Abstract
Nitroxide-mediated polymerization (NMP), (homo and block copolymerization with styrene (S) and butyl methacrylate/S) of ethylene glycol dicyclopentenyl ether (meth)acrylates (EGDEA and EGDEMA) was studied using BlocBuilder alkoxyamines. EGDEA homopolymerization was not well-controlled, independent of temperature (90–120 °C), or additional free nitroxide (0–10 mol%) used. Number average molecular weights (Mn) achieved for poly(EGDEA) were 4.0–9.5 kg mol−1 and were accompanied by high dispersity (Ð = Mw/Mn = 1.62–2.09). Re-initiation and chain extension of the poly(EGDEA) chains with styrene (S) indicated some block copolymer formation, but a high fraction of chains were terminated irreversibly. EGDEA-stat-S statistical copolymerizations with a low mol fraction S in initial feed, fS,0 = 0.05, were slightly better controlled compared to poly(EGDEA) homopolymerizations (Ð was reduced to 1.44 compared to 1.62 at similar conditions). EGDEMA, in contrast, was successfully polymerized using a small fraction of S (fS,0 ~ 10 mol%) to high conversion (72%) to form well-defined EGDEMA-rich random copolymer (molar composition = FEGDEMA = 0.87) of Mn = 14.3 kg mol−1 and Ð = 1.38. EGDEMA-rich compositions were also polymerized with the unimolecular succinimidyl ester form of BlocBuilder initiator, NHS-BlocBuilder with similar results, although Ðs were higher ~1.6. Chain extensions resulted in monomodal shifts to higher molecular weights, indicating good chain end fidelity.
Highlights
Ethylene glycol dicyclopentenyl ether acrylate (EGDEA) and the related ethylene glycol dicyclopentenyl ether methacrylate (EGDEMA) are imparted into polymers useful as reactive coalescents that aid film formation in coatings [1,2], reactive diluents to reduce exotherms in bone cement formulations [3], and anti-bacterial films and coatings without resorting to quaternary ammonium functionalities or metallic nanoparticles [4,5,6,7]
The acrylate homopolymerization was studied as a function of temperature and additional SG1 free nitroxide
EGDEA was best controlled at lower temperature (90 ◦ C) and r = 0.10, dispersity Đ steadily increased during the course of the polymerization and gelation began being observed as conversions increased above 30%
Summary
Ethylene glycol dicyclopentenyl ether acrylate (EGDEA) and the related ethylene glycol dicyclopentenyl ether methacrylate (EGDEMA) are imparted into polymers useful as reactive coalescents that aid film formation in coatings [1,2], reactive diluents to reduce exotherms in bone cement formulations [3], and anti-bacterial films and coatings without resorting to quaternary ammonium functionalities or metallic nanoparticles [4,5,6,7]. EGDEA and EGDEMA possess norbornene functionalities that open possibilities for orthogonal functionality, allowing modifications via thiol-ene click chemistry, for example [8,9,10,11] These two particular monomers were polymerized by conventional radical polymerization using photoinitiation (cross-linking) [4] and with peroxide or nitrile-based initiators [3]. In these cases, EGDEA and EGDEMA-containing polymers do not have the control over microstructure and molecular weight distribution that would impart additional properties. There have been no other reports using EGDEA or EGDEMA in other RDRP processes to the best of our knowledge
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