Effect of solvent treatment on morphology, crystallinity and tensile properties of cellulose acetate nanofiber mats

Aligned nanofiber mats were prepared from cellulose acetate using an electrospinning technique. The nanofiber mats were then immersed in an ethanol/acetone mixture. The solvent treatment led to denser, more compact fibrous structure and slight decrease in fiber alignment. It increased fiber diameter and polymer crystallinity within fibers. These effects resulted in increase in the tensile strength of fibrous mats. Solvent treatment may offer a simple, efficient approach to improve the mechanical strength of nanofibrous mats.

Electrical conductivity of single walled and multiwalled carbon nanotube containing wool fibers

The main purpose of this study was producing conductive wool fabric applying carbon nanotubes. Raw and oxidized wool samples were treated with carbon nanotubes in the impregnating bath in the presence of citric acid as a crosslinking agent and sodium hypophosphite as a catalyst while sonicating them in the ultrasonic bath. Electrical resistance, washing durability, and color variation of treated samples were assessed. Through SEM images, the surface morphology of treated samples was studied confirming the surface coating through carbon nanotubes. According to the results, the electrical resistance of treated wool with carbon nanotubes reduced substantially. However, the single-walled carbon nanotubes are more useful to increase the conductivity. In addition, the wool color changed into gray after the treatment.

Enhanced homogeneity and interfacial compatibility in melt-extruded cellulose nano-fibers reinforced polyethylene via surface adsorption of poly(ethylene glycol)-block-poly(ethylene) amphiphiles

In this paper, we demonstrate that an amphiphilic block copolymer such as polyethylene glycol-b-polyethylene can be used as both dispersing and interfacial compatibilizing agent for the melt compounding of LLDPE with cellulose nano-fibers. A simple and effective spray drying methodology was first used for the first time for the preparation of a powdered cellulose nano-fibers extrusion feedstock. Surface adsorption of the amphiphilic PEG-b-PE was carried out directly in solution during this process. These various dry cellulosic feedstock were subsequently combined with LLDPE via extrusion to produce a range of nano-composites. The collective outcomes of this research are several folds. Firstly we show that presence of surface adsorbed PEG-b-PE effectively hindered the aggregation of the cellulose nano-fibers during the extrusion, affording clear homogenous materials with minimum aggregation even at the highest loading of cellulose nano-fibers (∼23 vol.%). Secondly, the tailored LLDPE/cellulose interface arising from intra- and inter-molecular hydrogen and Van der Waals bonds yielded significant levels of mechanical improvements in terms of storage and tensile modulus. We believe this study provides a simple technological template to produce high quality and performant polyolefins cellulose-based nano-composites.

Barrier textiles for protection against microbes

The presence or growth of microbes on textiles may result in a series of problems such as unpleasant odors, cross infection, disease transmission, or discoloration and deterioration of textiles. Imparting textiles with antimicrobial property can effectively eliminate these adversities and thus has been attracting great attention. This chapter summarizes the commonly used antimicrobial agents such as silver, metal oxides, photoactive dyes, quaternary ammonium compounds, N-halamines, triclosan, polybiguanides, chitosan, and plant-derived bioactive agents, their characteristics, toxicity, antimicrobial ability, ecological acceptability, and related textile finishing techniques and evaluation methods. Since durability to repeated washing is the major challenge for the practical use of antimicrobial textiles, the chapter provides details on the technique to immobilize antimicrobial agents onto fibers. In addition, impacts of using antimicrobial textiles on the environment and health are discussed in the last section.

Treatment of textile wastewater with membrane bioreactor: a critical review

Membrane bioreactor (MBR) technology has been used widely for various industrial wastewater treatments due to its distinct advantages over conventional bioreactors. Treatment of textile wastewater using MBR has been investigated as a simple, reliable and cost-effective process with a significant removal of contaminants. However, a major drawback in the operation of MBR is membrane fouling, which leads to the decline in permeate flux and therefore requires membrane cleaning. This eventually decreases the lifespan of the membrane. In this paper, the application of aerobic and anaerobic MBR for textile wastewater treatment as well as fouling and control of fouling in MBR processes have been reviewed. It has been found that long sludge retention time increases the degradation of pollutants by allowing slow growing microorganisms to establish but also contributes to membrane fouling. Further research aspects of MBR for textile wastewater treatment are also considered for sustainable operations of the process.

Conductive polymer coatings

Conducting polymer-coated textiles possess a wide range of electrical properties. The surface resistivity is influenced by concentrations of the reactants, the thickness of the coating, the nature of the substrate surface, the extent of penetration of the polymer into the textile structure, and the strength of the binding of the coating to the textile surface. Low resistivity in fabric results from highly doped thicker coatings that penetrate well into the textile structure, thus enabling good electrical contact between fibers. Microwave studies showed that conductive textiles are not highly effective as electromagnetic shielding materials owing to their medium-level conductivity and therefore large skin depth. Combined with the fact that coatings are around 1. ?m thick, they cannot act as effective reflective barriers to electromagnetic radiation. However, because they are highly absorptive in the microwave region, absorbing materials can be designed in conjunction with conductive textiles. Study of Fourier transform-infrared spectra of aged polypyrrole films has shown an increase in intensity of an ?,?-unsaturated conjugated carbonyl peak that may be linked to the increase in resistance but cannot be the only factor, because the rate of electrical decay was influenced by several factors such as temperature, the type and concentration of the dopant, and the aging time, all of which signify a complex mechanism of degradation of conductivity. Degradation is a major concern for conductive textile systems that needs to be characterized before considering these materials for potential applications.

Nonlinear combining and compression in multicore fibers

We demonstrate numerically light-pulse combining and pulse compression using wave-collapse (self-focusing) energy-localization dynamics in a continuous-discrete nonlinear system, as implemented in a multicore fiber (MCF) using one-dimensional (1D) and 2D core distribution designs. Large-scale numerical simulations were performed to determine the conditions of the most efficient coherent combining and compression of pulses injected into the considered MCFs. We demonstrate the possibility of combining in a single core 90% of the total energy of pulses initially injected into all cores of a 7-core MCF with a hexagonal lattice. A pulse compression factor of about 720 can be obtained with a 19-core ring MCF.

Knowledge and attitudes towards dietary fibers - romania vs other european countries

Aim: The aim of our study was to evaluate the Romanian’s knowledge and attitudes regarding dietary fibers compared with other European countries. Materials and methods: We made a cross-sectional survey (part of multinational project from CI&DETS Research Centre, Instituto Politecnico Viseu, Portugal, with reference PROJ/CI&DETS/2014/0001) based on a questionnaire applied in 2015, over 670 Romanian consumers, focused on the attitudes and knowledge towards ingestion of foods rich in fibers. We used the software SPSS for statistics. Results: Our results showed that the knowledge about dietary fibers and also the ingestion of food products rich in fibers were low. The female participants ate more whole grains and fruits than males and pay more attention to food labelling, the Romanian people prefer to stay and eat home than at restaurants especially in rural areas, and the knowledge about fiber’s benefits was significantly related to high education and urban location. Comparing to other European countries, Romania had the highest level of knowledge about dietary fibers definition followed by Portugal, Turkey and Hungary, but the lowest regarding the fibers importance for health after Macedonia, Turkey and Latvia. Conclusion: We sustain the needs for more efficient community interventions and proper information about the importance of dietary fibers for our health and also for the dissemination of the nutritional standards among Romanian population.

Romanian Knowledge and Attitudes regarding Dietary Fibers

Presently, the scientists recognize the health benefits of food fibers in the menu and also plant food sources are at high interest both for general population and food companies. The food companies are responsible for a clear nutrition labelling that will assist consumers to make informed and healthy choices and health providers has to inform the population about the benefits of fibers.The aim of our study was to evaluate the Romanian knowledge and attitudes regarding dietary fibers from food products. We made a qualitative survey based on a questionnaire applied in 2015, over a period of 6 months, over 670 Romanian consumers. It was focused on testing the attitudes and knowledge towards ingestion of foods rich in fibers. For all data analysis we used the software SPSS, from IBM Inc. Our results showed that the knowledge about dietary fibers and also the ingestion of food products rich in fibers were low, and most of the subjects didn’t have any interest to read the nutritional information from food labels. The female participants ate more whole grains and fruits than males and pay more attention to food labelling. Romanian people prefer to stay and eat home than at restaurants especially in rural areas, and the knowledge about fibers benefits was significantly related to education and urban location. We underline the needs for more efficient community interventions and proper information about the importance of dietary fibers for our health and also to improve and disseminate nutritional standards and diet recommendation among population.

Disruptive Threads and Renegade Yarns: Domestic Textile Making in Selected Women's Writing 1811-1925

Thesis (Ph.D, English) -- Queen's University, 2016-08-03 13:57:45.102

Facile fabrication of polyester filament fabric with highly and durable hydrophilic surface by microwave-assisted glycolysis

Poly(ethylene terephthalate) (PET) fabric with highly and durable hydrophilic surface was fabricated using microwave-assisted glycolysis. Sodium hydroxide (NaOH) as a catalyst was proven to be suitable for PET glycolysis under assistance of microwave. The modified PET fabric (0.5% NaOH, irradiation 120 s) showed high surface hydrophilicity with a contact angle of 17.4 ° and a wicking length of 19.36 mm. The exposure of the carboxyl- and hydroxyl-end groups on the surface of PET and the introduction of etches were confirmed by Methylene Blue staining and field emission scanning electron microscopy (FESEM), receptively. Although the strength of PET fabric decreased after modification, it was still high enough for textile applications. The thermal properties of the modified PET fabrics were well maintained. The high hydrophilicity and its original properties of PET could be controlled by changing the irradiation time from 60 s to 120 s and adjusting the content of sodium hydroxide from 0.2% to 0.5%. These results suggest microwave-assisted glycolysis with sodium hydroxide is an effective method for PET hydrophilic finishing.

Structure–property relationships of elementary bamboo fibers

Natural fibers are promising alternatives to synthetic fibers because of their sustainability, low environmental footprint and specific properties desirable for a wide range of technical engineering applications. The industrial implementation of fine grade natural bamboo fibers, including technical (100–200 microns) and elementary fibers (<30 microns) has been of increasing interest in recent times because these fibers offer a unique set of properties including high tensile strength, antibacterial and UV absorption. However to date, very little scientific effort has been devoted to fully understand the inter-correlation between their mechanical, physico-chemical, microstructural and morphological properties. In this paper, we report for the first time the structure–property relationship of elementary bamboo fibers. The impact of the inner microstructural organization of fibers (including the micro-fibrils angle) and physico-chemical factors such as the cellulose content and crystallinity index, on the tensile performance of these fibers is discussed in detail. This work also provides an insight into the application of bamboo fibers as natural and low-cost sorbent material for the removal of Cu2+ metal ions from model industrial wastewater. The metal ion adsorption properties of the fibers are correlated to surface energy analysis obtained from inverse gas chromatography.

Photocatalytic TiO2/porous BNNSs composites for textile dyeing wastewater treatment

This project develops a novel photocatalyst for the cleaning of textile dyeing wastewater. The newly-developed photocatalyst was prepared by combing porous boron nitride nanosheets with titanium dioxide particles and these composites show potentials for the practical treatment of the textile dyeing wastewater in a large scale.

Cellulose-derived carbon fibers produced via a continuous carbonization process: investigating precursor choice and carbonization conditions

Here, the carbonization of two Lyocell type regenerated cellulose fibres is reported. Commercially available Lyocell as well as the experimental Lyocell type fibre known as Ioncell-F spun from the ionic liquid 1,5-diazabicyclo[4.3.0]non-5-ene-1-ium acetate ([DBNH]OAc) is investigated, which supports higher draw ratio and thus improves precursor mechanical properties. Lyocell fibres are known to have improved mechanical properties over other regenerated cellulose fibres and are therefore considered to be better carbon fibre precursor candidates. The Lyocell fibres used in this study are carbonized utilizing a scaled down identical replica of an in use carbon fibre line. The importance of this is the ability to assess the performance of the Lyocell fibres under more realistic continuous carbonization processing conditions. The tensile properties, morphology, and chemical composition of all fibres are determined. It is shown that by changing the carbonization temperature and atmosphere fibres with different mechanical properties and diameter can be produced. Elemental analysis confirms that each fibre has a carbon content of ≥90%.

Francisco Pizarro' s banner of arms: an analytical work contributing to latin America's history

The study of textiles is an open area of scientific research, which for its variety of material components and physical chemical diversity of conditions, makes a field of interest for scientific studies in the cultural heritage field. Archaeological/historical textiles offer the possibility to carry out studies on organic materials such as fibers, adhesion elements, dyes, paper, etc., as well as on inorganic compounds for instance metals, alloys, precious stones and other added ornamentation. That variety of composition, allow to use a combination of analytical techniques to solve the questions coming from the object in an archaeometric research. One kind of textile object that provides a valuable cultural information because of its linguistic representation employed by its carrier societies, are the flags/banners/emblems, objects made with a nonverbal communication purpose. As long as depending on the use and/or purpose of each object, varies both the materials/techniques used in its production and its iconography (style, color, emblem, shape), its study gives the possibility to extract information through their materials and manufacturing techniques about a temporal-spatial frame, a particular event or a specific character. The flags/banners have been used since the eleventh century as representative objects of power, hierarchy, social or military organization, or as communicative media. The use of these objects has been spread throughout the world, possibly due to its easy interpretation and/or appropriation by different societies, making it part of their own culture. The flags as symbols of territorial control, using emblems that represent a family, order or army, were introduced to the New World (America) with the arrival of the European conquerors at the end of the fifteenth century. Flags/banners representing the Royal dominion over conquered territories, the Catholic Church and conquistadors’ armies were the first to arrive. One of those flags that have endured over time, that have an invaluable cultural meaning for both American and Iberian societies, is the so-called Francisco Pizarro’s Banner of Arms. It is a textile object with metal threads decoration over a Royal emblem. According to historical sources, this object was used by Francisco Pizarro in 1532 on the conquest process of Peru, after received the permission by King Charles V to on behalf of him, to conquer the lands of the New World today known as Peru. After Pizarro’s control of the Inca territory, it is believed that Pizarro left his banner on top of the Inca’s Sun’s Temple as symbol of his rule. Centuries later, in the America libertarian campaigns, General Sucre, military at charge of the independence army in Peru, reports have found what he considered the Pizarro’s Banner, sending it to Bogotá as a symbol of victory, being kept since that time until today by the National Museum of Colombia. Due to historical discrepancies in the different movements of the so-called Pizarro’s Banner of Arms, its real meaning has been under discussion and because of the passage of time its physical condition has suffer deterioration. That is because its scientific study is now an interesting case study to respond to both historical and conservation questions of it. Through a collaboration with the National Museum of Colombia, a set of 25 samples of so-called Pizarro’s Banner of Arms were collected, covering the various components and areas from the object of study. These samples were subjected to analytical studies for physical and chemical characterization. Microscopic observation, VSEM-EDS analysis, Raman spectroscopy, chromatographic analysis (HPLC-MS, GCMS) and radiocarbon dating were done. Similarly, was sought through a direct in situ physical inspection to the object and through a research into historical sources, adequate information to solve the object’s problems. Results obtained allowed to identify as silk the textile used in the elaboration of the Banner’s fabric, as well as the use of natural dyes for dyeing the fibers used on the emblem: use of cochineal and brazil wood as a source of red, luteolin plant-based for yellow color, indigotine plant-based for blue, and a mixture of yellow and blue dyes for green were identified. Similarly, the use of animal glue in the manufacturing process and the use of rag paper was evident. The metal threads study from the Banner give a confirmation to a silver core wire gilded with a thin gold sheet, being flattened and entwined with silk threads for their use. Finally, using the radiocarbon results, it was possible to postulate with huge accuracy that the Banner date manufacture was between the XV-XVI century and subject to restoration processes with addition of textiles in modern times. Together with, was evident that the state of degradation of the fabric is due to natural degradation in the silk fibers, having that its color has faded and its mechanical properties decreased, leading to loss of rigidity and disappearance of the physical structure. Similarly, it was clear the original colors of the emblem and highlight problems of detachment of paper due to crystallization of the adhesive. In the same way, was found that the metal threads suffer corrosion by sulfur and detachment of its crystals. Finally, combining the analytical results and the historical sources data found from the so-called Francisco Pizarro’s Banner of Arms, allows to postulate that its manufacture process was done in Europe employing precious materials to obtain a long-life object with a deep message for its viewers. Also, the data obtained helps to support the possible idea that the object was employed by Francisco Pizarro in the Peru conquest process. However, by the symbols present in the object, its elaboration date and materials, this object its clearly unique in its kind, and the most important, by its linguistic message, does not represent to Francisco Pizarro or his army, meanwhile, represents the Spanish crown. Therefore, instead to be labeled as Francisco Pizarro’s Banner of Arms, it should be called the Colonial Royal Banner of Charles V in the New World; RESUMEN: El estudio de textiles es un área abierta de investigación científica, la cual por su variedad de componentes materiales y la diversidad de condiciones físico-químicas presentes en estos objetos, lo hace un campo de interés para estudios científicos en el patrimonio cultural. Los textiles arqueológicos/históricos brindan la posibilidad de realizar estudios en materiales orgánicos como fibras, elementos de adhesión, tinturas, papel, etc., e inorgánicos como metales, aleaciones, piedras preciosas y demás materiales decorativos añadidos. Por su variedad de composición, es posible emplear diversas técnicas analíticas para resolver aquellas preguntas propias del objeto en una investigación arqueométrica. Uno de los objetos textiles que brinda gran información cultural debido a su representación lingüística empleada por las sociedades portadoras, son las banderas/estandartes/emblemas. Donde varía dependiendo de su uso y/o propósito, los materiales empleados en su elaboración, al igual que su iconografía (estilo, color, emblema, forma). El estudio de estos objetos construidos con un propósito de comunicación no verbal, da la posibilidad de extraer información a través de sus materiales y técnicas de elaboración sobre un rango temporal-espacial, un evento determinado en la historia o incluso a un personaje en específico. Las banderas han sido empleadas desde el siglo XI como objetos representativos de poder, jerarquía, organización social o militar, o como medio de comunicación. El uso de estos objetos se ha extendido a lo largo del mundo posiblemente debido a su fácil interpretación y/o apropiación por distintas sociedades, haciéndolo parte de su cultura. Las banderas como símbolos de control territorial, empleando símbolos que representan a una familia, orden o armada fueron introducidas a el Nuevo Mundo (América) con la llegada de los conquistadores europeos al final del siglo XV. Las banderas/estandartes que representaban el dominio Real sobre territorios dominados, la iglesia católica y las banderas de ejércitos y/o conquistadores fueron las primeras en llegar al nuevo mundo. Una de aquellas banderas que ha soportado el paso del tiempo, teniendo un gran valor cultural tanto para las sociedades americanas como para las ibéricas, es el denominado Estandarte de armas de Francisco Pizarro. Siendo un objeto textil con decoración en hilos metálicos sobre un emblema Real. De acuerdo a fuentes históricas, este objeto fue usado por Francisco Pizarro en 1532 en el proceso de conquista del Perú, quien recibe por parte del Rey Carlos V el poder para que, en su nombre, Pizarro pueda conquistar las tierras del nuevo mundo hoy conocidas como Perú. Luego del dominio de Pizarro sobre el territorio Inca, se cree que Pizarro dejó su estandarte en la cima del templo Inca del sol como símbolo de su control. Siglos más tarde, en las campañas libertarias de América, el General Sucre, militar encargado de la armada independentista en Perú, reporta haber encontrado lo que él considera como el estandarte de Pizarro, enviándolo a Bogotá como muestra de victoria, siendo custodiada desde ese momento por el Museo Nacional de Colombia hasta la actualidad. Debido a discrepancias históricas, el verdadero significado del llamado estandarte de Pizarro ha sido objeto de discusión y debido del pasar del tiempo su estado de conservación se ha deteriorado. Dejando de este modo, un caso de estudio interesante para que por medio de estudios científicos al objeto se pueda dar respuesta a preguntas tanto históricas como de conservación del mismo. De este modo, por medio de una colaboración con el Museo Nacional de Colombia, se obtuvo un juego de 25 muestras del llamado Estandarte de armas de Francisco Pizarro, abarcando los diferentes componentes y áreas del objeto de estudio. Dichas muestras fueron sometidas a estudios analíticos para su caracterización físico-química. Análisis de observación al microscopio, análisis VSEM-EDS, espectroscopia Raman, análisis cromatográficos (HPLC-MS, GC-MS) y datación por radiocarbono catorce fueron realizados. Del mismo modo, por medio de una inspección física al objeto in situ y una profunda investigación en fuentes históricas del mismo, se buscó la información adecuada para resolver sus problemáticas. Los resultados obtenidos permitieron identificar como seda el textil empleado en la elaboración del estandarte, así como el uso de colorantes naturales para teñir las fibras en el emblema: uso de cochinilla y palo de Brasil como fuente del color rojo, plantas a base de luteolin para el color amarillo, plantas a base de indigotina para el color azul y mezcla de colorantes amarillos y azules para el color verde fueron identificadas. Del mismo modo se evidencio el uso de adhesivos animales y el uso de papel de trapos en el proceso de manufactura. El estudio de los hilos metálicos, permitió evidenciar el uso de alambres con núcleos de plata con un fino recubrimiento de oro en su exterior, siendo aplanados y entrelazados con hilos de seda para su uso. Finalmente usando la datación por radiocarbono, fue posible conocer con alta precisión que el estandarte fue elaborado entre los siglos XV-XVI y sufrió procesos de restauración con añadidura de textiles en tiempos modernos. Junto a lo anterior, es posible postular que el estado de degradación de la tela es debido a degradación natural en las fibras de seda, teniendo así que su color se ha desvanecido y sus propiedades mecánicas disminuidas, conllevando a perdida de rigidez y desaparición de la estructura. Del mismo modo se pudo conocer los colores originales del emblema y evidenciar problemas de desprendimiento del papel debido a cristalización del adhesivo. Asimismo, se comprobó que los hilos metálicos presentan corrosión por azufre y desprendimiento de sus cristales. Finalmente, combinando los resultados analíticos y la información de fuentes históricas encontradas del llamado Estandarte de armas de Francisco Pizarro, se puede postular que su elaboración fue realizada en Europa, usando materiales preciosos para obtener un objeto de larga vida con un profundo mensaje para sus observadores. También, los datos obtenidos ayudan a dar soporte la posible idea de que este objeto fue usado por Francisco Pizarro en el proceso de conquista del Perú. Sin embargo, debido a los símbolos presentes en el objeto, fecha y materiales de elaboración, este objeto es claramente único en su tipo, y lo más importante, por su mensaje lingüístico, este no representa a Francisco Pizarro o su armada, al contrario, representa a la Corona de España. Por ende, en vez de denominarse como Estandarte de armas de Francisco Pizarro, este objeto debería nombrarse como el Estandarte Real de la Colonia de Carlos V en el Nuevo Mundo.