Electrokinetic Phenomena of Cationised Cotton and its Dyeability with Reactive Dyes

Interface phenomena have a significant role in the wet finishing processes. Therefore in this paper the electrokinetic phenomena of cotton fabric cationised with a commercial cationic compound were researched. After cationisation, characterisation of the surface and chemical composition was performed by FTIR-ATR. Electokinetic phenomena - Zeta potential, Isoelectric point (IEP) and Point of zero charge (PZC), were determined according to the streaming current/streaming potential method and a specific amount of surface charge according to the back-titration method. The affinity of such modified cotton to reactive dyestuff of different functional groups was investigated through the K/S values. The influence of electrolyte addition to the dye bath was investigated as well

Modification of textile binary blends of polyester/natural fiber to enable simultaneous dyeing of components

Danas poznati postupci bojenja binarnih tekstilnih mešavina poliestar/prirodno vlakno koriste dve klase boja za bojenje komponenata u jednom ili dva rastvora, kada se stvaraju velike količine jako zaprljanih otpadnih voda koje opterećuju čitav eko sistem. Globalna inicijativa za racionalnim korišćenjem prirodnih resursa i sve strožije ekološke mere nameću potrebu za izučavanjem novih postupaka koji bi u odnosu na tradicionalno bojenje bili superiorniji u pogledu tehnološke produktivnosti, ekonomičnosti i zaštite vodotokova. Takođe, novi postupci bojenja treba da obezbede visoke performanse boje na tekstilu, i sa tog stanovišta glavni izazov kod bojenja mešavina je balansiranje intenziteta boje na komponentama mešavine. Ranija istraživanja diskretno su nagovestila da modifikacija površine vlakana može da bude perspektivan način za poboljšanje karakteristika bojenja različitih tekstilnih supstrata. U teorijskom delu doktorske disertacije razmatrana je struktura pamuka, vune i poliestra i konvencionalni i inovativni načini bojenja vlakana i njihovih mešavina. Takođe su obimno opisani dosadašnji rezultati u primeni postupaka modifikovanja vlakana, koji su korišćeni u eksperimentu. U eksperimentalnom delu disertacije proučavan je pod različitim procesnim uslovima uticaj alkalne hidrolize, niskotemperaturne plazme-korona pražnjenja i obrade biopolimerom hitozanom na hemijske i morfološke promene vlakana i uspostavljena je korelacija sa hidrofilnim i karakteristikama bojenja monokomponentnih i tkanina iz binarne mešavine. Korišćene su i hibridne obrade, pre svega radi poboljšanja konkurentnosti poliestra u postupku simultanog bojenja sa prirodnim vlaknima, anjonskim bojama. Hemijske i morfološke promene na poliestarskim i poliestarsko-pamučnim tkaninama nastale tokom obrade u vrućem rastvoru alkalije poboljšavaju komfornost tkanine kao i hidrofilne i osobine bojenja direktnom i reaktivnom bojom. Na mešavini intenziteti boja se povećavaju 25%, a kada se naknadno deponuje hitozan za 100%, u odnosu na prvobitni uzorak, pri čemu se značajno kompenzuju razlike u intenzitetu boje među komponentama. Obradom koronom ugrađuju se u strukturu svih vlakana kiseonične funkcionalne grupe koje su identifikovane pomoću XPS metode, zbog čega se dramatično poboljšava hidrofilnost vlakana, i minimalno intezitet boja. Obrada hitozanom ili kombinovani tretman plazma/hitozan značajno povećavaju količine direktne i reaktivne boje prevashodno na poliestru, što je doprinelo da intenzitet direktne boje na fabričkoj mešavini bude veći za 88%, i reaktivne za 114% u odnosu na netretirani uzorak, sa zadržanim nivoima postojanosti i stepena fiksiranja reaktivne boje. Veći stepen iskorišćenja boja smanjuje zaprljanje otpadne vode a jednostepeni postupak jednom bojom skraćuje i pojeftinjuje proces bojenja. Na mešavini poliestar/vuna povećava se intenzitet kisele boje obeju komponenata, ali se minimalno kompenzuju međusobne razlike i odabrana boja na poliestru ima nedovoljne mokre postojanosti. Dobijeni rezultati istraživanja omogućuju fundamentalno sagledavanje problematike bojenja modifikovanih mešavina jednom bojom sa osvrtom na ekološki aspekt bojenja.Currently known dyeing methods for textile binary blends of polyester/natural fiber using two classes of dyes to dye components in one or two solutions produce big amounts of highly polluted wastewaters loading the whole ecosystem. Global initiative for rational use of natural resources and severe environmental regulations impose the need to investigate new procedures that would be more superior regarding productivity, economy and protection of watercourses. Moreover, new dyeing procedures should provide high dyeing performances on textile and therefore the main challenge in dyeing blends is to balance color intensities on blend components. Previous studies discreetly indicated that fiber surface can be a promising way to improve dyeing characteristics of various textile substrates. In theoretical part of the dissertation the structure of cotton, wool and polyester is discussed and conventional and innovative dyeing methods of their blends are also considered. Previous results in fiber modification procedures, used in experiments, are also extensively described. In experimental part of the dissertation, the effect of alkaline hydrolysis under various process conditions, low temperature plasma – corona discharge and biopolymer chitosan treatment on the chemical and morphological changes on fibers are studied and a correlation between hydrophilic dyeing characteristics of mono component and binary blended fabrics was made. Hybrid treatments were also used, primarily to improve polyester competitiveness during simultaneous dyeing with natural fibers, using anion dyes. Chemical and morphological changes on polyester and polyester-cotton fabrics produced by treatment in hot alkaline solution improve fabric comfort and hydrophilic and dyeing properties with direct and reactive dyes. Color intensities on blends increase by 25%, and applying chitosan by 100% compared to original sample with significantly compensated color differences of components. Corona treatment introduces oxygen functional groups into the structure of all fibers identified by XPS method, dramatically improving fiber hydrophilicity and minimally color intensity. Chitosan and combined chitosan/plasma treatment significantly enhanced the amounts of direct and reactive dyes on polyester producing increased color intensities on factory’s blend by 88% and 114% for direct and reactive dyes, respectively, relative to untreated sample, and kept fastness levels and fixation degree of reactive dye. Higher degree of dye utilization decreases wastewater pollution and one stage procedure using one dye shortens and cheapens dyeing process. On polyester/wool blends color intensities of both components are increased with acid dyes, but component’s differences are minimally compensated and selected dye has insufficient wet fastnesses. Investigation results obtained enable a fundamental perception of modified blends dyeing using one dye, taking care of environmental aspect

A phenomenological analysis of sintering kinetics from the viewpoint of activated volume

The sintering kinetics of real systems has been viewed as a process of transport of activated volume. Activated volume is a parameter that can be used to describe mass transport during the sintering process. It defines the movement of point defects and dislocations during the sintering process. A phenomenological equation has been defined using this parameter, which can be applied to analyze kinetics of the sintering process. It has been applied to analyze the sintering process of several disperse systems. Values obtained for parameters of the equation have also been analyzed

The Influence of Tribophysical Activation on Zn2TiO4 Synthesis

Poster presented at the Seventh Yugoslav Materials Research Society Conference - YUCOMAT 2005, Herceg Novi, Crna Gora, September 12-16, 2005

Influence of mechanical activation on synthesis and properties of the MgO-TiO2 system

Materials applied in electronics such as multilayer capacitors are an important field of ceramic materials. Magnesium titanate based dielectric materials are used for producing type-I capacitors. A common way of obtaining this material is a solid-state reaction during reaction sintering. The process of sintering can be enhanced if mechanical activation precedes. In this work starting powders of magnesium carbonate (MgCO3) and titanium dioxide (TiO2) with a rutile crystal modification were weighed to attain a 1:1 molar MgCO3:TiO2 ratio. Mechanical activation of the starting mixture was performed by high energy ball milling using ZrO balls and vessels with a ball to powder mass ratio of 40:1. The observed grinding times were 15, 30, 60 and 120 minutes. Powder characterization was conducted using X ray powder diffraction, DTA analysis up to 1000 o C and particle morphology changes were observed with Scanning Electron Microscopy. Isothermal sintering of compacted powders was conducted at 1100ºC during 30, 60 and 180 minutes. For specimens synthesized in such a manner, microwave dielectric properties were measured, quality factor Q, specific electrical resistivity (ρ) and the dielectric constant (Єr). In this work we explain the influence of mechanical activation on the MgCO3-TiO2 system leading to titanate formation during sintering, as well as induced changes in microwave dielectric properties

Synthesis and characterization of zinc titanate nano-crystal powders obtained by mechanical activation

Development of dielectric materials for microwave frequencies is increasing with rapid progress in mobile and satellite communications systems, where zinc titanates have found application due to their semi-conducting and dielectric properties. Mechanical activation by grinding is a well-known method and common part of the powder preparation route in the field of ceramics. The aim of this work is investigation of the influence of experimental conditions for mechanochemical synthesis of zinc orthotitanate. Starting powder mixtures of ZnO and TiO2, in the molar ratio that is in accordance with the stoichiometry of zinc titanate spinel type Zn2TiO4, were mechanically activated using a high-energy planetary ball mill. The process of mechanical activation was performed during different time intervals from 0 to 300 minutes. Microstructure characterization was determined by X-ray diffraction analysis and scanning electron microscopy. Also, the specific surface area (SSA) of powders samples was measured by a nitrogen gas sorption analyzer using the BET method. The very first traces of zinc titanate are detectable after only 5 minutes of activation. The most interesting occurrence during the mechanical method of activation is that we have an almost pure phase after 90 minutes

The effect of nonionic surfactant treatment on dyeing of cotton fabrics

Proučavan je utjecaj obrade neionskim tenzidom FN-10 na karakteristike bojadisanja pamučne tkanine direktnim i reaktivnim bojilima. Različitim metodama identificirana je prisutnost neionskog tenzida na površini obrađenih uzoraka i mogućnost interakcije tenzida s upotrijebljenim bojilima. Obrađeni uzorci imaju bolju kvasivost i više upijaju bojilo u odnosu na neobrađen uzorak. Dubine obojenja direktnim i reaktivnim bojilima najveće su na obrađenim uzorcima bojadisanim u otopini sa standardnom količinom soli. Povećanje dubine obojenja može se smatrati razultat zajedničkog djelovanja soli i neionskog tenzida na povećanje afiniteta bojila za pamuk.The effect of nonionic FN-10 surfactant treatment on dyeing characteristics of cotton fabrics dyed with direct and reactive dyes was studied. Using different methods, the presence of nonionic surfactants on the surface of treated samples and the possibility of surfactant to interact with the used dyes were investigated. The treated samples have better wettability and absorb more dye than untreated sample. Intensities of direct and reactive dyes are the highest on treated samples dyed in a solution with standard amount of salt, and the intensity increase can be considered a mutual contribution of salt effect and that of deposited nonionic surfactant layer on the increase of dye affinity for cotton

The effect of nonionic surfactant treatment on dyeing of cotton fabrics

Proučavan je utjecaj obrade neionskim tenzidom FN-10 na karakteristike bojadisanja pamučne tkanine direktnim i reaktivnim bojilima. Različitim metodama identificirana je prisutnost neionskog tenzida na površini obrađenih uzoraka i mogućnost interakcije tenzida s upotrijebljenim bojilima. Obrađeni uzorci imaju bolju kvasivost i više upijaju bojilo u odnosu na neobrađen uzorak. Dubine obojenja direktnim i reaktivnim bojilima najveće su na obrađenim uzorcima bojadisanim u otopini sa standardnom količinom soli. Povećanje dubine obojenja može se smatrati razultat zajedničkog djelovanja soli i neionskog tenzida na povećanje afiniteta bojila za pamuk.The effect of nonionic FN-10 surfactant treatment on dyeing characteristics of cotton fabrics dyed with direct and reactive dyes was studied. Using different methods, the presence of nonionic surfactants on the surface of treated samples and the possibility of surfactant to interact with the used dyes were investigated. The treated samples have better wettability and absorb more dye than untreated sample. Intensities of direct and reactive dyes are the highest on treated samples dyed in a solution with standard amount of salt, and the intensity increase can be considered a mutual contribution of salt effect and that of deposited nonionic surfactant layer on the increase of dye affinity for cotton

Dilatometer Investigations of Reactive Sintering of Zinc Titanate Ceramics

Poster presented at the The Sixth Yugoslav Materials Research Society Conference - YUCOMAT 2004, Herceg Novi, Crna Gora, September 13-17, 2004

A geographical information systems-based approach to health facilities and urban traffic system in Belgrade, Serbia

We studied the geospatial distribution of health facilities in Belgrade, the capital of the Republic of Serbia, in relation to the public transport system. Analyses in this research were based on advanced geographical information systems using numerical methods. We calculated accessibility to health centres as based on public transport properties accounting for the movement of citizens, as well as patients, through the city. Based on results, the city of Belgrade has a moderate connectivity. Public health centres and a group of other health centres in the central-east part of the city have a better connectivity. Also, in this paper we estimated that the average time necessary to reach health facilities on foot is 100 minutes and by public transport vehicles such as buses, trams and trolleys is 42 minutes