Semibatch Terpolymerization of Ethylene, Propylene, and 5-Ethylidene-2-norbornene: Heterogeneous High-Ethylene EPDM Thermoplastic Elastomers

• DOI: 10.1021/acs.macromol.0c01123
• Publication Date: 2020-07-16T13:44:31Z
• Authors: Giuseppe Leone; Giorgia Zanchin; Rocco Di Girolamo; Fabio De Stefano; Christian Lorber; Claudio De Rosa; Giovanni Ricci; Fabio Bertini
• Keywords: Comonomer; Thermoplastic elastomer; Norbornene; Ethylene propylene rubber; Molar mass distribution

Thermoplastic elastomers (TPEs) are materials combining the processability of thermoplastics and elasticity rubbers. The global value demand TPEs expected to grow in coming years, advancement synthetic chemistry is key driving force. This contribution provides a simple synthesis high-ethylene EPDMs with high molecular weight, narrow weight distribution (1.9 < Mw/Mn 2.3), properties which can be adjusted from soft thermoplastic elastomer. prepared through terpolymerization ethylene propylene 5-ethylidene-2-norbornene (ENB), where continuously supplied reaction bath, while ENB added only at beginning. Polymerizations catalyzed by three known imido vanadium(IV) complexes, differing substituent coligand, combination Et2AlCl Cl3CCO2Et. obtained mixture macromolecules, each them featuring nonrandom comonomer nonuniform composition. Each chain likely contains multiblocks comonomers segmented, i.e., blocks content that may crystallize not crystallize. broad chemical composition due time drift occurs during polymerization, turn depends on experimental conditions ligand set. Composition causes variation instantaneous feed ratio hence terpolymer over period conversion. In proper conditions, behave as without need vulcanization, polymer blending, reinforcement addition fillers. They exhibit elongation break, strain hardening large deformation, remarkable shape retention (up 76% recovery after 10 cycles 300% about 90% 410% strain), remelting no fall for recycle reuse.