Preparation of monodisperse hydrophilic polyamide by anionic polymerization of bicyclic oxalactam

Abstract

The preparation of a monodisperse hydrophilic polyamide was achieved in the anionic polymerization of a bicyclic oxalactam, 8‐oxa‐6‐azabicyclo[3.2.1]octan‐7‐one (abbreviated BOL) with the use of N‐benzoyl BOL and potassium pyrrolidonate (2 and 0.5 mol % to BOL, respectively) in dimethyl sulfoxide at 25°C. The number‐average molecular weight of the polyamide increased in direct proportion to the monomer conversion, and was consistent with the value calculated from the amounts of the consumed monomer and activator. The molecular weight distribution (MWD) of the polyamide obtained until the middle stage of polymerization (polymerization time, < 10 min; monomer conversion, < 60%) was found to be narrow (Mw/Mn = 1.1). The MWD was gradually broadened in the later stage of the polymerization, which may result from the redistribution of molecular weight of the resulting polyamide not only by the polymerization–depolymerization equilibrium, but also by transamidation between polymer chains.

Synthesis of new hydrolyzable polyurethanes from L‐gulonic acid‐derived diols and diisocyanates

“…GPC chromatograms were measured with a Tosoh HLC‐8120 high‐performance liquid chromatogram apparatus (Tosoh TSK‐gel GMHXL column, ϕ7.8 × 600 mm; solvent, Me 2 SO; rate, 0.8 mL/min). Polyamides with narrow molecular weight distributions obtained by the quasi‐living anionic polymerization of 8‐oxa‐6‐azabicyclo[3.2.1]octan‐7‐one35, 36 were provided as standards. The thermal stability was recorded on a Shimadzu TGA‐50 thermogravimetric analyzer from 30 to 800°C at a heating rate of 10°C/min with dry nitrogen gas at a flow rate of 20 mL/min.…”

Synthesis of monodisperse polyamides by living anionic polymerization of β‐lactams in the mixture of N,N‐dimethylacetamide and lithium chloride

“…Therefore, the selection of solvents is important for the living anionic polymerization of lactams under mild conditions. In facts, monodisperse polyamides have been prepared, to date, through the living anionic polymerization of a P-lactam having a bulky substituent, 3-butyl-3-methyl-2-azetidinone (1) in tetrahydrofuran at 27OC,' and through the quasiliving polymerization of a bicyclic lactam, 8-oxa-6azabicyclo[ 3.2.11 octan-7-one (2) in dimethyl sulfoxide at 25°C.2,3 Although other different p-lactams having high polymerizability originating from their ring strains have been also polyrneri~ed,~-" the preparation of their monodisperse polyamides has not been reported yet.…”

Molecular weight distribution of polyamides obtained in anionic polymerization of methyl-substituted ?-lactams and aminolysis of theirN-benzoyl lactams

“…zoyl-4,4-dimethyl-2-azetidinone (7a), N-benzoyl-3-methyl-2-azetidinone (8a), N-benzoyl-a-pyrrol-Anionic Polymerization of Methyl-Substituted idone (9a), and N-benzoyl-e-caprolactam (10a) b-Lactams were prepared in pyridine from benzoyl chloride and the corresponding b-lactams. 5 6a; bp 141ЊC (3 In our previous article, 1 the anionic polymerization of 1 and 2 in DMAc containing 5 wt % of mmHg), yield 54%, m.p. 65-66ЊC (recrystallized from n-hexane): 7a; yield 75%, m.p.…”