Textiles physical degradation

Physical Properties. Relationships between fiber properties and their textile usefulness are in many cases quite obvious. Since fibers are frequently subjected to elevated temperatures, it is necessary that they have high melting or degradation points. It is also necessary that other fiber properties be relatively constant as a function of temperature over a useful temperature range. 

Com and rice starches have been oxidized and subsequently cyanoethylated (97). As molecular size decreases due to degradation during oxidation, the degree of cyanoethylation increases. The derivatized starch shows pseudoplastic flow in water dispersion at higher levels of cyanoethylation the flow is thixotropic. Com and rice starches have been oxidized and subsequently carboxymethylated (98). Such derivatives are superior in the production of textile sizes. Potato starch has been oxidized with neutral aqueous bromine and fully chemically (99) and physically (100) characterized. Amylose is more sensitive to bromine oxidation than amylopectin and oxidation causes a decrease in both gelatinization temperature range and gelatinization enthalpy. 

In any case the wastewater will finally be fed into rivers, lakes, or the sea thus some wastewater treatments have to be performed before the textile effluents are released either to the communal wastewater treatment plant (CWWT) or into the rivers, lakes, and so on. Normally physical and (bio-) chemical treatments (e.g., adjustment of pH, temperature, sedimentation, flocculation) are performed in the textile plant, while the following biological treatment (aerobic, anaerobic degradation) is performed either in the textile plant or in a CWWT. The site of the biological treatment is dependent on the location of the textile plant however, a biological treatment of textile effluents preceding release into surface water is state of the art. 

All kinds of building materials, furniture, textiles, computers etc. are potential sources of SVOCs/POMs and estimation of the total content in the material may be required. One reason to estimate the total or initial content is that it is an important parameter in physical based emission models for example, for phthalate emission from vinyl flooring (Clausen et al, 2007). The materials can be purchased as new, or sampled from the indoor environment under investigation. The materials should be stored in a way that preserves their content of SVOCs/POMs and prevents contamination and degradation of the materials and their content of SVOCs/POMs. The content of SVOCs/POMs in the sampled materials can be estimated by extraction (see Section 2.5.1). 

The development of methods and tests for preserving natural textile fibers is surveyed. The effect of the environment in which the textiles are stored or exposed, chemical, physical, and biological agents responsible for their degradation, and test methods for evaluating their performance and extent of damage are discussed. Emphasis is on cotton, wool, and silk, with selected references on other cellulosic fibers such as jute and linen. 

The mechanical, physical, and chemical properties of degraded ancient cotton textiles were partially characterized in Part I (1). An... 

The paper and textile industries have been concerned about the aging, deterioration, and degradation of cellulosic materials at elevated temperatures for practical reasons, such as the performance of tire yarn and electrical insulation paper, and the problems involved in drying or processing the cellulosic materials in general. However, due to the practical nature of these problems, the reactions involved have often been measured in terms of loss of strength and other physical properties. 

The natural degradation of wooden shipwrecks in-situ can be slowed down, or even eliminated, by covering the site with a physical barrier such as polyethylene or polypropylene textile (Figure 15). This method is very effective because it uses the wrecked environment to create an overlying mound of sediment, which becomes part of the site. It also physically prevents colonisation of any subsequently exposed wreck timbers by wood-boring animals, like shipworm. 

Handbook of Polymer Testing provides in one volume that comprehensive coverage of physical test methods for polymers. The properties considered cover the whole range of physical parameters, including mechanical, optical, electrical, and thermal as well as resistance to degradation, nondestructive testing, and tests for processability. All the main polymer classes are included rubbers, plastics, foams, textiles, coated fabrics, and composites. For each property, the fundamental principles and approaches arc discussed and particular requirements and the relevant international and national standards for the different polymer classes considered, together with the most-up-to-date techniques. 

Zinc oxide is commercially the most important compound of zinc and it is used to a considerable extent in the rubber, ceramic and paint industries. It is utilized to activate the organic accelerator of the vulcanization process for natural rubber and for most synthetic rubbers. Also zinc oxide serves as the accelerator for some types of elastomers. Further, it provides reinforcement to the rubber, it improves its heat conduetivity, it limits the degradation by UV radiation and it improves adherence. Typically, rubber eontains 2 % zinc oxide. A very broad range of other compounds are of extensive interest in chemistry, biology and physics and they make great practical contributions to the chemical, ceramic, fertilizer, paint, plastics, textile and electronics industries. 

Once heat is absorbed by a textile fibre, it may promote physical or chemical change or both. All organic fibre-forming polymers will eventually thermally degrade at or above a threshold temperature often defined as the pyrolysis temperature, T, sometimes influenced by the presence of oxygen in the air. Typical values of T are listed in Table 8.1 for the more common and selected high performance fibres. Once heated... 

We now discuss briefly the special criteria that the implant material and structure must meet in order for it to be accepted in vivo, and highlight some of the performance requirements for implants and the physical principles that can be employed to achieve them. A very basic general criterion for textiles used in the construction of implants is that all fibers are produced from the highest quality polymers that have narrow distribution of molecular weights and that no carcinogenic or toxic materials can be produced or released from them. If a material degrades, whether or not it is an intended phenomenon, the byproducts are not toxic or harmful and can be removed by the body s normal physiological process. 

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