vulcanise

/V AH1 L K AH0 N AY0 Z/
verb
  1. 1

    To treat rubber with heat and (usually) sulphur to harden it and make it more durable.

  2. 2

    To undergo such treatment.

Source: https://en.wiktionary.org/wiki/vulcanise, https://en.wiktionary.org/wiki/vulcanize