Browsing by Author "Maloney, Thad"

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  • 3D Formability of fibre, micro and nanofibrillated cellulose and PCC composite sheets
    (2016-02-02) Dinh, Thi
     Kemian tekniikan korkeakoulu | Master's thesis
    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.
  • Assessing wood pulp reactivity through its rheological behavior under dissolution
    (2019-01-01) Ceccherini, Sara; Maloney, Thad
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Abstract: Recent years have witnessed an increasing interest in man-made cellulosic fibers, whose production generally requires cellulose dissolution and regeneration. Cellulosic fibers are difficult to dissolve. Thus, the recalcitrance of wood pulp can be an estimate of its reactivity. Pulp reactivity is usually assessed via complex and time-consuming laboratory simulations of the viscose process. This study proposes a faster and more convenient approach. The dissolution-based torque reactivity (DTR) test measures the evolution of the rheological properties of a pulp suspension under dissolution in cupriethylenediamine. Reactivity is quantified in terms of initial dissolution rates (IDR) and dissolution times (DT). This study describes the measurement protocol for the DTR test and its application to some commercial pulps and a series of pulps hornified to different extents. The IDR and DT values were compared with other pulp features, including degree of polymerization, molecular weight distribution, specific surface area and water retention value. The DTR test proved to be reasonably precise and fast to carry out. Graphic abstract: [Figure not available: see fulltext.].
  • Characterising exfoliated few-layer graphene interactions in co-processed nanofibrillated cellulose suspension via water retention and dispersion rheology
    (2019-03-01) Dimi-Misic, Katarina; Phiri, Josphat; Nieminen, Kaarlo; Maloney, Thad; Gane, Patrick
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Few-layer graphene has been produced by mechanical delamination of exfoliated and naturally obtained graphite in aqueous suspension using the dispersion and suspension properties of nanofibrillated cellulose (NFC). Various degrees of graphene platelet integrity were obtained depending upon the processing conditions and the optional adoption of surfactant to aid dispersion of the hydrophobic agglomerates of nanometre-thin carbon material. The presence of NFC in the suspension acts similarly to the presence of surfactant, increasing the hydrodynamic coupling between the particles and water as a function of processing time, regardless of the graphene-comprising source. By fitting the stress growth region in the stress-shear rate relation to a concatenated series of single exponential functions of shear rate, the power law exponent and suspension consistency parameters (n and k), within a shear rate-localised Herschel-Bulkley (HB) expression, provide a straightforward characteristic for monitoring the desired suspension coupling response, and hence a measure of product constancy.
  • A comparative study of mechanical, thermal and electrical properties of graphene-, graphene oxide- and reduced graphene oxide-doped microfibrillated cellulose nanocomposites
    (2018-08-15) Phiri, Josphat; Johansson, Leena Sisko; Gane, Patrick; Maloney, Thad
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Micro-nanofibrillated cellulose (MFC/NFC) and graphene-based composites are interesting materials due to their complementary functional properties, opening up potential in a variety of applications. Graphene, graphene oxide (GO) and reduced graphene oxide (RGO) were used in this comparative study as reinforcement functional fillers for the fabrication of multifunctional MFC nanocomposites using a simple aqueous dispersion based mixing method. The MFC composites showed different properties depending on the type of filler used. Graphene was seen to agglomerate and was poorly dispersed in the MFC matrix, whilst GO and RGO were homogeneously dispersed due to the presence of functional groups that promoted a strong interfacial molecular interaction between the filler and the MFC matrix. At 0.6 wt% filler loading, the tensile strength for MFC/GO and MFC/RGO increased by 17 % and 22 %, respectively, whilst the Young's modulus increased from 18 GPa to 21 GPa and 25 GPa, respectively. Compared to the neat MFC, addition of 5 wt% of graphene enhanced the thermal stability by 5 % and whilst with the addition of GO and RGO stability increased by 2 and 3 %, respectively. Graphene/MFC and RGO/MFC showed a high electrical conductivity of 1.7 S m-1 and 0.5 S m-1, respectively while the GO reinforced composites were insulators.
  • Controlling of owen dry weight profile and factors affecting on it
    (2010) Juntunen, Valtteri
     School of Chemical Engineering | Master's thesis
    The aim of the Thesis was to study causes affecting to appearance of streaks in oven dry weight profile and minimizing of them, develop techniques to control streaking during production and analyze a proposal for updating used version of profile control software made by automation vendor. It has been noted at the paper machine, that most important single reason behind the appearance of streaks is in changing of the forming fabrics. Study which was made during Thesis covers this theory. Streakiness can be noticed to been significantly different after every time when forming fabric has been changed. Only in one case this has not been valid. Wetting of the fabrics in the beginning of start-up, controlling of the tension of the fabrics during the start-up phases and maintain of the tension after start-up are critical factors for the fabrics for acting properly during production. Effect of these factors were minimized during Thesis in three start-ups with new wires by clarifying actions during crawling and by developing automatic tension controlling The possibilities for controlling streakiness during production were studied in test-run which was established based on Taguchi-method. During test-run, which was made in co-operation with fabric vendor, the effect of under pressure levels on the water removal elements at gap and blade-area, the loading pressure of the MB-blades and tension of bottom fabric were tested. Target was to have effect on profile 2sigma and on max-min difference of single streaks. Results show that 2sigma-va!ue can he decreased, but no single streaks can he vanished. Part of the Taguchi-method was to re-test the best controlling parameters-set found in Taguchi-run for to confirmationo the possibility to reach again the same effect on profile. During this re-run, further research was made in the field of testing possibilities for controlling profile by studying effect of changing head box consistency and wire water consistency. Confirmation showed that increase in the profile was reached with optimal controlling parameters-set. During further research, biggest effect was in formation, although 2sigma was decreased also. Earlier it has been noticed at the machine, that the effect of the streaks appeared in the profile can be decreased when changing the fabrics position in the CD-direction of the machine. During Thesis, studies were made to develop this method further in the wire section. Based to the results reached in the actual and simulated test-runs show that there is high potential to affect to machine reel profile very effectively.
  • Effects of Pressing on the Dewatering Properties of Bleached Kraft Pulp
    (2007) Suokonautio, Timo
     Helsinki University of Technology | Master's thesis
    Sellun vedenpoisto-ominaisuuksilla on merkittävä vaikutus hienopaperikoneen tehokkuuden kannalta. Kuivattua paalimassaa käyttävän koneen tuotantotehokkuus on merkittävästi korkeammalla tasolla kuin kuivaamatonta sellua käyttävän koneen. Pääsyy tähän on kuivatun sellun paremmat vedenpoisto-ominaisuudet paperikoneen viira- ja puristinosalla. Ilmiötä selittää kuivatun sellun alhaisempi turpoaminen vedessä, joka parantaa vedenpoistoa erityisesti puristinosalla. Kuidun turpoamiskyvyn alenemista kuivatuksessa kutsutaan kuidun sarveistumiseksi. Sellun kuivaaminen sellutehtaan ja paperikoneen välissä parantaa paperikoneen tehokkuutta, mutta yleensä tällä saavutetut edut hävitään kohonneina kuivatusenergiakustannuksina ja konekustannuksina. Sellun puristaminen sellutehtaan ja paperikoneen rajapinnassa voi mahdollistaa kustannustehokkaamman menetelmän sarveistumisen aikaansaamiseksi. Tätä ilmiötä on kutsuttu märkäsarveistumiseksi. Toistaiseksi ei ole kuitenkaan ollut varmaan säilyykö puristamalla saavutettu sarveistuminen, esimerkiksi jauhatuksen jälkeen, kuten kertaalleen kuivatussa massassa. Tutkimuksessa tarkasteltiin koivu- ja mäntysellun sarveistumista puristamalla näytteitä eri kuiva-ainepitoisuuksiin muuttamalla puristuspaineita. Sarveistumista pyrittiin myös voimistamaan entsyymi-, polymeeri- ja märkälujakäsittelyillä. WRV mittaukset puristetuista näytteistä osoittivat koivusellun sarveistuvan tehokkaimmin kuiva-ainepitoisuuden kasvaessa. Tämä johtui todennäköisesti korkeammasta alkuperäisestä vesiretentiosta. Entsyymikäsittely ja käsittely korkeasti varautuneella lyhytketjuisella polymeerilla tuottivat parhaan tuloksen sarveistumisen kannalta. Sarveistumisen säilymistä jauhatuksen aikana tutkittiin jauhamalla esipuristetut näytteet Voithin laboratorio jauhimella. Käytettäessä tyypillistä jauhatusenergiaa koivumassalle, mittauksissa ei havaittu WRV palautumista referenssin tasolla. Näiden testien perusteella puristamalla aikaansaatu sarveistuminen olisi myös osittain palautumaton. Tätä johtopäätöstä tukee Metson materiaalin testauslaitteella (MTS) suoritetut puristintestit, jotka osoittivat 2,36 %:n kasvua kuiva-ainepitoisuudessa kolmella puristin sekvenssillä, kun massa oli jauhettu ominaisenergiatasolle 60 kWh/t. Työssä tutkittiin myös märän paperin lujuusominaisuuksien muutoksia eri käsittelyiden jälkeen. Käsiteltyjen näytteiden lujuudet heikkenivät, mutta riittävällä jauhatuksella päästiin vastaavalle tasolle kuin kuivaamattoman massan tapauksessa. Tehdaskuivatun massan märkälujuusominaisuudet olivat käsiteltyjä massoja alhaisempia. Märänrainan lujuuksien testauksessa luottamusvälit olivat huomattavan suuret joten erot eivät olleet tästä syystä tilastollisesti merkittäviä. Kannattavuuslaskelmien perusteella puristinratkaisu voi olla hyvin kannattava. Tämä edellyttää tuotannon kasvattamista, joka on riippuvainen koneesta ja puristimen kuiva-ainepitoisuuden antamasta potentiaalista tietyllä paperikoneella.
  • The Influence of Physical Mixing and Impregnation on the Physicochemical Properties of Pine Wood Activated Carbon Produced by One-Step ZnCl2 Activation
    (2023-03) Phiri, Josphat; Ahadian, Hamidreza; Sandberg, Maria; Granström, Karin; Maloney, Thad
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    In this study, two different sample preparation methods to synthesize activated carbon from pine wood were compared. The pine wood activated carbon was prepared by mixing ZnCl2 by physical mixing, i.e., “dry mixing” and impregnation, i.e., “wet mixing” before high temperature carbonization. The influence of these methods on the physicochemical properties of activated carbons was examined. The activated carbon was analyzed using nitrogen sorption (surface area, pore volume and pore size distribution), XPS, density, Raman spectroscopy, and electrochemistry. Physical mixing led to a slightly higher density carbon (1.83 g/cm3) than wet impregnation (1.78 g/cm3). Raman spectroscopy analysis also showed that impregnation led to activated carbon with a much higher degree of defects than physical mixing, i.e., ID/IG = 0.86 and 0.89, respectively. The wet impregnated samples also had better overall textural properties. For example, for samples activated with 1:1 ratio, the total pore volume was 0.664 vs. 0.637 cm3/g and the surface area was 1191 vs. 1263 m2/g for dry and wet mixed samples, respectively. In the electrochemical application, specifically in supercapacitors, impregnated samples showed a much better capacitance at low current densities, i.e., 247 vs. 146 F/g at the current density of 0.1 A/g. However, the physically mixed samples were more stable after 5000 cycles: 97.8% versus 94.4% capacitance retention for the wet impregnated samples.
  • New elasticity measurement technique for swollen fibre material
    (2008) Auranen, Jonna
     Helsinki University of Technology | Master's thesis
    Diplomityön tavoitteena oli kehittää mittaustekniikka, jonka avulla voidaan määrittää tarkasti turvonneen kuitumateriaalin isotrooppinen kimmokerroin. Kuidun saturaatiopiste (FSP) määritettiin solute exclusion -tekniikalla, jossa kuitumateriaali sekoitetaan polymeeriliuoksen kanssa. Se perustuu polymeeriliuoksen laimenemiseen kuidun turvotessa. Polymeeriliuoksen osmoottista painetta vaihdeltiin ja vastaavat FSP-muutokset määritettiin. Kimmokerroin laskettiin osmottisen paineen muutoksesta suhteessa FSP:n suhteelliseen muutokseen. Sen uskottiin olevan informatiivisempi kuidun yhdenmukaisuuden ja sitoutumisen mittari kuin FSP. Kirjallisuusosa keskittyi kuidun turpoamiseen ja viskoelastisuuteen, polymeeriominaisuuksiin ja polymeeri-kuitu - vuorovaikutuksiin. Siinä tarkasteltiin myös aiemmin kehitettyjä tekniikoita, joita käytetään mitattaessa elastisuutta yksittäisistä kuiduista, kuituverkostoista ja päällystyspastoista. Kokeellinen osa aloitettiin dekstraanipolymeerin ultrasuodatuksella, jonka tarkoituksena oli poistaa polymeeriliuoksesta pienet molekyylit ja täten estää niiden penetroituminen kuidun huokosiin. FSP-mittauksia tehtiin kemiallisilla ja mekaanisilla massoilla, puuvillalintterillä ja piilaseilla, joilla on tietty huokoskoko ja jotka eivät turpoa nesteessä. Ultrasuodatus ei erotellut pienempiä dekstraanimolekyylejä liuoksesta. Se poisti myös isompia molekyylejä antaen hyvin alhaisen saannon eikä sitä enää käytetty myöhemmin. Kemialliset massat antoivat korkeampia FSP-arvoja kuin mekaaniset massat. Jauhatus kasvatti kemiallisten massojen FSP-arvoja johtuen muun muassa kuitujen sisäisestä fibrillaatiosta. Kuivatus laski kemiallisten massojen FSP-arvoja, koska se aiheuttaa kuitujen sarveistumista. Puuvillalintterin FSP-arvot olivat pienempiä kuin kemiallisten massojen, mutta hieman suurempia kuin mekaanisten massojen. Piilaseista CPG 3000 Å:n FSP-arvot olivat lähellä nollaa, koska dekstraanimolekyylit penetroituivat sen suuriin huokosiin. Zeoliitilla oli pienin huokoskoko ja hyvin alhaiset FSP-arvot. CPG 10-75 Å:lla oli hieman suuremmat FSP-arvot kuin zeoliitilla. Herkkyysanalyysi osoitti, että FSP-mittausten luotettavuus laski jos mittaukset tehtiin alhaisessa osmoottisessa paineessa. Osmoottisen paineen laskiessa lähes kaikkien materiaalien FSP-arvot kasvoivat aluksi lineaarisesti, mutta tietyssä pisteessä ne kääntyivät laskuun. Kimmokertoimet laskettiin kuvaajien lineaarisesta osasta. Puuvillalintterillä ja jauhamattomalla, kuivatulla kemiallisella massalla oli selvästi suurimmat kimmokertoimet, mikä tarkoittaa hyvin jäykkiä ja huonosti turpoavia kuituja. Kuivaamattoman kemiallisen massan kimmokerroin laski hieman jauhatuksen edetessä. Jauhatus myös kompensoi kuivauksen vaikutusta antaen lähes saman kimmokertoimen kuivaamattomalle ja kuivatulle kemialliselle massalle. Mekaanisten massojen kimmokerroin oli lähes sama kuin kemiallisten massojen. Virherajat olivat hyvin suuret varsinkin jos itse kimmokerroin oli suuri. Kirjallisuusarvot olivat moninkertaisia mitattuihin kimmokertoimiin verrattuna. Tulokset osoittavat, että kuidun turpoaminen on monimutkainen ilmiö ja solute exclusion -tekniikka soveltumaton isotrooppisen kimmokertoimen määrittämiseen. Jatkossa olisi tärkeää selvittää syy FSP-arvojen laskuun alhaisessa osmoottisessa paineessa. Vaikka dekstraani on neutraali polymeeri, on mahdollista, että sen vuorovaikutus kuidun pinnan kanssa häiritsee FSP-mittauksia. Myös syy ultrasuodatuksen epäonnistumiseen pitäisi selvittää ja tutkia voisiko dekstraanimolekyylejä erotella jollain muulla tekniikalla. Jos kimmokerrointa tutkitaan solute exclusion -tekniikalla, koepisteitä tulisi tehdä lisää sillä osmoottisen paineen alueella, jolla FSP-arvot käyttäytyvät lineaarisesti. Tällöin tulosten luotettavuus parantaisi ja virherajat saattaisivat pienentyä.
  • Nitrogen plasma surface treatment for improving polar ink adhesion on micro/nanofibrillated cellulose films
    (2019-04-15) Dimic-Misic, Katarina; Kostić, Mirjana; Obradović, Bratislav; Kramar, Ana; Jovanović, Stevan; Stepanenko, Dimitrije; Mitrović-Dankulov, Marija; Lazović, Saša; Johansson, Leena Sisko; Maloney, Thad; Gane, Patrick
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We find that nitrogen plasma treatment of micro/nanofibrillated cellulose films increases wettability of the surface by both liquid polar water and nonpolar hexadecane. The increased wetting effect is more pronounced in the case of polar liquid, favouring the use of plasma treated micro/nanofibrillated cellulose films as substrates for a range of inkjet printing including organic-based polar-solvent inks. The films were formed from aqueous suspensions of progressively enzymatic pretreated wood-free cellulose fibres, resulting in increased removal of amorphous species producing novel nanocellulose surfaces displaying increasing crystallinity. The mechanical properties of each film are shown to be highly dependent on the enzymatic pretreatment time. The change in surface chemistry arising from exposure to nitrogen plasma is revealed using X-ray photoelectron spectroscopy. That both polar and dispersive surface energy components become increased, as measured by contact angle, is also linked to an increase in surface roughness. The change in surface free energy is exemplified to favour the trapping of photovoltaic inks.
  • The prerequisites and properties of a filler/fiber composite produced by in-line carbonation
    (2012) Pesonen, Tuomas
     School of Chemical Engineering | Master's thesis
  • Regeneration of hornified fiber properties
    (1999) Ye, Zhao
     Helsinki University of Technology | Master's thesis
  • Specialty pigments in wood containing papers
    (2004) Tähtikunnas, Janne
     Helsinki University of Technology | Master's thesis
    The objective of this thesis is to determine the mechanisms of print-through in mechanical paper with respect to specialty pigment use. The way in which certain specialty pigments influence the printing properties of mechanical papers in cold set printing is examined. Newsprint paper was made in HUT's paper laboratory. To test the print through and to find out the properties that have effect on it, sheets were made with 5 commercial filler and 7 experimental fillers. Sheets were done using a mixture (70%/30%) of ground wood pulp and TMP (thermo mechanical pulp) and a mixture (90%/10%) of DIP (de-inked pulp) and pinewood kraft. Experimental fillers were not used with recycled pulp. The target basis weight was 40 g/m2. Sheets optical and physical properties were measured in HUT paper laboratory and in J.M.Huber laboratory in Macon, GA before printing. All samples were printed with Prufbau laboratory printer with 4-color using cold-set newsprint ink. Scattering is a problem because of the independent variables. Small changes in basis weight have big effects on results. The changes in formation do the same thing in the small scale. When measuring the density, the measured spot is critical. It was chosen after visual inspection. Still the variation in the density measurements can be around 8%. Results are not precise enough to be trusted as they are. However the accuracy is enough to make conclusions about the most important properties. Surface area and porosity of the filler are one of the most important properties of the filler. When the filler content is low micropore surface area and total pore volume are the affecting properties. Aluminum treatment increases the micropore surface area and diminishes the particle size, but has negative effect on oil absorption. Hydrophilic treatment decreases the micropore surface area and filler performance is worse than without treatment. If the particle size is small, filter spreads more widely and the effects on paper properties are achieved with lower filler contents. With the higher filler content the oil absorption capability comes more important. Oil absorption capability goes in hand with external surface area.
  • Starch Modification to Increase Filler Content of Paper
    (2011) Juusela, Lasse
     School of Chemical Engineering | Master's thesis
    New ways to improve properties of paper and decreasing the cost is a common interest of papermakers. Introducing more filler material into the paper instead of wood fiber would lower the cost significantly. There are different theoretical ways to increase the filler content using starch. In this thesis starch crosslinking with citric acid is tested. The crosslinking agent introduces intermolecular bridges between polysaccharide macromolecules. The hydrogen bonds are reinforced with the chemical bonds that form intermolecular linkages. The crosslinks are studied with FTIR, turbidity test, and sulphuric acid phenol test. Reducing the particle size of starch to Nano scale would change the size ratios of starch and pee particles. These aggregates would have different properties that could be interesting when introduced to papermaking. In this study the available mechanical treatments are tested. Ultrasound was found out to be the only technique that reduced the starch particle size. The laboratory sheet experiments did not show statistical relation between starch gel treatment temperature and the pee filler retention, but tensile and tear strengths had higher values near the starch gelatinization temperatures.
  • Starch-based Pigments: Thermal Behavior and Utilization in Papermaking
    (2007) Zu, Xuejie
     Helsinki University of Technology | Master's thesis
    Starch granules and popcorn grits were studied in this work to function as fillers. The main purpose of this work was to study the thermal behaviours of starch-based materials and their effects on bulk and strength properties as filler. In this work, heat expandable thermoplastic microsphere was referred, when the potential of starch-based materials as in situ blown agent was studied. Similar to heat expandable thermoplastic micro spheres, starch-based materials can be puffed to gain a larger volume under certain conditions. However, the experimental results in this work show that the materials cannot be puffed under papermaking conditions, because the puffing requires high temperature and fast heating rate, which are very difficult to be realized in papermaking. Thermal behaviours of starch-based materials were studied by differential scanning calorimeter. DSC data showed that the phase transition temperatures of starches and popcorn grits were strongly dependent on the heating rate and moisture contents. Sorption of ethanol can shift the phase transition of starch-based materials to a lower temperature. In comparison with EXPANCEL microspheres, starch-based materials have much higher phase transition temperature, which is out of the temperature range of paper making. The laboratory sheets with potato starch granules as a filler had high bulk properties and low tensile strength. This discovery showed that uncooked potato starch can decrease paper density. The loss of tensile strength with uncooked potato starch can be lowered to a small extent by briefly cooking. When the starch was cooked longer, however, the starch functioned more as a strength agent than as a bulk agent.
  • Surface area of pulp fibers
    (2000) Wang, Xinshu
     Helsinki University of Technology | Master's thesis
  • True Microporous Cellulosic Materials
    (2021-05-09) Kääriäinen, Katri
     Kemiantekniikan korkeakoulu | Bachelor's thesis
  • Vaahtoprosessin implementointi koekoneelle
    (2015-03-03) Tienvieri, Lasse
     Kemian tekniikan korkeakoulu | Master's thesis
  • Wet pressing strategies for microfibrillates cellulose based furnishes
    (2012) Jarovisky, Matias
     School of Chemical Engineering |
    The 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.