Polypropylene man-made fibres, c 1970s.
© Science Museum / Science & Society Picture Library
This collection of polypropylene fibres includes two spools, two pieces of rope and two circular flat samples of fibre. Polypropylene (polypropene) is a thermoplastic polymer of propylene. Polypropene is particularly suited to rope manufacture as it is elastic, stronger than alternative natural materials, and is also light in weight, so much so that it will float.