ABSTRACTWhile numerous studies have addressed the morphological characteristics of diblock copolymer blends either with a second copolymer or a parent homopolymer, relatively few have examined comparable blends containing a triblock copolymer. In this study, we investigate the role of mid-block bridging on the morphological and physical characteristics of blends composed of a poly(styrene-b-isoprene-b-styrene) (SIS) triblock copolymer with either an unconstrained homo-polyisoprene (hI) or an end-grafted SI diblock copolymer. Blend compositions and molecular weights of the hi, as well as the I-block of the copolymer, have all been systematically varied to elucidate the effect of additive constraint on the extent of nonideal intramicrodomain mixing. Blend morphologies are characterized using transmission electron microscopy, while blend properties have been measured by dynamic mechanical analysis.
