[dipl] Kemian tekniikan korkeakoulu / CHEM

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1-Butanol dehydration
(2011) Väkevä, Minna; Airaksinen, Sanna; Kurkijärvi, Antti; Biotekniikan ja kemian tekniikan laitos; Kemian tekniikan korkeakoulu; School of Chemical Engineering; Krause, Outi
The purpose of this master's thesis was to examine 1-butanol dehydration reaction which is widely used as a model reaction to characterize acidic sites on catalysts. 1-Butanol is a linear C₄ alcohol that can be produced e.g. via ABE fermentation process. The first part of the thesis, the literature review, presents a wide variety of catalysts used in alcohol dehydration with emphasis on y-Al₂O₃, a binary oxide catalyst known to possess Lewis acidity. Reaction mechanisms and other possible reactions in similar conditions were reviewed. The main products of the reaction are different butenes that can be used in petrochemical industry. The selection of the catalyst and reaction conditions affects the product distribution. In the experimental part of the thesis, an analysis for 1-butanol dehydration was developed and a set of 1-butanol dehydration experiments was carried out. An online Fourier transform infrared (FTIR) gas analyser was calibrated for the expected products and the reactor set-up was modified to be used in 1-butanol dehydration. Two different types of flow reactors were used: a conventional packed-bed reactor and a small-scale micro channel reactor. y-Al₂O₃ was used as the catalyst in both of the reactors, as particles in packed-bed reactor and as coated on the channels of the micro channel reactor. One experiment in the packed-bed reactor was also done with a multi-walled carbon nanotube (MWCNT) catalyst treated with acid. The temperature range in the 1-butanol dehydration experiments was 280 - 450 °C and the reagent mass flow per the mass of the catalyst (weight hourly space velocity, WHSV) was varied between 47 and 391 h^-1, the total flow through the FTIR equipment being the limiting factor. Conversion and selectivity were found to be strongly dependent on the temperature. y-Al₂O₃ was very selective towards 1-butene at temperatures over 370 °C whereas dibutyl ether was the main product at temperatures under 300 °C. Higher conversions were achieved with the micro channel reactor. The y-Al₂O₃ catalyst was more active than the MWCNT catalyst.
1-dekeenin puhdistus
(2024-06-11) Saarenpää, Kasperi; Kuitunen, Susanna; Vikman, Kim; Kemian tekniikan korkeakoulu; Oinas, Pekka
Polyalfaolefiiniprosessien ongelmana usein on raaka-aineena käytettävien alfaolefiinien riittämätön puhtaus. Prosessin pääasiallinen raaka-aine on jokin alfaolefiini, mutta syöttöaine sisältää myös primäärikomponentin ko-isomeereja sekä muita hiilivetyketjuja jotka muistuttavat hyvin paljon kyseistä komponenttia. Tämän diplomityön tarkoituksena on löytää soveltuva erotustekniikka, jolla saadaan prosessoitua polyalfaolefiiniprosessin syöttöaineesta puhtaampaa. Työn kirjallisessa osuudessa keskitytään tutkimaan erilaisia 1-dekeenin valmistusmenetelmiä, C8-C12 hiilivetyisomeerien erotusta, niiden prosessikonsepteja ja sovelluskohteita. Työssä tutkitaan myös dekeenin isomeerien vaikutusta polyalfaolefiinituotteen laatuominaisuuksiin. Tämän lisäksi työssä käydään läpi polyalfaolefiinien valmistustekniikkaa ja sitä, miten eri alfaolefiineista valmistetut polyalfaolefiinituotteet eroavat toisistaan. Työn soveltavassa osuudessa valittiin kaksi lupaavinta 1-dekeenin erotustekniikkaa, joista luotiin virtauskaaviot. Molemmat erotusprosessit mallinnettin ja mitoitettiin käyttämällä Aspen Plus -mallinnusohjelmistoa. Lopuksi näitä kahta prosessia verrattiin keskenään ja listattiin niiden hyvät ja huonot puolet. Työn tulosten perusteella Diels–Alder-reaktio vaikuttaa lupaavalta keinolta puhdistaa alfaolefiineja. Prosessin lopputuotteeksi saadaan eroteltua erittäin puhdasta 1-dekeeniä korkealla saannolla.
3-dimensional layout for chemical processes at different scales
(2022-06-14) Toivonen, John; Sarwar, Golam; Kemian tekniikan korkeakoulu; Oinas, Pekka
Plant layout is used in chemical plants in different forms. The 2-dimensional (2D) layout solutions are usually given as top views of processes, visualizing the placement of process equipment. The 3-dimensional (3D) solutions require software built specifically for layout and equipment design. These Computer Aided Design (CAD) software are available by various companies on the market and have become an important part of different operations in the industry. Chemical plants use CAD software to improve process design, safety, and maintenance operations. 3D layouts offer clear dimensions of plants before the plant is built. This works as an assurance that the pieces of equipment have enough space, can be accessed, and necessary safety distances can be reserved at an early stage. CAD software providers offer several software solutions for different fields and industries. The software can be very specifically developed for example for the oil & gas industry, or chemical plants. The software can also be a basic CAD software, that focuses on being easy to use and adaptable to many industries. The more specifically developed CAD software are usually used for complex, large-scale plants where automated tasks, prebuilt designs, and cloud storage are of great use. The differences between different CAD software tend to be in the graphical user interface, navigation logic, and special packages of the software. The same 3D layouts can usually be designed with any of the CAD software, regardless of the software provider. MicroStation CONNECT Edition was used in this thesis to create three 3D layouts of chemical processes based on research projects at Aalto University. The layouts were done to test whether MicroStation is a suitable software for chemical plant layout and to determine how easy it is to learn. MicroStation is relatively easy to learn and it worked as CAD software for both small-scale and large-scale plants. After the layouts were completed and detailed pieces of equipment had been created, it was determined that CAD software with specialized tools for plant design would have been more fit for the purpose. These types of CAD software are more attractive for plant and process engineers, for example OpenPlant that, like MicroStation, is developed by Bentley. The application for layouts using virtual reality as training tools for operators was found to be useful. The virtual environment offers operator a practical way of learning while minimizing the need for supervisors and eliminating chemical and physical hazards such as toxic materials and high pressure and high temperature environments.
3D bioprinting inks based on cellulose nanofibrils and colloidal lignin particles
(2019-03-12) Äkräs, Laura; Sipponen, Mika; Kemian tekniikan korkeakoulu; Österberg, Monika
Three-dimensional (3D) bioprinting has been utilized for decades, and today its popularity is up surging. 3D bioprinting is based on the use of the natural, non-toxic, and tissue-mimicking bio-materials which are extruded in the form of bioinks to generate different structures layer-by-layer, from a simple cylinder to the shape of an ear. This method is gaining popularity in the field of regenerative medicine in which the focus is in regenerating and replacing injured tissues and organs. However, the major obstacles in the utilization of the current biomaterials are their insufficient properties, especially in the case of the mechanical strength. Therefore, new materials, hybrid materials, and material composites need to be developed. In this Master’s thesis, the novel CLP-CNF-alginate bioink compositions were prepared with the cellulose nanofibril (CNF) concentrations of 2.5 wt%, alginate concentrations of 0.5 wt%, and colloidal lignin nanoparticle (CLP) concentrations relative to the dry weight of CNF. The rheological properties of these bioinks were measured through the dynamic viscosity and amplitude sweep measurements, whereas the printability of the bioinks was tested in 3D bioprinting. This was followed by the compression tests and the evaluation of the hydrogels in different storage conditions. These various stability tests included freeze-drying, re-wetting, humidity chamber, salt-water solution, and free-standing at room temperature. The addition of CLPs into the CNF-alginate hydrogel offered many advantages. Most importantly, the existence of CLPs enhanced the printability and structural stability of the hydrogels directly after 3D bioprinting. On the other hand, the addition of CLPs increased the dimensional stability of the CLP-CNF-alginate hydrogels in high humidity and salt-water solutions. Nevertheless, dissolution in the salt-water solution, fast drying in the room air, and the non-toxicity of these hydrogels with the degradation rates inside the human body require further research. However, these multiple intrinsic properties of the CLP-CNF-alginate hydrogels make them a multifunctional material for the regenerative medicine.
3D Formability of fibre, micro and nanofibrillated cellulose and PCC composite sheets
(2016-02-02) Dinh, Thi; Rantanen, Juuso; Kemian tekniikan korkeakoulu; Maloney, Thad
The purpose of the research was to form pulp fibre-MNFC-PCC composites into three dimensional shapes with suitable forming parameters. In addition, this thesis investigated the effect of raw material fractions of MNFC, fillers and pulp fibres in formability and material properties. The study was commissioned by Omya AG. The study was conducted at Aalto University School of Chemical Technology in Espoo, Finland. The samples were provided by Omya AG. The work was divided into two parts. First part was to form the handsheets and test the material properties of various composites. On the other hand, the material properties of the composites were compared in order to determine the most suitable composites for the 3D forming trials. Second part was to form the composites in 3D-shapes with various forming parameters. The purpose was to pinpoint the suitable forming parameters for the 3D-forming process. The information was gathered from books, literatures, newspapers, journals, theses and the internet. These data support the view that the combination of MNFC, pulp fibre and PCC provided 100% filler retention, high optical properties as well as strength properties to the paper sheet. On the basis of the results of this research, it can be concluded that pulp fibre-MNFC-PCC composites can be formed in three dimensional shapes with suitable forming parameters.
3D inkjet-printing of photo-crosslinkable resins for optical components
(2020-12-15) Magazine, Rishabh; van Bochove, Bas; Borandeh, Sedigheh; Kemian tekniikan korkeakoulu; Seppälä, Jukka
3D printing of UV cross-linkable composites
(2024-08-19) Salah, Aisha; Baniasadi, Hossein; Kemian tekniikan korkeakoulu; Niskanen, Jukka
The rapid evolution of 3D printing has revolutionized the manufacturing sector, offering unparalleled adaptability, customized solutions, and enhanced productivity. Despite these strides, using materials derived from fossil fuels presents considerable environmental obstacles. This research delves into the creation of sustainable composite materials by strengthening a poly(trimethylene carbonate) (PTMC) polymer matrix with biochar, employing digital light projection stereolithography (DLP-SLA) and UV light exposure for the fabrication of these structures. The primary focus of this work was to achieve five key objectives: (1) Synthesizing PTMC macromer; (2) Preparing composite resins from PTMC macromer and biochar; (3) Creating composite structures using digital light projecting stereolithography (DLP-SLA) with a poly(trimethylene carbonate) (PTMC) matrix embedded with biochar particles, and assessing the compatibility of biochar with the DLP-SLA device; (4) Crosslinking PTMC/Biochar networks with UV light exposure; and (5) Characterizing the physical and chemical properties of the samples and assessing the compatibility of biochar with the PTMC polymer matrix. The PTMC macromer was synthesized and functionalized. To confirm the synthesis, 1H-NMR and size exclusion chromatography (SEC) analysis were utilized. The rheological properties of the photo-cross-linkable resins (PTMC0, PTMC10, and PTMC30) were examined. PTMC0 showed Newtonian fluid characteristics, while PTMC10 and PTMC30 exhibited shear-thinning behaviour, indicating non-Newtonian pseudoplastic fluids. DLP-SLA successfully fabricated PTMC0 and PTMC10 structures, showing its feasibility. All resins were effectively crosslinked with UV light exposure under. The thermal properties of the crosslinked structures were characterized using thermogravimetric analysis (TGA) and differential scanning calorimetry analysis (DSC). Mechanical testing indicated increased Young's modulus and toughness in biochar-reinforced composites (PTMC10 and PTMC30). SEM analysis confirmed even particle dispersion and compatibility between the matrix and biochar. Water contact angle tests demonstrated the hydrophobic nature of UV-crosslinked PTMC, showing increasing hydrophobicity as biochar content increased. Swelling tests indicated reduced water uptake with higher biochar concentrations. The thesis marks a significant advancement in the pursuit of sustainable 3D printing. By harnessing the unique properties of PTMC and biochar, this research has showcased their potential in DLP-SLA technique. This not only holds the promise of developing environmentally friendly, high-performance products but also has the potential to significantly impact the broader acceptance of sustainable approaches in additive manufacturing. Furthermore, our study supports the integration of intelligent, environmentally friendly manufacturing systems, which is in line with Industry 4.0 aims.
3D printing of UV-curable cellulose derivatives
(2024-08-29) Kruse, Jan-Philipp; Baniasadi, Hossein; Egede Daugaard, Anders; Kemian tekniikan korkeakoulu; Niskanen, Jukka
The main goal of this project was to create a resin for stereolithography (SLA). This includes the functionalization of cellulose with allyl chloride or methacrylic anhydride. It was shown that the functionalization of cellulose is possible, but more effective if methacrylic anhydride is used. The creation of a resin only with functionalized cellulose, water as a solvent and a photo ini-tiator was not possible. Therefore, the focus was shifted to the creation of cellulose composites with a commercially available resin. The comparison of the tensile test result showed that the introduction of cel-lulose particles can lead to an improvement in tensile stress at break and Young’s modulus. Although the composite CR95Cell05 0.05 lh, the cellulose resin composite, does not present the highest values for the samples for 0.05 mm layer height. The Young’s modulus for CR95Cell05 with a layer height of 0.1 mm is 1797.63 MPa. The Young’s of CR95Cell05 0.05 lh is 1814 MPa and is exceeded by the post cured commercial resin with a value of 1949.98 MPa. The tensile stresses at break show a similar trend. It is again the case that CR95Cell05 0.1 lh presents the highest value for tensile stress at break with 27.12 MPa when compared to the other samples with a layer height of 0.1 mm. In the case of CR95Cell 0.05 lh the value for tensile stress at break is 33.08 MPa. This is less than the value determined for the post cured commercial resin with 39.39 MPa. Through differential scanning calorimetry (DSC) the thermal properties of the commercial resin and the composite were determined. The results of all thermograms show the presence of a curing peak, melting peak and a Tg at 80°C. The melting peak was detected at 125°C and the peak associated with curing was located at 106°C.
3D-printed mold inserts in the injection molding of liquid silicone rubber
(2023-06-13) Oivanen, Maija; Savolainen, Matti; Kemian tekniikan korkeakoulu; Franssila, Sami
3D-Printed molds for micro-injection molding
(2015-03-03) Lahtinen, Sampo; Korhonen, Harri; Kemian tekniikan korkeakoulu; Seppälä, Jukka
Stereolithography (SLA) 3D-printed micro-injection molds could decrease the price and lead times when compared to traditional steel molds. In addition, an increase in design freedom could be achieved. This thesis aims to study the feasibility of SLA 3D—printed injection molds in general as well as in manufacturing of patient specific trachea prostheses. Perfactory SXGA+ Mini Multi Lens SLA was utilized. Resin used was Envisiontec's HTM140V2 high temperature molding resin. Molds created were tensile test specimen, three different tubes, and one 1:1 scale trachea mold. Tensile specimens were molded from USP Class VI (United States Pharmacopeia) and ISO 10993-5 approved biocompatible thermoplastic polyurethanes of different hardness (Shore 5A-75A) and polypropylene (PP). Tensile specimen molded with SLA molds were compared to ones molded with steel mold. General quality of parts was observed by eye and with light microscope. More accurate surface quality studies were done with scanning electron microscope (SEM). Thermal properties were compared using differential scanning calorimetry (DSC) and mechanical properties with tensile tests. As a result, no significant differences in mechanical or thermal properties were observed. Parts produced with SLA molsd were not more birttle and no increased crystallinity was observed when compared to parts molded with steel molds. It was concluded that due to small size of the micro-injected parts, that itself enables fast cooling, the lower heat conductivity of SLA molds compared to steel molds does not cause alterations on the properties of molded parts. SLA molds lasted for 15 injection cycles on average, 50 cycles being the maximum. Failure occurred in brittle manner. Most significant contributor to the breaking was warping of the molds during printing and post-curing. Another significant contributor to the breaking was relatively high mold closing pressure of 130 bar. Trachea tube prototypes were molded using TPU5A and TPU15A. Designs with different wall thicknesses of 2 mm and 1 mm were tested. In addition a mold with denser “cartilage” rings spacing and a mold with realistic trachea dimensions were produced. The quality of produced tubes was good. The shape of the tube was clearly transferred from mold to the part. Tube prototype molds lasted for 4 cycles. Breaking occurred in brittle manner, likely initiated by high mold closing pressure. Realistic trachea mold lasted only for one cycle. Nonetheless the poor cycle performance of the realistic trachea mold, it yielded a good quality trachea prosthesis with realistic dimensions from Shore 5A TPU .
Aallonpituusdispersiivisen röntgenfluoresenssispektrometrin käyttöönotto ja menetelmävalidointi
(2014-01-21) Raitala, Titta-Miia; Parvinen, Pekka; Kemian tekniikan korkeakoulu; Kulmala, Sakari
Työn tarkoituksena oli kuvata röntgenfluoresenssispektrometrian perusteet, ja raportoida röntgenfluoresenssispektrometrin käyttöönottoon liittyvät toimenpiteet sekä käytettävän analyysimenetelmän validointimenettelyt kemian analyysipalveluita tarjoavassa laboratoriossa. Validointi suunniteltiin erityisesti geologisille-, mutta myös muille vastaaville mineraalipohjaisille näytematriiseille, kuten tuhkille ja mineraalivilloille. Näytteet mitattiin aallonpituusdispersiivisellä röntgenfluoresensispektrometrillä pääasiassa jauhepuristemuodossa käyttäen kalibroinnissa ja tulosten laskennassa Rautaruukin kehittämää perusparametriohjelmaa. Ohjelma laskee röntgensäteilyn fysikaaliset perusparametrit huomioivan matemaattisen matriisikorjausmallin avulla yhteyden kalibrointinäytteiden alkuaineiden mitattujen intensiteettien ja näytteiden koostumuksen välille. Kalibroinnissa käytetään mahdollisimman puhtaita alkuaineita, joko metalleina tai oksideina. Perusparametriohjelmaa käytettäessä tarvitaan ainoastaan yksi peruskalibrointi alkuainetta kohden mahdollisimman monelle alkuaineelle, minkä jälkeen erillisiä kalibrointeja ei enää tarvita eri näytetyypeille. Tämä on etu esimerkiksi palvelulaboratorioissa, joissa sekä näytteitä että erilaisia näytetyyppejä on paljon ja kustannustehokkuus sekä tulosten toimitusaika tulisi saada optimaaliseksi. Perusparametriohjelman heikkoutena on määritysrajojen nouseminen hieman konventionaalisella kalibroinnilla toteutettua määritystä korkeammiksi. Validointikokeiden perusteella voitiin todeta, että menetelmä soveltuu tarkkuudeltaan ja toistettavuudeltaan testatuille näytetyypeille varsin hyvin silloin kun matriisissa ei ole poikkeuksellisen korkeita (prosenttiluokan) metallipitoisuuksia tai esim. merkittäviä määriä raskaita alkuaineita, kuten uraania. Esimerkiksi rikastenäytteille menetelmä ei tällöin ole paras mahdollinen. Myös korkeat rikkipitoisuudet näytteessä voivat häiritä määrityksiä.
Ab initio molecular dynamics simulation of the platinum–water interface: Insights into structure and electrocatalytic properties
(2018-07-31) Kronberg, Rasmus; Holmberg, Nico; Kemian tekniikan korkeakoulu; Laasonen, Kari
In this thesis, the electrocatalytically relevant platinum--water interface was studied using ab initio molecular dynamics simulations based on density functional theory (DFTMD). Specifically, the structural and electronic properties of the unreconstructed (111), (100) and (110) crystal facets of platinum were investigated with explicit inclusion of chemisorbed hydrogen species and a considerable water film. The RPBE-D3 exchange-correlation functional was applied. The employed equilibrium hydrogen coverages were estimated based on static calculations to ca. 2/3 ML on Pt(111) and 4/3 ML on Pt(100) and Pt(110). Performed DFTMD simulations demonstrate that all hydrogen covered surfaces are more hydrophobic than their clean counterparts, exhibiting negligible water ordering. A slight preference of H-down water orientation was observed in the water contact layer of all systems. The chemisorbed hydrogen atoms on Pt(111) and Pt(110) were found to be surprisingly mobile, while a more stationary adlayer was evidenced on Pt(100). This finding was observed to correlate with the hydrogen adsorption energies and the magnitude of hydrogen--hydrogen repulsion in vacuum. Surprisingly, hydrogen adatoms on the Pt(111) surface were found to spontaneously migrate from the presumed deep face-centered cubic sites to the slightly less preferential top sites. The electronic properties were studied dynamically by sampling the potential of zero charge (PZC) as well as adsorption and solvation induced changes in the work function and the surface dipole density. The PZCs 0.40 V, 0.55 V and 0.92 V were observed for the (111), (100) and (110) facets, respectively. The value for the Pt(110) surface was found to disagree with experimental estimates suggesting a significantly lower PZC. The work function change due to interfacial charge redistribution was observed to be negative for all surfaces, indicating an induced surface dipole oriented away from the surface. This was attributed to an adsorption and solvation induced depletion of the surface overspill electron density. In contrast, the work function change due to interfacial water reorientation was found to be positive, in line with the negatively directed dipole moment of the preferential H-down orientation. Ultimately, a work function reduction was evidenced for the Pt(111) and (100) facets, while for Pt(110) a net work function increase was observed. This structure dependence was attributed to a pronounced charge transfer from Pt to the hydrogen adlayer on the less close-packed surfaces, consequently decreasing the magnitude of the negative work function change due to electronic effects.
Abrasive and adhesive wear properties of nanodiamond enhanced electroless nickel composite coatings
(2017-08-29) Koskinen, Miro; Myllymäki, Vesa; Rostedt, Niko; Kemian tekniikan korkeakoulu; Koskinen, Jari
The wear of machine parts and products causes significant economic costs to our societies. Wear can be prevented by using more durable materials, but it is usually more cost-efficient to use cheaper matrix materials coated with a wear resistant coating. Hard chrome is one of the most used coatings to reduce friction and increase the wear resistance of a surface. However, the use of hard chrome plating is declining due to the health issues related to it. Electroless nickel and especially electroless nickel composite coatings have been suggested as a potential alternative to hard chrome coatings. This thesis studied the tribological properties, such as surface roughness, hardness, friction as well as abrasive and adhesive wear properties, of some electroless nickel composite coatings. The studied coatings were nickel-nanodiamond, nickel-PTFE-nanodiamond and nickel–hexagonal boron nitride-nanodiamond composite coatings, where the concentration of nanodiamonds was varied. The abrasive wear properties were studied with a Taber abrader, whereas the friction and adhesive wear were studied with a Pin-On-Disc tribometer. The codeposited nanodiamonds resulted in higher hardness values and better abrasive wear resistance in all the tested samples. PTFE particles lowered the friction coefficient values as well as improved the adhesive wear resistance. Boron nitride particles together with nanodiamonds resulted into a decrease in both abrasive and adhesive wear resistance. Best improvements were obtained on electroless nickel-PTFE-nanodiamond composite coatings, that combined the increase to abrasive wear resistance caused by the nanodiamonds as well as low friction coefficient and increase in adhesive wear resistance caused by the PTFE-particles.
Acetone-butanol-ethanol (ABE) fermentation by clostridium acetobutylicum using xylose recovered from birch wood hydrolysis
(2018-10-02) Ayyanar Ramachandran, Praniesh; Chandgude, Vijaya; Kemian tekniikan korkeakoulu; Banksr, Sandip
The focus of this study is to find the efficiency of xylose and birch wood hydrolysate in Acetone-butanol-ethanol (ABE) fermentation. There is a need to find an effective raw material for the commercial production of butanol which was the reason for this work to be carried out. The literature studies include the background and biochemistry of the process, different types of microorganisms used for this process, pretreatment methods for hydrolysate and detoxification of hydrolysate. The experimental part of this thesis is about finding the effect of glucose and xylose, effect of electron carriers, effect of different concentration of the potent electron carrier and the efficiency of birch wood hydrolysate in ABE fermentation. The results obtained are compared with the results from previous works of different researchers and the discussion are done based on it. The results showed that 60:40 (xylose:glucose) is the best ratio as it yielded 7.99 g/L of overall solvent concentration and also lower residual acid of about 2.68 g/L. Methylene blue was found to give higher solvent concentration of about 9.48 g/L when compared to other electron carriers. The concentration of 0.1 mM methylene blue produced higher solvent concentration and A:B ratio which was about 9.47 g/L and 2.82:1. From this work, it was found that birch wood hydrolysate can be very effective for the ABE fermentation if proper pretreatment and detoxification methods are carried out.
Acidity characterisation of zeolites for glycerol aromatisation with temperature-programmed desorption
(2024-01-23) Järvinen, Ellen; Karinen, Reetta; Velasco, Jorge; Kemian tekniikan korkeakoulu; Puurunen, Riikka
Zeolites are among the most industrially significant solid acid catalysts. Effective and accessible methods for analysing the acidity of solid materials are critical for zeolite-related catalyst research, as the acidity characterisation elucidates the relationship between the properties and the catalytic activity of the material. The temperature-programmed desorption (TPD) of basic probe molecules is a widely reported method for characterising the acidity of solids. Automated TPD instruments requiring little operator input are available commercially, which makes the method particularly accessible for routine acidity characterisation. Typical probe molecules used in the analysis of zeolites with TPD include ammonia (NH3) and isopropylamine (IPAm). This work implemented a NH3-TPD and an IPAm-TPD method for determining the total acidity and the Brønsted acidity of zeolitic samples respectively. This work also compared NH3-TPD and IPAm-TPD as acidity characterisation methods for zeolites. The theory part of this work covered the principles of zeolite catalysts and TPD and examined previously reported NH3-TPD and IPAm-TPD methods. In the experimental part, a NH3-TPD and an IPAm-TPD method were developed, and sample materials intended for glycerol aromatisation were characterised with the developed NH3-TPD and IPAm-TPD methods. The NH3-TPD and IPAm-TPD methods developed in this work produced TPD profiles that corresponded well to descriptions of zeolite NH3-TPD and IPAm-TPD profiles available in literature. Out of the tested materials, only the Zn-modified zeolite sample produced an abnormal IPAm-TPD profile. The total acidity and Brønsted acidity results calculated from the TPD data were logical with respect to the theoretical acidity of the studied materials. As an exception, the IPAm-TPD analysis of the γ-Al2O3 reference sample yielded a higher value for Brønsted acidity than expected. This was suspected to be due to Brønsted acid sites associated with impurities. The relative standard deviation of both the total and Brønsted acidity results was 4% in the repeat tests.
The activity and stability of tertiary amine catalysts in the presence of hypochlorous acid
(2018-08-28) Dawson, Owain; Perrin, Jordan; Kemian tekniikan korkeakoulu; Vuorinen, Tapani
Hypochlorous acid is an electrophilic oxidizing agent capable of reacting with a range of unsaturated organic substrates. Previously, these reactions have been shown to be catalysed by the use of a tertiary amine, and Hcat hardwood pulp bleaching stages using the tertiary amine DABCO, as well as its derivative CM-DABCO, have proved efficient. Within this work, a range of DABCO-derivative structures were synthesised, and their catalytic abilities and stabilities were tested via the use of stopped-flow UV-Vis spectroscopy. DABCO-derivatives produced in this work all involved mono-N-substitution, and generally high yields could be achieved in simple synthetic routes. Derivative structures tested included allyl (AL), carboxymethyl (CM), carboethoxymethyl (CEM), carbamoylmethyl (AA) and 2-hydroxyethyl (EA) groups. The pKa of the tertiary amine group within these were measured, and found to each be between 3.0 and 3.4, close to the second pKa of DABCO itself (2.97). Both pH and substrate structure were found to have a significant impact on the catalytic ability of all the tested structures. Due to the chlorinating action of Cl2 at pH 3, and the large difference between pH and DABCO-derivative catalyst pKa at pH 7, generally low catalytic factors were found at these pH values. At pH 5, higher catalytic factors could be found, with a catalyst pKa closer to 5 producing an increased catalytic ability. The substrate structure affects the rates of catalysis but not the order of activities between the different catalysts. CM-DABCO was the most active derivative for all substrates at pH 5, and it was concluded that further increases to the catalyst pKa could further improve the results obtained. Unlike DABCO, all the synthesised derivatives were shown to be close to fully stable for up to 10 seconds of pre-incubation with hypochlorous acid. Stability is concluded then to not be a concern in the selection and design of an optimal DABCO-derivative catalyst structure.
Adding nanofibrillated cellulose to effect coating color and coated paper properties
(2010) Lindholm, Mikko; Pynnönen, Hanna; Puunjalostustekniikan laitos; Kemian tekniikan korkeakoulu; School of Chemical Engineering; Paltakari, Jouni
The goal of this thesis was to examine the effects of adding nanofibrillated cellulose to coating color and also the properties of coated paper. In the literature part, pigment coating was examined along with coating color components and their properties. In addition to properties of nanofibrillated cellulose, the properties of coated paper were also examined. The experimental part was divided into preliminary tests and actual tests. During the preliminary study coating color of calcium carbonate and kaolin was prepared. Coating color was then added to different amounts of NFC's. The viscosities and retentions of the coating color were then measured. Based on preliminary tests calcium carbonate was selected as pigment. In actual experiments only one pigment was used in which the variables were NFC dosage, NFC's grinding level and latex/starch ratio. Coating color viscosities were measured as well as retentions. LWC paper was coated with blade coating once on the other side. Coated papers were measured in opacity, whiteness, gloss, PPS-roughness and surface strength. The results were divided into three groups according to the coat weight and were analyzed using regression analysis to determine the impact. Viscosity increased by NFC's dosage, while the retention decreased. Increasing NFC's grinding ratio did impact viscosity where no starch was involved. Other effects from the degree of grinding were not established. Effects on optical properties and roughness were only marginal and on gloss NFC's had no impact at all. NFC is a good thickener on coating color but bad co-binder. NFC's impact is greater at low coating weights. Effect on optical properties and roughness is marginal, especially in noncalandered papers. Grinding NFC's has a significant impact on the viscosity.
Additives to optimize kraft-lignin pelletizing and pellet performance
(2022-03-25) Laukkanen, Sanna; Pykäläinen, Nina; Pietarinen, Suvi; Kemian tekniikan korkeakoulu; Maloney, Thaddeus
Lignin is a highly abundant natural polymer found in lignocellulosic plants and extracted from wood in various pulping processes. Kraft-lignin is a by-product of kraft-pulping process and is mainly used as a fuel for energy production but its application potential as an alternative for fossil-based polymers in production of chemicals and materials has become increasingly recognized. Currently kraft-lignin is often transported and used in a fine powder form which creates challenges of material loss, dust hazards, flowability and handling problems as well as lower cost-efficiency of the shipping. Aim of this thesis was to investigate potential binding additives, added in dosages of 0,5 and 2w%, to improve kraft-lignin pellet formation, their physical characteristics and ability to resist wear, and ultimately improve kraft-lignin feasibility through material efficiency. Moisture content, pelleting pressure and temperature were found to have a significant effect on the quality of the lignin pellets and optimizing these parameters was essential to achieve stable quality during production. Binder effectiveness was evaluated based on pellet fines content, bulk density, mechanical durability in ambient and elevated temperature / relative humidity (RH) conditions, solubility in water and sodium hydroxide, glass transition temperature and visual appearance. The pellets released ~5w% of fines with majority under 1,4mm in size and their bulk density stayed rather stable at around 0,5g/cm3. The results of mechanical durability showed the highest increase and consistency of performance with 2% of carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA) and Bentonite, although variability between individual products was considerable. Pellet solubility was mildly affected by the binder content whereas glass transition temperature was mostly related to the lignin moisture content. Physical appearance and thickness of the pellets varied depending on the binder type and its dosage but visually the best quality was achieved with 2% of CMC A, CMC C, guar gum, PVA B and Bentonite.
Adhesion phenomena of bio-based polymer composite coatings on fibre surfaces
(2018-10-02) Li, Sai; Helanto, Karoliina; Hiltunen, Eero; Kemian tekniikan korkeakoulu; Paltakari, Jouni
Adhesive properties of the silk-mussel protein
(2022-06-13) Purho, Timo; Yin, Yin; Kemian tekniikan korkeakoulu; Linder, Markus
There is a rising interest in the use of new adhesive materials in the field of tissue engineering, especially in working in wet environments. Silk protein is one of the natural polymers showing great potential in future applications of tissue engineering as a bioadhesive with high biocompatibility, great mechanical properties, and chemical and physical modifiability. The challenge is that most synthetic adhesives won’t work properly in wet environments. Wet-resistant adhesion proteins from marine mussels have the ability to form adhesive solid interactions with many different types of substrates in wet conditions. A key element for good adhesive properties has been suggested to be the high content of 3,4-dihydroxyphenyl-L-alanine (DOPA). Combining mechanical properties from silk protein with the wet adhesion of mussel foot protein could create great bioadhesives for medical applications. The aim of this thesis was to investigate the adhesive properties of the silk-like fusion protein with the aid of mussel foot protein and DOPA modification. The hypothesis was that mussel foot protein and DOPA modification enhance the adhesive properties of the silk protein. Escherichia coli (E.coli) was used to produce protein constructs SC2-ADF3-SC2, SMT3-mfp1-ST, and SMT3-mfp1-ST-DOPA. Adhesive properties were then tested on acrylic (poly(methyl methacrylate)), aluminum, and glass slides, and adhesive strength was tested with lap shear tests. The results were promising showing a higher increase in adhesive strength with samples including DOPA. The results followed the hypothesis but the limited amount of successful tests prevents full acceptance of the hypothesis. Consequently, further conclusions must be drawn with this in mind.

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