• Question: Why is kevlar so hard?

    Asked by telford007 to Tom, Hugh, Douglas on 24 Jun 2010 in Categories: .
    • Photo: Tom Hardy

      Tom Hardy answered on 21 Jun 2010:

      It’s not. Kevlar is actually very tightly woven fibres. It is almost like material, and you can trust me on this as I have worked with it! Because of the structure it is able to take shock and distribute it evenly across its surface, deflecting the impact. Because of its tight weave, pointed things like knives find it difficult to get through.

    • Photo: Douglas Blane

      Douglas Blane answered on 24 Jun 2010:

      It has loads of hydrogen bonds, which is one of the ways molecules stick together. A kind of glue for molecules. Usually you get these bonds with big complicated molecules, like in Kevlar.

      But you also get them in water, which is why water has a high boiling point. Hydrogen bonds between the H2O molecules need to be broken to get the steam. And that takes a lot of energy from the heat.

Comments