Editing Natural rubber (section)

=== Vulcanized rubber ===
{{Unreferenced section|date=April 2018}}
{{Main|Sulfur vulcanization}}
[[File:Torn latex rubber dry suit wrist seal P8180011.jpg|thumb|Torn latex rubber dry suit wrist seal]]

Natural rubber is reactive and vulnerable to oxidization, but it can be stabilized through a heating process called vulcanization. Vulcanization is a process by which the rubber is heated and [[sulfur]], [[peroxide]], or [[bisphenol]] are added to improve resistance and [[elasticity (physics)|elasticity]] and to prevent it from oxidizing. [[Carbon black]], which can be derived from a petroleum refinery or other natural incineration processes, is sometimes used as an additive to rubber to improve its strength, especially in vehicle tires.<ref>{{Cite journal |last1=Schuster |first1=Jens |last2=Lutz |first2=Johannes |last3=Shaik |first3=Yousuf Pasha |last4=Yadavalli |first4=Venkat Reddy |date=2022-10-01 |title=Recycling of fluoro-carbon-elastomers – A review |journal=Advanced Industrial and Engineering Polymer Research |series=Recycling of Rubbers |language=en |volume=5 |issue=4 |pages=248–254 |doi=10.1016/j.aiepr.2022.08.002 |issn=2542-5048 |doi-access=free |s2cid=251658624}}</ref><ref>{{Cite journal |last1=Asaro |first1=Lucia |last2=Gratton |first2=Michel |last3=Seghar |first3=Saïd |last4=Aït Hocine |first4=Nourredine |date=2018-06-01 |title=Recycling of rubber wastes by devulcanization |journal=Resources, Conservation and Recycling |language=en |volume=133 |pages=250–262 |doi=10.1016/j.resconrec.2018.02.016 |bibcode=2018RCR...133..250A |issn=0921-3449 |s2cid=115671283}}</ref>

During vulcanization, rubber's polyisoprene molecules (long chains of isoprene) are heated and cross-linked with molecular bonds to sulfur, forming a 3-D matrix. The optimal percentage of sulfur is approximately 10%. In this form, the polyisoprene molecules orientation is still random but they become aligned when the rubber is stretched. This sulfur vulcanization makes the rubber stronger and more rigid, but still very elastic.<ref>{{Cite journal |last1=Ducháček |first1=Vratislav |last2=Kuta |first2=Antonín |date=October 1986 |title=Long-time sulfenamide-accelerated sulfur vulcanization of natural rubber/chlorobutyl rubber compounds |journal=Journal of Applied Polymer Science |volume=32 |issue=5 |pages=4849–4855 |doi=10.1002/app.1986.070320507 |issn=0021-8995}}</ref> And through the vulcanization process, the sulfur and latex are meant to be totally used up in individual form.