Polybutadiene microstructure variations

Microstructure variation in both polybutadiene and polyisoprene polymers has been realized by using alkyllithium initiators in the presence of polar modifiers. 

MICROSTRUCTURE VARIATION IN POLYBUTADIENE MICROSTRUCTURE (VINYL. CIS AND TRANS)... 

Microstructure variation in polybutadiene microstructure (vinyl, cis and tram). 

Further exploration [57] into the variation in properties available in the fully saturated poly(styrene-bl-butadiene-bl-styrene) materials focused on modifying the vinyl content in the polybutadiene block. Exploring practical elastomeric properties such as rebound and modulus, this work showed plainly that the level of vinyl in the polybutadiene block dominated the room temperature elastomeric properties of the block copolymer with a preferred level of about 40mol% percent 1,2-microstructure. 

In part because of the amorphous nature of SBRs microstructural variables play less important a role than with polybutadienes and polyisoprenes. The cisitrans ratio does not appear to exert much influence on properties. As with the polybutadienes the vinyl percentage is a factor and is capable of significant variation with the solution polymers. Such polymers with low percentage vinyl contents have lower TgS than the emulsion polymers whilst the reverse is the case for those polymers with high vinyl contents. 

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