Cellulose acetate chain scission

Typical degrees of substitution for plastics applications [21] are DS(acetate) = 2.5 for cellulose acetate, DS(propionate) = 2.6 andDS(acetate) = 0.1 for cellulose acetate propionate (CAP), and DS(butyrate) = 1.8 and DS(acetate) = 1.1 for cellulose acetate butyrate (CAB). In the industrial process of catalysed esterification, chain scission is a competitive reaction that can, however, be fairly well controlled under appropriate conditions [22]. Degrees of polymerization of commercial products can be estimated from literature data [22-25] to be in the range of 200 to 300. 

Photodegradation of cellulose acetate fibres by u.v.-irradiation in vacuo at 77 or 293 K resulted in deacetylation and chain-scission. ... 

It has been reported that the viscosities of aqueous solutions of a number of polyelectrolytes, such as sodium salts of poly(acrylic acid), carboxymethyl cellulose and copolymer of maleic and vinyl acetate, decrease rapidly when they are UV irradiated, due to chain scission reactions [1049]. 

Depolymerisation is initiated by the scission of acetal bonds of the glycosidic xmits, followed by splitting of volatile fuel-forming levoglucosan, the cyclic monomer of cellulose, from ensuing chain ends. Competing dehydration reactions lead to thermally stable aliphatic structures (char I), which subsequently are converted via Stage II into... 

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