Shoemaker's Nightmare: Deterioration of Shoe Soles and Tests for the Conservation of degraded closed-cell Polyester Urethane Museum Objects

As part of an ongoing research project at the Deutsches Bergbau-Museum Bochum, 20 original miners' shoes from the museum's collection were studies. They were produced in the late 1980s and today the outsoles made of polyurethane ester integral skin foam show an advanced state of deterioration: they have little cohesion left, are sticky and show degradation phenomena related to adipic acid release. The research presented here explores cold storage possibilities and consolidation tests on degraded polyurethane ester. Firstly, the effects of low temperature were studied by cooling test samples down to -20 °C on a SEM cooling stage and in a cooling chamber. For comparison, both artificially aged test specimens stored in the cold and those stored at standard laboratory conditions were mechanically tested (Shore hardness, compression set). While the mechanical properties were not affected by the treatment, some microscopic changes were noticed by SEM. Secondly, the application of consolidation agents to stabilise the aged polyurethane by means of low vacuum was tested, as well as a method for the adhesion of detached fragments. The evaluation of the adhesive performance was done by means of tensile strength tests.     «

As part of an ongoing research project at the Deutsches Bergbau-Museum Bochum, 20 original miners' shoes from the museum's collection were studies. They were produced in the late 1980s and today the outsoles made of polyurethane ester integral skin foam show an advanced state of deterioration: they have little cohesion left, are sticky and show degradation phenomena related to adipic acid release. The research presented here explores cold storage possibilities and consolidation tests on degrade...     »