Back to transparency, back to life Investigating issues and developing treatments for conservation of transparent plastics in art and design

Transparent plastics, such as unsaturated polyester (UP) and poly(methyl methacrylate) (PMMA), have gained immense popularity among artists and designers for their optical properties, making them widespread in heritage collections. However, in the conservation field, these materials are notoriously difficult to repair when damaged, whether scratched, chipped, cracked or broken. The challenge lies in identifying suitable materials and methods that can repair these types of damage without harming the plastic and restoring its transparency.
Due to the lack of suitable treatment options, damaged objects made of transparent plastics often undergo invasive treatments entailing the removal of original material. Many are relegated to storage, de-accessioned from collections, and in some cases re-fabricated.
Therefore, this dissertation investigates treatment strategies for damaged transparent plastic objects, particularly UP and PMMA, aiming to effectively repair these artifacts, preserving the physical integrity of the original materials and recovering their transparency.
Through extensive scientific investigations and treatment testing, the research identifies suitable materials (adhesives and fillers) and develops methods for filling scratches, chips and cracks, compensating losses, and bonding broken parts. It also provides a methodological approach, information on materials’ properties and behavior, a classification of bonding defects, and practical tools (e.g. an Adhesive Comparison/Selection Chart) that conservators can use to effectively and safely repair other transparent plastics.
The treatment strategies developed are successfully applied to case studies, including the monumental sculpture Giraffa Artificiale by Gino Marotta. This final case study serves as a practical step-by-step guide for conservators on how the research findings can be applied in practice to bring these objects back to life.