Biopolymers cellulose ethers

Cellulose, the feedstock for cellulose ethers, is a polysaccharide like xanthane, guar and starch. It is a biopolymer made by photosynthesis and thus a renewable raw material. Cellulose is water insoluble, and only becomes water-soluble after hydrolysis and etherification [104, 105] (Fig. 5). 

Ethers make bonds in biopolymers such as cellulose (see Box 4.11). 

Approximately 2% of the 5 x 1011 metric tons of cellulose generated yearly by biosynthesis throughout the world is recovered industrially and of these 108 tons, about 2% is transformed into various esters (3/4) and ethers (1/4). Historically, cellulose nitrate is the oldest (inorganic) ester synthetized, but it has found almost no applications as a biopolymer. The first organic ester and which remains widely used in the field of life sciences is cellulose acetate (1865). Ethers are more recent, since methylation was first described in 1905. 

Other polymers which have been the subject of thermal degradation studies include ethylene-vinyl acetate [29, 66, 67], ethylene-vinyl alcohol [68], poly(aryl-ether ketone) [69], poly-2-vinyl-naphthalene-co-methyl maleate [34], polyphenylenes based on diethyl-benzophenone [70], polyglycollide [71-73], poly(a-methylstyrene tricarbonyl chromium [74], polytetrahydrofuran [75], polylactide [76-78], poly(vinyl) cyclohexane [79], styrene-vinyl cyclohexane [80], isopropenylacetate-maleic dianhydride [80], polyethylene glycol containing a 1,3-disubstituted phenolic group [81], poly-2-vinyl naphthalene-co-methacrylate [34], collagen biopolymers [82], chitin graft poly (2-methyl-oxazoline - polyvinyl chloride blends [83], cellulose [32, 83-88] and side-chain cholestric elastomers [89, 90]. 

Polymer nanocomposites can be synthesized using cellulose in the form of cellulose nanocrystals or CWs. Pure cellulose is a biopolymer, specifically the polysaccharide of D-anhydroglucose units connected through the (1-1,4-glycosidic ether bond [31], as shown in Figure 6.2. 

Cellulose is a polysaccharide made up of repeating 1,4-(J-hydroglucose imits coimected to each other by p-ether linkages and is the most abundant natural biopolymer in the world. Cellulosic fibers are broadly defined as fibers from plants or plant-based materials which contain cellulose and is drawn out into fibers for several applications. The long linear chains of cellulose permit the hydroxyl functional groups on each hydro-glucose... 

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