Difference between SBS and SBR
Elastomers TPE > Blocks
Do you understand the difference between SBS and SBR thermoplastic elastomers?
The styrene-based thermoplastic elastomer (SBS rubber) is a triblock copolymer based on styrene-butadiene, a unit of long sequence of the main chain, and then covalently bonded to each other formed by the copolymer. SBS: synthetic thermoplastic elastomer obtained by the polymerization of a mixture of styrene and butadiene. It should not be confused with styrene-butadiene rubber, commonly known as SBR, which is not thermoplastic.
SBS is a thermoplastic elastomer, is a type of styrene block copolymers (SBC), with characteristics of plastic and rubber, known as the "third generation of synthetic rubber". SBS is the abbreviation in English of Styrene-Butadiene -Styrene (styrene-butadiene-styrene), since said copolymer is constituted by a short polystyrene chain, followed by another long polybutadiene chain and finally by another short polystyrene chain.
The SBR (styrene-butadiene rubber) is a random copolymer of butadiene and styrene, and the two monomers are randomly distributed in the main chain, in which the mass percentage of styrene is 23.5% ~ 25%.
But they have some similar characteristics: contact with water / weak acid / alkali, with excellent tensile strength, coefficient of surface friction.
The SBS butadiene block can be hydrogenated to give another soft block, with a structure that is close to the random ethylene-butylene copolymers. The block copolymer thus formed is called SEBS. It has a higher thermal stability than SBS thanks to the elimination of the double bonds of the rubber block. SEBS: SBS which has undergone a hydrogenation process, through which the establishment of the polybutadiene chain is eliminated. This new rubber has a high resistance to the environment, temperature, UV (ultraviolet) radiation, etc. without losing the properties of a thermoplastic, making them very useful in applications where a normal SBS is not suitable.
SIS: Styrene-isoprene-styrene block copolymer. Its characteristic thermoplastic, high elasticity and low melting temperature and viscosity make the SIS popular among the fields of adhesives, plastic modification, used mainly to produce plastic bags to load, women's wipes, paper diapers, double ribbons face and labels resistant to oil.
The SIS butadiene block can be hydrogenated to give another soft block, with a structure that is close to the random ethylene-butylene copolymers. The block copolymer thus formed is called SEPS. It has a higher thermal stability than SIS. The SEPS structure generates high elongation properties as well as improved low temperature properties without crystallization. SEPS: SIS that has undergone a process of hydrogenation, through which the establishment of the polybutadiene chain is eliminated. This new rubber has a high resistance to the environment, temperature, UV (ultraviolet) radiation, etc. without losing the properties of a thermoplastic, making them very useful in applications where a normal SIS is not suitable.