Dr. Sudhin Datta
Propylene-based elastomers—introduced commercially between 2003 and 2007 by ExxonMobil, Dow, and Mitsui—are semicrystalline, elastomeric copolymers composed predominantly of propylene with limited amounts of ethylene or other alpha olefins. The concentration of propylene is typically greater than 80 wt%. The polymers derive their key differentiating properties of easy processing, elasticity, and compatibility in blends from their composition and the tacticity of the propylene residues. A key property of these elastomers is the formation of compatible blends with number of hydrocarbon polymers such as isotactic polypropylene and polyisobutylene. These blends extend the applicability of these polymers. The range of utility of these polymers is enhanced by the ability to process them in typical thermoplastic and elastomeric fabrications; thus both nonwoven fabrics and compounded elastomeric products are now available. A more recent development is the ability to vulcanize these polymers by including a limited amount of a cyclic diene during synthesis; the polymers combine the ease of processing of soft thermoplastics with the durability of crosslinked elastomers. Finally, the development of propylene-based elastomers, like the previous generation of ethylene-predominant plastomers, is derived essentially from the control of the composition and structure from the new generation of olefin polymerization catalysts.