| The copolymerization of polar and non-polar olefins has gained increased attention because the combination of the two can greatly enhance the range of currently attainable polymer properties. The polymerization of methyl acrylate with 1-alkenes ranging from ethene to 1-octene, was found to proceed by conventional free-radical polymerization under mild reaction conditions. The afforded polymers were found to be random copolymers as was verified by size exclusion chromatography and NMR spectroscopy. In addition, the copolymer triad sequences were determined.; Copolymers of methyl acrylate (MA) and norbornene were also synthesized by atom transfer radical polymerization (ATRP) under mild conditions to afford random copolymers. Several other norbornene derivatives were also copolymerized with MA. Surprisingly, when 5-methylene-2-norbornene was polymerized with MA, both C=C double bonds participated in the polymerization. Kinetic studies revealed that the copper-mediated polymerization system displays characteristics of a living system. For comparison, the polymerizations were carried out under conventional free radical conditions. Similar results were obtained.; An additional area of current interest is the alternating copolymerization of olefins with carbon monoxide (CO) due to the interesting properties of the resulting copolymers. Expansion of this concept to the copolymerization of functional alkenes with CO would afford highly functionalized materials of great importance. The cationic palladium(II) complex, Pd(MeCN)4(BF 4)2, in the presence of a chiral bidentate ligand, was found to polymerize 5-hexen-2-one with CO to afford an alternating copolymer containing a mixture of poly(1,4-ketone) and poly(spiroketal) units in the polymer backbone. Optical rotation measurements showed a molar optical activity indicating the isotactic nature of the polymer chains. The copolymerization of norbornene and norbornene derivatives with CO was also achieved.; Acrylates are readily polymerized by radical and anionic pathways. The neutral palladium(II) complex Pd(C6F5)Br(NCCH3 )2 in the presence of excess halide ligand, tetrabutylammonium halide (NBu4X where X = Cl, Br, I), was found to homopolymerize acrylates. While the homopolymerization of methyl methacrylate was not very successful, the copolymerization with methyl acrylate (MA) resulted in the formation of random copolymers. Random copolymers of MA and 1-hexene were also synthesized. Mechanistic studies including an examination of polymer microstructure, revealed that the polymerizations probably proceed through a radical pathway. |
