Muutosilmiöt soodakattilakeossa

Soodakattilan sulakeon epästationaarinen käyttäytyminen sekä keon pitkä jäähtymisaika alasajon jälkeen ovat aiheuttaneet ongelmia kattilan taloudellisessa käytettävyydessä. Keon käyttäytymisestä on luotu CFD-malleja, joiden tavoitteena on havainnollistaa keon lämpötilajakaumaa ja rakennetta. Mallien ongelmana on se, että niissä huomioidaan vain keon aktiivinen pintakerros. Keon sisäosan rakennetta ja siinä tapahtuvia prosesseja ei toistaiseksi tunneta kunnolla luotettavan, koko keon kattavan mallin luomiseen. Tässä työssä tutkittiin sulakeon käytön aikana havaittuja muutosilmiöitä, jotka vaikuttavat keon rakenteeseen ja ominaisuuksiin sekä tutkittiin ilmiöiden taustalla olevia tekijöitä. Näitä tekijöitä ovat keon sisässä tapahtuvat kemialliset ja fyysiset prosessit, jotka aiheuttavat muutoksia niin lämpöteknisesti kuin fyysisesti sekä ulkoapäin tulevat tekijät, jotka aiheutuvat ajotilanteiden seurauksena tapahtuvista muutoksista. Työn kokeellisena osana luotiin sulakeon jäähtymismalli käyttäen 1-dimensionaalista ADL-mallia. Mallin pohjana käytettiin StoraEnso Oy:ltä Oulun soodakattilan sulakeosta saatua mittausraporttia. ADL-mallin avulla luotiin keon jäähtymiskäyrät lämpötilan ja syvyyden funktiona. Saadut käyrät täsmäsivät hyvin mittausraportin tuloksiin. Mallin avulla keolle saatiin muodostettua energiatase, jonka tuloksena keosta 12 tunnin aikana poistuva lämpövirta pinnalla oli noin 9.8kW/m2 ja pinnan lämmönsiirtokerroin 58.3W/m²°C. Pohjan poistuvaksi lämpövirraksi saatiin 14.1kW/m2 ja lämmönsiirtokertoimeksi 75.4W/m²°C. Termiseksi diffuusiokertoimeksi saatiin 3.9•10-7m²/s.

Synthesis and Characterization of Cellulose fiber-silica nanocomposites

Cellulose fiber-silica nanocomposites with novel mechanical, chemical and thermal properties have potential to be widely applied in different area. Monodispered silica nanoparticles play an important role in enhancing hybrids properties of hardness, strength, thermal stability etc. On the other hand, cellulose is one of the world’s most abundant and renewable polymers and possesses several unique properties required in many areas and biomedicine. The aim of this master thesis is to study if silica particles from reaction of sodium silicate and sulphuric acid can be adsorbed onto cellulose fiber surfaces via in situ growth. First, nanosilica particles were synthesized. Effect of pH and silica contents were tested. In theoretical part, introduction of silica, methods of preparation of nanosilica from sodium silicate, effect factors and additives were discussed. Then, cellulose fiber-silica nanocomposites were synthesis via route from sodium silicate and route silicic acid. In the experiment of route from sodium silicate, the effects of types of sodium silicate, pH and target ratio of silica to fiber were investigated. From another aspect, the effects of types of sodium silicate, fiber concentration in mixture solution and target ratio of silica to fiber were tested in the experiment of route from silicic acid. Samples were investigated via zeta potential measurement, particle size distribution, ash content measurement and Scanning Electron Microscopy (SEM). The Results of the experiment of preparing silica sol were that the particle size of silica sol was smaller prepared in pH 11.7 than that prepared in pH 9.3. Then in the experiment of synthesis of cellulose fiber-silica nanocomposites, it was concluded that the zeta potential of all the samples were around -16 mV and the highest ash content of all the samples was only 1.4%. The results of SEM images showed only a few of silica particles could be observed on the fiber surface, which corresponded to the value of ash content measurement.

Modification of commercial poly-lactide for extrusion coated food packaging applications

Poly-L-lactide (PLLA) is a widely used sustainable and biodegradable alternative to replace synthetic non-degradable plastic materials in the packaging industry. Conversely, its processing properties are not always optimal, e.g. insufficient melt strength at higher temperatures (necessary in extrusion coating processes). This thesis reports on research to improve properties of commercial PLLA grade (3051D from NatureWorks), to satisfy and extend end-use applications, such as food packaging by blending with modified PLLA. Adjustment of the processability by chain branching of commercial poly-L-lactide initiated by peroxide was evaluated. Several well-defined branched structures with four arms (sPLLA) were synthesized using pentaerythritol as a tetra-functional initiator. Finally, several block copolymers consisting of polyethylene glycol and PLLA (i.e. PEGLA) were produced to obtain a well extruded material with improved heat sealing properties. Reactive extrusion of poly-L-lactide was carried out in the presence of 0.1, 0.3 and 0.5 wt% of various peroxides [tert-butyl-peroxybenzoate (TBPB), 2,5-dimethyl-2,5-(tert-butylperoxy)-hexane (Lupersol 101; LOL1) and benzoyl peroxide (BPO)] at 190C. The peroxide-treated PLLAs showed increased complex viscosity and storage modulus at lower frequencies, indicating the formation of branched/cross linked architectures. The material property changes were dependent on the peroxide, and the used peroxide concentration. Gel fraction analysis showed that the peroxides, afforded different gel contents, and especially 0.5 wt% peroxide, produced both an extremely high molar mass, and a cross linked structure, not perhaps well suited for e.g. further use in a blending step. The thermal behavior was somewhat unexpected as the materials prepared with 0.5 wt% peroxide showed the highest ability for crystallization and cold crystallization, despite substantial cross linking. The peroxide-modified PLLA, i.e. PLLA melt extruded with 0.3 wt% of TBPB and LOL1 and 0.5 wt% BPO was added to linear PLLA in ratios of 5, 15 and 30 wt%. All blends showed increased zero shear viscosity, elastic nature (storage modulus) and shear sensitivity. All blends remained amorphous, though the ability of annealing was improved slightly. Extrusion coating on paperboard was conducted with PLLA, and peroxide-modified PLLA blends (90:10). All blends were processable, but only PLLA with 0.3 wt% of LOL1 afforded a smooth high quality surface with improved line speed. Adhesion levels between fiber and plastic, as well as heat seal performance were marginally reduced compared with pure 3051D. The water vapor transmission measurements (WVTR) of the blends containing LOL1 showed acceptable levels, only slightly lower than for comparable PLLA 3051D. A series of four-arm star-shaped poly-L-lactide (sPLLA) with different branch length was synthesized by ring opening polymerization (ROP) of L-lactide using pentaerythritol as initiator and stannous octoate as catalyst. The star-shaped polymers were further blended with its linear resin and studied for their melt flow and thermal properties. Blends containing 30 wt% of sPLLA with low molecular weight (30 wt%; Mwtotal: 2500 g mol-1 and 15000 g mol-1) showed lower zero shear viscosity and significantly increased shear thinning, while at the same time slightly increased crystallization of the blend. However, the amount of crystallization increased significantly with the higher molecular weight sPLLA, therefore the star-shaped structure may play a role as nucleating agent. PLLA-polyethylene glycol–PLLA triblock copolymers (PEGLA) with different PLLA block length were synthesized and their applicability as blends with linear PLLA (3051D NatureWorks) was investigated with the intention of improving heat-seal and adhesion properties of extrusion-coated paperboard. PLLA-PEG-PLLA was obtained by ring opening polymerization (ROP) of L-lactide using PEG (molecular weight 6000 g mol-1) as an initiator, and stannous octoate as catalyst. The structures of the PEGLAs were characterized by proton nuclear magnetic resonance spectroscopy (1H-NMR). The melt flow and thermal properties of all PEGLAs and their blends were evaluated using dynamic rheology, and differential scanning calorimeter (DSC). All blends containing 30 wt% of PEGLAs showed slightly higher zero shear viscosity, higher shear thinning and increased melt elasticity (based on tan delta). Nevertheless, no significant changes in thermal properties were distinguished. High molecular weight PEGLAs were used in extrusion coating line with 3051D without problems.

Dynamic Model of a Small Once-Through Boiler

In this study, a model for the unsteady dynamic behaviour of a once-through counter flow boiler that uses an organic working fluid is presented. The boiler is a compact waste-heat boiler without a furnace and it has a preheater, a vaporiser and a superheater. The relative lengths of the boiler parts vary with the operating conditions since they are all parts of a single tube. The present research is a part of a study on the unsteady dynamics of an organic Rankine cycle power plant and it will be a part of a dynamic process model. The boiler model is presented using a selected example case that uses toluene as the process fluid and flue gas from natural gas combustion as the heat source. The dynamic behaviour of the boiler means transition from the steady initial state towards another steady state that corresponds to the changed process conditions. The solution method chosen was to find such a pressure of the process fluid that the mass of the process fluid in the boiler equals the mass calculated using the mass flows into and out of the boiler during a time step, using the finite difference method. A special method of fast calculation of the thermal properties has been used, because most of the calculation time is spent in calculating the fluid properties. The boiler was divided into elements. The values of the thermodynamic properties and mass flows were calculated in the nodes that connect the elements. Dynamic behaviour was limited to the process fluid and tube wall, and the heat source was regarded as to be steady. The elements that connect the preheater to thevaporiser and the vaporiser to the superheater were treated in a special way that takes into account a flexible change from one part to the other. The model consists of the calculation of the steady state initial distribution of the variables in the nodes, and the calculation of these nodal values in a dynamic state. The initial state of the boiler was received from a steady process model that isnot a part of the boiler model. The known boundary values that may vary during the dynamic calculation were the inlet temperature and mass flow rates of both the heat source and the process fluid. A brief examination of the oscillation around a steady state, the so-called Ledinegg instability, was done. This examination showed that the pressure drop in the boiler is a third degree polynomial of the mass flow rate, and the stability criterion is a second degree polynomial of the enthalpy change in the preheater. The numerical examination showed that oscillations did not exist in the example case. The dynamic boiler model was analysed for linear and step changes of the entering fluid temperatures and flow rates.The problem for verifying the correctness of the achieved results was that there was no possibility o compare them with measurements. This is why the only way was to determine whether the obtained results were intuitively reasonable and the results changed logically when the boundary conditions were changed. The numerical stability was checked in a test run in which there was no change in input values. The differences compared with the initial values were so small that the effects of numerical oscillations were negligible. The heat source side tests showed that the model gives results that are logical in the directions of the changes, and the order of magnitude of the timescale of changes is also as expected. The results of the tests on the process fluid side showed that the model gives reasonable results both on the temperature changes that cause small alterations in the process state and on mass flow rate changes causing very great alterations. The test runs showed that the dynamic model has no problems in calculating cases in which temperature of the entering heat source suddenly goes below that of the tube wall or the process fluid.

Puun jäätyminen ja jäätyneen puun ominaisuudet sahauksen kannalta

Työn tavoitteena oli tutkia puun jäätymisnopeutta, puun kosteuden ja tiheyden vaikutusta siihen sekä kosteussuhteessa tapahtuvia muutoksia jäätymisen aikana. Lisäksi tavoitteena oli kirjallisuuden pohjalta selvittää jäätymisen vaikutusta puun sahauksen kannalta merkittäviin ominaisuuksiin. Puun jäätymisnopeuden määrittämiseksi puun lämpötilaa mitattiin pakastuksen aikana viiden minuutin välein pintapuusta, sydän-puusta ja puun sydämestä. Mittauksista saatujen tulosten pohjalta piirrettiin käyrästö lämpötilan kehittymisestä ajan funktiona puun eri kohdissa. Lämpötilakäyrät jaettiin jäätymisen osalta kolmeen vaiheeseen: jäähtymiseen, jäätymiseen ja loppujäätymiseen. Käyrille piirrettiin trendiviivat, joiden kulmakertoimista saatiin lämpötilan muutosnopeudet eri vaiheille. Mittauksissa käytetyille koekappaleille määritettyjen kosteussuhteiden ja kuivatiheyksien avulla selvitettiin näiden ominaisuuksien vaikutusta lämpötilan muutosnopeuksiin. Tulokseksi saatiin kuva jäätymisen etenemisestä puussa. Saatujen tietojen pohjalta pystytään arvioimaan puun jäätymisaste tietyn ajan kuluttua. Jäätymisasteen arviointia tullaan käyttämään jatkossa tehtävien jäätyneen puun sahauskokeiden yhteydessä.

Täyteaineen ja tärkkelyksen annostelun optimointi paperikoneen lyhyeen kiertoon

Diplomityön tavoitteena oli selvittää tärkkelyksen ja täyteaineen annostelupaikkojen sekä – tapojen vaikutukset SC- heatset web offset -paperin ominaisuuksiin ja pintalujuuteen. Lisäksi selvitettiin, muuttuuko paperin pölyäminen annostelupaikkojen tai – tapojen vaikutuksesta. Diplomityön kirjallisuusosiossa käsiteltiin heatset web offset -painokoneen rakennetta ja sen toimintaa. Lisäksi käsiteltiin heatset web offset -painokoneella ilmenevät pölyongelmien tyypit ja, mitkä eri paperin tekijät vaikuttavat heatset web offset -painokoneen pölyämisongelmiin. Lisäksi kirjallisuusosiossa käsiteltiin yleisimmät pintalujuutta parantavat kemikaalit sekä näiden kemikaalien annostelupaikat paperikoneen lyhyeen kiertoon. Alkutason määrityksessä ja ensimmäisessä koeajossa havaittiin, että paperin huokoisuus ja huokosrakenne olivat tärkeimmät SC heatset web offset -paperin pintalujuuteen vaikuttavat tekijät. KCL:n HSWO–koepainokoneella painetuista rullista annostelutapa 4, jossa tärkkelystä ja täyteainetta annosteltiin perälaatikon syöttöpumpun imupuolelle perinteisesti, oli pintalujuudeltaan kestävin. Ahmatti-kokeissa havaittiin, että tärkkelyksen ja täyteaineen annostelu TrumpJet- laitteistolla lähempänä paperikoneen perälaatikkoa, annostelutapa 6, pienentää rullan sisäistä vetolujuushajontaa. Ahmatti -pilotkokeissa havaittiin myös, että paperin lujuusominaisuudet ja vetolujuushajonnat voitiin säilyttää entisellään, kun tärkkelystä ja täyteainetta annosteltiin perinteisesti perälaatikon syöttöpumpun imupuolelta. Toisesta koeajon koepainorullasta havaittiin KCL:n koepainatuksissa, että paperin pintalujuus heikentyy annosteltaessa tärkkelystä 8 kg/t verrattuna 10 kg/t tärkkelysannosteluun. Näiden tapojen ero ei ole merkittävä.

Effects of Surface Properties and Wood Modification into Direct Printing on Wood

Building industry is a high volume branch which could provide prominent markets for wood based interior decoration solutions. Competition in interior decoration markets requires versatility in appearance. Versatility in wood appearance and added value could be achieved by printing grain patterns of different species or images directly onto wood. The problem when planning wood printing’s implementing into durable applications is basically how to transfer a high quality image or print sustainably onto wood, which is porous, heterogeneous, dimensionally unstable, non-white and rough. Wood preservation or treating, and modification can provide durability against degradation but also effect to the surface properties of wood which will effect on printability. Optimal adhesion is essential into print quality, as too high ink absorbance can cause spreading and too low ink absorbance cause pale prints. Different printing techniques have different requirements on materials and production. The direct printing on wood means, that intermedias are not used. Printing techniques with flexible printing plates or in fact non-impact techniques provide the best basis for wood printing. Inkjet printing of wood with different mechanical or chemical surface treatments, and wood plastic composite material gave good results that encourage further studies of the subject. Sanding the wood surface anti-parallel to the grain gave the best overall printing quality. Spreading parallel to the grain could not be avoided totally, except in cases where wood was treated hydrophobic so adhesion of the ink was not sufficient. Grain pattern of the underlying wood stays clearly visible in the printed images. Further studies should be made to fine tune the methods that already gave good results. Also effects of moisture content of wood, different inks, and long-term exposure to UV-radiation should be tested.

Surface Modification of Ceramics

Ceramics are widely used in industrial applications due to their advantageous thermal and mechanical stability. Corrosion of ceramics is a great problem resulting in significant costs. Coating is one method of reducing adversities of corrosion. There are several different thin film deposition processes available such as sol-gel, Physical and Chemical Vapour Deposition (PVD and CVD). One of the CVD processes, called Atomic Layer Deposition (ALD) stands out for its excellent controllability, accuracy and wide process capability. The most commonly mentioned disadvantage of this method is its slowness which is partly compensated by its capability of processing large areas at once. Several factors affect the ALD process. Such factors include temperature, the grade of precursors, pulse-purge times and flux of precursors as well as the substrate used. Wrongly chosen process factors may cause loss of self-limiting growth and thus, non-uniformities in the deposited film. Porous substrates require longer pulse times than flat surfaces. The goal of this thesis was to examine the effects of ALD films on surface properties of a porous ceramic material. The analyses applied were for permeability, bubble point pressure and isoelectric point. In addition, effects of the films on corrosion resistance of the substrate in aqueous environment were investigated. After being exposured to different corrosive media the ceramics and liquid samples collected were analysed both mechanically and chemically. Visual and contentual differences between the exposed and coated ceramics versus the untreated and uncoated ones were analysed by scanning electron microscope. Two ALD film materials, dialuminium trioxide and titanium dioxide were deposited on the ceramic substrate using different pulse times. The results of both film materials indicated that surface properties of the ceramic material can be modified to some extent by the ALD method. The effect of the titanium oxide film on the corrosion resistance of the ceramic samples was observed to be fairly small regardless of the pulse time.

Influence of plasma modification on surface properties and offset printability of coated paper

The properties of the paper surface play a crucial role in ensuring suitable quality and runnability in various converting and finishing operations, such as printing. Plasma surface modification makes it possible to modify the surface chemistry of paper without altering the bulk material properties. This also makes it possible to investigate the role of the surface chemistry alone on printability without influencing the porous structure of the pigment-coated paper. Since the porous structure of a pigment coating controls both ink setting and optical properties, surface chemical changes created by a plasma modification have a potential to decouple these two effects and to permit a better optimization of them both. The aim of this work was to understand the effects of plasma surface modification on paper properties, and how it influences printability in the sheet-fed offset process. The objective was to broaden the fundamental understanding of the role of surface chemistry on offset printing. The effects of changing the hydrophilicity/ hydrophobicity and the surface chemical composition by plasma activation and plasma coatings on the properties of coated paper and on ink-paper interactions as well as on sheet-fed offset print quality were investigated. In addition, the durability of the plasma surface modification was studied. Nowadays, a typical sheet-fed offset press also contains units for surface finishing, for example UVvarnishing. The role of the surface chemistry on the UV-varnish absorption into highly permeable and porous pigment-coated paper was also investigated. With plasma activation it was possible to increase the surface energy and hydrophilicity of paper. Both polar and dispersion interactions were found to increase, although the change was greater in the polar interactions due to induced oxygen molecular groups. The results indicated that plasma activation takes place particularly in high molecular weight components such as the dispersion chemicals used to stabilize the pigment and latex particles. Surface composition, such as pigment and binder type, was found to influence the response to the plasma activation. The general trend was that pilot-scale treatment modified the surface chemistry without altering the physical coating structure, whereas excessive laboratory-scale treatment increased the surface roughness and reduced the surface strength, which led to micro-picking in printing. It was shown that pilot-scale plasma activation in combination with appropriate ink oils makes it possible to adjust the ink-setting rate. The ink-setting rate decreased with linseed-oil-based inks, probably due to increased acid-base interactions between the polar groups in the oil and the plasma-treated paper surface. With mineral-oil-based inks, the ink setting accelerated due to plasma activation. Hydrophobic plasma coatings were able to reduce or even prevent the absorption of dampening water into pigmentcoated paper, even when the dampening water was applied under the influence of nip pressure. A uniform hydrophobic plasma coating with sufficient chemical affinity with ink gave an improved print quality in terms of higher print density and lower print mottle. It was also shown that a fluorocarbon plasma coating reduced the free wetting of the UV-varnish into the highly permeable and porous pigment coating. However, when the UV-varnish was applied under the influence of nip pressure, which leads to forced wetting, the role of the surface chemical composition seems to be much less. A decay in surface energy and wettability occurred during the first weeks of storage after plasma activation, after which it leveled off. However, the oxygen/carbon elemental ratio did not decrease as a function of time, indicating that ageing could be caused by a re-orientation of polar groups or by a contamination of the surface. The plasma coatings appeared to be more stable when the hydrophobicity was higher, probably due to fewer interactions with oxygen and water vapor in the air.

Influence of topography and surface chemistry on the wetting properties of TiO2-based ceramic coatings

Vätning av fasta ytor är ett viktigt fenomen i såväl naturen som i en lång rad av industriella tillämpningar. Det är allmänt känt att vätningen av en fast yta styrs av ytans kemi samt struktur. Målsättningen med avhandlingen var att studera hur kemisk heterogenitet och ytråhet på nanometernivå påverkar vätningsegenskaperna hos en fast yta. Ytorna som studerades var titandioxid-baserade kerama ytor som framställdes med hjälp av en sol-gel process. Vätningstudierna utfördes genom kontaktvinkelmätningar, vilket innebär att man mäter vinkeln som vätska/luft-gränsskiktet hos en vätskedroppe bildar mot en fast yta. Ytråheten hos materialen studerades främst genom atomkraftsmikroskopi (AFM). I AFM detekteras ytans struktur av en mycket skarp nål som skannar ytan. Resultaten i avhandlingen kunde framgångsrikt modelleras med existerande teorier för vätning av heterogena ytor.

Bonding of Composite Resin to Alumina and Zirconia Ceramics with Special Emphasis on Surface Conditioning and Use of Coupling Agents

Dental oxide ceramics have been inspired by their biocompability and mechanical properties which have made durable all-ceramic structures possible. Clinical longevity of the prosthetic structures is dependent on effective bonding with luting cements. As the initial shear bond strength values can be comparable with several materials and procedures, long-term durability is affected by ageing. Aims of the current study were: to measure the shear bond strength of resin composite-to-ceramics and to evaluate the longevity of the bond; to analyze factors affecting the bond, with special emphasis on: the form of silicatization of the ceramic surface; form of silanization; type of resin primer and the effect of the type of the resin composite luting cement; the effect of ageing in water was studied regarding its effect to the endurance of the bond. Ceramic substrates were alumina and yttrium stabilized zirconia. Ceramic conditioning methods included tribochemical silicatization and use of two silane couplings agents. A commercial silane primer was used as a control silane. Various combinations of conditioning methods, primers and resin cements were tested. Bond strengths were measured by shear bond strength method. The longevity of the bond was generally studied by thermocycling the materials in water. Additionally, in one of the studies thermal cycling was compared with long-term water storaging. Results were analysed statistically with ANOVA and Weibull analysis. Tribochemical treatment utilizing air pressure of 150 kPa resulted shear bond strengths of 11.2 MPa to 18.4 MPa and air pressure of 450 kPa 18.2 MPa to 30.5 MPa, respectively. Thermocycling of 8000 cycles or four years water storaging both decreased shear bond strength values to a range of 3.8 MPa to 7.2 MPa whereas initial situation varied from 16.8. Mpa to 23.0 MPa. The silane used in studies had no statistical significance. The use of primers without 10-MDP resulted spontaneous debonding during thermocycling or shear bond strengths below 5 MPa. As conclusion, the results showed superior long-term bonding with primers containing 10-MDP. Silicatization with silanizing showed improved initial shear bond strength values which considerably decreased with ageing in water. Thermal cycling and water storing for up to four years played the major role in reduction of bond strength, which could be due to thermal fatigue of the bonding interface and hydrolytic degradation of the silane coupled interface.

Polymer surface modification by atomic layer deposition

Current industrial atomic layer deposition (ALD) processes are almost wholly confined to glass or silicon substrates. For many industrial applications, deposition on polymer substrates will be necessary. Current deposition processes are also typically carried out at temperatures which are too high for polymers. If deposition temperatures in ALD can be reduced to the level applicable for polymers, it will open new interesting areas and applications for polymeric materials. The properties of polymers can be improved for example by coatings with functional and protective properties. Although the ALD has shown its capability to operate at low temperatures suitable for polymer substrates, there are other issues related to process efficiency and characteristics of different polymers where new knowledge will assist in developing industrially conceivable ALD processes. Lower deposition temperature in ALD generally means longer process times to facilitate the self limiting film growth mode characteristic to ALD. To improve process efficiency more reactive precursors are introduced into the process. For example in ALD oxide processes these can be more reactive oxidizers, such as ozone and oxygen radicals, to substitute the more conventionally used water. Although replacing water in the low temperature ALD with ozone or plasma generated oxygen radicals will enable the process times to be shortened, they may have unwanted effects both on the film growth and structure, and in some cases can form detrimental process conditions for the polymer substrate. Plasma assistance is a very promising approach to improve the process efficiency. The actual design and placement of the plasma source will have an effect on film growth characteristics and film structure that may retard the process efficiency development. Due to the fact that the lifetime of the radicals is limited, it requires the placement of the plasma source near to the film growth region. Conversely this subjects the substrate to exposure byother plasma species and electromagnetic radiation which sets requirements for plasma conditions optimization. In this thesis ALD has been used to modify, activate and functionalize the polymer surfaces for further improvement of polymer performance subject to application. The issues in ALD on polymers, both in thermal and plasma-assisted ALD will be further discussed.