Polyester is a class of polymers that contains ester in its main functional group (which means that at least one hydroxyl group is replaced with an alkoxy group). Polyesters are widely used in the clothing and textile industries, as well as packaging, consumer goods, and more. Polyesters may be thermoplastic or thermoset, often depending on the ester group attached to the polymer chain. See Polyester fiber, Polyester film, or Polyester resin.
|Polymer Name||Common or
|Polybutylene succinate (PBS)||1||Biodegradable||Wikipedia|
|Plybutylene terephthalate (PBT)||2||4||Polybutylene terephthalate|
|Polyethylene adipate (PEA)||4||8||Wikipedia|
|Polyethylene naphthalate (PEN)||Advance Photo System film||10||Wikipedia|
|Polyethylene terephthalate (PET)||Polyester fiber; Melinex, Mylar, Dacron, Terylene, Teijin Fibers||[[Polyethylene terephthalate]]|
|Polyglycocide or polyglycolic acid (PGA)||Dexon, Vicryl||Biodegradable||Wikipedia|
|Polylactic acid (PLA)||3||Biodegradable||Polylactic acid|
|Polytrimethylene terephthalate (PTT)||4||8||Wikipedia|
|Vectran LCP)||Liquid Crystal Polymer||10||Wikipedia|
- While this may be a commonly applied term for PET, the use of “polyester” as a synonym for PET is an oversimplification. Always clarify which polyester is used in a product if on a product page it is only listed as “polyester”.
The risk to collections is entirely dependent on which polyester is in use.
The biodegraded polymers have the risk of attracting pests and giving off volatile organic compounds that may be damaging.
The polyester terephthalate polymers generally are stable, and are typically useful vapor barriers. However this vapor barrier may trap damaging gases or water with an at risk object (McGath, 2017, Hall 2019) Additionally, there are instances where PET has been engineered to be acidic (https://www.innovationintextiles.com/skin-friendly-polyester-has-stable-ph-level/)
Physical and Chemical Properties
Resources and Citations
- Contributions: Molly McGath, AIC Plastics Panel, 2020.
- McGath MK, Hall AKI, Zaccaron S, Wallace J, Minter WD, Mcguiggan PM (2017). Stewing in its own juices? The permeability of PET by water and acetic acid. Restaurator 38(4). 355-382.
- Hall AKI, McGath MK, Minter WD, McGuiggan PM (2020). The breathability of PET to water vapor: Thickness effects. Journal of the American Institute for Conservation 59(1). 40-52.