Acryl-and methacryl-type macromonomers and telechelics of poly(2-alkyl-2-oxazolines) (PROZO) have been prepared for the first time by terminating the living ends in the electrophilic (cationic) ring-opening polymerization of 2-alkyl-2-oxazolines (ROZO) with suitable reagents. The synthesis of macromonomers was achieved via the following two methods: (1) by the reaction of acryloyl or methacryloyl chloride with a PROZO alcohol obtained by the hydrolysis of the living PROZO propagating species under basic conditions (indirect method) and ( 2) by the termination of the living species with carboxylate anions of acrylic or methacrylic acids or with trimethylsilyl methacrylate (direct method). The production of telechelics of PROZO was achieved by using a bis(2-oxazolinium salt) initiator. Termination of both living ends of the PROZO with water, ammonia, or an alkylamine afforded the corresponding telechelics of PROZO as glycols and diamines in good yields.
ABSTRACT:The radical copolymerization ofvinylbenzyl-terminated poly(2-methyl-2-oxazoline) macromonomers (I Me-n; n (degree of polymerization)=3, 15, 28, 31) (M 1 ) with vinyl monomers (M 2 ), i.e., methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) was performed using 2, 2'-azobis(isobutyronitrile) (AIBN) as an initiator at 60"C in ethanol (EtOH), CD 3 0D, or CD 3 CN. Monomer reactivity ratios r1 and r2 were evaluated based on the terminal model. Copolymerization oft Me-3 with MMA gave reactivity ratios as r 1 = 1.86 ±0.15 and r2 =0.07 ±0.03 in EtOH, and r1 = 1.25 ±0.10 and r 2 =0.18±0.05 in CD 3 0D. exhibiting remarkably higher reactivity of the Me-3 compared with the comonomers and corresponding small monomer, styrene. In CD3CN, however, copolymerization of I Me-3 with MMA gave r 1 =0.41 ±0.10 and r 2 = 0.66 ± 0.1 0, showing rather lower reactivity of the macromonomer compared with MMA. With HEMA, I Me-3 showed high reactivity in EtOH, i.e., r 1 = 1.44± 0.10, r2 =0.04 ±0.02. The reactivity of HEMA against the macromonomers was found higher than that of MMA, possibly due to affinity to aprotic poly(2-methyl-2-oxazoline) graft chains on growing species. The high reactivity of I Me-n in EtOH and CD30D would be due to the formation of a micelle-like state. The reactivity of macromonomers decreased generally with chain length (n).KEY WORDSPoly(2-alkyl-2-oxazoline)s (PROZO) having the poly-(N-acylethylenimine) structure given by cationic ringopening polymerization of 2-alkyl-2-oxazoline (ROZO), can be regarded as a polymer homologue of polar a protic solvents such as N,N-dimethylacet-amide, showing hydrophilic (R =Me, Et) or hydrophobic (carbon number of R 2: 4) properties. 1 Monodisperse macromonomers ofPROZO, e.g., styryl-, 2 methacryloyl-, 3 and vinylester-terminated4 macromonomers, have been synthesized using living polymerization of ROZO. Longer alkyl groups (R) in PROZO chain make macromonomers with regularly branched structure.In general, homopolymerization of macromonomers produces star-like or comb-like polymers, while copolymerization with ordinary vinyl monomers forms graft copolymers. In particular, the synthesis of graft copolymers using the macromonomer method is believed very good for those with well-defined structure. We examined the kinetics of radical homopolymerization of methacryloyl and vinylbenzyl-terminated PROZO macromonomers, and found reactivity to be particularly influenced by longer alkyl (R) branches and remarkably enhanced in water. 5 Previously, radical copolymerization of hydrophilic PROZO macromonomers was found to produce micron to submicron-size polymer particles using the functions of macromonomers as stabilizers or emulsifiers. 6 Amphiphilic graft copolymers were obtained by copolymerization of hydrophilic PROZO macromonomers with hydrophobic monomers. 7 The reactivity of PROZO macromonomers in copolymerizations is of interest, though detailed examination on copolymerizability has not been reported.In the present study, reactivity of radical copolymerization of p-vi...
Novel macromonomers and telechelics of poly(2‐alkyl‐2‐oxazoline) (PROZO) were syn‐thesized by utilizing termination of propagating species (2‐oxazolinium ions) in the living polymerization of 2‐alkyl‐2‐oxazoline (ROZO) with suitable nucleophiles. Two types of p‐vinylbenzyl–type macromonomers were obtained by terminating living PROZO with sodium p‐vinylbenzyl alkoxide or with sodium p‐vinylbenzyl mercaptide. The synthesis of telechelics having a functional group (SH, COOH) on both ends of PROZO was achieved by using a bis(2‐oxazolinium salt) initiator. The PROZO dithiol was synthesized by two methods: (1) termination of the living species on both ends with NaSH, and (2) aminolysis of PROZO bis(O‐ethyldithiocarbonate) given by treatment of the living PROZO with potassium O‐ethyldithiocarbonate. Termination of the living PROZO with the sodium salt of di‐t‐butyl malonate yielded a PROZO with di‐t‐butyl malonate moieties on both polymer ends, from which the PROZO dicarboxylic acid was derived via free tetracarboxylic acid. © 1995 John Wiley & Sons, Inc.
ABSTRACT:For preparation of a graft copolymer having a polyethylene main chain and poly(N-acylethylenimine) graft chain, poly[ ethylene-co-(vinylacetate )-g-(2-alkyl-2-oxazoline )]s ( 4) were prepared. First, poly[ethylene-co-(vinyl acetate)] (1) was saponified to give polymer (2) having a hydroxy group. Secondly, 2 was tosylated or bromoacetylated giving rise to polymer (3a) or (3b). Then, polymer 3 was employed to initiate the cationic ring-opening polymerization of 2-methyl-2-oxazoline or 2-ethyl-2-oxazoline to produce a graft copolymer which was isolated by reprecipitation. During the graft copolymerization, a homopolymer of 2-oxazoline was produced probably due to chain-transfer, the highest graft-efficiency being 50%. KEY WORDSPoly(2-oxazoline) Graft Copolymer / Poly[ethyl-co-vinyl acetate)] / Vinyl Alcohol Unit / Tosylation / Bromoacetylation / Polymerization chemistry of 2-oxazolines and other cyclic imino ether monomers has greatly developed for these two decades. The cationic ring-opening polymerization of 2-alkyl-2-oxazolines produces poly(N-acylethylenimine )s and their hydrolysis gives linear polyethylenimine. 1 Through our recent studies on the polymerization of 2-oxazolines 2 we observed the following characteristic features; i) polymerization can be initiated by alkyl sulfonates or alkyl halides, ii) propagation is of a highly living nature, and iii) the product poly(N-acylethylenimine) is hydrophilic or lipophilic depending upon the nature of the acyl group. Based on these characteristics, various block and graft copolymers of 2-oxazolines have been prepared.1. 2 Several papers have reported graft copolymers from 2-oxazolines: poly[ styrene-g-(2-methyl-2-oxazoline )], 3 .4 poly[butadiene-g-(2-methyl-2-oxat To whom all correspondence should be addressed.zoline)], 5 poly[(vinyl chloride)-g-(2-methyl-2-oxazoline )] 6 poly[(2-phenyl-2-oxazoline )-g-( ethylene oxide)],7 and cellulose diacetate-gpoly(2-alkyl-2-oxazolines), 8 and poly[methyl methacrylate-g-(2-oxazoline)]s. 9 We also prepared graft copolymers having poly(2-oxazoline) segments both in the main and graft chains, which show good surfactant nature reflected by a surface tension (y) value. 10 The present paper describes the synthesis of graft copolymers having poly[ethylene-co-(vinylacetate)] [poly(E-co-V Ac)] main chain and poly(2-alkyl-2-oxazoline) (polyROZO) graft chain, which is an extension study of the synthesis of graft copolymers from 2-oxazolines. 3 -5 • 7 -10 The main purpose of this study is to modify the surface nature of polyethylene by introducing the graft chain of poly(N-acylethylenimine).
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