ROMP of novel hindered phenol-functionalized norbornenes and preliminary evaluation as stabilizing agents†

Abstract

A series of new norbornene monomers containing sterically hindered phenol groups have been synthesized and polymerized via ring-opening metathesis polymerization (ROMP) using the Grubbs 3 rd generation catalyst (G3'). ROMPs exhibit first-order kinetics and molar masses increase linearly with monomer conversion and well-controlled phenol hindered-functionalized polynorbornenes were obtained with a monomer to initiator ratio up to 1 0 0 0. The first-order rate constants show that the ROMP activity is closely associated with the norbornene monomer steric congestion. The antioxidant behavior of these hindered phenol-containing polynorbornenes with different para -bridged side groups in polypropylene (PP) was estimated by onset oxidation temperature (OOT) measurements. The ability of these hindered phenol-containing norbornenes to copolymerize by ROMP with dicyclopentadiene (DCPD) was used to bound covalently the antioxidant moiety onto a polydicyclopentadiene (PDCPD) resin whose thermal ageing has been investigated.

Antimigration Polypropylene Antioxidants: A Review

“…One of the strategies is the development of high-molecular-weight antioxidants with outstanding antioxidative activity and antimigration performance. Until now, the following two methods have been developed: (I) direct synthesis − and (II) polymer grafting, which involves the grafting of reactive antioxidants onto the polymer skeleton (for instance, polybutadiene, natural rubber, polyethylene, and polypropylene).…”

Polymeric Antioxidant via ROMP of Bioderived Tricyclic Oxanorbornene Based on Vanillin and Furfurylamine

“…Consequently, polymeric antioxidants have gained much interest to overcome these drawbacks by limiting the mobility of antioxidant molecules due to their high molar masses. , Polymeric antioxidants could be synthesized via two main strategies: (I) conjugation of sterically hindered phenol moieties to a pre-synthesized or natural polymer and (II) polymerization of antioxidant monomers. ,− In this context, several studies have reported the radical polymerization of vinyl monomers bearing hindered phenol moieties. , However, the generated radicals during the polymerization process could be inhibited by means of the pendant antioxidant moieties. Hence, ring opening metathesis polymerization (ROMP) arises as an impressive technique for the development of well-defined polymers with antioxidant moieties due to the tolerance of Grubbs catalysts (Ru-based) toward many functional groups. − Driven by strain release, (oxa)­norbornenes as typical ROMP monomers have been conjugated with different hindered phenol moieties and successfully polymerized by ROMP. − …”

Enhanced thermo-oxidative stability of polydicyclopentadiene containing covalently bound nitroxide groups

“…In our group, we have studied the copolymerization of DCPD with an hindered phenol-containing norbornene ( Scheme 2 A). Thermal ageing of the resulting resin has shown an induction period while virgin PDCPD oxidized instantly [32] . Furthermore, we have for the first time shown the efficiency of 2,2,6,6-tetramethylpiperidine-1-oxyl ( TEMPO )-containing dicarboximide polynorbornenes as stabilizing agents in polypropylene [33] .…”