Some of these natural materials have synthetic equivalents but it is still hard to find anything quite like Angora wool, or silk or just plain shoe leather. A craftsman who builds string instruments insists that there is nothing comparable with animal glues for joining the panels of a violin or a harpsichord. So he boils apart the collagen fibres from animal bones and puts up with the smell. There are others of us, perhaps just as old fashioned, who insist on cotton underwear. Long before the complexity of the natural fibrous polymers was understood, chemists were taking the first steps towards copying their molecular structure.
Modern plastics are of sterner stuff and more properly called resins.
The latest techniques used to make very strong, heat resistant resins, are based on principles of polymer mechanics which owe their heritage to living organisms. Like the natural structural polymers, an essential requirement of a synthetic fibre is its ability to resist tension. If a material is being pulled out, it is less likely to break if it is made from a bundle of long fibres than if it is one solid block. A metal rod is more likely to snap under tension than a wire cable of the same dimension and made from the same metal. The components of the cable may in turn be smaller cables which in turn may be made from fine wire.