Anionic ring‐opening polymerization of N‐glycidylphthalimide: Combination of phosphazene base and activated monomer mechanism

Abstract

Anionic ring‐opening polymerization of glycidyl phthalimide, initiated with alcohol–phosphazene base systems and based on monomer activation with a Lewis acid (iBu3Al), has been studied. No propagation occurred for initiator: iBu3Al ratios less or equal to 1:3. For larger Lewis acid amounts, the first anionic ring‐opening polymerizations of glycidyl phthalimide were observed. Polymers were carefully characterized by NMR, MALDI‐TOF mass spectrometry, and size exclusion chromatography and particular attention was given to the detection of eventual transfer or side‐reactions. However, polymer precipitation and transfer reaction to aluminum derivative were detrimental to monomer conversion, polymerization control, and limited polymer chain molar masses. The influence of reaction temperature and solvent on polymer precipitation and transfer reactions was studied and reaction conditions have been optimized leading to afford end‐capped poly(glycidyl phthalimide) with narrow molar mass distributions. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1091–1099

pH‐Sensitive Poly(ethylene glycol)/Poly(ethoxyethyl glycidyl ether) Block Copolymers: Synthesis, Characterization, Encapsulation, and Delivery of a Hydrophobic Drug

“…mPEG hydroxyl end-groups were deprotonated by tBuP 4 phosphazene base, [47] generating extremely reactive alcoholates associated with phosphazenium cations, which initiated the polymerization of EEGE monomers. [48,49] Molar masses determined by size exclusion chromatography and 1 H NMR are in good agreement with the theoretical ones ( Table 2). The polymerization degree of the hydrophobic EEGE block is defined by the [M] 0 /[I] 0 ratio, allowing the control of the copolymer hydrophilic-hydrophobic balance.…”

Modification of proline‐based 2,5‐diketopiperazines by anionic ring‐opening polymerization

“…30 In particular, alcohol/phosphazene base initiating systems combined with i-Bu 3 Al have been used to synthesize high molar mass poly(propylene oxide) 31 or to polymerize N-glycidylphthalimide. 32 These systems strongly increase the rate of polymerization due to the monomer activation and minimize transfer and side reactions thanks to the selective reactivity of the Lewis acid-anion-counter-ion complexes formed as initiating and propagating species. Therefore, we have investigated the effect of C(A-P)/t-BuP 4 /i-Bu 3 Al initiating system on the reactivity of active centers and the occurrence of side reactions during polymerization.…”

“…The incorporation of Lewis acid to the reaction mixture has already been used to promote the activated monomer mechanism for the polymerization of oxirane monomers with various initiators . In particular, alcohol/phosphazene base initiating systems combined with i‐Bu 3 Al have been used to synthesize high molar mass poly(propylene oxide) or to polymerize N ‐glycidylphthalimide . These systems strongly increase the rate of polymerization due to the monomer activation and minimize transfer and side reactions thanks to the selective reactivity of the Lewis acid‐anion‐counter‐ion complexes formed as initiating and propagating species.…”

Role of donor‐acceptor functional groups in N3P3 cyclic‐triphosphazene backbone. Unraveling bonding characteristics from natural orbitals within an extended transition state‐natural orbital for the chemical valence scheme

“…Phosphazene compounds depict an important class of compounds because they exhibit outstanding properties that can be involved in the development of new applications, such as liquid crystals, and in the obtaining of photosensitive materials. [1][2][3][4][5][6][7][8][9][10][11] Such systems give rise to potential applications including drug delivery systems, [12] biological activity, [5,13] and catalysis. [14][15][16][17][18][19][20] Such systems have also been used as base support for the formation of nanomaterials, [21][22][23][24][25][26] as well as heterocyclic-triphosphazenes that can form interacting host-guest systems.…”