ABSTRACT:A bicyclic oxalactam, 8-oxa-6-azabicyclo[3.2. l)octan-7-one was anionically polymerized in dimethyl sulfoxide at room temperature and the resulting hydrophilic polyamide having an acyllactam-type growable chain end was isolated from the polymerization system. The reactive end group was found to be easily converted to other functional groups by the hydrolysis or aminolysis with suppressing the simultaneous decomposition of the polyamide chain. The terminal acyllactam group in the polyamide, which was used as an activator in the anionic polymerization of 2-pyrrolidone, was quantitatively consumed and all of the macromolecular activator could be incorporated into the resulting copolymer. The thermal behavior and crystallization of the AB-type block copolymer composed of the hydrophilic polyamide and nylon-4 segments were influenced by the characteristics of the hydrophilic polyamide segment. KEY WORDSBicyclic Oxalactam / Anionic Polymerization / Reactive End Group / 2-Pyrrolidone / Block Copolymer / The polymerizability of a bicyclic oxalactam, 8-oxa-6-azabicyclo[3.2. l ]octan-7-one (abbreviated as BOL, 1), is so high that it can be easily polymerized using anionic catalysts under mild conditions such as in dimethyl sulfoxide (Me 2 SO) at room temperature,1-3 which should be desirable for suppressing possible side reactions. In fact, the resulting hydrophilic high molecular weight polymer (polyBOL, 2) has a purely alternating arrangement of an amide group and a tetrahydropyran ring along the main chain but has no other repeating unit ( eq 1 ). 1 -3 The vinylbenzyl-type polyamide macromer (3) was prepared by the anionic polymerization of BOL followed by the reaction with p-vinylbenzylamine. 4 • 5 This suggests that the generated acyllactam-type growable chain end is not destroyed by any side reaction during 321

In the polymerization of various cyclic monomers, the equilibria were observed between the resulting polymers and the unreiicted monomers.'-3 Thus the equilibrium monomer concentrations or the thermodynamic parameters were estimated in the polymerization of several monocyclic lactams:-"The polymerizability of a variety of atom-bridged bicyclic lactams was also found by H. K. Hall, Jr.12 to be dependent upon their ring strain. This article will describe the equilibrium anionic polymerization of a bicyclic oxalactam, 8-oxa-6-azabicyclo[3.2.l]octan-7-one (1) and discuss its thermodynamic polymerizability.(1)Recently the anionic polymerization of 1 in dimethyl sulfoxide (Me,SO) at 25°C was found to give the monodipserse hydrophilic polyamide having an acyllactam-type growable end group (2).'3914 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 a~tivator.'~ From these results 1 can be speculated to have been polymerized without side reaction under the above-mentioned conditions. Nevertheless, the monomer conversion has not yet reached 100% under any Polymerization ~ondition.'~-'~ The refore, we expect the existence of the monomer-polymer equilibrium in the polymerization of 1.In the present work, the polymerization of 1 activated with N-(p-nitrobenzoy1)-8-oxa-6-azabicyclo[3.2.l]octan-7-one in Me,SO at 25°C was first followed by the gravimetrical determination of the resulting polyamide, and the residual monomer concentration ( [ M I , ) was found to reach 0.36 mol/L in about 20 min.'4 The polymer-

ABSTRACT:A polyamide macromonomer (1) having a vinylbenzyl group at one chain end was copolymerized with 2-vinylpyridine (VP) using a radical catalyst in N,N-dimethylformamide at 60°C. The resulting graft copolymer composed of a poly(VP) stock and polyamide branches was separated from the unreacted 1 by fractional precipitation in dimethyl sulfoxide-water mixed solvent. A graft copolymer membrane was easily prepared by casting a methanol solution of the copolymer, while a homopolymer ofVP had poor film-forming ability. The crosslinked membrane was found to exhibit extremely high permeability of cupric chloride in aqueous solution.