Preparation and polymerization of methylenecyclobutene and 1‐methyl‐3‐methylenecyclobutene

Wu, Chester Cherng-chiou; Lenz, Robert W.

doi:10.1002/pol.1972.170101209

Cited by 7 publications

(1 citation statement)

References 29 publications

(4 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In 1964, Furukawa et al reported that unsubstituted MCH was efficiently polymerized by cationic and Ziegler catalysts, most likely via 1,4-addition . The high reactivity of MCH in cationic polymerization was also studied by comparison to the linear conjugated diene 2-methyl-1,3-pentadiene in 1974 by Higashimura et al For smaller-ringed exo -methylene conjugated dienes, 3-methylenecyclobutene (MCB) , and 3-methylenecylcopentene (MCP), − which contain four- and five-membered rings, respectively, have been subjected to cationic, radical, and coordination polymerizations, among which highly 1,4-selective cationic polymerizations have also been reported. Although these studies suggested that exo -methylene-containing dienes with fixed transoid structures are generally reactive in cationic polymerizations, the effects of substituents on monomer reactivity and polymer properties are unknown.…”

Section: Introductionmentioning

confidence: 99%

Model and Terpenoid-Derived exo-Methylene Six-Membered Conjugated Dienes: Comprehensive Studies on Cationic and Radical Polymerizations of Substituted 3-Methylenecyclohexenes

et al. 2022

View full text Add to dashboard Cite

This work was designed as a comprehensive study of cationic and radical polymerizations of exo-methylene six-membered conjugated dienes, i.e., 3-methylenecyclohexenes, which were prepared from bio-and petroleum-based compounds, to determine the effects of substituents on monomer reactivities and thermal properties of the polymers. To clarify the effect of a methyl group on the conjugated diene as well as those of isopropyl substituents at other positions in the biobased monomers, a series of model monomers with or without a methyl group at the 3-or 4-position of the exo-methylene moiety were prepared from petroleum-derived compounds. Cationic homopolymerizations of the model monomers were extremely fast, but radical processes were very slow, which was consistent with results reported for terpenoid-derived exo-methylene-conjugated dienes. Kinetic studies of living cationic copolymerizations involving the model monomers and isobutyl vinyl ether indicated that the methyl group on the conjugated diene moiety strongly influenced the cationic reactivity of the monomers; a methyl group at the 4-position provided the highest reactivity due to formation of a stable conjugated tertiary cationic propagating species, whereas a methyl group at the 3position resulted in the lowest reactivity due to steric hindrance around the exo-methylene moiety. The monomer reactivity ratios observed for radical copolymerizations of exomethylene-conjugated dienes with methyl acrylate or styrene revealed that a methyl group at the 3-position decreased the reactivities of the exo-methylene-containing dienes due to steric hindrance around the exo-methylene moiety. In addition, the effects of isopropyl substituents at the other positions in the terpenoid-derived monomers depended on the specific position. The polymers obtained from the terpenoid-derived monomers showed higher glass transition temperatures than those obtained from the corresponding model monomers due to additional isopropyl substituents originating from the biobased compounds, and this indicated that unique naturally occurring structures enhanced the thermal properties of the resulting polymers.

show abstract

Section: Introductionmentioning

confidence: 99%

Model and Terpenoid-Derived exo-Methylene Six-Membered Conjugated Dienes: Comprehensive Studies on Cationic and Radical Polymerizations of Substituted 3-Methylenecyclohexenes

et al. 2022

View full text Add to dashboard Cite

show abstract

Thermal and autoxidation reactions of poly‐3‐methylenecyclobutene and poly‐1‐methyl‐3‐methylenecyclobutene

Lenz

1972

J. Polym. Sci. A‐1 Polym. Chem.

View full text Add to dashboard Cite

The thermal ring‐opening reactions, autoxidation and hydrogenation of polymethy‐lenecyclobutene (PMCB) and poly‐1‐methyl‐3‐methylenecyclobutene (PMMCB), were investigated. Both polymers were prepared by cationic polymerization and consisted almost entirely of 1,5‐repeating units containing cyclobutene rings in the polymer backbone. Both polymers showed well behaved exothermic processes at elevated temperatures which apparently resulted in crosslinking. These processes were investigated by differential scanning calorimetry and interpreted to involve thermal ring‐opening reactions. Autoxidation occurred very rapidly in PMCB but much more slowly in PMMCB as predicted by Bolland's rules. Attempts to hydrogenate the cyclobutene rings in both polymers resulted in the occurrence of hydrogenolysis in PMCB and little or no reaction with PMMCB for a Pd‐catalyzed reaction and partial hydrogenation of the latter for a diimide reaction.

show abstract

Cationic copolymerization of isobutene and conjugated small‐ring dienes

Tsao

Lenz

1979

J. Polym. Sci. Polym. Chem. Ed.

View full text Add to dashboard Cite

Synopsisl-Methyl-3-methylenecyclobutene (MMCB) and 1,2-dimethylenecyclobutane (DMCB) copolymerized readily with isobutene with aluminum chloride as initiator in methyl chloride solution at temperatures from -95 to -78OC. No polymers were obtained with methylenecyclobutene (MCB) under similar conditions. The copolymerization of MMCB with isobutene took place through a 1,5-addition reaction while that of DMCB through both 1,2-and l,4-addition reactions. Large amounts of gel were present in the copolymers obtained from DMCB if the reaction was carried to high conversion. The commonly observed effects of dienes (i.e., rate retardation and molecular weight depression) on cationic copolymerization reactions were observed but to a much higher degree with these small ring dienes. The thermal crosslinking behavior of the resulting copolymers was investigated. In conjunction with the copolymerization studies, homopolymers of MMCB, DMCB, and 3,3-dimethyl-l-isopropylidene-2-methylenecyclobutane (IMCB) were prepared and their chemical structures examined.

show abstract

Preparation and polymerization of methylenecyclobutene and 1‐methyl‐3‐methylenecyclobutene

Cited by 7 publications

References 29 publications

Model and Terpenoid-Derived exo-Methylene Six-Membered Conjugated Dienes: Comprehensive Studies on Cationic and Radical Polymerizations of Substituted 3-Methylenecyclohexenes

Model and Terpenoid-Derived exo-Methylene Six-Membered Conjugated Dienes: Comprehensive Studies on Cationic and Radical Polymerizations of Substituted 3-Methylenecyclohexenes

Thermal and autoxidation reactions of poly‐3‐methylenecyclobutene and poly‐1‐methyl‐3‐methylenecyclobutene

Cationic copolymerization of isobutene and conjugated small‐ring dienes

Contact Info

Product

Resources

About