Synthesis of block copolymer additives for examining phase morphology and improving mechanical properties of thermoplastics elastomers.

Polystyrene-block-poly(1,4-butaidene)-block-polystyrene (PS-PB-PS) triblock copolymers are one of the most widely studied thermoplastic elastomers (TPEs) due to their ease of synthesis, non-polar nature, and commercial applicability. Like many block copolymers, incompatibility between PS and PB causes these TPEs to undergo microphase segregation. Many studies have examined the mechanical properties of blends of TPEs and PS homopolymer additives. However, there have been few studies focused on understanding the morphology and mechanical properties of blends of TPEs and copolymer additives with different architectures. Herein, I describe the synthesis of linear and graft copolymer additives based on the random copolymers poly(methyl methacrylate-random-cyclohexyl methacrylate) (PrC). These copolymers offer composition-tuned miscibility with PS domains of PS-PB-PS TPEs, allowing their enthalpic and entropic effects on morphology, thermal properties, such as glass transition temperature (T_g), and mechanical properties, such as tensile and creep behaviors, to be studied.