Chemical Makeup
Latex is a natural polymer of isoprene (most often cis-1,4-polyisoprene) – with a molecular weight of 100,000 to 1,000,000. Typically, a small percentage (up to 5% of dry mass) of other materials, such as proteins, fatty acids, resins and inorganic materials (salts) are found in natural rubber. Polyisoprene is also created synthetically, producing what is sometimes referred to as "synthetic natural rubber".
Some natural rubber sources called gutta-percha are composed of trans-1,4-polyisoprene, a structural isomer which has similar, but not identical, properties.
Natural rubber is an elastomer and a thermoplastic. However, it should be noted that once the rubber is vulcanized, it will turn into a thermoset. Most rubber in everyday use is vulcanized to a point where it shares properties of both; i.e., if it is heated and cooled, it is degraded but not destroyed.
The final properties of a rubber item depend not just on the actual rubber used, but on modifiers and fillers like carbon black, factice, whiting, and a host of others.
Read more about this topic: Natural Rubber
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