Mathematical modelling of paper degradation in books

Paper cannot be prevented from degrading and does not necessarily degrade uniformly across its volume. It has been established that as paper degrades, VOCs (Volatile Organic Compounds) are produced. This body of work studies paper degradation with respect to the role VOCs play. The thesis investigates how a VOC a ecting the paper's acidity can in turn a ect the degradation rate and through modelling the VOC concentration pro le, the degradation pro le is found. To create the model from a chemical engineering perspective, mass transfer fundamentals are explored: di usion through porous a medium, chemical reaction, and adsorption are utilised. Current literature highlights acetic acid as a representative VOC in paper due to its presence in all di erent paper types and is used as the VOC for the model. To aid simulation of the model, experimentation was carried out for four di erent paper samples for the porosity, surface area, pore diameter, e ective di usion coe cient and the adsorption coe cient. For adsorption experimentation, propionic acid was used as a substitute for acetic acid due to limitations of measuring devices available. To run the simulations, gPROMS was used and the results showed how acetic acid negatively a ects the degradation rate of paper, how the degradation pro le can vary across a paper volume and what measures can be taken to improve the life span of paper. The results also showed how paper with an alkaline reserve can avoid the e ects of acetic acid as it is neutralised by the reserve. The simulations showed how storing paper in a sealed tted container ensures uniform degradation, but the VOC cannot escape and so increases the degradation rate. Paper stored on a shelf allows the VOC to escape, but can cause noticeable non-uniform degradation across the volume. The simulations displayed the advantage of using the lower temperature and relative humidity