Cellulose segment

As the figures are now reported, the industry really includes the plastics materials and resins for elastomers, rather than the elastomers themselves. In the Tariff Commission s annual figures, elastomers, including synthetic rubber, are in a separate schedule. The cellulosic segment of the industry includes cellulosic plastic materials but excludes cellu-losics for surface coatings. The entire lacquer industry is excluded as well as the cellulosic flake for the lacquer industry. In the synthetic resin segment, resins for both plastics and protective coatings are included. 

Figure 15-16. A cellulose segment with the lowest energy, as indicated by the combined information from the crystal structure surveys and the point of minimum energy on the QM MM3 hybrid energy surface See Color Plate of this figure beginning on page 355)...

Two important classes are cellulose esters (qv) and cellulose ethers (qv). Cellulose esters are not water soluble and are not discussed here cellulose ethers are an important segment of water-soluble polymers. 

There is more activity in dairy products than anywhere else in the food industry. Ice milk and fro2en yogurt, early leaders in the field, rose rapidly in sales then plummeted. Fat-free ice cream has been marketed, but final results are not yet available. Sales of these products have not cannibalized traditional ice cream (35). Standards for traditional ice cream call for a minimum of 10% butterfat. One fat-free ice cream product is prepared from nonfat milk (skim) and cellulose gum. Fat-free ice creams have encountered strong resistance in some segments of the retail trade. Retailers in Maine and New York, states with important dairy producing industries, refuse to sell such products (36). 

Some commercial durable antistatic finishes have been Hsted in Table 3 (98). Early patents suggest that amino resins (qv) can impart both antisHp and antistatic properties to nylon, acryUc, and polyester fabrics. CycHc polyurethanes, water-soluble amine salts cross-linked with styrene, and water-soluble amine salts of sulfonated polystyrene have been claimed to confer durable antistatic protection. Later patents included dibydroxyethyl sulfone [2580-77-0] hydroxyalkylated cellulose or starch, poly(vinyl alcohol) [9002-86-2] cross-linked with dimethylolethylene urea, chlorotria2ine derivatives, and epoxy-based products. Other patents claim the use of various acryUc polymers and copolymers. Essentially, durable antistats are polyelectrolytes, and the majority of usehil products involve variations of cross-linked polyamines containing polyethoxy segments (92,99—101). 

Fig. 1. A segment of a cellulose chain composed of four P-D-glucopyianose residues (ceUotetiaose), showing (a) the chemical bonds and election clouds around the atoms. The molecule has the twofold hehcal conformation typical of many models of crystalline cellulose, (b) The (Haworth) stmctural formula...

There are a number of possible locations within the cell wall for the pectin further away from cellulose. If there are covalent links between pectins and xyloglucans (16), then pectic chain segments close to these links would appear in the region sharing the same mean mobility characteristics as cellulose. The majority of the pectic molecule, diverging from the microfibrils would appear in the region with greater mean mobility. 

Experimental studies of the adsorption of polyelectrolyte have been reported by several authors Pefferkom, Dejardin, and Varoqui (3) measured the hydrodynamic thickness of an alternating copolymer of maleic acid and ethyl vinyl ether adsorbed on the pore walls in cellulose ester filter as a function of the molecular weight and the concentration of NaCl. Robb et al. (4) studied the adsorption of carboxy methyl cellulose and poly (acrylic acid) onto surfaces of insoluble inorganic salts. However, their studies are limited to the measurements of adsorbance and the fraction of adsorbed segments. 

An example of such a surface is shown in Figure 2, which presents the "Ramachandran map" for the disaccharide segment, cellobiose, of cellulose. In this case, since cellulose is homopolymeric. Figure 2 contains all of the energetic infor-... 

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