Search results
Results from the WOW.Com Content Network
Rubber elasticity is the ability of solid rubber to be stretched up to a factor of 10 from its original length, and return to close to its original length upon release. This process can be repeated many times with no apparent degradation to the rubber. [1] Rubber, like all materials, consists of molecules.
The major commercial source of natural rubber latex is the Amazonian rubber tree (Hevea brasiliensis), [1] a member of the spurge family, Euphorbiaceae.Once native to Brazil, the species is now pan-tropical.
Tires of the time would become soft and sticky with heat, accumulating road debris that punctured them. Goodyear tried heating rubber in order to mix other chemicals with it. This seemed to harden and improve the rubber, though this was due to the heating itself and not the chemicals used.
It also does not become brittle like paste does. Older formula rubber cements are not considered an archivally sound adhesive because of their low pH value (making them acidic) and will cause deterioration of photographs and paper over time. Modern rubber cements are acid-free, making them ideal for archival purposes.
As the latex dries, it becomes quite sticky and will stick to itself if accidentally folded over. Most manufacturers offer a slick spray for latex once it is dry to remove tackiness, allowing the movement of the model's limbs. Alternatively, powders can be dusted over dried liquid latex to create metallic effects.
In its uncured state, silicone rubber is a highly adhesive gel or liquid. To convert it to a solid, it must be cured, vulcanized, or catalyzed.This is normally carried out in a two-stage process at the point of manufacture into the desired shape, and then in a prolonged post-cure process.
Sulfur, by itself, is a slow vulcanizing agent and does not vulcanize synthetic polyolefins. Even with natural rubber, large amounts of sulfur as well as high temperatures and prolonged heating periods are necessary, with the end products often being of an unsatisfactory quality.
Natural rubber-based sticky adhesives were first used on a backing by Henry Day (US Patent 3,965) in 1845. [20] Later these kinds of adhesives were used in cloth backed surgical and electric tapes. By 1925, the pressure-sensitive tape industry was born. [ 3 ]