General conservation and collection care advice applies also to those made of semi- and fully synthetic fibres and should be followed. Such advice can be found at: https://collectionstrust.org.uk/wp-content/uploads/2017/02/Museums-Galleries-Commission-An-Illustrated-Guide-to-the-Care-of-Costume-and-Textile-Collections-2000.pdf.
For most synthetic garments, dissociation and loss of material information poses the greatest risk for identifying future preservation needs. In 2022 a relatively small number of synthetic textiles show signs of degradation and research to understand why is starting. So, at this time, early signs of change should be documented, and conservation advice sought as needed. It is recommended that collections containing synthetic and semi-synthetic fibres are examined at six-monthly intervals. If staffing levels and work programmes make this ideal impossible, regular checks at longer intervals can still detect problems developing. Vigilance is also needed for synthetic plastic decorative elements like buttons, and stiffening interfacings in belts, collars and cuffs that are particularly vulnerable to degradation. Appropriate care advice is available in the PSSN’s ‘A Curator’s Guide to plastics’.
Environmental conditions
The temperature at which some synthetic garments are stored and displayed has more impact on their long-term preservation than is the case with natural materials. As a rule, the storage for all semi- and fully synthetic garments should be kept below 20°C. Relative humidity levels are also more crucial and, again as a general guide, should not drop below 40%. This is especially important for cellulose triacetate, nylon, polyester, and acrylic fibres which are prone to an increase in static charge when air humidity is low and has little air moisture. At the other end of the air-moisture scale, rayons and protein-based fibres readily attract water, making them vulnerable to mould in damp conditions when relative humidity exceeds 70%.
Textiles may fade and degrade easily in the light. Ideally maintain light levels where textiles are displayed at a maximum of 50 lux with UV levels as low as possible, but preferably below 30 µwatts/lumen (a total UV exposure of 1500 μW/m2) or restrict the length of time they are in the light.
Storage
Store textiles in the dark but also ensure that light levels in storage areas are sufficient so that textiles can be examined without strain when necessary. Storage space in museums can be cramped. While some garments will be robust enough to be hung in wardrobes, it is very important to combine vertical storage with horizontal storage such as acid-free boxes for textiles, small items of clothing and garments that are too fragile to be supported from their shoulders or waist, or might become distorted if hung. Bias cut garments and garments made from jersey and other stretch fabrics should always be stored flat.
Objects showing signs of degradation should ideally be stored in the configuration they would be displayed, for instance on a display mount or padded board. Otherwise, like garments prone to stretching, they should be stored flat.
Conservation-grade covers should be used to protect against the static attraction of dust to cellulose triacetate, nylon, polyester and acrylic fibres. Care should also be taken to minimise static build from textiles rubbing together in storage and when handled. This applies to used and unused static-prone garments because anti-static treatments readily wash off after a few cycles of domestic laundering and it appears that their protective properties reduce with ageing.
Handling and display
As is the case with garments made of traditional materials, well-fitting, powder free nitrile gloves should be worn for routine handling. If you want to experience the feel of the fabric it is important to wash and dry your hands thoroughly before doing so and then to wash them again once you have finished. Gloves should always be worn when handling materials which incorporate or are decorated with metal threads as oils from the skin can cause tarnishing. There are recycling schemes for disposing used nitrile gloves.
Synthetic fibres, compared with natural fibres, have increased potential for stretching under load, especially nylon, and synthetic rubber. Elastanes, for instance, can stiffen and become misshapen. Supported handling and careful mounting for display is very important, paying careful attention to minimising flex at seams, areas weighted with metal zips, beads and suchlike, and bonded fabrics and coated fibres where layers can delaminate.
Viscose rayon dating from before the 1940s has poor wet strength. These garments need particularly careful handling if they undergo water-based cleaning treatments and will require gentle reshaping while drying.
Like wool, some synthetic fabrics, for example acrylic, cuprammonium, nylon and polyester are prone to pilling. Home gadgets to comb or shave off pilling have been available for decades and may have been used by previous owners, so well-worn garments with and without pilling are best displayed unmounted in case their structure has been weakened. Removing attached pills, or even loose ones, from historical garments is not recommended because of material and information loss.
Examples of degradation and vulnerability
Observation suggests that many semi-synthetic and synthetic fibres are relatively stable. However, some aged synthetic finishing and coating materials on garments in museum and archive environments are showing signs of chemical degradation and irreversible changes.
Migration of plasticiser to the surface is seen on PVC garments and PVC-based 'Pleather'. Polyurethane-based 'Pleather' degrades by oxidation- resulting in the synthetic 'leather' surface crazing and delaminating from its textile base. Removal of this sticky material from the surface is only a temporary solution as more of the plasticiser will migrate eventually leading to brittleness. These types of materials are best stored wrapped in silicon release paper to avoid adhesion enclosed in either acid-free costume boxes or encased in calico slings/covers in a cool environment.
Some semi-synthetics and fully synthetic materials attract dust which can accumulate on the surface of the textile. Gentle and regular brushing with soft conservation grade brushes can help reduce the impact of dust damaging garments on display, particularly those on open display where garments are displayed without vitrines.
Wear and tear can affect the condition of some semi-synthetics and synthetic garments. A typical example is the effect of perspiration from previous wearers. This can often lead to synthetic fibres staining and/or rotting in local areas, for example, the under arm and torso.