Analysis of ethylene oxide sequences of the acetal copolymer from trioxane and ethylene oxide

Abstract

An NMR method for the analysis of the ethylene oxide sequence of the acetal copolymer from trioxane and ethylene oxide has not yet been established. We found three novel cyclic compounds composed of 1 mol of ethyelene oxide and 1 mol of trioxane, 2 mol of ethylene oxide and 1 mol of trioxane, and 3 mol of ethylene oxide and 1 mol of trioxane. These compounds gave only one consecutive oxyethylene unit, two consecutive oxyethylene units, and three consecutive oxyethylene units in three consecutive oxymethylene units, respectively, and gave different 1 H NMR spectra for each oxyethylene unit. Considering these data, we synthesized three polymeric model compounds that have one consecutive oxyethylene sequence, two consecutive oxyethylene sequences, and three consecutive oxyethylene sequences in an oxymethylene main chain. By a linear combination of the 1 H NMR spectrum of each oxyethylene unit of the three polymeric model compounds, we succeeded in determining the ethylene oxide sequence by the 1 H NMR method for the copolymer from trioxane and ethylene oxide. Good agreement was observed between the 1 H NMR method and the hydrolysis method for the analysis of the ethylene oxide sequences.

Synthesis and crystallization behavior of acetal copolymer/silica nanocomposite by in situ cationic ring‐opening copolymerization of trioxane and 1,3‐dioxolane

“…Acetal copolymer resin is typically prepared by the cationic ring‐opening copolymerization of trioxane and a cyclic ether, such as ethylene oxide2–9 or 1,3‐dioxolane 10–13. The copolymerization can be initiated by Lewis acid such as BF 3 · O(Et) 2 , TiCl 4 14 and CH 3 CO ClO 4 15 as well as MoO 2 (C 5 H 7 O 2 ) 2 11.…”

A Novel Branched Polyoxymethylene Synthesized by Cationic Copolymerization of 1,3,5‐Trioxane with 3‐(Alkoxymethyl)‐3‐ethyloxetane

“…[ 2 ] A common method that has been industrialized is the end-capping reaction of the terminal hemiacetals with acetic anhydride; however, the end-capping process is very energy-intensive, requiring high reaction temperature (≈170 °C) due to the poor solubility of POM. [ 3,4 ] The other way to improve the thermal stability of POM is by copolymerizing of 1,3,5-trioxane (TOX) with cyclic ethers such as ethylene oxide, [5][6][7][8][9] 1,3-dioxolane, [10][11][12][13] 1,3-dioxepane, [ 14 ] and 1,3-dioxep-5-ene. [ 15 ] The random introduction of −[(CH 2 ) n −O] ( n ≥ 2)− units limits the unzipping of the chain and improves the thermal stability of the −(CH 2 −O) n − units in the copolymer.…”

Ring‐Opening Polymerization

“…Polyoxymethylene, also referred to as acetal resin or POM, is obtained either by anionic polymerization of formaldehyde or cationic ring-opening copolymerization of trioxane with a small amount of a cyclic ether or acetal (e.g., ethylene oxide or 1,3-dioxolane) [Cherdron et al, 1988;Dolce and Grates, 1985;Yamasaki et al, 2001]. The properties and uses of POM have been discussed in Sec.…”