Description

Polystyrene-Block-Polyisoprene-Block-Polystyrene (SIS) is a high-performance thermoplastic elastomer (TPE) formed by the sequential anionic polymerization of styrene and isoprene. This triblock copolymer is valued for its unique combination of tack, elasticity, and easy processability, making it a versatile material for demanding formulations. It is essential for manufacturers in the adhesive, sealant, and polymer modification industries seeking to enhance product performance and durability.

Application

• Hot-Melt and Pressure-Sensitive Adhesives (HMAs/PSAs): Primary component providing tack, peel strength, and cohesive strength for tapes, labels, and packaging.
• Sealants and Caulks: Imparts flexibility, adhesion, and weatherability in construction and automotive applications.
• Polymer Modification: Used as a compatibilizer or impact modifier to enhance the toughness and flexibility of plastics like polystyrene and polypropylene.
• Bitumen Modification: Improves the high-temperature performance, elasticity, and fatigue resistance of asphalt for road paving and roofing.
• Footwear and Sporting Goods: Provides cushioning, flexibility, and durability in soles and other molded components.
• Medical Devices: Used in non-implantable applications requiring soft-touch, flexible, and biocompatible materials.

Basic Information

Product Name	Polystyrene-Block-Polyisoprene-Block-Polystyrene
CAS No.	25038-32-8
Molecular Formula	(C8H8)x-(C5H8)y-(C8H8)z
Molecular Weight	Varies by grade (typically 50,000 - 300,000 g/mol)
Synonyms	SIS Triblock Copolymer; Styrene-Isoprene-Styrene Block Copolymer; Polystyrene-polyisoprene-polystyrene; Kraton D (Series); Vector (Series); Thermoplastic Rubber SIS; TPE-S; Styrenic Block Copolymer (SBC); 1,3-Butadiene, polymer with ethenylbenzene
EINECS	246-562-9

Quality Control

Our SIS triblock copolymers are manufactured under stringent process controls to ensure batch-to-batch consistency in molecular weight, block ratio, and microstructure. Quality is verified through a suite of analytical techniques including GPC, NMR, and DSC. Certificates of Analysis (COA) detailing specifications for styrene content, viscosity, and tensile properties are available upon request.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, and well-ventilated area at room temperature (15-25°C). Keep away from heat sources and open flame. For long-term storage, consider holding under an inert atmosphere to prevent oxidative degradation.

Specification

Item	Specification
Appearance	Clear to translucent pellets or crumbs
Styrene Content	15% - 30% (typical)
Volatile Matter	< 0.5%
Melt Flow Index (MFI)	5 - 50 g/10 min (200°C/5kg)
Solution Viscosity (25°C, 25% in Toluene)	500 - 5000 cP
Tensile Strength	> 20 MPa
Elongation at Break	> 800%

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.