Embrittlement, paper deterioration

Celluloses are similar to other linear polymeric materials in that they can possess one-dimensional order within an individual chain as well as three-dimensional order within an aggregate of chains. Increments in the levels of order occur during the isolation of native celluloses and also as a result of exposure to conditions that promote molecular mobility, such as elevated temperatures and immersion in plasticizing fluids. These increments generally result in embrittlement of the cellulosic materials. Similar effects are expected to occur upon aging of cellulosic textiles and papers over extended periods, and may be accelerated by hydrolytic cleavage of cellulosic chains. The implications of these effects for conservation practices, both with respect to recovery of function as well as in the assessment of deterioration, are reviewed. 

It is a fact that actinic deterioration of Degradable Plastic films will, in due course, lead to the crumbling of them into fine particles. Such disintegration obviates the plastics litter problem and provides the possibility of a solution to the agricultural plastics residue situation. There is evidence in this paper and elsewhere ( ) that there are commercially viable formulations with which packaging (and related) plastics can be made to have controlled, short embrittlement times outdoors but no indoor stability problems. 

Less recognized but also important is SO- damage to paper and leather. Paper products produced from about 1/50 on are embrittled by sulfur compounds converted to sulfuric acid which causes hydrolysis. Thus old books which are not stored in sealed cases undergo a gradual deterioration. Leather bindings are similarly affected. 

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