Why SBS needs to be modified by adding plastic products? This mainly results from its poor processing performance and product properties that can’t meet the practical application requirements. In general, SBS is rarely used in the finished products independently. To satisfy the special requirements of applications and reduce costs, SBS must be modified by adding additives, resins and others.
With excellent elasticity, SBS elastomers can be mixed with other polymer materials in the molten state, extruded and cut, then cooled to prepare the modified SBS thermoplastic elastomers. This improves SBS’s flowability and mechanical properties such as hardness, abrasion resistance and tear strength, and expands its application range. The major polyolefin plastic polymers used for SBS modification include PE, PP, PS, etc. They share common characteristic in the good compatibility with SBS, thus the modified SBS has excellent bonding property.
PE / PP: Both polyethylene (PE) and polypropylene (PP) have outstanding properties, including ease of processing, excellent electrical properties, excellent flexural strength, low temperature flexibility, excellent corrosion resistance, and low permeability. The use of PE and PP for SBS modification can improve the abrasion resistance, hardness, weatherability, tear strength and melt flow rate of SBS elastomers, while maintain high tensile strength and elongation at break.
PS: Polystyrene (PS) has the advantages such as easy molding, low shrinkage, low hygroscopicity, and good thermal performance. PS has good compatibility with SBS. Strong bonding force exists at the phase interface of two polymers, and increases as the rising number of styrene chain segments in SBS. The tensile strength and elongation at break of the SBS modified by PS will decrease as the increase of PS content, while the hardness will rise slightly.
SBS modified by plastics is mainly applied in footwear, bitumen modification,plastic modification,adhesives and other sectors.