Sulfur, a common mineral in nature, has very important medicinal value.But in the eyes of rubber people, sulfur may have a more important use than medicine – rubber products in the vulcanizing agent.The origin of sulphur and rubber goes back to Charles Goodyear, the “father of rubber”.
Rubber’s historical association with sulfur
As an ancient material, rubber was used by our ancestors long ago. At that time, rubber was mostly used for adhesives and waterproof clothing.Rubber’s fatal flaw is that it is too sensitive to temperature.The temperature is a little higher it will become soft and sticky, and smelly;It becomes brittle and hard at low temperatures.
In the summer of 1834, Goodyear visited the Indian rubber company in New York. He learned that this property of rubber troubled the whole rubber industry, but rubber also had a series of excellent properties such as high elasticity, plasticity, durability, waterproof and insulation. Therefore, Goodyear was determined to study the modification of rubber.In January 1839 Goodyear accidentally heated rubber, lead oxide and sulfur to produce a leather-like substance.This material does not break down at higher temperatures as is commonly known for elastomeric rubber.After a series of modifications, Goodyear became convinced that his product would not decompose at any temperature below the boiling point.So it was this unintentional discovery by Goodyear that led to an improvement in rubber performance, 38 years after Goodyear’s death, in honor of Charles.Goodyear’s great contribution to the American rubber industry, frank.Mr Coughlin named his tyre and rubber company Goodyear and is now one of the world’s top three tyremakers.
The classification of sulfur
The sulfur used in rubber industry includes sulfur powder, insoluble sulfur, colloidal sulfur, precipitated sulfur, sublimated sulfur, deacidified sulfur and noncrystalline sulfur.The first three are more commonly used.
Sulfur powder: it is the most widely used sulfur in the rubber industry.
Insoluble sulfur: homopolymer of sulfur, also known as polymerized sulfur.Its biggest advantage is that the products are not easy to spray frost, widely used in high-grade rubber products such as steel radial tire.
Colloidal sulfur: paste made by grinding sulfur powder or settling sulfur with dispersant.Mainly used for latex products.
The role of sulfur in rubber products
In order to obtain good performance of traditional rubber, linear macromolecular chains must be cross-linked to form a three-dimensional network structure.The crosslinking process is often referred to as vulcanization of rubber because the original crosslinking was done with sulfur.Rubber after vulcanization, with the change of structure, properties have changed: rubber no longer flow when heated, no longer dissolved in its good solvent, modulus and hardness, mechanical properties, aging resistance and chemical stability improved.Therefore, only after the discovery of sulfur, rubber has become a good performance, widely used polymer materials.
Of course, the formation of sulfur in rubber vulcanization network also requires the addition of active agents, promoters and other additives to form a complete vulcanization system, and with the development of the rubber industry, people put forward higher requirements for the performance of rubber products, therefore, the types of sulfur and substitutes are also gradually being developed and produced.