Synthesis and performance study of Polybutene-1 synergistically engineered via H-Shaped long-chain-branching and ethylene co-monomer incorporation

Abstract

This paper discusses the synthesis of H-shape long-chain-branched (LCB) 1-butene/ethylene copolymers via ω-alkenylmethyldichlorosilane copolymerization-hydrolysis (ACH) chemistry catalyzed by Ziegler-Natta and metallocene catalysts, where the LCB structures are joined by ethylene co-units to cooperatively modulate the sluggish Form II-I transition kinetics intrinsic to polybutene-1 (PB-1). The results reveal a synergistic effect between the two structural modifications in accelerating the Form II-I transformation. Such an enhancement proves substantially more pronounced with the metallocene catalyst system, where the conventionally 7-day transition period is shortened to within 24 h. Though ethylene incorporation disrupts chain regularity, reducing crystallinity and tensile modulus, it is found that LCB structures effectively counteract such destructive effects by enhancing nucleation and molecular chain entanglement. This research provides a new chemical approach to PB-1 modification that greatly improves its processing properties without significantly affecting mechanical properties.