Stabilisation of Natural Colourants and Lignocellulosic Textiles

<p>The lignocellulosic fibres extracted from the leaves of New Zealand flax, Phormium tenax, have been used as the principal textile fibre by Maori since pre- European times. Variations of antifungal activity were observed in Phormium fibres of different cultivars. The most resistant cultivars of P. tenax in an aqueous antifungal assay also possessed the greatest variety of naturally-occurring 7-hydroxycoumarins as identified by mass spectroscopy, ESI-MS. In addition to antifungal effects, coumarins function as fluorescent whitening agents in Phormium fibres and play a role in the fibre’s photodegradation. Ultraviolet irradiation (350 – 400 nm) of the fibre resulted in a substantial loss of the blue fluorescence originating from a number of 7-hydroxycoumarins present, together with the formation of new fluorophores absorbing and emitting at longer wavelengths, which contribute to the photoyellowing of the fibre. The photolysis of two standard 7-hydroxycoumarins in aqueous solution was examined and two primary photoproducts were elucidated by ESI-MS: a photodimer containing a linking cyclobutane ring and a monomeric photooxidation product. The formation of at least some of the photoproducts is associated with the coumarin-sensitised generation of reactive oxygen species, hydrogen peroxide and superoxide. The fluorescence properties and photodegradation of Chinese handmade papers were also investigated. Papers manufactured by traditional methods were found to be more photostable than that produced from chemically-facilitated techniques.</p>

Stabilisation of Natural Colourants and Lignocellulosic Textiles

<p>The lignocellulosic fibres extracted from the leaves of New Zealand flax, Phormium tenax, have been used as the principal textile fibre by Maori since pre- European times. Variations of antifungal activity were observed in Phormium fibres of different cultivars. The most resistant cultivars of P. tenax in an aqueous antifungal assay also possessed the greatest variety of naturally-occurring 7-hydroxycoumarins as identified by mass spectroscopy, ESI-MS. In addition to antifungal effects, coumarins function as fluorescent whitening agents in Phormium fibres and play a role in the fibre’s photodegradation. Ultraviolet irradiation (350 – 400 nm) of the fibre resulted in a substantial loss of the blue fluorescence originating from a number of 7-hydroxycoumarins present, together with the formation of new fluorophores absorbing and emitting at longer wavelengths, which contribute to the photoyellowing of the fibre. The photolysis of two standard 7-hydroxycoumarins in aqueous solution was examined and two primary photoproducts were elucidated by ESI-MS: a photodimer containing a linking cyclobutane ring and a monomeric photooxidation product. The formation of at least some of the photoproducts is associated with the coumarin-sensitised generation of reactive oxygen species, hydrogen peroxide and superoxide. The fluorescence properties and photodegradation of Chinese handmade papers were also investigated. Papers manufactured by traditional methods were found to be more photostable than that produced from chemically-facilitated techniques.</p>

Review of Natural Fibre Reinforced Polymer Composite and Textile Fibre Composite for Sustainable Construction

In today's world, natural fibre reinforced polymer composites (NFRPC) are becoming increasingly popular because to their eco-friendliness, lightweight superiority in life cycles, biodegradability, low cost and good mechanical quality. In a number of engineering applications NFRPCs are widely used and research in that field is progressing quickly. Due to natural fibres, researchers face various challenges during NFPRC construction and deployment (NFs). Among the challenges are fibre quality, thermal stability, water absorption and incompatibility with polymer matrices. Steel strengthening is continuously required to fulfil the tensile strength and ductility requirements of concrete buildings, because the most often used building medium on the globe is concrete. Furthermore, corrosion of steel reinforcement is one of the most severe issues facing civil engineers today; hence promoting sustainable concrete as well as structures to reduce their negative influence on the environment is vital. The development of new environmental materials to replace the bars of steel as a reinforcement of the concrete structure is a key step towards assuring the long-term durability of the cement and construction. According to this evaluation document, strengthened concrete constructions create a wide range of environmental concerns including significant CO2 and other greenhouse gas emissions. Keywords: Environmentally friendly materials, Natural fibre reinforced polymer composite, textile fibre composite, Sustainability, composite materials

Flexural Performance of Small-Scale Textile-Reinforced Concrete Beams

Textile-reinforced concrete (TRC) as a novel high-performance composite material can be used as a strengthening material and component bearing load alone. The flexural performance of TRC beams strengthened with textile reinforcement such as carbon tows was experimentally examined and associated with those of steel-reinforced concrete (SRC) beams. Through four-point bending tests, this research explores the effects of textile layers and dosages of short textile fibre on the flexural strength of concrete beams. A total of 64 prism samples of size 100 mm × 100 mm × 500 mm were made, flexure-strengthened, and tested to evaluate various characteristics and the efficiency of TRC versus SRC beams. TRC beams performed exceptionally well as supporting material in enhancing concrete’s flexural capacity; in addition, TRC’s average ultimate load effectiveness was up to 56% than that of SRC specimens. Furthermore, the maximum deflection was about 37% lesser than SRC beams. The results showed that by increasing the number of layers, the TRC’s effectiveness was significantly increased, and the failure mode became more ductile.

Single Fibre Swelling Behavior for Natural and Man-Made Cellulose Fibres Under Industrial Steeping Conditions

Swelling behavior of cotton, dissolving wood pulp (DWP), viscose staple fibre (VsF), and Tencel staple fibre (TsF) in varying sodium hydroxide (NaOH) were investigated by means of optical microscopy and were characterized by molecular mass distribution, X-ray diffractometer, and dynamic vapor sorption. Effect of temperature (20-45 °C) and duration (0-120 min) was studied. The results reveal that the swelling ratio of fibre in alkali solution depends on fibre accessibility and NaOH concentration. Among all the materials, VsF exhibited the highest swelling ratio and lowest swelling ratio has been observed for cotton fibre. The results suggest that the swelling is limited by the presence of plant cell wall structures in cotton and DWP, rather from fringed-fibrillar, semi-crystalline sub-structures, which result from the inherent tendency of cellulose molecules to form such structures during the biosynthesis of plant cell walls as well as during the formation of regenerated cellulosic textile fibre in wet-spinning.

Modelling the Effect of Resin-Finishing Process Variables on the Dimensional Stability and Bursting Strength of Viscose Plain Knitted Fabric Using a Fuzzy Expert System

The application of cross-linking resin is an effective method for improving and controlling dimensional sta¬bility, such as the shrinkage of viscose single jersey knits. However, such treatment often leads to a significant deterioration in the bursting strength of treated fabrics. In this regard, resin treatment using a softening agent can be an additional potential solution for retaining the bursting strength of treated fabrics. Resin treatment is one kind of chemical finishing process that inhibits cellulosic textile fibre swelling during wetting, provides fibre resistance to deformation and prevents shrinkage. The key objective of this study was to model the effect of resin-finishing process variables for predicting the shrinkage control and bursting strength of viscose single jersey knitted fabrics. The MATLAB (Version 8.2.0.701) fuzzy expert system was used to model the optimum resin and softener concentrations, as well as the best curing time for the prediction of maximum shrinkage control with a minimum loss in fabric bursting strength. The optimal process variables were found to be a resin concentration of 75 g/l, a softener concentration of 45 g/l and a curing time of 225 seconds. The fuzzy expert model developed in this study was validated using experimental data. It was found that the model has the ability and accuracy to predict fabric shrinkage and bursting strength effectively in the non-linear field.

Using fuzzy logic to select coloured-fibre cotton genotypes based on adaptability and yield stability

Cotton (Gossypium hirsutum L.) is the world’s leading natural textile fibre and is grown in over 60 countries, including Brazil, where it is an important agricultural commodity. The cultivation area currently covers approximately one million hectares in Brazil and has expanded into every region of the country, especially the Cerrado biome. Because of this expansion, it is necessary to analyse the influence of the environment on the genotype behaviour to optimize yields. Thus, the objective of this study was to compare fuzzy logic to traditional methods for selecting coloured-fibre cotton genotypes with high adaptability and yield stability. The experiment was conducted on the 2013/2014, 2014/2015, 2015/2016, and 2016/2017 crops of the Capim Branco farm at the Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil. The following methods were used to select genotypes for adaptability and stability: the Lin and Binns model, additive main effects and multiplicative interaction (AMMI) analysis and the Sugeno fuzzy logic controller. An interaction of the genotype with the environment that affected yield was detected. Environment 4 (the 2016/2017 crop) showed to the lowest genotype to environment interaction. The fuzzy logic approach showed agreement with AMMI and the nonparametric Lin and Binns method. The linguistic fuzzy logic used in the Sugeno fuzzy logic controller demonstrated the potential for selecting cotton genotypes in plant breeding programmes. The UFUJP-16 and UFUPJ-17 genotypes were adaptable, stable and showed promising yields within the tested environments. The fuzzy logic method was effective for estimating adaptability and stability.