Fiber Processing Method Research Articles

An eco-friendly enzymatic treatment to prepare spinnable banana fibers as an alternative to cotton for textile applications

Banana fibers are a sustainable material with natural mechanical strength and antibacterial properties. These fibers are extracted from the large amount of waste produced by banana pseudo stems annually. However, despite their numerous advantages, their stiffness and rough texture impede their full use in the textile. This research investigates the degumming treatment of banana fibers using enzyme combination and chemical methods to achieve spinnable soft banana fibers. An L9 orthogonal array was used in a Taguchi design of the experiment to optimize the process parameters. For enzyme combination degumming, the experimental setup comprised different quantities of hemicellulase, laccase, amylase, and pectinase; for chemical degumming, varied amounts of sodium hydroxide (NaOH) were used. The results indicate that enzyme-based degumming procedures produce better results than chemical treatments. Optimum enzyme combinations for various fiber qualities were found using the Taguchi design of experiments. These combinations included Hemicellulase 5 %, Laccase 5 %, Amylase 3 %, and Hemicellulase 5 %, Laccase 3 %, Pectinase 5 %. Without degrading the cellulose structure, these ideal enzyme combinations produced fibers with lower lignin content and higher cellulose percentages, moisture content, and tenacity values. By determining the most efficient enzyme combinations and their effects on fiber qualities, the study offers sustainable fiber processing methods for textile grade banana fiber.

Effect of harvesting time and water retting fiber processing methods on the physico-mechanical properties of kenaf fiber

Fiber processing is an important factor that affects the physical and mechanical properties of long kenaf fiber. The physical-mechanical properties, such as color, tensile strength, and moisture regain (MR), are the main characteristics that influence the processing and performance on the final products from kenaf fiber. The objective of this research was to evaluate the physical and mechanical properties of kenaf fiber at the week of planting, with different processing methods that were planted in a selected location in Malaysia. Kenaf fiber was separated by the water retting method, where the combination of water retting and mechanical retting was based on the available facilities and proficiency at the sites. The tensile strength and chemical composition of kenaf fiber showed large variability for every location collected and for each processing technique used. Visual observations and color testing indicated that kenaf fiber with extended water immersion exhibited higher lightness and smoother fiber. A slight reduction in moisture regains was observed with increased crystallinity index. The differences among properties of the kenaf fiber that were influenced by harvesting week and processing methods could give some references and overview for the planters, suppliers, industries, and researchers to identify the suitable fiber quality for their targeted final products.

Printed Soft Optical Waveguides of PLA Copolymers for Guiding Light into Tissue.

The application of optical technologies in treating pathologies and monitoring disease states requires the development of soft, minimal invasive and implantable devices to deliver light to tissues inside the body. Here, we present soft and degradable optical waveguides from poly(d,l-lactide) and derived copolymers fabricated by extrusion printing in the desired dimensions and shapes. The obtained optical waveguides propagate VIS to NIR light in air and in tissue at penetration depths of tens of centimeters. Besides, the printed waveguides have elastomeric properties at body temperature and show softness and flexibility in the range relevant for implantable devices in soft organs. Printed waveguides were able to guide light across 8 cm tissue and activate photocleavage chemical reactions in a photoresponsive hydrogel (in vitro). The simplicity and flexibility of the fiber processing method and the optical and mechanical performance of the obtained waveguides exemplify how rational study of medically approved biomaterials can lead to useful inks for printing cost-effective and flexible optical components for potential use in medical contexts.

Influence of harvesting time and maceration method of Spanish Broom (Spartium junceum L.) fibers on mechanical properties of reinforced cement mortar

This paper investigated the use of Spanish Broom fibers for cement mortar reinforcement. The characterization of the fibers separated with different separation methods was carried out through FTIR and TG/DTG analysis. The influence of harvesting time, fiber processing method, fiber length and amount of fibers on the mechanical characteristics of cement composite have been studied. Compressive and flexural strengths of cement mortar specimens were determined after 28 days and compared with reference mortar. Five specimens were also tested after 56 days and obtained results are opposed to the results on 28-day old samples. According to the results obtained Spanish Broom fibers are very strong and able to reinforce cement matrix at micro level. Fibers picked in summer will result in better mechanical properties of mortars than fibers picked in fall. Considering the maceration method, it is concluded that fiber maceration with sea water is as effective as chemical treatment with NaOH but cheaper and more environment-friendly.

Advanced Multimaterial Electronic and Optoelectronic Fibers and Textiles.

The ability to integrate complex electronic and optoelectronic functionalities within soft and thin fibers is one of today's key advanced manufacturing challenges. Multifunctional and connected fiber devices will be at the heart of the development of smart textiles and wearable devices. These devices also offer novel opportunities for surgical probes and tools, robotics and prostheses, communication systems, and portable energy harvesters. Among the various fiber-processing methods, the preform-to-fiber thermal drawing technique is a very promising process that is used to fabricate multimaterial fibers with complex architectures at micro- and nanoscale feature sizes. Recently, a series of scientific and technological breakthroughs have significantly advanced the field of multimaterial fibers, allowing a wider range of functionalities, better performance, and novel applications. Here, these breakthroughs, in the fundamental understanding of the fluid dynamics, rheology, and tailoring of materials microstructures at play in the thermal drawing process, are presented and critically discussed. The impact of these advances on the research landscape in this field and how they offer significant new opportunities for this rapidly growing scientific and technological platform are also discussed.

Effect of leaf fiber modification methods on mechanical and heat-insulating properties of leaf fiber cement-based composite materials

Using plant leaves as eco-friendly heat-insulating building materials, five poplar leaf modification methods were employed to improve the compatibility between leaf fibers and cement-based materials in composites. Mechanical properties, water absorption and heat-insulating properties of leaf fiber cement-based composite materials (LFCCM) containing unmodified and modified leaf fibers were analyzed. The results indicated that pure acrylic emulsion spray was the best fiber processing method in terms of mechanical properties of LFCCM, followed by sodium silicate solution spraying; water dipping was also recommended and the strength of LFCCM with lye fiber dipping performed the worst. The optimal fiber treatment method of improving thermal insulation properties of LFCCM was lye dipping, followed by pure acrylic polymer emulsion spraying and sodium silicate solution spraying had the worst performance. With a thermal conductivity < 0.250 W/(m.K), LFCCM is an ideal heat-insulating material. Overall, considering strength and thermal conductivity, pure acrylic polymer emulsion spraying is an optimal treatment method of leaf fibers.

Blue-Agave Fiber-Reinforced Polypropylene Composites for Automotive Applications

As consumer demand for more fuel-efficient vehicles increases, automakers are looking for innovative ways to reduce the weight of vehicles. Many automotive-grade plastics contain traditional reinforcing fillers, such as glass or talc, to improve the mechanical properties of the material. By replacing these high-density fillers with natural fibers, the material and corresponding weight can be reduced, which results in an improvement of the vehicle fuel economy. The objective of this study was to investigate the use of blue-agave bagasse fibers, which was sourced from tequila manufacturing waste, as a reinforcing agent in polypropylene composites. The effects of the fiber processing method, fiber loading level, and addition of a compatibilizer (polypropylene-grafted maleic anhydride) on the composite properties were determined. Samples were produced via twin-screw extrusion and injection molding. The resulting mechanical properties and morphology of the fracture surfaces were investigated. The fiber processing method (Agave C vs. Agave R) did not significantly affect the composite properties. Higher loading levels of fiber reduced both the elongation at break and impact strength, but increased the stiffness of the agave composites. The compatibilizer increased the fiber matrix adhesion, but reduced impact strength because the polymer matrix was softened.

Cladding Glass Development for Semiconductor Core Optical Fibers

Glass‐clad optical fibers comprising a crystalline semiconductor core have garnered considerable recent attention for their potential utility as novel waveguides for applications in nonlinear optics, sensing, power delivery, and biomedicine. To date, cladding compositions have relied on commercially‐available expedients and have not been tailored for the specific semiconductor core nor the application. In this work, more‐optimum silicate and nonoxide glass compositions are developed for unary (Si, Ge), binary (InSb, GaAs), and ternary (GaAlSb) semiconductor cores based on two main design criteria: (1) matching the thermal expansion coefficient between semiconductor core and glass cladding and (2) matching the viscosity‐temperature dependences such that the cladding glass draws into fiber at a temperature slightly above the melting point of the semiconductor. While this latter requirement is critical to the molten core fabrication method, which offers a practical approach to long fiber lengths at acceptable manufacturing speeds (&gt;m/s), these compositions are more broadly applicable to other semiconductor fiber processing methods. Preliminary experimental results on silicon core optical fiber are provided and show a marked diminution in oxygen content relative to analogous fibers drawn using a pure silica cladding.

Dry matter and fiber yields, and the fiber characteristics of five nettle clones ( Urtica dioica L.) organically grown in Austria for potential textile use

The aim of the field trial was to quantifiy yield, fibre content and fibre quality of 5 fibre nettle clones cultivated according to the principles of organic farming. The field trial started in 1997 and was organized in a randomised block design with 4 replications per clone. The field trial was situated in Neulengbach, Lower Austria. Since fibre nettle does not provide sufficient yields in the first cultivation year, the harvest of the second and third cultivation year (1998 respectively 1999) was used for calculation of yield per hectar and for the analysis of fibre content and quality. The dry matter yield (stalks) of the 5 nettle clones in the second cultivation year (1998) lies between 2,3 – 4,7 t/ha. Clone 1 and Clone 7 achieve the highest yields. This result was statistically significant. The dry matter yields of that year correspond with the dry matter yield achieved under extensive cultivation conditions (without nitrogen fertilizer) as described by SCHMIDKE ET AL. (1998). The dry matter yields of the third cultivation year (5,6 – 9,7 t/ha), however, are more than twice as high as those of the second cultivation year. They are also higher than the yields from the nitrogen intensive cultivation system described by VETTER ET AL. (1996) with 200 kg N/ha + 100 kg N/ha after the first cutting (per year; the fertilizer used was calcium ammonium nitrate). This large increase in yield in the third cultivation year is caused by an increase in the height (20 – 40 cm higher) and by the production of runners: the number of stalks per plot more than doubled in the third cultivation year. Additionally the undersowing of clover (Trifolium repens) seems to have had a positive effect on the growing of fibre nettle. The fibre yields lie between 335 – 411 kg/ha in the second cultivation year and between 743 – 1.016 kg/ha in the third cultivation year. Clones with a high dry matter yield have a low fibre content and vice versa. Therefore the differences between the clones in dry matter yield/ha and fibre content are balanced and there is no more difference between the fibre yield/ha of the clones. The fibre content after chemical processing lies in both the second and the third cultivation year between 8 – 16 % drymatter (stalks). This result confirms the maximum fibre contents reported in recent literature (DREYER ET AL. 1996, DREYER & DREYLING 1997, SCHMIDTKE ET AL. 1998, KOHLER ET AL. 1999, FRANCKEN-WELZ ET AL. 1999). Clone 8 and Clone 9 have the highest fibre content in 1998 (16,0 respectively 14,5 %), and Clone 8 (15,7 %) in 1999. There is no significant difference between the fibre quality (fibre strength, elongation, fibre fineness, lenght of fibre) of the five nettle clones. In general the fibre material is very inhomogeneous, which is caused by the differing consistence of the upper and the lower part of the stalk and by fibre processing methods. In principle, nettle fibres are suitable for textile use, however, the further developement of an economic and functional method for processing along with high yields is essential. The results show that higher yields and fibre contents were achieved in the third cultivation year under the described cultivation conditions of organic farming than other authors (BREDEMANN 1959, VETTER ET AL. 1996, DREYER ET AL. 1996, SCHMIDTKE ET AL 1998, FRANCKEN-WELZ ET AL. 1999). The yields of the third cultivation year are higher than the minimum for economic cultivation as defined by DREYER & DREYLING (1997). The cultivation of fibre nettle under the conditions of organic farming in Austria is therefore possible, as long as fibre processing plants and consumer demand exists. There is a need for further research in optimizing cultivation methods in organic farming (undersowing of leguminosae, manuring with slurry, row width, crop rotation) as well as in optimizing fibre processing methods for the quality of raw materials available and taking into account further processing into textiles (e.g. production of a pure yarn or a mixed yarn with cotton). There is also a need for research into possibilities to use fibres from different parts of the nettle plant for different purposes (e.g. textile and industrial uses).

Fabrication of lead zirconate titanate ceramic fibers by gelation of sodium alginate

A novel ceramic fiber processing method by gelation of Na-alginate, a natural innoxious polymer, is reported. The ion exchange reaction between Na and Ca, and associated gelation process is utilized to fabricate lead zirconate titanate piezoelectric ceramic fibers using a Na-alginate based ceramic suspension. Effects of solid loading, viscosity of the starting sodium alginate and its amount in the slurry, and the chelator content were investigated as main parameters in obtaining uniform, dense fibers. Slurries with 64 wt% solid loading containing 1.0–1.5 wt% low or 0.5 wt% medium viscosity Na-alginate and 0.25–1.0 wt% chelator resulted in dense fibers with uniform shapes and dimensions. Electrical measurements taken from pellets prepared from reprocessed slurry and fibers indicate a decrease in the properties with increasing Na-alginate content of the slurry. However, the dielectric constant and piezoelectric charge coefficient values prove that this is a viable process to produce piezoelectric ceramic fibers.

Development of a glass optical fiber containing ZnO–Al 2O 3–SiO 2 glass-ceramics doped with Co 2+ and its optical absorption characteristics

A new type of glass fibers with optical characteristics unattainable by the conventional fiber processing method is presented. Silica glass fibers containing ZnO–Al 2O 3–SiO 2 (ZAS) glass-ceramics particles doped with Co 2+ in the core region of the optical fiber were developed using a silica slurry method. The ZAS glass-ceramics particles were found to be preserved in the core of the fiber even after the modified chemical vapor deposition (MCVD) process and the fiber-drawing process at high temperatures. The observed absorption bands at IR regions were due to the tetrahedral Co 2+ in the ZnAl 2O 4 crystals of the ZAS glass-ceramics in the core of the fiber.

Screening and genetic improvement of pectinolytic fungi for degumming of textile fibers

Aiming at contributing to technological improvements in plant fiber processing methods, this paper reports research work on the obtainment of more efficient pectinase-producing fungi strains. More specifically, this work reports the analysis of 18 strains of filamentous fungi, with the purpose of obtaining enzymes for textile fibers degumming. The strains were evaluated for production of pectinolytic enzymes under several growth conditions (culture medium and growth temperature). Production of pectinases was measured by an enzymatic index (EI) in solid pectin medium. Among the tested strains, Penicillium chrysogenum IFO 4626 (Q 176) showed the best performance. Genetic improvement of this strain was carried out to increase its pectinase production, while keeping cellulase activity down to a negligible level, since cellulases are known to decrease the resistance of the fiber. Variability was induced through several cycles of mutation and selection by exposing conidea to ultra-violet light (UV). We selected 39 out of 390 isolated colonies. Resulting mutants produced nine times more pectin lyase (PL) than the original strain in terms of PL specific activity, and five times more in terms of PL activity (i.e. mmoles liberated per minute of reaction per mL of medium). Periodically, mutant performance was evaluated in solid pectin medium. Genetic stability was maintained for four years after isolation.

Creep limitations of current polycrystalline ceramic fibers

The objective of this paper is to present an overview of the issues, property status, and potential for use of creep-prone polycrystalline ceramic fibers in thermostructural ceramic composites. Issues arise because the fine-grained microstructures of high-strength fibers can result in creep-related property changes, often at temperatures as low as 800°C. The underlying mechanism is grain boundary sliding controlled by grain size and grain boundary character, and thus by the fiber processing method. With the assumption of upper and lower limit creep requirements, the creep properties of a variety of current SiC and Al 2O 3 polycrystalline fibers are reviewed and discussed. Property evaluation is based on the results of a simple bend stress relaxation test which allows predictive creep equations to be developed for each fiber type describing the effects of time, temperature, and applied stress. It is shown that sintered SiC fibers with grain sizes below 1000 nm appear to offer the best performance in terms of strength and creep resistance. However, even these fibers may not be capable of long-term service above 1400°C.