Plastics were first formulated in 1840’s, but it wasn’t until late 1920’s that they became a part of everyday, commercial life. Plastics are synthetic polymers made of specific units (monomers) connected to form long chains. The chains are held together by chemical forces – their type and strength influences the properties of the polymer.
The properties and appearance of the polymer can be modified through specific formulation of the plastic. Different compatible monomers can be mixed to obtain specific characteristics of the final product. In addition, other materials can be added to adjust appearance and performance. These can include a huge variety of colourants, plasticisers, fillers, lubricants, forming agents etc. Some other materials such as anti-oxidants may be added to stabilise an unstable polymer, and UV absorbers can be added to reduce degradation during use. This variation in materials, and the unpredictability of composition of a given object adds to the difficulty of assessing the condition, and predicting its long-term behaviour and stability.
There are several general types of plastics – their classification is based on the chemical composition of the polymer.
An increasing number of works of art are made using modern materials (polymers) either in entirety or in part. They are inexpensive, accessible, often easy to use, provide spectacular visual statements, have good working properties. Their long-term stability is as varied as the number of types, and formulations of plastics. Some break down quickly, with minimal amount of exposure to light, moisture, or simply to oxygen; some do not show any signs of deterioration even after a considerable period of time. Conservation of modern materials is still fairly undeveloped, as conservators have not dealt with modern materials for long enough to have built up a body of knowledge. In addition, polymer formulations change very fast, and new materials become available.