Fibres natural polymers

This cost will depend on the nature of the product. For liquids collected at the site in the customer s own tankers the cost to the product would be small whereas the cost of packaging and transporting synthetic fibres or polymers to a central distribution warehouse would add significantly to the product cost. 

We know that cellulose (chief component of the cell walls of a plant), proteins essential constituents of living cells, rubber, leather and natural fibres like silk, wool, etc. are all polymers and these are known as natural polymers. 

Much of our technology has been developed by observing and imitating the natural world. Synthetic polymers, such as those you just encountered, were developed by imitating natural polymers. For example, the natural polymer cellulose provides most of the structure of plants. Wood, paper, cotton, and flax, are all composed of cellulose fibres. Figure 2.15 shows part of a cellulose polymer. 

Cellulose is one of the most widely distributed natural polymers, since it is one of the principal components of vegetable tissue. It always occurs in nature in the form of fibres varying from the knap-like fibres covering cotton seeds, to the woody substance of trees. The name cellulose is used both for cellulose isolated from the plant, and thus a chemical compound, and for cellulose in situ in the form normally occurring in the plant. In the second case cellulose together with hemicelluloses and lignin form the main constituents of the plant. 

White, T. R. Melting behavior of crystalline polymer fibres. Nature (London) 175, 895 (1955). 

The third main class of separation methods, the use of micro-porous and non-porous membranes as semi-permeable barriers (see Figure 2c) is rapidly gaining popularity in industrial separation processes for application to difficult and highly selective separations. Membranes are usually fabricated from natural fibres, synthetic polymers, ceramics or metals, but they may also consist of liquid films. Solid membranes are fabricated into flat sheets, tubes, hollow fibres or spiral-wound sheets. For the micro-porous membranes, separation is effected by differing rates of diffusion through the pores, while for non-porous membranes, separation occurs because of differences in both the solubility in the membrane and the rate of diffusion through the membrane. Table 2 is a compilation of the more common industrial separation operations based on the use of a barrier. A more comprehensive table is given by Seader and Henley.1... 

Natural polymers include cellulose (the "fibre" in your food) and DNA. Synthetic polymers include plastics, polystyrene (see below), and the material you will produce in this activity. 

C. Z Carroll Porezynski, Natural Polymer Man-made Fibres, National Trade Press Ltd., London, 1961. 

Natural Polymers and Cellulose Esters The photodegradation of painted wood panels has been found to fail at the wood paint interface 4 while acid treatment of methylcellulose accentuates its rate of photodegradation . Silk fibres have been found to form a roll-like structure after laser ablation with 193 nm light whereas the weatherability of lacquer coated leather has been investigated in a number of weatherometers . Poly(acrylic acid) up to 25% w/w has been found... 

B.S. Kaith, and A.S. Singha, "Modification of natural polymers-VII Ceric ion induced grafting of methylacrylate onto Flax fibre" International Congress of Chemistry and Environment, 2001. 

Synthetic fibres, manufactured fibres can be divided into those derived from natural polymers (such as regenerated protein fibres rayon, cellulose acetates, or alginates) and those derived from synthetic polymers including nylons, polyesters, acrylics, and polyolefins. 

In the mid twenties several circumstances permitted a revised orientation of both content and style of areas of research at the Central Research Laboratory. In 1925 the Technical Committee (TEA) of I.G. Farben discussed the possibilities for producing artificial fibres. At this time, I.G. Farben was the second largest producer of artificial fibres in Germany. Therefore polymer chemistry became more important for the company at the same time as dyestuffs chemistry lost its former position. However, the science of synthetic, semi-synthetic and natural polymers was not yet established in the same way as structural chemistry was for organic dyestuffs, pharmaceuticals, and intermediates. Colloid chemists regarded substances such as cellulose, silk, and wool as... 

Plastics are semi-synthetic or synthetic materials which can be manipulated to form films, fibres, foams or three-dimensional olgects. Natural polymers from plants, insects and animals are not discussed in this book. Synthetic paints, synthetic textiles and photographic film contain plastics but will not be discussed in this book because their conservation is the focus of specialist publications (Chiantore and Rava, 2005 Learner, 2005 Timar-Balazsy and Eastop, 1998 Lavedrine et al., 2003). Plastics are based on polymers, also known as macromolecules, which are large molecules made by joining together many smaller ones. The chemical and physical properties of liquid polymers are modified with additives and shaped to convert them into solids with dimensionally stable forms. 

Natural polymers often owe their important properties to the fact that they are highly oriented, e.g. cellulose, in the form of wood and cotton, and silk fibre, which is a protein. 

Thakur, V. K., Singha, A. S. (2010). Natural fibres-based polymers Part 1-mechanical analysis of pine needles reinforced biocomposites. Bull Mater. Sci.. 33(3), 257-264. 

Torres, F.G., Flores, R., Dienstmaier, J.F., Quintana, O.A. Transport and flame properties of natural fibre reinforced polymers. Polym. Polym. Compos. 13, 753-764 (2005)... 

Natural polymers such as starch and protein are potential alternatives to petroleum-based polymers for a number of applications. Unfortunately, their high solubility in water limit their use for water sensitive applications. To solve this problem thermoplastic starches have been laminated using water-resistant, biodegradable polymers. For example, polylactic acid and P(3HB-co-3HV) were utilised as the outer layers of the stratified polyester/PWS (plasticized wheat starch)/polyester film strucmre in order to improve the mechanical properties and water resistance of PWS which made it useful for food packaging and disposable articles [65]. Moreover, improved physic-chemical interactions between P(3HB-CO-3HV) and wheat straw fibres were achieved with high temperature treatment. It resulted in increased P(3HB-co-3HV) crystallization, increased Young s moduli and lowered values of stress and strain to break than the neat matrix of P(3HB-co-3HV). There was no difference in the biodegradation rate of the polymer [66]. 

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