Cyclo- and Cyclized Diene Polymers. XVIII. Microstructure and Mechanism of Cyclopolymerization of Isoprene and Butadiene with C₂H₅AlCl₂+ TiCl₄Catalyst

Cationic Polymerization of 1,3-Pentadiene Initiated by Aluminum Chloride: Determination of the Various Side Reactions

“…2,3,14,[17][18][19] The most abundant work related to the cyclization reaction in cationic polymerization is described in some papers concerning polyisoprenes and polybutadienes. [20][21][22][23][24][25][26][27][28][29] The authors mentioned the formation of monocyclic structures as well as polycyclic structures. However no direct proof of the cyclic structures were given though several teams announced a cyclization rate, estimated mainly by 1 H NMR analysis.…”

“…Cyclization, Double Bond Isomerization, and Branching Reactions. Until now, few works have been devoted to the study of the cyclization mechanism in PPDs. ,,,− The most abundant work related to the cyclization reaction in cationic polymerization is described in some papers concerning polyisoprenes and polybutadienes. − The authors mentioned the formation of monocyclic structures as well as polycyclic structures. However no direct proof of the cyclic structures were given though several teams announced a cyclization rate, estimated mainly by 1 H NMR analysis.…”

Stereochemistry of Polymerization

“…There is a general tendency toward 1,4-polymerization with trans 1,4 favored over cis 1,4. Cyclization occurs during propagation with the extent of unsaturation in the product varying from about 80% to almost zero depending on initiator, monomer, and reaction conditions [Delfour et al, 2003;Gaylord and Svestka, 1969;Gaylord et al, 1968;Hasegawa and Asami, 1978;Hasegawa et al, 1977].…”

A Novel Ladder Polymer. Two-Step Polymerization of Oxetanyl Oxirane Leading to a “Fused 15-Crown-4 Polymer” Having a High Li+−Binding Ability

“…The synthesis of ladder polymers has been extensively studied using the two-step polymerization of a specifically designed difunctional monomer using suitable polymerization conditions; in particular, the process of forming ladder segments depends on the nature of the zipping-up or multistage cyclization reactions of multiple functional groups as side chains of the precursor polymers. According to the method using a difunctional monomer, ladder polymers were prepared from the second-stage cyclopolymerization of the conventionally preformed 3,4-polyisoprene and 1,2-polybutadiene. − Other monomers such as acrolein, vinyl isocyanate, vinyl acetylene, and cyanoacetylene also lead to ladder polymers by using the appropriate polymerization initiators. − …”

“…[1][2][3] Other monomers such as acrolein, vinyl isocyanate, vinyl acetylene, and cyanoacetylene also lead to ladder polymers by using the appropriate polymerization initiators. [2][3][4][5][6][7][8][9][10][11][12][13] Since the resulting ladder polymers have unique structures with fused cyclic segments in the polymer main chain, it is of interest to design and synthesize novel ladder polymers with intelligent cyclic structures. For example, the second cyclopolymerization of cyclic ethers in a preformed polyether should lead to a novel type of ladder polymer having crown ether units, i.e., a "fused crown polymer".…”