segunda-feira, 31 de maio de 2010

A encolagem de gelatina e o seu impacto na degradação da celulose do papel

A seguinte tese de doutoramento está livremente disponível aqui:

Anne-Laurencee Dupont, Gelatine Sizing of Paper and Its Impact on the Degradation of Cellulose During Aging. A Study Using Size-exclusion Chromotography, Amsterdam, Universiteit van Amsterdam, 2003.


The issue of permanence and durability of paper is one of the major concerns in cellulose research and paper conservation. From the perspective of conservation research, the understanding of the long-lasting properties of paper begins with the investigation of the characteristics of papers in good physical condition that have best survived the passage of time. In European papermaking history, this is the case with early papers, which for the most part, present far better state of conservation than papers of more recent origins. Several facets that could explain the longevity and stability of paper have been investigated in the past, but one that has been largely neglected to date is the process of sizing. Papers dating from the fourteenth to the eighteenth centuries, in addition to having been fabricated from good quality fibres which partly explains their durability, have also inn common that they were sized almost systematically with gelatine. The present study is dedicated to the investigation of the role of gelatine in pure cellulose paper. The research is approached mainly from the angle of polymer chemistry. The impact of gelatine sizing upon aging on the molecules of cellulose, and the changes incurred by varying the sizing material are studied. The analytical technique selected is size-exclusion chromatography (SEC), which is employed in the characterisation of both cellulose and the gelatine, and in thee investigation of their degradation upon aging. Model papers were fabricated for this purpose, but the study also includes the characterisation of naturally aged papers.