1. SEBS is a linear triblock copolymer with polystyrene as the terminal block and ethylene-butylene copolymer obtained by hydrogenation of polybutadiene as the intermediate elastic block. SEBS does not contain unsaturated and double bonds, so it has good stability and aging resistance.
II. Use of SEBS:
1.SEBS has good ultraviolet stability, oxidation resistance and thermal stability, so it can also be used in asphalt for roofs and roads. 2.SEBS has good compatibility with paraffin wax, so it can be used as a more flexible surface coating for paper products.
3.SEBS is not sensitive to temperature when it is heated without obvious shear flow, so it can be used as a template for IPN. (The basic principle of IPN: two immiscible polymers can achieve interpenetration of entangled segments. For example, the first one can "lock" the two immiscible polymers together through covalent bond crosslinking. )
4. The organic solution of SEBS oil blend can replace natural latex to make surgical gloves and other products. Since SEBS does not contain unsaturated double bonds and has high purity, it has the following two advantages: (1) good oxidation resistance and ozone resistance; (2) Natural rubber contains protein, which will cause some patients to have dangerous allergic reactions, but this blend will not.
III. Specific Performance of SEBS:
SEBS has excellent aging resistance, plasticity and high elasticity. It can be processed and used without vulcanization, and leftover materials can be reused. It is widely used in the production of high-grade elastomers, plastic modification, adhesives, lubricating oil tackifiers, wire and cable fillers and sheathing materials. SEBS has good weather resistance, heat resistance, compression deformation resistance and excellent mechanical properties:
(1) Good temperature resistance, brittle temperature ≤-60℃, maximum service temperature up to 149℃, decomposition temperature over 270℃ in oxygen atmosphere.
⑵ Excellent aging resistance. The degradation rate of its performance is less than 10% after aging in an artificial accelerated aging box for one week and less than 10% after ozone aging (38℃) for 100 hours.
(3) Excellent electrical properties, with a dielectric constant of 1.3*10-4 at 1 kHz and 2.3 * 10-4 at 1 MHz; Volume resistance is 9 * 1016 Ω/cm per minute; 2*1017Ω/cm in 2 minutes.
⑷ It has good solubility, blending performance and excellent oil-filling property, can be dissolved in many common solvents, its solubility parameter is between 7.2 and 9.6, can be blended with various polymers, and can be filled with oils commonly used in rubber industry, such as white oil or naphthenic oil. (5) Elastomers that can be used without vulcanization have processing properties similar to SBS, leftover materials can be reused, and meet the requirements of environmental protection, innocuity and FDA.
(6) The specific gravity is relatively light, about 0.91, and more products can be produced with the same weight.
IV. Appearance of Materials
(1) White powder
It is a pure SEBS polymer and does not add any other blending materials.
2 granular (transparent or solid color)
SEBS powder is added with oil, resin, filler, compatilizer and other functional additives for blending, modification and granulation to obtain granule material.
V. Processing Methods
SEBS powder polymers are generally not used and processed separately. SEBS blended composite granules can be used to manufacture various articles by thermoplastic processing methods such as injection, extrusion and blow molding. SEBS and SBS are different in product structure and processing temperature. In terms of processing temperature, SBS processing temperature is generally between 150~200℃, while SEBS is generally between 190~260℃. When SBS is processed, the shear rate is required to be lower, while SEBS is required to be higher. During injection molding, SBS generally adopts moderate shear rate, while extrusion molding generally adopts screw with low compression ratio, while SEBS processing should adopt screw with high injection rate and high compression ratio.
