Ring-opening polymerization olefins

Ring opening polymerization of strained cyclic olefins, discussed previously, might exemplify such a system. The metalla-carbene, Met=CHR, is the active, and presumably labile form, while the ring species,... 

By using a transition metal chloride catalyst and an iodine modified cocatalyst, ring-opening polymerization of C5 and C8 monocyclic olefins is controlled to prepare either cis polymers or trans products that are crystallizable. In copolymerization, the cis/trans units in the copolymers are regulated by adjusting the C5/C8 olefin monomer ratio. As the comonomer is increased, the copolymer becomes less crystalline and then completely amorphous at equal amounts of cis/trans units. Polymerization results are reported from WC16 and MoCl5 catalysts. 

Ring opening polymerization of cyclic monomers to yield thermoplastic polymers has been studied by a number of investigators [1-19] over the years. A variety of cyclic monomers ranging in structures from the more commonly encountered olefins, ethers, formals, lactones,... 

V. Dragutan, A.T. Balaban, and M. Dimonie, Olefin Metathesis and Ring-Opening Polymerization of Cyclo-Olefins, Editura Academiei, Bucuresti, and Wiley, Chichester, 1985. 

Ring-Opening Polymerization, Ring-opening polymerization of cyclo-olefins in the presence of tungsten- or molybdenum-based catalysts proceeds by a metathesis mechanism,... 

Ivin KJ (1983) Olefin metathesis, Academic, New York Dragutan V, Balaban AT, Dinonie M (1985) Olefin metathesis and ring-opening polymerization of cycloolefins, Wiley, New York... 

In the following years, a number of other monocyclic, bicyclic and polycyclic olefins including cyclobutene, [4] cyclopentene [3 a, 5] and cyclooctene [6] were found to undergo ring-opening polymerization. 

Independently from the results of ring-opening polymerization, Banks and Bailey [16] reported a disproportionation reaction of acyclic olefins, the formation of ethylene and 2-butene from propylene Eq. (2). 

Reviews on Olefin Metathesis (a) Grubbs RH (1982) In Wilkinson G (ed) Comprehensive organometallic chemistry, Pergamon, Oxford, vol 8, p 499 (b) Dragutan V, Balaban AT, Dimonie M (1985) Olefin metathesis and ring-opening polymerization of cyclo-olefins, Wiley, Chichester (c) Ivin KJ (1983) Olefin metathesis, Academic, London... 

Ring-Opening Polymerization Ring-Opening Olefin Metathesis Polymerization (ROMP)... 

Metathesis of Cycloolefins. The same general catalysts which promote the ring-opening polymerization of cycloolefins are also effective in the olefin metathesis reaction in which acyclic internal olefins undergo a unique redistribution process (1, 2, 5, 6). 

Block copolymers of olefins and acrylates or vinylesters can be obtained by lanthanoid compounds. Living polyethylene-biseyclopentadienyl samarium systems can continue the polymerization with acrylate monomers by group transfer polymerization or cyclolactone monomers by ring opening polymerization [216, 217]. 

The catalyst systems are also effective as initiators for ring-opening polymerization of olefin sulfides (57, 58, 224, 232, 284, 285, 297, 303, 548). Asymmetric selection polymerization has also been performed with olefin sulfides (14, 156, 430, 470-472). 

Aromatic onium ions are a unique class of onium ions which are photoactive and decompose in the presence of light to generate radical-cations [58]. These radical-cations react with solvent or residual moisture to release protons that initiate cationic polymerization [Eq. (43)]. Thus, aromatic onium ions are used as cationic photoinitiators in both carbocati-onic olefin and ring-opening polymerizations, especially in photocuring and photolithographic processes. 

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