Investigating the efficacy of interleaving materials in the preservation of plasticised PVC slip-cover notebooks in Yang Zhichao’s artwork Chinese Bible

Abstract Plasticised poly(vinyl chloride) (PVC-P) is known to degrade rapidly and emit acidic gases and, as such, it is ideally stored separately from other materials. However, due to historic or aesthetic value, PVC-P book covers in paper-based collections cannot always be removed or replaced. There is currently a gap in the literature addressing strategies for storing PVC-P associated with paper materials. Prompted by a case study of the Chinese artist Yang Zhichao’s Chinese Bible (2009)—a performance installation artwork of 3000 notebooks including approximately 1000 notebooks with PVC-P covers—three potential interleaving materials (Mylar®, Hollytex® and buffered tissue) were tested to simulate use during long-term storage. Notebooks and PVC-P book covers were purchased and assembled to model stacked storage conditions, and thermally aged at 70°C and 50% relative humidity for 130 days. Before and after ageing, samples were analysed using visual examination techniques, ATR-FTIR spectroscopy, colourimetry and weighing. It was found that all three interleaving materials lowered the probability of ink offsetting. However, cover deformation and a blotchy surface haze were more commonly observed in interleaved samples compared to non-interleaved samples. More research is necessary to identify a suitable strategy to manage PVC-P degradation in close contact storage with paper materials. This study contributes to a better understanding of the storage of plastic-covered books that may be found in libraries and archives, highlighting the complexity of conserving plastic and paper composite materials.