Fibrous products

In fiber—cement constmction materials, several alternatives are being practiced, either using ceUulosic fibrous products or synthetic organic fibers such as polypropylene or polyacrylonitrile. 

A white fibrous product obtained when chlorine is passed into a solution of rubber. It was used mainly in corrosion-resistant paints and varnishes but has been superseded by tailored synthetic polymers systems. 

PULP (Wood) PRODUCTION AND PROCESSING. Pulps can be defined as fibrous products derived from cellulosic fiber-contaiumg materials and used in the production of hardboard, fiberboard, paperboard, paper, and molded-pulp products. With suitable chemical modification, pulps can be used in Hie manufacture of rayon, cellulose acetate, and other familiar products. Pulps can be produced from any material containing cellulosic fiber but in North America and several other regions of the world, wood is the predominant source of pulp. This description is confined to the production and processing of wood pulp,... 

This section concentrates upon the development of materials based on aromatic polyamides, particularly poly(p-phenylene terephthalamide) (PPT) (II) u,7 l) and on poly(p-phenylenebenzobisthiazole) (PBT) (IV)75). These material, are primarily intended to satisfy the demands of industry for lightweight, high-performance hiaterials suitable for reinforcement purposes, especially in composites. The polymers have therefore been fabricated mainly into fibrous products. 

The most recent publication reviewed was by Einspahr and Harder (63), who discuss the basic properties of hardwood barks that could be important in the manufacture of any fibrous product. This was a progress report showing results for 16 pulpwood species work is in progress on 16 additional species. Measured were such bark factors as specific gravity, extractives content, strength, toughness, reaction to hammermilling, and ash content. 

Cord A relatively thick fibrous product made by twisting together two or more plies of yarn. 

Nonwovens is a general term used to denote fibrous products that are made without using the weaving, knitting or braiding processes described above. 

Nonwoven fibrous products are cheaper to produce because the number of steps required is small. Weaving, on the other hand, can be very complex and consequently expensive. Nonwoven products such as mats are porous and have lower strength and flexibility compared to the woven fabrics. Nonwovens can be made by a variety of different methods ... 

Rope represents a very useful form of fibrous product. A rope or cord consists of a bundle of fibers. The fibers may be continuous or they may be made of staple fibers, i.e. short, fine fibers. The tensile strength of a rope comes from the strength of individual fibers and the friction between them. The interliber friction prevents their slip past one another. Quite obviously, a rope or a cord has very anisotropic properties. It is strong in tension along the axis direction but not in the transverse or radial direction. Strength in compression is also very poor. 

Paper of course is perhaps the most commonplace example of a fibrous product. Although most common paper products are made of cellulosic fibers, paper-like products can also be made from the so-called high performance fibers such as aramid, glass, carbon, or other ceramic fibers. 

Yet another example of a unique application where materials in a fibrous form are necessary is that of filters of all kinds. We have already mentioned one commonplace example of a fibrous product, namely a tea bag. The proper tea bag... 

JOKINEN K, SAVOLAINEN M and soDERHJELM L (2001) Photobacterium test for evaluation of toxicity of fibrous products. Pap. Puu, 83, 332-335. 

By the treatment of Cross and Bevan cellulose, or cellulose isolated by some other purification procedure, with 17.5% sodium hydroxide under carefully controlled conditions, and then carefully washing, a fibrous product is obtained which is termed a-cellulose. As previously indicated, Cross and Bevan used this procedure for determining the purity of cellulose preparations. This product upon further similar treatments continues to lose weight, indicating the empirical nature of the treatment and terminology. Upon acidif3ring the alkaline filtrate a precipitate is formed. This fraction is known as /3-celIulose. The alkali-soluble extract which remains in solution after acidification of the solution is termed -y-cellulose. Since continued extraction of a-cellulose with caustic causes the formation of increasing amounts of /3-and y-cellulose, the incomplete removal of these fractions in one operation or the conversion of o-cellulose into 0- and -y-cellulose is indicated. In practice... 

Growth Characteristics. As a fibrous product from living trees, wood is subjected to many environmental influences as it is formed and during its lifetime. These environmental influences can increase the variability of the wood material and, thus, increase the variability of the mechanical properties. To reduce the effect of this inherent variability, standardized testing procedures using small, clear specimens of wood are often used. Small, clear specimens do not have knots, checks, splits, or reaction wood. However, the wood products used and of economic importance in the real world have these defects. Strength estimates derived from small clear specimens are reported because most chemical treatment data have been generated from small clear specimens. 

Numerous fibrous products are used as fillers in plastics materials. Fibers are generally divided into natural and man-made fibers. The natural fibers belong to three groups vegetable, animal, and mineral fibers. Natural mineral fibers were... 

Nature s polymer chemistry has selected two basic molecular building blocks for fibrous products. 

The preparation starts with the production of seed crystals. Thus 85 g. of NajgHPO and 15 g. of NH4H3PO4 are heated at 800-900°C until all water and NH3 are removed. Then the mixture is allowed to cool and kept at a constant temperature between 650 and 550°C for a few hours. The melt solidifies almost completely to a fibrous product, which is still somewhat Impure, since an excess of phosphoric acid was used. The fibrous mass is pulverized, washed several times with water and dried with alcohol and ether. 

In the method of Belscher [1], a nitrogen stream saturated with Fe(CO)5 at some temperature is combined in the bulb-shaped reactor of the apparatus hown in Fig. 338 with a stream of very hot nitrogen. The hot-gas quantity is always several times that of the cold one. Thus, for example, if the carbonyl-saturated Ng flows at a rate of 2 liters/hour, the flow rate of the hot N g must be 40-100 liters/hour. If the reaction temperature is maintained between 200 and 700°C and the Fe concentration in the decomposition zone does not exceed 10 mg./liter, a uniform, fibrous product collects in the settling chamber. 

Activated, see Terminology, Activated, p.231 Carbon paper, see Fibres and Fibrous Products, p.90... 

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