Ageing paper size

The effect of acidity caused by alum-rosin size has been obviated by the substitution of sizing agents which are effective slightly on the alkaline side of neutrality. It has been established that papers of satisfactory permanence can be manufactured with such sizes. It is possible to use rosin as a size and to avoid the conjunction with alum by a number of processes. There are insufficient data on the aging characteristics of paper sized with the available modified rosin sizes to judge the effect on permanence. Possible reactions of the rosin, such as oxidation and formation of peroxides, must be considered. 

This does not mean that the earliest predictions of Sperm Competition Theory have all been supported. In particular, it now seems that there are many more elements to a competitive ejaculate than simply sperm number, with sperm size, sperm morphology and now sperm age being just three that have so far been implicated. It also seems, from this paper, that the most strategic ejaculate may well be different for the IPC male and the EPC male. 

No specific information on the possible effect of the synthetic sizes on permanence is available, and they are not mentioned in the standard 04), but it seems unlikely that they would be deleterious. Presumably they have been used in comnercial grades of neutral/alkaline paper subjected to accelerated ageing tests. In terms of general effects on paper, the synthetic sizes have a tendency to reduce the surface frictional properties of paper to a greater extent than rosin. For example, this makes it more difficult to stack piles of cut sheets without slippage. However, the effect is less noticeable when high proportions of chalk filler are used, because the blocky particles increase friction. 

Of the two test papers employed in this study, the wood pulp waterleaf better represents natural cellulose, while Foldur Kraft paper, which is sized with alum-rosin, is fifteen years old and also fairly acidic, more closely resembles average library book paper. Both the papers were aged as sheets freely suspended on a rack, as... 

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