Manufacture Of Synthetic Fibres Research Articles

Flexural behaviour of geopolymer concrete beams with hybrid natural–synthetic fibre reinforcement

The requirement of excellent flexural stiffness in construction elements has initiated the use of fibre reinforcement. However, the processing complexity involved in the manufacture of synthetic fibres is environmentally hazardous. The use of natural fibres in geopolymer concrete (GPC) structures was investigated in this work using a hybridisation of natural and synthetic fibre. Natural basalt fibre (BF) was used with synthetic steel fibre (SF) in various proportions in GPC and tests were conducted to evaluate the workability, compressive strength, split tensile strength and flexural strength. It was found that, compared with the plain GPC, the addition of 1.5% BF and 0.5% SF resulted in 45%, 27% and 12% improvements in compressive, split tensile and flexural strengths, respectively. The compatibility between the SF and BF resulted in enhanced post-peak flexural behaviour, with 37% improvements in the modulus of elasticity and stiffness. As BF possesses more tensile strength than SF, the use of 1.5% BF and 0.5% SF provided better flexural and ductility properties than the use of SF alone, which could lead to the development of ductile GPC members under dynamic loading conditions.

Bridging Disciplines: Applications of Forensic Science and Industrial Hemp.

Forensic laboratories are required to have analytical tools to confidently differentiate illegal substances such as marijuana from legal products (i.e., industrial hemp). The Achilles heel of industrial hemp is its association with marijuana. Industrial hemp from the Cannabis sativa L. plant is reported to be one of the strongest natural multipurpose fibers on earth. The Cannabis plant is a vigorous annual crop broadly separated into two classes: industrial hemp and marijuana. Up until the eighteenth century, hemp was one of the major fibers in the United States. The decline of its cultivation and applications is largely due to burgeoning manufacture of synthetic fibers. Traditional composite materials such as concrete, fiberglass insulation, and lumber are environmentally unfavorable. Industrial hemp exhibits environmental sustainability, low maintenance, and high local and national economic impacts. The 2018 Farm Bill made way for the legalization of hemp by categorizing it as an ordinary agricultural commodity. Unlike marijuana, hemp contains less than 0.3% of the cannabinoid, Δ9-tetrahydrocannabinol, the psychoactive compound which gives users psychotropic effects and confers illegality in some locations. On the other hand, industrial hemp contains cannabidiol found in the resinous flower of Cannabis and is purported to have multiple advantageous uses. There is a paucity of investigations of the identity, microbial diversity, and biochemical characterizations of industrial hemp. This review provides background on important topics regarding hemp and the quantification of total tetrahydrocannabinol in hemp products. It will also serve as an overview of emergent microbiological studies regarding hemp inflorescences. Further, we examine challenges in using forensic analytical methodologies tasked to distinguish legal fiber-type material from illegal drug-types.

High fire-safety phosphorus-containing polyethylene terephthalate with well-balanced comprehensive performances by reactive blending with liquid crystalline copolyester

With increased public awareness of fire-safety, flame retardant materials have been widely used and developed. Among them, a polyester called CPET, synthesized by the copolymerization of polyethylene terephthalate and 2-carboxyethyl (phenyl) phosphinic acid, has a good fire-safety and has been employed in the manufacture of synthetic fibers. However, the fabricated fiber made of CPET simultaneously possessing good flame retardancy and mechanical properties is a dilemma. Herein, we resolve this problem through the reactive blending of CPET with a type of thermotropic liquid crystal copolyester (PPDT) and subsequently solid-state polymerization (SSP). Thus, the fire-safety of the CPET/PPDTSSP blend improves greatly. The peak heat release rate, total heat release, and total smoke release decrease by 31.2%, 16.3%, and 11.0%, respectively, compared with those of CPET. Meanwhile, the CPET/PPDTSSP shows better crystallization and mechanical properties than CPET. The strength at yield and Young’s modulus of CPET/PPDTSSP increase by 20.0% and 15.8%, respectively. This blend shows great potential in the fabrication of fire-safety fibers with high strength.

Long-term performance and metagenomic analysis of full-scale anaerobic granular sludge bioreactors for low aerobically-biodegradable synthetic fiber manufacturing wastewater treatment

The synthetic fiber manufacturing wastewater (FMW) contained large amounts of tetrahydrofuran (THF), 3-buten-1-ol (BDO) and 1,4-butanediol (BTO) and showed a high chemical oxygen demand (COD) of 7,992 ± 2,252 mg L−1. Ratio of the biological oxygen demand (BOD5) and COD of the FMW stream was analyzed as only 0.094, which reflected the low aerobically biodegradable property. For complementing existed aerobic biological treatment process, an external circulation sludge bed (ECSB) system consisting of two full-scale anaerobic granular sludge (AnGS) bioreactors was constructed and continuous operation for more than 25 months. Even though feed fluctuations occurred, robust performance of the system was exhibited with consistent high removals of COD (85.5 ± 4.4%), THF (79.8 ± 8.6%), BDO and BTO (both 100%). Fractionation analyses of AnGS at nine heights of the two bioreactors showed that the bigger size (>0.5 mm) dominated at the bottom (>92.1%). Morphology and elemental analyses of AnGS were helpful to see surface depositions in line with water analyses. Anaerobic biodegradations were also highlighted in a comprehensive analysis of carbon and nitrogen fractions, phosphates, sulfates and other minerals. Moreover, metagenomic analyses revealed Methanomicrobia and Methanosaeta in archaea and Exilispira in bacteria were the dominant genera in microbial community structure, which given more insights of anaerobic biodegradation in the two full-scale bioreactors.

Relationship Between Gamma-glutamyl Transpeptidase Activity and Inflammatory Response in Lichen Planus

Chemicals used in the manufacture of synthetic fibers have been associated with undesirable side effects such as itching or skin lesions and it seems that they are involved in the induction of pathological processes such as oxidative stress and inflammation. Lichen planus (LP) can be regarded as an inflammatory disorder, chemical and physical factors playing an important role in the perpetuation of the inflammatory process. Gamma-glutamyl transpeptidase (GGT) plays an important role in the preservation of skin architecture and modulation of skin inflammation. In this study, we found that GGT activity is increased in LP patients with mild inflammation, whilst GGT is inactivated under conditions of severe inflammation. Therefore, GGT is involved in the inflammatory process, but there is no a positive correlation between its activity and the intensity of the inflammatory response. This functional adaptation of the enzyme may be due to down-regulation of its synthesis under free radical overload conditions. Understanding the molecular mechanisms involved in the modulation of intracellular redox homeostasis is an important step in the pharmacological management of patients with LP.

Phytoscreening-based assessment of mercury in soil.

This study was conducted to determine whether phytoscreening techniques could be used to characterize the distribution of Hg in soil at the South River, VA. An estimated 500 to 1000 kg of Hg was released to the South River in the 1930s and 1940s from a synthetic fiber manufacturing plant located in Waynesboro, contaminating the floodplain downstream. Under background conditions (soil Hg <0.03 μg/g), phytoscreening sample Hg concentrations ranged from 1.9 to 3.9 ng/g. With soil Hg concentrations ranging from 0.1 to 94 μg/g in the top 30.5 cm of nearby soil, phytoscreening sample Hg concentrations ranged from 5.0 to 145 ng/g. The variability of Hg concentrations in soil solution over the scale of the entire rhizosphere of the large trees sampled was likely high. Furthermore, the mean depth of water uptake and the exact proximity of the soil profile samples for each tree could not be determined. Nevertheless, the phytoscreening results of this study could be used to reliably provide a qualitative delineation of Hg-contaminated soil.

Development and characterization of thin polymer films relevant to fiber processing

Dilute solutions of cellulose, polypropylene, polyethylene, nylon and polyester were spun cast onto gold and silica wafers to generate thin films of these polymers, which are commonly used in the manufacture of synthetic fibers. The thin films were used as substrates in the quartz crystal microbalance and nano-indentation techniques to monitor adsorption and friction behaviors after treatment with a polymer solution (as a mimic of a textile finish). The spin coating conditions were optimized in terms of the resulting film morphology, thickness and surface energy. Atomic force microscopy, X-ray photoelectron spectrometry, ellipsometry and contact angle were used to probe the physical and surface properties of the resulting films. Overall, we developed thin films that are helpful to inquire, at the molecular level, phenomena relevant to fiber and textile processing including swelling, degradation, and adsorption of polymers and surfactants.

Kinetics studies on copolymerization of acrylonitrile vinyl acids by solvent–water suspension polymerization

AbstractPolyacrylonitrile is an important polymer that is widely used in the manufacture of synthetic fibers, particularly for applications in apparel. Although a vast amount of literature is available on the polymerization process of acrylonitrile (AN) with other monomers, there are few reports of studies on polymerization in a mixed solvent of water with an organic solvent. It is conceivable that this method could combine the advantages of the solution and suspension polymerization methods. Synthesis of AN copolymers with two vinyl acids, methacrylic acid (MAA) and itaconic acid (IA), is carried out by solvent–water suspension polymerization. The polymerizations are performed with an equal ratio mixture of dimethylformamide as a solvent and water as a nonsolvent at 60°C using α,α‐azobisisobutyronitrile as an initiator. The kinetics of polymerization are studied by plotting the conversion versus reaction time for different mole ratios of AN with vinyl acids. Copolymers are characterized by FTIR and capillary viscometery. The results show that IA depresses the rate of polymerization more than MAA in this reaction medium, and this effect becomes more significant at higher vinyl acid mole ratios. High conversion in a short reaction time is obtainable for copolymers with a low vinyl acid mole fraction. However, for mole ratios of more than 93:7, the rate of the reaction is drastically reduced and low conversion (&lt;60%) results, even after 8 h. The intrinsic viscosities of all cases are surprisingly high. Although they are reduced with increasing acidic comonomer mole fraction, this reduction is more significant for IA compared to MAA. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1284–1291, 2005

Kontaktallergie auf chirurgisches Nahtmaterial

A 48-year-old former hairdresser developed eczematous lesions after contact with the suture material consisting of a polyamide 6 thread (Perlon®). In the past she had undergone approximately 40 surgical operations in order to remove multiple nevus cell nevi and two melanoma. Epicutaneous tests with the blue dye and the precursor of the polyamide thread gave a 3+-plus reaction to acid blue 158 and a 2+-response to e-caprolactam. Further results were obtained with such common hairdresser's sensitizers like ammonium persulfate and p-toluene diamine. It is likely that the pre-existing p-toluene diamine allergy prepared the way for acquiring hypersensitivity to the azo dye acid blue 158. e-Caprolactam is used in the manufacture of synthetic fibres of the polyamide type. Sterile non-absorbable sutures may contain tiny amounts of intermediate products among which the monomer e-caprolactam plays a major role. Although a rare sensitizer specific hypersensitivty to e-caprolactam may be acquired after prolonged and extensive contact. In the early epoch of poyamid 6-production high rates of irritant and allergic contact dermatitis have been observed. In the subsequent operations which became necessary an uncolored resorbable polylglactine thread has been used (Vicryl®).

An historical cohort mortality study of synthetic fiber workers potentially exposed to glycerol polyglycidyl ether.

We report an update of the mortality experience of a cohort of 8878 employees who worked between November 1, 1965, and December 31, 1988, at a synthetic fiber manufacturing facility with potential exposure to glycerol polyglycidyl ether (T55) and were followed through December 31, 1998. The mortality experience of the race/gender groups within the cohort was strikingly similar, with both the all causes of death and all cancer causes of death below unity on both national and local standards. For white men, there were no statistically significant increases for any cause of death, with the exception of benign neoplasms. Thirty-four percent of the cohort had worked at the plant for less than 1 year. Standardized mortality ratios were compiled for those with less than 1 year of employment and for those with 1 year or more of employment. Exclusion of those cohort members who worked less than 1 year had little impact on the standardized mortality ratios.

Biotechnological production of itaconic acid.

Itaconic acid (IA) is an unsaturated dicarbonic organic acid. It can easily be incorporated into polymers and may serve as a substitute for petrochemical-based acrylic or methacrylic acid. It is used at 1-5% as a co-monomer in resins and also in the manufacture of synthetic fibres, in coatings, adhesives, thickeners and binders. The favoured production process is fermentation of carbohydrates by fungi, with a current market volume of about 15,000 t/a. Due to the high price of about US$ 4/kg, the use of IA is restricted. At present, the production rates do not exceed 1 g l(-1) h(-1), accompanied by product concentrations of about 80 g l(-1). New biotechnology approaches, such as immobilisation techniques, screening programmes and genetic engineering, could lead to higher productivity. Also, the use of alternative substrates may reduce costs and thus open the market for new and increased applications.

Industrial Pretreatment: Trickling Filter Performance and Design

An 11-month trickling filter pilot study was conducted at a synthetic fiber manufacturing facility. COD removals increased linearly as organic loading increased from 2.53 to 4.90 kg TCOD/m³/d (158–306 lb TCOD/1000 ft³/d) and then reached a constant maximum from 4.90–5.78 kg TCOD/m³/d (306–361 lb TCOD/1000 ft³/d). Hydraulic loadings did not significantly affect removals over a broad range of 27.1–70.6 m³/m²/d (666–1733 gpd/ft²). Four design models were evaluated for their ability to model the data. Two models, (including the Modified Velz equation), incorporated hydraulic loading as the major independent variable, while the other two equations were based on organic loading. The design equations based on organic loading modeled the data much more accurately. For the two organic loading models evaluated, a Monod-like, psuedo-mixed order model gave slightly superior results to the first order model. In addition, significant stabilization of influent total suspended solids (TSS) was observed. The implications for industrial pretreatment design of trickling filters, as opposed to traditional methodologies developed largely from municipal treatment data, are discussed.

繊維機械の進展 （その１） 巻取機を中心とした合成繊維製造設備技術の変遷

繊維機械の進展 （その１） 巻取機を中心とした合成繊維製造設備技術の変遷

Qed and the men who made it: Dyson, Feynmann, Schwinger and Tomonaga

Poly(lactic acid) (PLA) is a compostable bioplastic manufactured by the polymerization of lactic acid monomers derived from the fermentation of starch as a feedstock. Since its first commercialisation in the late 1990's, PLA production has grown annually and currently it estimated that worldwide production will reach at least 800,000 tons by 2020 with Japan and the USA the two major producers. PLA is used as a replacement to conventional petrochemical based plastics, principally as food packaging containers and films and more recently, in electronics and in the manufacture of synthetic fibres. Consequently, there has been a marked increase in PLA contamination in the environment as well as increasing amounts being diverted to commercial composting facilities. This review focuses on the development, production, stability and degradation of PLA in a range of differing environments and explores our current knowledge of the environmental and biological factors involved in PLA degradation.

Quantitative monitoring of polyethylene glycol in aqueous dimethyl acetamide mixtures in the manufacture of synthetic fibres

-- A photometric procedure has been developed for the quantitative determination of the PEG (5000) content in precipitation bath solutions and technological solutions in the manufacture of synthetic fibres.

Systems for automating technological processes of synthetic fibre and yarn preparation

-- Some basic special features in devising a “panel-free” technology in the manufacture of synthetic fibres and yarns have been examined. -- Some advantages of an approach based on parallel designing of the technological process and the control system over the traditional approach have been shown. -- The new methodical approach has found application in developing automation systems at a number of synthetic fibre and yarn manufacturing plants.

Synthetic fibre technology and company strategy

The authors' aim is to examine the socioeconomic setting in which the modern technologies of synthetic fibre manufacture emerged. Their specially developed methodology consists in analysing the emergence at three hierarchical levels of analysis — at the ‘macro’ level, tracing the dominant line of development, the so‐called technological trajectory; at the ‘meso’ level, characterizing the industry environment (the main focus of the paper); and at the ‘micro’ level within which each company's development strategy is formulated and implemented.The paper contains a brief history of the development of the technology of synthetic fibre production. The long‐term macro trajectory, pursued by the participant firms in significantly different ways, was towards making a polyamide polymer by solution condensation and spinning it into fibres by existing technology, the aim of each firm being to produce its own high performance fibre selling into a premium market. The paper describes how a number of leading firms chose their particular routes to a marketable product. The motivations varied considerably depending, for example, on legal and patent factors, previous technological choices made by the firm, the need to defend an existing core business, and identification of an empty market niche.In spite of the general similarity of the outcomes of the technological development the authors hold that the industry is still far from standardization, a situation they explain in terms of a model of standardization put forward by Reddy and colleagues.

Basic principles in developing waste-free technology for regeneration of components from spent solutions in synthetic fibre manufacture

A methodological approach is given to the development of a technological process for regenerating the components from spent technological solutions. As the object we have examined a very complex system containing an aprotic amide solvent, a monohydric alcohol, water, and a salt component — a chloride of an alkali metal or alkaline earth metal.

Low-waste technology and protection of the environment in synthetic fibre manufacture

Problems in development and quantitative evaluation of low-waste synthetic fibre technology have been examined. Examples have been given of improvement in existing technological processes and development of new ones to ensure economies in material and energy resources; and contemporary schemes for neutralizing discharges into air and water have been described.

Synthetic fibre manufacture in some developing nations

Synthetic fibre manufacture in some developing nations