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A method for the synthesis of well-defined poly (alkyl vinyl ether-2-ethyl-2-oxazoline) diblock copolymers with hydrolytically stable block linkages has been developed. Monofunctional poly (alkyl vinyl ether) oligomers with nearly Poisson molecular weight distributions were prepared via a living cationic polymerization method using chloroethyl vinyl ether together with HI/Zn12 as the initiating system and lithium borohydride as the termination reagent. Using the resultant chloroethyl ether functional oligomers in combination with sodium iodide as macroinitiators, 2-ethyl-2-oxazoline was polymerized in chlorobenzene/NMP to afford diblock copolymers. A series of poly (methyl vinyl ether-2-ethyl-2oxazoline) diblock materials were found to have polydispersities of ~1.3-1.4 and are microphase separated as indicated by two T,'s in their DSC thermograms. These copolymers are presently being used as model materials to study fundamental parameters important for steric stabilization of dispersions in polar media. 0 1993 John Wiley & Sons, Inc. Keywords: poly( methyl vinyl ether); poly (butyl vinyl ether) poly (2-ethyl-2-oxazoline) block copolymers living cationic polymerization.

The preparation of new block and graft copolymers containing poly (2‐alkyloxazoline)s using macroinitiator methods have been investigated. Hydroxy terminated poly(2‐alkyloxazoline) oligomers can be synthesized using alkyl iodide initiators and potassium hydroxide as the terminating reagent. Polymerizations of ϵ‐caprolactone using monofunctional poly(2‐alkyloxazoline)s as macroinitiators and Sn(oct)2 as the catalyst yield diblock copolymers of poly(2‐alkyloxazoline‐b‐ϵ‐caprolactone) with controlled molecular weights. Graft copolymers have also been prepared by first generating a poly(alkyl vinyl ether) backbone. Copolymerization of a low molar percentage of 2‐chloroethyl vinyl ether with alkyl vinyl ethers was performed using a heterogeneous cationic catalyst to yield high molecular weight random copolymers with pendent ethyl chloride groups interspersed along the chain. This pendent chlorine group, together with NaI, was used as the initiation system for 2‐alkyloxazoline grafts. Characterization of the resultant copolymers by gel permeation chromatography, intrinsic viscosity, DSC, solution and solid state 1H and 13C NMR is discussed. These materials are being evaluated as emulsifiers for polymer blends containing aliphatic polyamides as one component.

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