Use of ultrasonic energy in reactive dyeing of cellulosic fabrics

The use of ultrasonic energy in dyeing cotton fabrics with monochlorotriazine and vinylsulphone reactive dyes has been studied spectrophotometrically. The dyeings carried out conventionally and by the use of ultrasonic techniques were compared in terms of percentage exhaustion, total amount of dye transferred to the washing bath after dyeing, fastness properties and colour values of the dyed materials. Overall results have shown that the use of ultrasound in reactive dyeing of cellulosic fabrics can result in energy savings, less water consumption, increased depth of colour and better process conditions. © 1995 Society of Dyers and Colourist

Microwave-assisted dyeing of poly(butylene terephthalate) fabrics with disperse dyes

In this study, conventional heating and microwave dielectric heating in the exhaust dyeing of poly(butylene terephtalate) fabrics with disperse dyes were studied in order to determine whether microwave heating could be used to increase the dyeability of poly(butylene terephtalate) fibre in shorter processing times and enable dyeings of adequate wet fastness to be obtained. Accordingly, the samples of 100% poly(butylene terephtalate) single jersey knitted fabric were dyed with CI Disperse Yellow160 and CI Disperse Yellow42, CI Disperse Red177 and CI Disperse Red91, CI Disperse Blue79:1 and CI Disperse Blue54 at 98 degrees C with or without microwave dielectric heating. The colouristic properties, colour fastnesses and the tensile properties of the dyed fabrics were investigated and compared with each other. Microwave dielectric heating is regarded as a tool for green chemistry' and provides many advantages over conventional heating without any deterioration in the properties of the dyed materials. Microwave heat dyeing enhances the exhaustion and the fixation of dye, and good colour fastnesses and repeatability in dyeings are achieved in short heating times of the dyebath

Preservice Elementary Mathematics Teachers’ Concept Images Related to the Period Concept

Bu araştırmanın amacı, ilköğretim matematik öğretmen adaylarının periyotla ilgili kavram imajlarını belirlemektir. Araştırma, 2011-2012 eğitim-öğretim yılında bir devlet üniversitesinin İlköğretim Matematik Öğretmenliği programının 1.sınıfına kayıtlı 58 öğretmen adayı ile gerçekleştirilmiştir. Araştırmanın deseni nitel araştırma yöntemlerinden durum çalışmasıdır. Öğretmen adaylarının periyot kavramıyla ilgili imajlarını ortaya çıkarmak amacıyla araştırmacı tarafından geliştirilen Periyot Testi (PT) uygulanmıştır. Maksimum çeşitlilik örneklemesi ile seçilen katılımcılarla yapılan yarı yapılandırılmış görüşmelerden elde edilen veriler, içerik analizine tabi tutulmuş ve öğretmen adaylarının periyot imajları Tall ve Vinner'in (1981) kavram imajı - kavram tanımı teorisi çerçevesinde belirlenmiştir. Veri analizi sonucunda öğretmen adaylarının periyot imajları "belirli aralıklarla tekrarlanan olay", "bir olayın tekrarlanması için geçen süre" ve "bir olayın tekrarlandığı uzunluk, aralık" olarak belirlenmiştirThis study has been conducted to investigate preservice elementary mathematics teachers’ concept images related to the period concept. The sample consists of 58 freshmen preservice elementary mathematics teachers who were registered to a Turkish state university in 2011-2012 academic year. This study is a case study and qualitative in nature. A questionnaire (Period Test, PT) designed by the researcher was applied to investigate preservice teachers’ period images. After collecting data through PT and semi-structured interviews done with some participants who were selected according to maximum variation sampling, content analysis was examined to investigate period images in the spotlight of Tall and Vinner’s (1981) concept image–concept definition theory. “Regularly repeated events”, “the time between two repeats” and “the distance between two repeats” are common period image

A new process of combined pretreatment and dyeing: REST

Use of enzymes in textile processes has many advantages as far as the environmentally friendly processes are concerned. These advantages include water and energy savings, less chemical use, less fabric damage, mild and environmentally friendly process conditions. In this work, C.I. Reactive Yellow 15, C.I. Reactive Red 21 and C.I. Reactive Blue 19 were used to dye untreated woven cotton fabric in a laboratory scale dyeing machine, on a pilot scale jig and on a pilot scale winch by using a single bath combined process, in which various enzymes, namely, amylase, pectinase, and catalase were employed. This new process was named as the Rapid Enzymatic Single-bath Treatment (REST), since it was completed almost in half of the conventional dyeing time, and all of the stages, namely, desizing, scouring, bleaching and dyeing were carried out in a single bath without replacing the process water with fresh water until the end of the dyeing. In the REST process, the untreated, starch-sized fabric was first desized by amylase enzyme, and this was followed by a pectinase treatment in the same bath. The fabric was then bleached by H2O2 in the same bath, and after the hydrogen peroxide bleaching; the catalase enzyme was added to the bath to remove H2O2 residues before reactive dyeing. Without carrying out intermediate washings/rinsings between these processes, the reactive dyeing was carried out in a conventional way in the same bath, and finally, the fabric was taken from the bath and washed out. The colour yield was compared with the dyeings which were carried out conventionally in separate baths. Finally, the REST has many benefits in terms of water saving, reduced process time and energy consumptions compared to the conventional preparatory and dyeing process of cotton fabrics. (C) 2011 Elsevier Ltd. All rights reserved

Developing a thermo-regulative system for nonwoven textiles using microencapsulated organic coconut oil

Organic coconut oil was investigated as a bio-based phase change material in core, and melamine formaldehyde was used as shell material to fabricate microencapsulated phase change material for thermo-regulation in nonwoven textiles. The microcapsules were synthesized using in situ polymerization method. The produced microcapsules (microencapsulated phase change material) were applied by knife coating in different ratios (1:5 and 1.5:5; MPCM: coating paste by wt.) to 100% polypropylene nonwoven, porous, and hydrophilic layer of a laminated, spunbond, and double-layer fabric. The coated layer was confined within two layers of the fabric to develop a thermo-regulative system on the nonwoven fabric to regulate the body temperature in surgeries. The two layers were composed by applying heat (140 degrees C) and pressure (12 kg/cm(2)). Organic coconut oil, the fabricated microcapsule, and the composite fabrics were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. Scanning electron microscopy results revealed that spherical and uniform microcapsules were obtained with an approximate particle size of 2-6 mu m. Differential scanning calorimetry results indicated that microencapsulated phase change material and the composite fabrics possessed significant melting enthalpies of 72.9 and 8.4-11.4 J/g, respectively, at peak melting temperatures between 21.6 and 22.8 degrees C within human comfort temperature range. The utilization of coconut oil as a phase change material and the composite integration of this phase change material to a nonwoven fabric bring forward a novelty for future applications

Microencapsulated organic coconut oil as a natural phase change material for thermo-regulating cellulosic fabrics

In this work, coconut oil was utilized as a natural phase change material (PCM) and applied on cellulosic fabrics for thermo-regulation. Organic coconut oil was microencapsulated in melamine formaldehyde and poly (methyl methacrylate) polymer shells by in situ and suspension polymerization methods, respectively. The fabricated microcapsules were applied on a daily wear stretch denim fabric and a cotton shirting fabric by knife-coating to impart thermo-regulation functionality. The microencapsulated PCMs and the treated fabric samples were characterized using Fourier transform infrared spectroscopy, differential scanning calorimetry, thermal gravimetric analysis and scanning electron microscopy. The results indicated that latent heats of 81.9 J/g and 39.1 J/g at melting peak temperatures of 21.5 degrees C and 22.1 degrees C were successfully achieved with the microencapsulated PCMs which enabled the fabrics to possess remarkable latent heats in between 6.7 and 14.9 J/g. Graphic abstrac