vulcanize

present singular third person vulcanizes · participle present vulcanizing · participle past vulcanized · past vulcanized · alternative vulcanise

1. transitiveTo treat rubber with heat and (usually) sulfur to harden it and make it more durable.

   1 more example

   Local workers hike up the side of the mountain and down into the crater at the top to harvest its sulfur—a byproduct of the gas that escapes from the volcano’s vents and collects near the shores of an acidic lake at the crater’s center. The chemical is used in industry worldwide, from making matchsticks to vulcanizing rubber, but Ijen’s sulfur goes mostly to local factories, which use it to bleach sugar.

   2015 February 25, Kevin McElvaney, “Inside Indonesia's Ijen Volcano”, in The Atlantic, archived from the original on 06 Mar 2016

2. intransitiveTo undergo such treatment.

   These vulcanized hearts, they only become more resistant when you ask for mercy.

   1976 September, Saul Bellow, Humboldt’s Gift, New York, N.Y.: Avon Books, →ISBN, page 404

   1 more example

   Natural rubber […] vulcanizes readily at the double bonds to give a strong cross-linked structure.

   2012, Theodore Rochow, Resinography