Enhanced Mechanical Performance of Polybutene-1 Terpolymers via Crystallization Modulation

Achieving an optimal balance between mechanical strength and elastic recovery remains a challenge in the development of high-performance thermoplastic elastomers. This study utilized a rational method of modulating crystallite structure to overcome the intrinsic trade-off between strength and recovery. Polybutene-based terpolymers were designed and synthesized through the controllable incorporation of the cyclic methylene-1,3-cyclopentane counits and linear α-olefin counits with different lengths. This method selectively produced both trigonal and tetragonal phases, which have distinct macromolecular mobility within the crystal lattice, resulting in improved mechanical performance. The trigonal crystallites, which served as robust physical cross-links, not only increased the tensile strength and breakage elongation up to 1140% but also effectively suppressed irreversible deformation to yield excellent elastic recovery. Differently, the polybutene-based terpolymers mainly comprising mobile tetragonal crystallites regained superior strength and elastic recovery after undergoing a solid–solid phase transition into trigonal crystals. The rationally designed copolymerization provides an effective pathway to simultaneously enhance the strength and elasticity.