Versatile Production of Multivariate, Hyperdimensional End Group and Main Chain Functionalized Polyolefins

Abstract

The (stereoselective) living coordinative copolymerization of 1‐alkenes with 4‐aryl‐1,6‐heptadienes, in both the absence and presence of multiple equivalents of a reversible chain transfer agent, is established as a highly versatile strategy for production of multivariate hyperdimensional functionalized semi‐crystalline or amorphous polyolefins that optionally possess either mono‐ or difunctionalized (telechelic) end‐groups in combination with a programmable level of incorporation of orthogonal functional groups within the main‐chain. The non‐conjugated diene comonomers are readily obtained from a diverse range of aryl carboxaldehyde precursors through a one‐step bis‐allylation process. These results serve to provide a new platform for exploring the science and technology of a vast new landscape of functionalized classes of polyolefins that are now accessible in practical and scalable quantities.

Stereoblock vs Stereoblend: Orchestrating Competing Living Coordination Chain Transfer Polymerizations for the One-Pot Production of New Viscoelastic Grades of Poly(4-methyl-1-pentene)

“…Scheme presents the new multistate strategy that is the subject of the present report in which isospecific and aspecific LCCTP processes for 4M1P are pitted against each other within a single reactor using varying equivalents of diethylzinc, ZnEt 2 (DEZ), as a chain transfer agent (CTA) . As with other multistate LCP and LCCTP processes that we have proposed and experimentally validated, in the absence of chain termination, all the desired features of a living polymerization can be retained if the rate and rate constants for reversible group and polymeryl chain transfer between active transition-metal propagators and either dormant species, in the case of LCP, or an excess population of main-group-metal “surrogate” chain growth centers, in the case of LCCTP, are far greater in magnitude than the corresponding kinetic parameters for chain growth occurring at the transition-metal centers. , This includes the ability to have control over the number-average degree of polymerization, DP n , and a very narrow molar mass distribution (MMD), as defined by a dispersity index, Đ (= M w / M n ) ≤ 1.1, where M n and M w are the number-average and weight-average molar mass indices. However, the key advantage of multistate LCP and LCCTP processes lies with introduction of new mechanistic control points that can be manipulated and brought under external control to direct product formation as an infinite variety of different grades with differing properties that formally exist within a spectrum defined by two limiting ends.…”

“…Further investigations are now in progress to explore the bulk structure and rheology of these new stereoblends of PMP and of their potential for new technological applications. In addition, given the wealth of structural diversity for CPAM group 4 metal complexes that we have previously shown to be competent as preinitiators for LCP and LCCTP, , we are further investigating the strategy of Scheme to produce stereoblock polyolefins under optimized conditions through directed manipulation of the CPAM ligand steric environments about each active species. The results of these studies will be reported in due course.…”

“…However, a critical disadvantage of iPMP is that molded films are highly brittle with a low impact and tensile strength. Herein, we present the results of a successful project undertaken to develop new viscoelastic grades of PMP through extension of “multistate” living coordinative polymerization (LCP) and living coordinative chain transfer polymerization (LCCTP) as a toolbox of processes for greatly expanding the range of new forms and properties of polyolefins that can be produced from the very small set of industrially relevant commodity olefin feedstocks. ,− …”

“…Scheme presents the experimental methods that were employed to investigate the viability of Scheme for delivering new viscoelastic grades of PMP and Table provides results obtained from these efforts. To begin, as we have previously reported, run 0 serves as a benchmark for production of amorphous aPMP ( Ia ) using only the C s -symmetric cyclopentadienyl, amidinate (CPAM) hafnium dimethyl preinitiator 1 in combination with 1.1 equiv of the anilinium borate, [PhNHMe 2 ]­[B­(C 6 F 5 ) 4 ] ( B1 ), as co-initiator and 5 equiv of DEZ as CTA. ,, Runs 1–9 document results obtained with an increasing amount of the chiral (but racemic) C 1 -symmetric CPAM zirconium dimethyl preinitiator 2 being introduced while keeping the total number of transition-metal active propagators (Hf + Zr) and the number of equivalents of CTA constant. Finally, run 10 serves to provide the other benchmark in which use of only 2 as the preinitiator, and with all other factors remaining the same, produced highly crystalline iPMP ( Ib ).…”