields, such as in the aerospace and automotive industry. In this work, the multifunctionality of epoxy-based and polypropylene (PP)-based SFs was increased by including a microencapsulated Phase Change Material (PCM), able to impart Thermal Energy Storage (TES) capability at phase transition temperatures of 43 °C and 57 °C. The rheological, morphological, thermal, and mechanical properties of the prepared materials were systematically investigated. A final comparison of the two systems was performed to obtain a better comprehension of their potential in emerging industrial applications.

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Polymeric materials have attracted a lot of attention for the past several decades. Different sectors of manufacturing industry, such as packaging, building and automotive industry have introduced polymeric materials in their applications. Common polymer manufacturing processes include thermoforming and blow molding. In this research, characteristics of a new polymer manufacturing process, referred to as axial-feed hot gas tube forming (HGTF) are studied. Experimental studies were conducted to form a simple axisymmetric component from extruded polypropylene (PP) tube by varying several key process parameters such as internal pressure, temperature and axial feed. Tube shape and deformation characteristics were studied as a function of the above process parameters. In addition, two consecutive material models have been utilized for finite element simulation of axial-feed HGTF of PP tube using a commercial FE code. One of them is conventional hyperelastic Ogden material model and another is more advanced viscoelastic-viscoplastic Augmented Hybrid material model (AHM), that has been recently developed. Simulation results from two models were analyzed and compared with the experimental results and good general agreement has been obtained. Results showed that application of more advanced AHM material model led to improved prediction of part shape and strain distribution over the part profile. / Thesis / Master of Applied Science (MASc)

No / The Leeds die drawing process has been used to produce biaxially oriented polypropylene pipes with significant enhancement of hoop mechanical properties in terms of tensile modulus and tensile strength owing to a unique orientation of the ¿ crystallites throughout their cross-section. Pendulum impact tests on these pipes show major improvements in impact resistance. Hydrostatic pressure tests were undertaken at room temperature 95 and 110°C. Major improvements in behaviour were found including more than an order of magnitude increase in lifetime at 95°C. Furthermore, the toughness was improved enormously leading to a brittle tough transition temperature below ¿70°C.

Doctor of Philosophy / Enhancing and recycling plastic are two important focuses in plastics research. In this dissertation, enhancing the property of polyetherimide (PEI) is first discussed, and two methods are introduced. Later, a new recycling strategy, the degradation-upcycling (Deg-Up) strategy, is presented. The potential of Deg-Up is evaluated on three plastics: polystyrene (PS), polyethylene (PE), and polypropylene (PP). These plastics serve broad applications in daily life, such as Styrofoam, food containers, shopping bags, garden decorations, and furniture. PEI, a powerful plastic resilient to high temperature and strength, is broadly used in aerospace, defense technology, space exploration, and transportation. However, PEI can only be processed at high temperatures, and PEI films can be easily dissolved or compromised in many solvents, such as solmethine, chloroform, and furanidin. Water is not permeable in PEI, and therefore, it is strongly demanded to modify the PEI structure, giving PEI new and improved properties for water filtration and purification. We have investigated two methods for modifying PEI. Influencers affecting the PEI film's performance are also studied. Plastic upcycling, which converts low-value wastes to high-value chemical products, is a vital technology that mitigates the environmental crisis and the plastic recycling problem. However, effective plastic upcycling improving waste value with good selectivity toward products with ten-fold or even greater value is uncommon due to the lack of upcycling theories/methodologies. This dissertation presents a new upcycling strategy; the degradation-upcycling strategy (Deg-Up) comprises degradation reactions yielding preliminary chemicals and upcycling reactions converting the preliminary chemicals to desired high-value products. Based on the Deg-Up strategy, PS is converted to fragrances and drug precursors, and PE and PP are Deg-Up to fats and soaps. The economic and industrial possibilities are also discussed through a preliminary industrial design and an economic analysis.

A spinning apparatus was built for the investigation of the phase-separation technique as applied to the production of polypropylene fibers from naphthalene solutions. The solutions were spun through a single 2.00 millimeter spinneret at compositions of 15 and 22 per cent polymer and at temperatures of 145 and 160°C. Linear velocities in the spinneret and draw ratios ranged from 0.125 to 0.277 meters per minute and from 759 to 2198, respectively. It was found that naphthalene could be extracted from the fibers by diethyl ether in less than one minute; however, this extraction was not necessary prior to properties testing because all of the naphthalene in the fibers exposed to air was lost by sublimation. Deniers of 14 selected fiber samples varied inversely with draw ratio and directly with solution composition in a range from 2.5 to 8.0. After the samples were cold-drawn 3:1, tests with a Scott Tensilgraph showed that tenacities, per cent elongations at break, and secant moduli varied directly with draw ratio in ranges from 0.9 to 1.6 grams per denier, from 50 to 150 per cent, and from 17 to 30 grams per denier, respectively. Per cent elongations at break also varied directly with solution composition. The fibers, in general, exhibited good hand, bulk, tangling, and self-crimping characteristics. Photographs of four of the fiber samples were made to show the tangling and crimp qualities. / Master of Science

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