Similarity to cellulose

A common surface cartridge is the pleated paper constmction type, which allows larger filtration areas to be packed iato a small space. Oil filters ia the automobile iadustry are of this type. The paper is impregnated, for strength, with epoxy or polyurethane resia. Any other medium ia sheet form, similar to cellulose paper, such as wool, polypropylene, or glass may be used. 

Cellulose acetate-propionate (Tenite Propionate-Kodak) is similar to cellulose propionate. With the shorter side chains, cellulose propionate and cellulose acetate propionate tend to be harder, stiffer and of higher tensile strength than CAB. Like CAB they are easy to vacuum form and also tend to be used for similar applications such as steering wheels, tool handles, safety goggles and blister packs. 

Xanthan gum is a long-chain polysaccharide composed of the sugars glucose, mannose, and glucuronic acid. The backbone is similar to cellulose, with added side chains of trisaccharides (three sugars in a chain). 

A polysaccharide such as xanthan gum is a chain of sugars. Some familiar polysaccharides are starch and cellulose. The backbone of xanthan gum is similar to cellulose, but the trisaccharide side chains of mannose and glucuronic acid make the molecule rigid, and allow it to form a right-handed helix. These features make it interact with... 

Chitin is a polysaccharide similar to cellulose except that the OH at C-2 is replaced by an acetamido group (CH3CONH). Chitin is the main component of the hard external covering (exoskeleton) of crustaceans such as lobsters, crabs, and shrimp. Like cellulose, the processing of chitin into polymeric products is limited by its insolubility and decomposition without melting. The availability in huge quantities has encouraged many attempts to find commercial applications of chitin, but very few have been found to be economically feasible. 

By variation of the conditions of crystallization (see Sect. 1.3.3.3) polyethylene can be obtained either as folded lamellae, as extended chain crystals (high strength fiber), or as so-called shish kebabs (fibrils with a morphology similar to cellulose). All these variants differ in properties. 

Chitosan Chitosan has a molecular structure similar to cellulose. This material is produced from chitin, which is widely found in the exoskeleton of shellfish and crustaceans. Chitin is the second most abundant natural biopolymer after cellulose. Chitosan is a good adsorbent for all heavy metals. It has been estimated that chitosan can be produced from shellfish and crustaceans at a market price of 15.43 /kg. 

Comparative investigations with related monomeric compounds, glucose pentaacetate, and cellobiose octaacetate indicate that, on a qualitative basis, these materials undergo photolytic changes in a manner similar to cellulose triacetate. These materials may serve as model compounds for future quantitative investigations of cellulose triacetate. 

Chitin is a long-chain polymer (similar to cellulose) composed of /S-N-acetyl glucosamine unit (Meyer and Mark [53]). Every unit contains two OH groups and one NH-COCH3 group ... 

The exoskeletons of shellfish such as crabs and lobsters as well as many insects contain a high concentration of chitin, which is very similar to cellulose (b 1,4-glycoside linkages), except that instead of an OH group at carbon-2, chitin has a substituted amine group (an amide) ... 

Bioconversion of Shellfish Chitin Waste. In the quest of finding ways to utilize tne nutrients m shellfish processing waste, another avenue has been discovered. A process has been developed which bioconverts shellfish chitin to yeast single-cell protein (96-98). The product of this process is a protein-rich material wRTcfT can be used as an animal and aquaculture feed supplement. Since chitin s chemical structure is nearly similar to cellulose, the concept of this process was inspired from the bioconversion... 

Derivatives of celluloses like Ac-di-Sol and E.C.G. 505 act as the so-called super disintegrants. Their microscopic pictures are similar to cellulose fibers. The materials, however, could not be distinguished by microscopic examination. 

Hemicelluloses are a family of four basic types of polysaccharides, composed of two or more monosaccharide residues. All have structural features similar to cellulose in that they have their main chains that are -(1 4) linked, with the exception of the arabinoglactans that are /3-(l—>3) linked. The main chains are homopolysaccharides composed of a single monosaccharide residue, but they are highly branched by one or two different kinds of monosaccharides that are linked for the most part to give single monosaccharide branches. 

Amylose and amylopectin are the two main constituents of starch. Similarly to cellulose, starch is very common in plant cells. The proportion of amylose and amylopectin in starch varies, and cornstarch for example contains about 27% amylose and 73% amylopectin. 

The discovery of nylon is one example. In 1928, E.l. DuPont de Nemours and Company appointed a young, 32-year-old chemist from Harvard, Wallace Carothers, as the director of its new research center. The goal was to create artificial fibers similar to cellulose and silk. In 1930, Julian Hill, a member of Carothers team, dipped a hot glass rod in a mixture of solutions and unexpectedly pulled out long fibers such as the one shown in Figure 1-14. Carothers pursued the development of these fibers as a synthetic silk that could withstand high temperatures and eventually developed nylon in 1934. Nylon s first use was in a toothbrush with nylon bristles. During World War 11, nylon was used as a replacement for silk in parachutes. Nylon is used extensively today in textiles and some kinds of plastics. 

It is found as a component of fungal and bacterial cell-walls, in insect cuticles, and as the shell of crustaceans. Being so similar to cellulose in chemical composition, its structure is important, if for no other reason than that comparison of the two structures might aid in our understanding of each. The similar fibrillar fine-structure (see Fig. 12) of these two polysaccharides is noteworthy, as the lateral forces between molecules are different. Although chitin does not occur in Nature specifically as a fiber, it is frequently found well-oriented in bristles and as tendon material. Samples from invertebrates are usually admixed with protein and carbonate, both of which must be removed before x-ray diagrams of high quality can be obtained. 

The mixed-linkage (l->3),(l-+4)/ -D-glucan synthase possesses more similarities to cellulose synthase than do synthases of other non-cellulosic polymers... 

On the other hand, Buckeridge et al.4 proposed that /J-glucan synthase is an ancestral cellulose synthase that has an additional site of glycosyl transfer, giving it its unique ability to make cellotriose units. Our proteinase K results predict that, similar to cellulose synthase at the plasma membrane, /1-glucan synthase would also share an active site on the cytoplasmic face of the Golgi membrane,... 

Chitin, a polysaccharide similar to cellulose, is Earth s second most abrmdant polysaccharide (after cellulose). It is present in the cell walls of fungi and is the fundamental substance in the exoskeletons of crustaceans, insects, and spiders. The structure of chitin is identical to that of cellulose, except for the replacement of the OH group on the C-2 carbon of each of the glucose units with an -NHCOCH3 group. The principal source of chitin is shellfish waste. Commercial uses of chitin waste include the making of edible plastic food wrap and cleaning up of industrial wastewater. 

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