High‐efficiency synthesis of the transparent cyclo‐olefin elastomers with high catalytic activity at high temperature in a gas‐liquid slug flow mini‐tubular reactor

Abstract

A facile approach for synthesis of the ethylene‐norbornene copolymer (ENC) elastomers via creatively utilizing ethylene “rich” and “poor” regions within slug flow was developed by the copolymerization of ethylene (E) and norbornene (NB) in toluene solution under high temperature (90–150°C) and moderate pressure with ultra‐high catalytic activity of 2.7–11.3 × 109 gpolymer molZr−1 h−1 and efficiency of 10–17.5 kgpolymer gZr−1, respectively. For the ENC elastomers with random structure, a sharply decline of tensile strength (σ from 53.5 to 6.4 MPa), Young's modulus (E from 723.6 to 7.5 MPa) and toughness (UT from 60.3 to 12.0 MJ·m−3) were observed with the decrease of glass‐transition temperatures (Tg) of the copolymers, while the elongation at break showed the opposite trend. The ENC elastomers with multiblock structure enhanced stiffness and toughness balance with tensile strength (σ) of 13.6–41.2 MPa, Young's modulus (E) of 23.5–33.7 MPa, toughness (UT) of 31.9–47.3 MJ·m−3, and tunable elongation at break (ε = 325%–515%), which may be attribute to a certain number of controlled tiny PE crystallites acting as critical physical cross‐linking points. Moreover, all of the ENC elastomers exhibited excellent transparency (≥88%). This strategy is rather fascinating because of its simple procedure, the utilization of slug flow pattern to generate the cyclo‐olefin copolymers of diverse structures and properties, usage of only one common metallocene catalyst with two cocatalysts to achieve remarkable activity and efficiency under high temperature and the production of cyclo‐olefin elastomers with excellent performances. It is envisioned that this work would provide new perspective for the employment of flow patterns to make a difference in polymer synthesis.