Thermoplastic elastomers are attractive materials because of their ability to be melt-processed, reused, and recycled, unlike chemically cross-linked elastomers such as rubber. We report the synthesis and mechanical properties of polyolefin-based thermoplastic elastomer block copolymers. A simple one-pot procedure is employed, using a living arylnaphthyl-α-diimine Ni(II) "sandwich" complex to generate high crystallinity hard blocks from 1-decene and low crystallinity soft blocks from ethylene. Various block structures are accessed, ranging from a diblock up to a heptablock copolymer. Statistical copolymers of 1-decene and ethylene are also synthesized for comparison. All resulting polymers behave as elastomers, with properties that modulate with hard and soft block composition, block architecture, and polymerization solvent. Triblock copolymers demonstrate strain at break values up to 750%, with elastic strain recoveries up to 85%. Interestingly, statistical copolymers demonstrate strain at break values upward of 1120% and elastic strain recoveries up to 77%. Creep experiments were performed to determine the resilience of these materials to deformation. It is found that higher block architectures (triblock and above) have greater resistance to strain-induced deformation than lower block architectures (diblock and statistical).
Bibliographical noteFunding Information:
This work (support for K.S.O., A.W., and T.V. and partial support for A.M.L.) was provided by the Center for Sustainable Polymers, a National Science Foundation (NSF)-supported Center for Chemical Innovation (CHE-1413862). We are also grateful to the Office of Naval Research (N00014-14-1-0551; partial support for A.M.L.) and Mitsubishi Chemicals for generous financial support. We also acknowledge Albemarle Corporation for their generous donation of MAO.
© 2016 American Chemical Society.