Living/controlled cationic cyclopolymerization of divinyl ether with a cyclic acetal moiety: Synthesis of poly(vinyl ether)s with high glass transition temperature based on incorporation of cyclized main chain and cyclic side chains

Abstract

Cationic cyclopolymerization of 2‐methyl‐5,5‐bis(vinyloxymethyl)‐1,3‐dioxane (1), a divinyl ether with a cyclic acetal group, was investigated with the HCl/ZnCl2 initiating system in toluene and methylene chloride at −30 °C. The reaction proceeded quantitatively to give gel‐free, soluble polymers in organic solvents. The number‐average molecular weight (Mn) of the polymers increased in direct proportion to monomer conversion, and further increased on addition of a fresh monomer feed to the almost completely polymerized reaction mixture, indicating that the polymerization proceeded in living/controlled manner. The contents of the unreacted vinyl groups in the produced soluble polymers were less than ∼3 mol %, and therefore, the degree of cyclization was determined to be ∼97%. In contrast, the pendant cyclic acetal groups remained intact in the polymers under the present cationic polymerization conditions. These facts show that cyclopolymerization of 1 almost exclusively occurred and the poly(vinyl ether)s with the cyclized repeating units and cyclic pendant acetal rings were obtained. Glass transition temperature (Tg) and thermal decomposition temperature (Td) of poly(1) (Mn = 7870, Mw/Mn = 1.57) were found to be 166 and 338 °C, respectively, indicating that poly(1) had high Tg and high thermal stability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 952–958, 2010

Cationic cyclopolymerization of divinyl ethers with norbornane‐, norbornene‐, or adamantane‐containing substituents: Synthesis of cyclopoly(divinyl ether)s with bulky rigid side chains leading to high glass transition temperature

“…Polymerizations of norbornane‐containing divinyl ether 1 and norbornene‐containing divinyl ether 2 were then investigated in toluene or CH 2 Cl 2 at −30 °C with use of the HCl/ZnCl 2 initiating system. A relatively low initial monomer concentration ([M] 0 = 0.15 M) was used to suppress the intermolecular propagation leading to uncyclized repeating units against intramolecular propagation (cyclization reaction) . The reactions proceeded up to ∼100% monomer conversion to give completely soluble polymers throughout all the polymerizations, whose rates were higher in CH 2 Cl 2 than in toluene.…”

Star-shaped cyclopolymers: A new category of star polymer with rigid cyclized arms prepared by controlled cationic cyclopolymerization and subsequent microgel formation of divinyl ethers

“…In our previous study of cyclopolymerization of a similar divinyl ether, 2-methyl-5,5-bis(vinyloxymethyl)-1,3-dioxane, it was found that the eight-membered cyclic repeating units are predominantly incorporated into the polymer main chains via the head-to-tail ring closure. 23 This may be the case for the cyclopolymerizations of 1. The early study of the cyclopolymerization of divinyl ethers also reported that the head-to-tail addition for the ring formation exclusively occurred.…”

“…The broadening of polymer MWD in the course of cyclopolymerization of divinyl ethers comes from the occurrence of a minor extent of crosslinking and/or branching reactions to consume the pendant unreacted vinyl groups. 19,20,23,24 Figure 4 also shows the time-conversion plots (A), the M n (B), and M w /M n (C) of the product polymers vs. monomer conversion plots for the polymerization of 1 at 0 C. The polymerization proceeded smoothly and rather fast (conversion 5 100% at 10 min), and the M n s of the produced polymers increased in direct proportion to monomer conversion before and after the monomer addition with the polymer MWDs being narrow and were in good agreement with the calculated values assuming that one HCl molecule formed one polymer chain. The results of these plots in Figure 4 confirm living nature of the cyclopolymerization of 1 at 0 C. However, close inspection of the M n of the product polymers versus monomer conversion plots [ Fig.…”

“…In other words, the degree of cyclization for the poly(1) was over 97%, high value and similar to those of the reported cyclopolymers from other divinyl ethers. 19,20,23,24 To check living nature of the present cyclopolymerization systems, a fresh monomer feed (equivalent to the first stage) was added to the almost completely polymerized reaction mixture. The polymers obtained after the monomer addition were also soluble and the peak top of the MWD curves of the polymers clearly shifted toward high molecular weight region.…”

“…[15][16][17][18][19][20] The incorporation of consecutive cyclic groups into the polymer backbones provides rigidity, and hence high thermal stability and high T g to the resulting polymers. [21][22][23] Our recent study showed that some of cyclopoly(divinyl ether)s possessed high T g (up to 200 C) and high thermal decomposition temperature (up to 300 C). 24 The present study concerns the synthesis of star-shaped polymers consisting of cyclopoly(divinyl ether) arm chains and crosslinked poly(divinyl ether) microgel core by the combination of controlled cyclopolymerization and the subsequent crosslinking polymerization of divinyl ethers.…”