Morpholine deacidification

Sulfite paper has a relatively short life span, since residual acid will continue to hydrolyze the cellulose and cause embrittlement. Further sources of acid include aluminum sulfate (which is added together with resin to suppress bleeding or feathering of ink into the paper) and S02 and NO from the atmosphere. Much of the world s library collections and archives will soon be lost as the paper crumbles. Various deacidification treatments (e.g., with ammonia, morpholine, cyclohexylamine carbamate, or diethyl-zinc) have been proposed and tried, but at best they can only halt the process of embrittlement and cannot reverse it.14 With the move to kraft pulping, alkaline peroxide bleaching, and increasing use of precipitated calcium carbonate as a filler, the high quality papers produced today are intrinsically acid free and should also resist subsequent acidification by S02-polluted air fairly well. 

B.F. Walker, Morpholine Deacidification of Whole Books in Preservation of Paper and Textiles of Historic and Artistic Value (J.C. Williams, ed.), 1977, pp. 72-87. 

Permanence of Deacidification. If paper were composed of chemically inert fibers, one would expect that a brief exposure to the alkaline vapor of morpholine would have no appreciable effect since there would... 

Overall, it is believed that these occasional changes are to be expected in a process of this type they imply that the books to be deacidi-fied should be selected when neutralization and life extension of the paper are the primary objectives and minor appearance changes can be tolerated. All deacidification processes demand that the conservator exercise a degree of judgement, and the morpholine process is no exception. 

The last three disadvantages are not unique to the morpholine process they would probably apply to a greater or lesser extent to any bulk deacidification process. These advantages and disadvantages represent what is considered to be an optimum balance between many factors, including cost, effectiveness, process speed, and potential damage to book covers. 

Cyclohexylamine carbonate, morpholine, amines in general and ammonia itself have all been considered as deacidifying treatments. Many are liquids with a significant vapour pressure or are gases, which makes them potentially useful for mass processes. However, all suffer from the problem that the deacidification produced is not permanent and some cause yellowing of the paper. None is currently in favour. 

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