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Comb‐Like Graft Copolymers of Poly(oxa)norbornene: Efficient Synthesis Using a Combination of ROMP and Click Chemistry
Author(s) -
Eissa Ahmed M.,
Khosravi Ezat
Publication year - 2015
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201400604
Subject(s) - romp , norbornene , macromonomer , click chemistry , polymer chemistry , azide , polymerization , copolymer , peg ratio , ethylene glycol , alkyne , ring opening metathesis polymerisation , materials science , chemistry , polymer , metathesis , organic chemistry , catalysis , finance , economics
The combination of ring‐opening metathesis polymerization (ROMP) and copper‐catalyzed azide–alkyne cycloaddition (CuAAC) is described as an efficient click reaction to synthesize a new range of well‐defined comb‐like polynorbornene/polyoxanorbornene graft copolymers containing poly(ethylene glycol) (PEG) and/or poly(ε‐caprolactone) (PCL) as side chains. The “grafting through” method is applied for the synthesis of polyoxanorbornene‐ g ‐PEG via ROMP of oxanorbornenyl di‐PEG macromonomer prepared by click coupling of azide‐terminated PEG with di‐alkyne‐functionalized oxanorbornene. The well‐characterized macromonomer is then subjected to ROMP. Polynorbornene‐ g ‐PCL and polynorbornene‐ g ‐PEG are prepared by the “grafting onto” route. This is achieved by ROMP of 5‐bromohexyloxymethyl norbornene followed by reaction with NaN 3 and then click reaction with alkyne‐terminated PEG and PCL. (Polyoxanorbornene‐ g ‐PEG)‐ ran ‐(polynorbornene‐ g ‐PCL) is prepared by ROMP of a mixture of oxanorbornenyl di‐PEG and 5‐bromohexyloxymethyl norbornene followed by reaction with NaN 3 and subsequently click reaction with alkyne‐end‐capped PCL. All intermediates and final products are characterized by IR, NMR, MS, and size exclusion chromatography (SEC). Self‐assembly of these comb‐like polymers in solution into micro/nanostructures is foreseen, leading to a wide range of potential applications.