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In this study, the use of potato fruit juice (PFJ) to make plastic films is presented. PFJ is an interesting raw material as it is obtained as a by-product from the potato-starch industry. The films showed uniquely high oxygen barrier properties, and the PFJ material is therefore a potential replacement for the most commonly used, expensive and petroleum-based ethylene-vinyl alcohol copolymer (EVOH) as a barrier layer in future packaging. The films also exhibit good grease resistance. As expected for hydrophilic materials, they exhibited high water vapour transmission rate, which shows that they, as for EVOH, have to be laminated with hydrophobic polymers in food packaging. The films, having a glass transition temperature between −5 °C and 10 °C, showed elastic-plastic behaviour with stable crack growth. publishedVersion

This thesis work deals with the fabrication of bionanocomposite films composed of cellulose acetate (CA) biopolymer and graphene oxide (GO) by melt extrusion process. Desired amount of triethyl citrate (TEC) was used as a plasticizer to produce flexible CA and CA/GO composite films. The GO 0.25, GO 0.5 and GO 0.65 composite samples were fabricated, where the numbers presented after GO indicate the weight % of GO with respect to CA. The TEC plasticized CA polymer film was also manufactured in similar way without using any GO for comparison purpose. GO was produced by the oxidation of graphite using modified Hummers method and used as a nano filler for composite manufacturing. Structural, thermal and mechanical properties of the TEC plasticized CA and CA/GO composite films were also explored in this thesis. Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC) study of the composite films confirm the presence of the interfacial interaction between the GO and CA polymer chain. Wide Angle X-ray Scattering (WAXS) results and Scanning Electron Microscopy (SEM) images demonstrate that GO sheets are well dispersed into the CA matrix in GO 0.25 and GO 0.50 composite films, whereas prominent agglomeration of the GO sheets in CA matrix was observed in GO 0.65 composite film. Isothermal Thermogravimetric Analysis (TGA) curves show the lower mass loss of the composite films compared to the TEC plasticized CA film. Mechanical testing results show a noticeable increase of tensile strength and Young’s modulus in the TEC plasticized CA/GO composite films compared to the TEC plasticized CA film.

In this thesis, normally highly immiscible blends of low-density polyethylene and polyamide 66 were created and studied. Blends, which are based on engineering thermoplastic, like polyamide, and on commodity plastic, like polyethylene, are an interesting research target because it would be possible to create blends, with many desired properties and low cost. These blends could be then exploited in many applications in different fields. The usual problem of polymer blending is related to the different chemical structures of blend’s components. This leads to phase separation in the blend, which leads to poor properties. To tackle this problem, a third component can be added to the blend. These components are called compatibilizers and they are usually block or graft copolymers but using them in blends has many challenges. That is why in this work, graphene oxide was used as a compatibilizer to research its potential to enhance blends properties. The theoretical part of the thesis presents information about low-density polyethylene, polyamide66, polymer blending and graphene. The basic properties, structural information and typical uses of low-density polyethylene and polyamide 66 are discussed first. Followed by this, is a section of polymer blending. Polymer blending is introduced by providing information about extruders, mixing processes and thermodynamics. Also, compatibilizers are introduced. Finally, graphene is presented. The focus is mainly on graphene oxide and reduced graphene oxide, providing information about their structures, properties and ways to produce them. The functionalization of graphene oxide is also presented. The experimental part included modified Hummers’ method to produce graphene oxide and preparation of suitable masterbatches for processing. Melt compounding with twin-screw extruder was performed to mix the blends and to potentially partially reduce and functionalize the graphene oxide. Various characterization methods were used in this work with suitable programs to analyze the samples and to see if there were any indications about successful blending. Several characterization methods indicate, that the dispersion of polyamide 66 in low-density polyethylene matrix was enhanced with the use of partially reduced and non-covalently functionalized graphene oxide as a compatibilizer. This is a key thing in blending and in enhancing blends properties. Also, positive results on enhanced thermal properties and chemical interactions between components are witnessed.

Manufacturing of small diameter polymeric medical tubes with high dimensional tolerances is a challenging process that requires high end extrusion equipment to meet the strict quality standards. Microextruders along with controllable die systems are used in clean room environments to assure the uniform product quality and sterility. The tube extrusion process is a continuous process that is affected by the polymer melt temperature, pressure of the melt mass inside the extruder, line speed, cooling rate and other parameters which may greatly influence the quality of the finished product. By measuring the surface roughness continuously and monitoring the surface topography on-line during the manufacturing process, one can see the changes in the product in real time, which give indication on changes in the overall quality of the product. If the surface roughness increases or decreases past set boundaries one can take corrective actions immediately, possibly saving time, material and improving the productivity of the process. Optical on-line measurement technique was used in this thesis to measure the surface roughness parameters during the production of small diameter plastic tubes in laboratory conditions. Prior to the laboratory measurements, few commercial samples were acquired and surface roughness was measured from the sample tubes using two different techniques: an on-line method and optical profilometry. The comparison of the results showed similar values with some variation due to differences between the techniques. The laboratory measurements were conducted with two thermoplastic materials, linear low density polyethylene, being the reference material, and thermoplastic urethane, being a material commonly used in medical tubing. In addition, to understand medical tube requirements, materials and manufacturing better, an expert interview was conducted and literature references were studied to form the theory basis of the thesis. Although some challenges were faced, the measurements were conducted successfully and the effect of different processing parameters could be interpreted from the results. The optical on-line measurement technique proved to be a useful tool to control and monitor the quality of the tube during manufacturing, measuring the surface roughness with great precision. In addition, if one wishes to find correct processing parameters for a new material, the technique can provide information when adequate shear rates and material plasticization is achieved. This could be a great benefit in plastic tubing industry where long test runs may be required to find suitable process parameters for new materials.

Selective laser sintering (SLS) is a powder based additive manufacturing method especially equipped to produce small batch sizes of products with customized properties. However, the limited raw material availability restricts the production of functional parts with SLS. The purpose of this master’s thesis is to investigate the usability of polyolefins, namely polypropylene and polyethylene, as possible materials to be used in the SLS. The theoretical part of this thesis includes basic information about selective laser sintering and its requirements. In addition, possible powder production methods are investigated including mechanical and physiochemical methods. Furthermore, some general information about polyolefins is discussed. The experimental part investigates injection moulding grade polypropylene and polyethylene as well as two different commercial polypropylene powders. The material properties of these polyolefins were investigated to determine their suitability to be used in the SLS. Grinding was employed to pulverize materials in granulate form. Furthermore, the flowability of the powders was evaluated with a SLS machine and tensile specimens were produced with the SLS for the tensile testing. In addition, the fracture surfaces of the tensile specimens were investigated with SEM to evaluate the sintering quality and porosity of the specimens. Thermal analysis showed that all the investigated polypropylenes had adequate thermal properties, however, the investigated polyethylene did not. Rheological properties were superior for the commercial polypropylene powders compared to the injection moulding grade. The commercial powders had a relatively spherical morphology and sufficient particle size. However, grinding did not lead to the desired extrinsic properties. The flowability evaluation showed that the grinded polypropylene could not be spread evenly enough to be able to use it in the SLS. However, both of the commercial powders showed promising flowability and the tensile specimens could be manufactured with one of the commercial powders. The tensile specimens were produced with the different energy density levels to determine the optimal value for the specific material. According to the tensile tests, increasing the energy density level increases the tensile strength. However, all the SLS specimens showed very brittle behavior and quite low tensile stress at break. The sintering quality evaluation with SEM showed that the powder particles were not completely coalescence and the individual powder particles could be seen quite clearly in the structure. Using higher energy density levels could lead to lower porosity and better tensile properties.

Humidity tends to condense as water droplets and fog on the inner surfaces of food packaging films. This phenomenon is common especially when product with high mois-ture content is packed in plastic package and stored in cold conditions. A great amount of water droplets makes visual appearance of package unattractive and unhygienic, and additionally, fog prevents consumer from seeing the packed food supply. The surface of polymer film is hydrophobic by its nature, in which case condensation of water droplets on the surface of film can be prevented by changing the surface to hydrophilic. In this case, condensed water droplets spread as uniform water layer on the surface of film, and transparency of film is improved. This phenomenon is called antifog effect. Hydrophilic-ity of surfaces of films can be improved with different antifog additives and coatings. Additionally, surfaces of films can be treated with several physical methods. Good antifog properties are difficult to achieve and maintain for the resealable polyeth-ylene structure. This is because antifog masterbatches utilizing polyethylene carrier are not well applicable, and on the other hand, antifog lacquers do not anchor well on poly-ethylene surface. Antifog property should maintain at acceptable level for six months, which is the demanded shelf-life of the product. However, recent tests have shown that antifog performance significantly reduces as a function of time. Goal of this research was to find out, how functionality of antifog lacquer could be im-proved on the surface of polyethylene film. The dilemma was approached by studying functionality of antifog lacquers of two different suppliers on resealable polyethylene structure. Antifog properties, sealability and static contact angle were studied from film samples coated with studied antifog lacquers during test period of six months. During this research, differences were detected between durability of antifog perfor-mances of studied antifog lacquers. One of studied antifog lacquers maintained its anti-fog properties for desired six months. Sealability properties of all antifog lacquer coated film samples were at acceptable level. It was detected that dilution ratio of antifog lac-quers affected the studied properties.

Muovit muodostavat merkittävän materiaaliryhmän, joka on laajasti käytetty muokattavuutensa vuoksi. Muovit ovat tyypillisesti eristeitä, mikä rajoittaa useasti niiden käytettävyyttä joissain kohteissa. Tämän vuoksi sähköä johtavien muovien tutkiminen on herättänyt laajaa mielenkiintoa, sillä ne mahdollistavat aikaisempien kalliiden ja ominaisuuksiltaan epätoivottujen materiaalien korvaamisen edullisemmilla ja samalla mahdollistaen täysin uudet sovellukset. Tämän diplomityön tavoitteena on selvittää ionista nestettä sisältävän polyolefiini dispersion soveltuvuus sähköä johtavien muovien sekä antistaattisten pinnoitteiden valmistuksessa. Tällaisella seoksella saadaan vähennettyä ionisten nesteiden kulutusta, sekä valmistettua tuotteita jotka ovat vain halutulta alueelta sähköä johtavia. Nestemäisen dispersion muodossa olevat sähköä johtavat muovit mahdollistaisivat paino ja tulostustekniikoiden käytön elektroniikka komponenttien valmistuksessa. Työ sisältää teoriaosion ja kokeellisen osion. Teoriaosiossa käydään lävitse teoria muovin sähkönjohtavuudesta sekä ionisten nesteiden rakennetta ja ominaisuuksia. Lisäksi lävitse käydään adheesion toimintaa ja pintakäsittely menetelmien soveltuvuutta työn kannalta. Lopuksi selvitetään käytettävien materiaalien toiminnallisuutta. Käytännön osiossa tarkastellaan koekappaleiden valmistusta, sekä niiden sähkön johtavuuden ja adheesion selvittämistä. Lopuksi työssä analysoidaan tuloksia ja pohditaan niiden merkitystä.

Keywords: polyolefin, polypropylene, polyethylene, fused deposition modeling, 3D printing, shrinkage, warping With the continuous developments, FDM has surpassed the status as rapid prototyping method, and matured to the point where it is widely applied in direct manufacturing of various end-use products. However, the end-use applications are partly limited due to most current feedstock materials being prone to degradation in high-temperature, humid and chemically aggressive environments. The goal of this thesis was to evaluate the per-formance of polypropylene (PP) and polyethylene (PE) as alternative feedstock materi-als in the FDM process. PP and PE are prevalent polyolefin plastics and their principal value lies in the attractive balance of physical properties in the solid state and chemical inertness, and for the same reasons, they represent attractive FDM feedstock materials for the environmentally challenging conditions. However, as highly semi-crystalline plastics they show substantial solidification shrinkage upon cooling, and the shrinkage induced contractile stresses can deform the deposited parts. In this work, the performance of PP and PE as feedstock materials in FDM was evaluat-ed through several deposition experiments. The entire manufacturing chain from fila-ment fabrication to deposition of specimens was controlled. Bonding quality between deposited filament strands at varying deposition conditions was assessed by preparing and testing tensile specimens, and comparing the results to injection molded counter-parts. The effects of deposition conditions on the shrinkage and warp deformation were studied by depositing specimens with different geometrical features. Based on the results, FDM of PP and PE feedstock materials is feasible and holds a great potential, but requires special arrangements and awareness of the inherent chal-lenges. Bonding quality was highest at high temperature deposition conditions, and only roughly 10% loss in yield strength was observed when compared to injection molded counterparts. All specimens, regardless of deposition conditions, showed poor ductility and little to no correlation was found between the elongation and deposition tempera-tures. Excessive heat flow to the specimen during deposition caused substantial shrink-age due to prolonged cooling of the deposited plastic, and consequently the most di-mensionally stable specimens were produced by limiting the deposition temperatures or increasing interlayer cooling time. Specimens with sharp protruding features showed higher tendency to peel off from the build platform than circular specimens did, due to differences in contractile stress distributions. Warp deformation became also more prom-inent when feature thickness was reduced. Nevertheless, the deposition performance under optimal conditions was for the most parts on par with many traditional feedstock materials.

The goal of this thesis was to deduct the composition for recycled multilayer film plastic waste and how it could be compatibilized in theory. The composition analysis was carried out using three different methods: differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and polarized light optical microscopy. Recycled multilayer plastic film samples were provided by Arcada University of applied sciences after initial screening. FTIR and optical microscopy were used on all samples. Some samples had their materials written on the packages. DSC was used only on samples with unknown material composition. Optical microscopy was used to produce cross-section images of the multi-layer films. Layer thicknesses and the number of layers were differentiated from these images. Different plastics exhibit various interference colors with polarized light, thus individual layers could be identified. Top and bottom layers were analyzed by FTIR and then cross-referenced with the data from the layer analysis. Analysis was carried out for 121 samples and 738 layers. This lead to the total thickness of each material used in the sample pool, which was used to further calculate the proportions of each material in relation to volume for different package types and the whole sample pool. The sample pool consisted of 56.7 % polyethylene (PE), 13.5 % of polypropylene (PP), 9.5 % of polyamide-6 (PA-6), 7.8 % of polyethylene terephthalate (PET), 4.5 % of copolymers of PE and PP, 4.1 % of print, 2.0 % of ethylene vinyl acetate (EVA) or tie layers and of 1.9 % ethylene vinyl alcohol (EVOH). This data could be possibly used for future research into the compatibilization of commingled postconsumer multilayer plastic film waste and possible applications.

Muovikalvon pinnankarheuden mittaaminen ekstruusiolla valmistetusta kalvosta on ollut pitkään haastavaa. Erilaisten leikenäytteiden kerääminen koeajoista mittauslaitteita varten on aikaa vievää. Lisäksi tulosten vertailukelpoisuus vaihtelee näytepisteiden välillä. Pinnankarheuden määrittäminen optisen on-line mitta-anturin avulla nopeuttaa mittaustulosten saantia ja tehostaa ekstruusioprosessin laadunvalvontaa. Menetelmän avulla saadaan reaaliaikaista tietoa kalvon pinnan ominaisuuksista. Tällöin negatiivisiin muutoksiin voidaan reagoida prosessiparametreja tai materiaaleja säätämällä. Lisäksi muovikalvon pinnalla esiintyvät prosessointivirheet voidaan havaita optisella mittauksella tarkasti. Työn kokeellisessa osuudessa valmistettiin tasokalvoa laboratorio-olosuhteissa ekstruuderilla. Kelauslaitteistoon asennettua on-line mitta-anturia käytettiin koeajoissa kalvon pinnankarheuden määrittämiseen. Kokeellisessa osuudessa käytettiin kahta teollisuudessa paljon käytettyä muovilaatua ja kalvoa valmistettiin niin läpinäkyvänä kuin Masterbatchin avulla valkoiseksi värjättynä, jolla tutkittiin materiaalin vaikutusta tutkimustuloksiin. Työhön kuului myös kirjallisuus-katsaus, jossa tarkasteltiin yleisellä tasolla ekstruusiota, muovikalvon valmistusta, kalvonvalmistuksen materiaaleja sekä optista mittaamista. Tarkoituksena oli tarkastella eri prosessointivirheiden, erityisesti pinnalla tapahtuvana aaltoiluna esiintyvän sharkskin-ilmiön ja laajemman sulamurtuman esiintyminen muovikalvoa prosessoitaessa. Lisäksi työhön kuului optisen mitta-anturin kapasiteetin määrittäminen teollista tuotantoa varten ja mahdollisten kehittämiskohteiden arviointi. Työssä saatiin valmistettua onnistuneesti muovikalvoa erilaisilla prosessiparametreilla ja optinen mitta-anturi myös kykeni määrittämään kalvon pinnankarheuden tarkasti. Ongelmaksi syntyivät suuret vaihtelut kalvon paksuudessa johtuen eri prosessiparametreista tai prosessivirheistä, jolloin pinnan karheuden määrittäminen oli haastavaa. Tutkimuksen perusteella mitta-anturi soveltuu erinomaiseksi työkaluksi sovelluksiin, joissa pinnankarkeuden tarkka määrittäminen on tärkeää.