Browsing by Author "Rantanen, Juuso"
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- 3D Formability of fibre, micro and nanofibrillated cellulose and PCC composite sheets
Kemian tekniikan korkeakoulu | Master's thesis(2016-02-02) Dinh, ThiThe 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. - Consolidation and dewatering of a microfibrillated cellulose fiber composite paper in wet pressing
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2015) Rantanen, Juuso; Maloney, Thaddeus - Construction of a single bar refiner
Helsinki University of Technology | Master's thesis(2009) Rantanen, JuusoThe target of this thesis work was to construct a laboratory scale low-consistency refiner by modifying an existing design to enable more realistic refining conditions. The aim of the modification was to be able to study refining energy and forces affecting fibres more closely, particularly enabling the determination of bar coverage and pulp consistency in the gap by image analysis. The designing and construction of a pulp flow system for the refiner unit was also an important part of the thesis. Setup and testing of a system for imaging fibres in the refining gap was realized. The modification of the original design was made by designing a new stator bar with dimensions similar to the rotor bar. The purpose of this design was to create more realistic conditions during refining. This design was first tested with the original stator bar by machining it with a groove similar to the one in the rotor bar, and later constructing two additional bars to reach the desired smaller gap size. The pulp flow system was designed and constructed to enable even flow conditions for the refiner unit. The installing and setup of the laser illuminated imaging system was conducted to enable image capture of the refining phenomena. Some problems were encountered during the course of this work. The errors in measuring the original gap size resulted in wrong dimensioning of the new stator parts. For this reason some modifications had to be made afterwards to reach the targeted gap sizes. The pulp flow system was constructed without any major issues, but problems with the refiner unit clogging when operating with pulp consistencies > 2 % left some room for improvement. The imaging system installation and preliminary trials were successful, resulting iii some good images from the gap between the rotor and stator bars. Images showed e.g. that bar coverage is clearly not 100 % at 2 % pulp consistency with 150 µm gap size, and that there is potential in developing the image analysis method aiming to determine bar coverage and pulp consistency in the gap. The target of the thesis to construct a research tool for refining studies was achieved - Erikoispaperin huokoisuuden hallinta
Kemian tekniikan korkeakoulu | Master's thesis(2020-08-18) Santikko, Santeri - High filler content composites with microfibrillated cellulose
School of Chemical Engineering | Master's thesis(2013) Heiniö, TeresaThe aim of this thesis was to evaluate whether micro fibrillated cellulose (MFC) enables higher filler content in composites. Due to the high filler content exceptional optical properties were anticipated. The composites consisted of Masuko ground MFC, precipitated calcium carbonate (PCC), unrefined wood pulp and synthetic fiber. The composites were formed by pressure filtration. A membrane was used over a conventional wire in a standard laboratory sheet former. The effect of MFC, fiber and PCC was evaluated in a three component mixture design on different measured properties of the prepared laboratory hand sheets. In all test points a constant amount of 15 w-% of synthetic fibers was added, which was omitted from the model. The data of the results was analysed by stepwise regression using a special cubic model. All results were compared to laboratory or industrial reference as well. The high surface area of MFC increased the bonding ability of the fibrillated material in the composites and hence increased the strength properties. The tensile index was highest at the highest MFC levels; the test point containing 47 wt.-% MFC had a tensile index of 44 Nm/g. The effect of the three dimensional networking ability of MFC was apparent in the z-directional strength measurements, as the test point with highest amount of MFC was almost three times higher than that of the industrial reference material. Tear strength did not benefit from MFC additions, but the synthetic fiber raised the tear index linearly. Virtually all optical properties exceeded those of the reference material. Even the wet opacity was higher than the reference, although no titanium dioxide was added to the furnish. The small size of MFC efficiently lowered the porosity of the composites. This did not diminish the water uptake however; all test points were highly hydrophilic and had a water uptake of more than 100 wt.-%, higher than the reference. The regression analyses on optical and strength properties were fairly reliable, since the explanatory degrees (R2-values) were high. For roughness, porosity, water uptake and wet elongation the R2 values were lower. Drainage testing revealed that the membrane in itself already slowed down the process and MFC even more so. Future challenges include faster dewatering times. In summary, the property space of the composites comprised of highly favourable proportion mixtures, which could be developed to fit industrial applications. - The manufacturing potential of micro and nanofibrillated cellulose composite papers
School of Chemical Technology | Doctoral dissertation (article-based)(2016) Rantanen, JuusoThis study presents a novel approach for producing composite papers that have fundamentally different properties to the traditional products in the paper industry. The main focus of this work was to evaluate the use of micro and nanofibrillated celluloses (MNFCs) as a component in paper in conjunction with traditional fillers and pulp fibers. The main hypothesis of this thesis work was that it is possible to form and subsequently dewater furnishes that contain considerable amounts of MNFC. Moreover, the properties of these new MNFC composite papers were expected to differ from traditional paper characteristics. The properties of MNFC composite papers were studied with different compositions of pulp fibers, MNFC, and filler. It was concluded that the optical properties of the composite papers were excellent and that the use of fillers together with MNFC results in a unique micro and nanoporous network structure of the paper. The in-situ precipitation of calcium carbonate directly on the MNFC fibrils was also shown to be a promising method for adjusting the water uptake of the MNFC and the resulting paper properties. The cost structure of the MNFC composite proved to be very attractive due to a reduction in the level of more expensive fibers required. The shear thinning behavior of the MNFC composite suspension was shown to enable 5-10 % solids content in forming, and subsequent wire dewatering to 33 % solids content. In addition, this work demonstrated that a wet pressing process can be used for the efficient dewatering of the MNFC composite furnishes if long enough press pulses are used. Under some conditions the dewatering was found to be better than with kraft pulp fibers alone. This thesis work clearly establishes that a wide range of high value MNFC based products can be formed using a feasible, efficient and economical process – a critically important step towards the next generation of products and processes based on forest resources. - Nanomittakaavan selluloosapohjaisen kuitumateriaalin ominaisuudet ja tuotantomenetelmät
Kemian tekniikan korkeakoulu | Bachelor's thesis(2011) Muurimäki, Anssi - Production of fibrillated cellulose materials - Effects of pretreatments and refining strategy on pulp properties
Kemian tekniikan korkeakoulu | Master's thesis(2014-05-06) Zheng, HongliangThe aim of this work was to manipulate the sub-cell wall swelling of wood fibers and then refining in a conventional refiner to demonstrate the possibility of producing useful fibrillated cellulose product. The swelling was changed by two different pretreatments: enzymatic hydrolysis and anionic polymer adsorption. In addition, a modified Valley beater was tested to study the effect of fiber cutting as a pretreatment. Both pretreatment methods: cellulase hydrolysis and anionic polymer adsorption showed potential on manipulating the swelling properties of cellulose fiber and facilitating disintegration of pulp during refining. The swelling results showed it is possible to increase internal fibrillation of fibers without increasing the fiber swelling by using both methods, especially by cellulase hydrolysis. The sharp edge bars of modified Valley beater mainly shorten the fiber rather than fibrillate it compared with standard one. - Treatments for enhancing accesibility an reactivity of cellulose and their analysis
School of Chemical Engineering |(2015) Debnath, Subham - Wet pressing strategies for microfibrillates cellulose based furnishes
School of Chemical Engineering |(2012) Jarovisky, MatiasThe main objective of this work was to make a first approach to the micro fibrillated cellulose (MFC) impact on wet pressing when added to termomechanical pulp (TMP) based furnishes. In this research two types of MFC in a concentration ranging from 0% to 20 % were tested. TMP fines and cationic starch were also used to evaluate if the interaction of them with the MFC affects the water removal during wet pressing. The wet pressing simulation was done using a MTS 810, which was also developed further, with which two different pulses were applied to all furnishes. Results indicated that MFC addition to TMP furnishes can, in some conditions, improve dewatering during wet pressing. The interaction between the furnish components present a great dependence on the controlling mechanism of dewatering during wet pressing. In order to achieve good water removal, it is fundamental to determine what is the mechanism controlling dewatering, whether flow or pressure controlled, for the furnish to be pressed. Both types of MFC tested had similar behaviour in most wet pressing experiments, neither presented higher dewatering constantly.