Cationic Polymerization of Norbornene Derivatives in the Presence of Boranes

Abstract

Cationic polymerization of 5-methylene-2norbornene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, dicyclopentadiene, and norbornadiene-2,5 in the presence of boranes was systematically studied. It was found that B(C 6 F 5 ) 3 in combination with caprylic acid, 1-phenylethanol or water was a highly active catalyst for the polymerization of 5-alkylidene-2norbornenes. The corresponding cationic polymers were obtained with up to yields 95% and with high molecular weights (M w ≤ 430 000). The activity of 5-alkylidene-2-norbornenes in the polymerization using B(C 6 F 5 ) 3 containing systems was the highest among the other monomers (5-vinyl-2-nobornene, dicyclopentadiene, and norbornadiene-2,5). BF 3 •O(C 2 H 5 ) 2 based catalysts turned out to be not so active for cationic polymerization of monomers compared with the systems containing B(C 6 F 5 ) 3 . They produced polymers predominantly containing the addition (vinyl) units instead of isomerization units. The structure of the polymer main chain units depended on the nature of the monomers: in the case of norbornadiene-2,5, 5-methylene-2-norbornene, and 5-ethylidene-2-norbornene the transannular polymerization proceeded, while dicyclopentadiene and 5-vinyl-2-norbornene formed the addition type polymers under the studied conditions.

Addition Homo‐ and Copolymerizations of Dicyclopentadiene and 5‐n‐Hexylnorbornene in the Presence of Pd‐N‐Heterocyclic Carbene Complexes

“…These directions of DCPD transformations, unlike metathesis polymerization, will lead to polymers with saturated and more rigid main chains. Cationic polymerization of DCPD resulted in only low molecular weight polymer products or oligomers . In contrast to this, addition polymerization of DCPD is a more thermodynamically favorable process.…”

“…Norbornene and its derivatives are an unusual class of monomers that can be polymerized by various mechanisms forming polymers with different structures of main chains and properties . This feature, along with the ability to synthesize series of norbornenes with a regularly varying structure, has made these compounds attractive for the macromolecular design of polymers with desired properties and for the systematic study of the relationships “polymer structure‐properties.” Depending on the nature of the side substituents and the structure of the main chain, norbornene‐based polymers can have attractive optical properties, low moisture absorption, thermal and chemical stabilities, promising membrane characteristics, etc.…”

“…weight polymer products or oligomers. [3,[17][18][19] In contrast to this, addition polymerization of DCPD is a more thermodynamically favorable process. Despite this, the number of papers devoted to addition polymerization of DCPD is quite limited in comparison to the polymerization of unsubstituted norbornene and only several works were published.…”

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

“…74) [318]; (7) a tris(norbornenecarboxylate) connected to a carbon nanotube [319]; (8) bis(norbornenecarboxylate ester)s (e.g. 73) [320]; (9) 5-ethylidenenorbornene (68) [321], including its use as a part of a self-healing system [322]; (10) vinylnorbornene [323]; (11) tetracyclododecene (69) [324]; (12) norbornadienes connected to various hydrophobic groups, including a steroid system [325]; (13) dicyclopentadiene [326,327,328,329,330,331,332,333,334,335,336], including polymerizations performed in the presence zinc oxide nanoparticles [337], urea formaldehyde microcapsules [338],mildly oxidized graphene oxide [339], barium titanate [340], and high internal phase emulsions [341,342]; (14) the norbornadiene-anthracene Diels-Alder adduct (76) [343,344]; (15) norbornenedicarboxylate esters connected to cyanobiphenyl groups [345], to anthracene groups [346], and to nitroxide groups (e.g. 79) [347]; (16) the three stereoisomeric dimethyl norbornenedicarboxylates (determination of the relative rates of ROMP) [348]; …”

Experimental and Theoretical Study of [2σ + 2σ + 2π]–Cycloaddition of Quadricyclane and Ethylenes Containing Three Silyl-Groups

“…Norbornenes are unique monomers which could be polymerized via different routes to give polymers with various backbones [1][2][3][4]. It has been recently shown that among norbornene derevatives exo-tricyclononenes were more attractive due to their enhanced activities in polymerization [5][6][7][8][9].…”