Polymerization of Ethylene through Reversible Addition–Fragmentation Chain Transfer (RAFT)

Abstract

The present paper reports the first example of a controlled radical polymerization of ethylene using reversible addition-fragmentation chain transfer (RAFT) in the presence of xanthates (Alkyl-OC(=S)S-R) as controlling agents under relative mild conditions (70 8C, < 200 bars). The specific reactivity of the produced alkyl-type propagating radicals induces a side fragmentation reaction of the stabilizing O-alkyl Z group of the controlling agents. This fragmentation, rarely observed in RAFT, was proven by NMR analyses. In addition, semicrystalline copolymers of ethylene and vinyl acetate were also prepared with a similar level of control. Angewandte Chemie 6801

RAFT‐Mediated Polymerization‐Induced Self‐Assembly

“…Since the edition of the first "The Handbook of RAFT" published by Wiley in 2008, [2] RAFT has been confirming its significance and great potential over the existing RDRP techniques.T his is attested by an ever-growing interest in RAFT polymerization since it was first reported in the open literature in 1998, [3] and by constantly improving the control over the molar mass while expanding the range of controllable monomers. [4][5][6][7] In addition, the development of RAFT in heterogeneous media [8] has provided new tools to design macromolecular objects,thereby contributing to the develop-As we will see in this Review,p olymerization-induced self-assembly (PISA) is probably the best example of this evolution. Indeed, as mentioned above,the myriad of macromolecular architectures that have been obtained through the use of RDRP techniques lies in the fact that the formed chains can be further extended for the generation of asecond block.…”

RAFT‐vermittelte polymerisationsinduzierte Selbstorganisation (PISA)

“…Molmasse bei gleichzeitiger Erweiterung des Bereichs kontrollierbarer Monomere [4][5][6][7] aus.D es Weiteren hat die Entwicklung von RAFT in heterogenen Systemen [8] neue Werkzeuge zum Entwerfen makromolekularer Objekte bereitgestellt, die zur Konzipierung origineller Anwendungen beigetragen haben. [9] Wiew ir in diesem Aufsatz sehen werden, ist die polymerisationsvermittelte Selbstorganisation (PISA;p olymerization-induced self assembly) wahrscheinlich das beste Beispiel fürd iese originellen Anwendungen.…”

Facile Access to Polar-Functionalized Ultrahigh Molecular Weight Polyethylene at Ambient Conditions

“…Recent improvements (< 250 bar, < 100 o C) on these issues via controlled radical polymerization techniques are appealing, but molecular weights (M n ) of polymers are still low, which are less than 10 5 g mol -1 and usually 10 3 -10 4 g mol -1 . [20][21][22][23][24][25][26][27] In contrast, since the milestone's discovery from Ziegler and Natta, early-and late-transition and rare-earth metal catalyzed coordination-insertion polymerization of ethylene requires prominently mild reaction conditions (1-100 bar, < 100 o C) and is highly controlled to produce PEs with a variety of molecular weights (10 -10 g mol -1 ) and well-defined architectures.…”