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2.
Study of crosslinking efficiency of cotton cellulose by different physical-chemical methods and genetic programming
Olivera Šauperl, Miran Brezočnik, 2006, izvirni znanstveni članek

Opis: We have investigated the crosslinking effect of unmercerized and mercerized cotton celluose crosslinked with different BTCA mass fractions in the impregnation bath. Crosslinking efficiency was analyzed using FT-IR spectroscopy, water retention capacity method, tensiometry and the methylene blue method. On the basis of the experimental data which was obtained with theseparate physical-chemical methods, different prediction models for crosslinking efficiency was developed. Modelling was taken out with the genetic programming method. Research shows good accordance of the experimentaldata with the genetic models.
Ključne besede: textile fibres, cotton, cellulose, crosslinking, FTIR spectroscopy, methylene blue method, water retention capacity, tensiometry, genetic programming
Objavljeno: 30.05.2012; Ogledov: 1397; Prenosov: 52
URL Povezava na celotno besedilo

3.
The effect of pretreatment on the environment and dyeing properties of a selected cotton knitted fabric
Darinka Fakin, Darko Golob, Zoran Stjepanović, 2008, izvirni znanstveni članek

Opis: The current preparation of cotton knitted fabric prior to dyeing mainly involves a combined process consisting of scouring and peroxide bleaching. In this research two pre-treatment procedures, i.e. combined alkaline scouring/bleaching and enzymatic scouring/bleaching, were compared and their effects evaluated regarding environmental impact, whiteness and dyeing properties. Different pre-treated samples of cotton knitted fabrics were subsequently dyed with a chosen set of bifunctional reactive Cibacron LS dyes.The results obtained indicate that combined pre-treatment by enzymatic scouring/bleaching can be regarded as a good alternative to alkaline scouring/bleaching since it results in lower pollution of waste-water, lower SAK value after dyeing, washing and soaping, and consequently lower hydrolysation of dyestuff. Furthermore, added advantages are that it produces similar whiteness, similar dye exhaustion and, with the exception of black dyestuff, comparable dyeing results.
Ključne besede: cotton, pretreatment, bleaching, dyeing, ecological parameters
Objavljeno: 31.05.2012; Ogledov: 1271; Prenosov: 17
URL Povezava na celotno besedilo

4.
Analysis of the oxidation of cellulose fibres by titration and XPS
Lidija Fras Zemljič, Leena Sisko Johansson, Peer Stenius, Janne Laine, Karin Stana-Kleinschek, Volker Ribitsch, 2005, izvirni znanstveni članek

Opis: The purpose of this study was to evaluate the effect of selective oxidation on the surface properties of cotton cellulose fibres. Four different methods to evaluate the accessibility, nature and content of ionisable acidic groups (charge) in the fibres were applied: potentiometric and conductometric titrations, polyelectrolyte adsorption and X-ray photoelectron spectroscopy (XPS). The results from this combination of methods show that two processes take place when the oxidation method is applied: elimination of low molecular mass non-cellulosic compounds and formation of new acidic groups in the cellulose chains. Which of these processes is predominating depends on oxidation time, but the first one is initially more important. Polyelectrolyte adsorption and XPS show that the surface concentration of acidic groups is considerably lower than the bulk concentration, i.e. during oxidation the content of carboxyl groups in the surface region decreases, while it increases in amorphous regions. The decrease is due to the dissolution of low molecular weight compounds; the increase is due to the formation of new acidic groups. The use of titration methods in combination with XPS appears to be a very useful tool for identification of the formation and distribution of ionic groups in cotton fibres and their surfaces.
Ključne besede: textile fibres, cotton fibres, cellulose fibres, oxidation, X-ray photoelectron spectroscopy, XPS, acid groups in fibres
Objavljeno: 01.06.2012; Ogledov: 1460; Prenosov: 76
URL Povezava na celotno besedilo

5.
Characterization of amino groups for cotton fibers coated with chitosan
Lidija Fras Zemljič, Simona Strnad, Olivera Šauperl, Karin Stana-Kleinschek, 2009, izvirni znanstveni članek

Opis: The adsorption of chitosan onto cellulose cotton fibers introduces antimicrobial properties, mainly created by the amount and location of amino groups. Therefore, it is important to be able to analyze both parameters, especially in a heterogeneous system, namely cotton fibers coated with chitosan. In this research, three different analytical techniques were applied to determine amino groups of cotton fibers coated with chitosan. The number of positively charged groups was determined indirectly by the spectrophotometric method using Acid Orange 7 dye, and the use of polyelectrolyte titration. In addition, the chemical surface composition regarding non-modified, as well as modified cotton fibers (coated with chitosan), was investigated using X-ray Photoelectron Spectroscopy (XPS). The results from a combination of these methods show that chitosan treatment introduces more than 14 mmol/kg of accessible amino groups onto the cotton fibers. The results were in good agreement with the results of XPS. The use of spectrophotometric and titration methods in combination with XPS appears to be a very useful tool for identifying the formation of amino groups in modified cotton fibers and their surfaces.
Ključne besede: cotton, cellulose, oxidation, chitosan, amino-groups, titration, XPS
Objavljeno: 01.06.2012; Ogledov: 1144; Prenosov: 113
URL Povezava na celotno besedilo

6.
Grafting of ethylcellulose microcapsules onto cotton fibres
Roxana Badulescu, Vera Vivod, Darja Jaušovec, Bojana Vončina, 2008, izvirni znanstveni članek

Opis: In this paper a treatment of cotton with ethylcellulose (EC) microcapsules wasinvestigated. EC microcapsules containing Rosemary oil were obtained by phase separation method. The surface and morphology of microcapsules were characterized by scanning electron microscopy (SEM). Microcapsules with a regular spherical shape in the 10-90 m size range were prepared and grafted onto cotton using the crosslinking reagent 1,2,3,4-butanetetracarboxylic acid (BTCA) in the presence of catalysts. The influence of the two catalysts, cyanamide (CA) and N,N'-dicyclohexylcarbodiimide (DCC) on curing efficiency (grafting) was investigated. SEM and Fourier transform infrared spectroscopy (FT-IR) were used to study the formation of ester bonds between BTCA and hydroxyl groups of cotton and/or hydroxyl groups of EC. When DCC was used as acatalyst, the esterification took place slowly at room temperature. In the case of CA, the cotton was cured at 110 °C for several minutes. After 2 min curing, the microcapsules, which kept their original shape, were bonded to thecotton fibers. Increasing the curing time altered the microcapsule shell. Grafting and crosslinking reactions of the thermofixed EC microcapsules onto cotton were proposed.
Ključne besede: textiles, chemical modification, cotton fibres, ethylcellulose, microcapsules, BTCA, SEM, FT-IR, grafting
Objavljeno: 01.06.2012; Ogledov: 1242; Prenosov: 30
URL Povezava na celotno besedilo

7.
Topochemical modification of cotton fibres with carboxymethyl cellulose
Lidija Fras Zemljič, Peer Stenius, Janne Laine, Karin Stana-Kleinschek, 2008, izvirni znanstveni članek

Opis: The research reported in this paper demonstrates that the capacity of cotton fibres to adsorb cationic surfactants as well as the rate of the adsorption process can be increased by adsorbing carboxymethyl cellulose (CMC) onto the fibre surfaces; in addition, the adsorption can be restricted to the fibre surface. CMC was deposited by means of adsorption from an aqueous solution. The adsorption of N-cetylpyridinium chloride (CPC) from an aqueous solution onto the CMC-modified fibres was measured using UVspectrometric determination of the surfactant concentration in the solution. Adsorption onto the cotton fibres was studied in a weakly basic environment (pH 8.5) where cotton fibres are negatively charged and the CPC ion is positively charged. Modification of the fibres by adsorption of CMC introduces new carboxyl groups onto the fibre surfaces, thereby increasing the adsorption capacity of the fibres for CPC. The initial rate of adsorption of CPC increased proportionally with the amountof charge; however, this rate slowed down at high degrees of coverage onfibres with a high charge. The adsorption of cationic surfactant to the anionic surface groups was stoichiometric, with no indication of multilayer oradmicelle formation. It was evident that the acidic group content of the fibres was the primary factor determining cationic surfactant adsorption to these fibres.
Ključne besede: textile fibres, cotton fibres, modification, carboxymethyl cellulose, acid groups, charge increase, conductiometric titration, phenol-sulphuric acid test, practical applications
Objavljeno: 01.06.2012; Ogledov: 1190; Prenosov: 77
URL Povezava na celotno besedilo

8.
Application of spectrophotometric methods in assessing the influence of alkaline treatment on the degree of crosslinking of cotton cellulose with BTCA
Olivera Šauperl, Karin Stana-Kleinschek, Bojana Vončina, Majda Sfiligoj-Smole, Alenka Majcen Le Marechal, 2003, izvirni znanstveni članek

Opis: Polycarboxylic acids appear to be the most promising nonformaldehyde crosslinking agents to replace the traditional, mostly formaldehyde-based, compounds. The most effective among these acids is 1,2,3,4-butanetetracarboxylic acid (BTCA). In this study, a comparison was made of the crosslinking effect on mercerized and on unmercerized as well as with different BTCA mass fractions crosslinked cotton fibres using FT-IR spectroscopy, the methylene blue method and water retention determination. The main purpose of the research was to evaluate how the structural changes of mercerized cotton (transformation of cellulose I into cellulose II) influence the crosslinking of cellulose fibres.
Ključne besede: textile fibres, cotton fibres, cotton cellulose, mercerization, crosslinking
Objavljeno: 01.06.2012; Ogledov: 1480; Prenosov: 84
.pdf Celotno besedilo (169,10 KB)
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9.
Economic and social diversity in Australia's cotton-producing communities
Tony Sorensen, Bernice Kotey, 2009, izvirni znanstveni članek

Opis: Australia’s highly profitable cotton industry is geographically constrained to districts in northern New South Wales and Southern Queensland. However, the rural towns servicing the industry are facing unprecedented stress on account of fierce commercial competition between them, many years of drought during the 2000s, technological innovation in cotton production, the chance occurrence of non-agricultural economic opportunities, and even ethnic composition. Our research focuses on the role of innovative small business in overcoming community stress and we have selected a small sample of six local government areas to examine this link in depth. The selection of a representative sample entailed the classification of cotton communities on the basis of their economic and social profiles and how they had evolved over the inter-census period 2001-06. This analysis surprisingly showed that cotton growing regions are highly differentiated not just at a single point in time (2006), but also in their development trajectories. This considerably complicated the process of sample selection, but also demonstrated the diversity of rural settlement.
Ključne besede: diversity of rural settlements, non-agricultural activity, cotton industry, innovative SME’s
Objavljeno: 19.03.2018; Ogledov: 370; Prenosov: 54
.pdf Celotno besedilo (153,68 KB)
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