Synthesis of Eight-Membered Lactone Having Tertiary Amine Moiety by Ring-Expansion Reaction of 1,3-Benzoxazine and Its Anionic Ring-Opening Polymerization Behavior

J. Polym. Sci. A Polym. Chem.

Endō

2011

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A polymer bearing 1,3‐benzoxazine moiety in the side chain was synthesized successfully from poly(allylamine) based on a stepwise strategy consisted of three steps: (1) treatment of poly(allylamine) with salicylaldehyde to convert the amino group in the side chain into the corresponding o‐(iminomethyl)phenol moiety, (2) reduction of the o‐(iminomethyl)phenol to obtain the corresponding o‐(aminomethyl)phenol moiety, and (3) formation of 1,3‐benzoxazine moiety by the reaction of the o‐(aminomethyl)phenol with formaldehyde. The content ratio of benzoxazine moieties and o‐(aminomethyl)phenol moieties in the polymer were tunable by varying amount of formaldehyde. The presence of o‐(aminomethyl)phenol moieties exhibited a significant promoting effect on the crosslinking reaction. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Section: Crosslinking Reaction Mechanismmentioning

confidence: 99%

Synthesis of polymers bearing 1,3‐benzoxazine moiety in the side chains from poly(allylamine) and their crosslinking behaviors

Oie

J. Polym. Sci. A Polym. Chem.

Endō

2011

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“…As shown in Scheme 2, the ring-opening reaction of benzoxazine gives the corresponding intermediate bearing phenol and iminium moieties. [30][31][32][33] For this highly polar species, highly polar media are favorable and thus the ring-opening reaction of benzoxazines can be promoted. In addition to this polarity factor, acidity of solvents would be another important factor, SCHEME 3 Polyaddition of bifunctional benzoxazines 2 and 2methylresorcinol (MR).…”

Section: Resultsmentioning

confidence: 99%

Polyaddition of bifunctional 1,3‐benzoxazine and 2‐methylresorcinol

Oie

Mori

J. Polym. Sci. Part A: Polym. Chem.

et al. 2013

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A polyaddition system consisted of a bifunctional N‐n‐propyl benzoxazine and 2‐methylresorcinol (MR) that proceeds at ambient temperature has been developed. In this system, the aromatic ring of MR acted as a bifunctional monomer, reacting with a two equivalent amount of benzoxazine moieties via their ring‐opening reaction. The polyaddition gave the corresponding linear polymer bearing phenolic moieties bridged by Mannich‐type linkage in the main chain. The linear polymer had a high glass transition temperature, which was comparable to that of the linear polybenzoxazine synthesized by the ring‐opening polymerization of a monofunctional N‐n‐propyl benzoxazine. The employment of a bifunctional N‐allyl benzoxazine in the polyaddition system resulted in the formation of the corresponding polymer with allyl pendants, which exhibited improved heat resistance due to its thermally induced crosslinking reaction. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3867–3872

“…The dissociation of urethanes can give the corresponding isocyanates, and as was evidenced experimentally, phenyl isocyanate promoted the polymerization significantly. So far, we have considered that a zwitter ionic intermediate bearing phenoxide and imminium moieties can be one of possible reactive species in the ring‐opening polymerization of benzoxazine 20, 27–30. The resulting imminium moiety can undergo intermolecular Mannich reactions with phenoxide‐type species and phenolic compounds that can contribute to propagation of poly(benzoxazine); however, such intermolecular reactions must compete with the intramolecular nucleophilic attack of the phenoxide moiety that gives the benzoxazine again.…”

Section: Resultsmentioning

confidence: 99%

Promoting effects of urethane derivatives of phenols on the ring‐opening polymerization of 1,3‐benzoxazines

J. Polym. Sci. A Polym. Chem.

Mori

Endō

2011

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For the purpose of reducing the induction period of the ring-opening polymerization of N-methyl-1,3-benzoxazines, several urethanes were examined as promoters. The examined promoters 3a-d were the adducts of resorcinol and phenyl isocyanate, that of bisphenol A and phenyl isocyanate, that of resorcinol and butyl isocyanate, and that of 1,3-propanediol and phenyl isocyanate, respectively. The aromatic urethanes 3a and 3b, which were adducts of the phenolic compounds and phenyl isocyanate, exhibited significant promoting effects. EXPERIMENTAL MaterialsAll reagents and solvents were used as received. A 40% methanol solution of methylamine, a 35% aqueous solution of formaldehyde, p-cresol, and 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) were purchased from Wako Pure Chemical Industries. Using these chemicals, 1 21 and 2 22 were synthesized according to the reported procedure 23 and purified by column chromatography (silica gel, eluent ¼ hexane þ ethyl acetate (v/v 50:50-0:100) followed by recrystallization from ethyl acetate. 20 Their purity was proven by the 1 H NMR spectra shown in Figure S1 and Figure S2 (in Supporting Information). Phenyl isocyanate, butyl isocyanate, resorcinol, 1,3-propanediol, and dibutyltin dilaurate were purchased from Wako Pure Chemical Industries. Using these chemicals, 3a (the adduct of resorcinol and 2 eq phenyl isocyanate), 3b (the adduct of bisphenol A and 2 eq phenyl isocyanate), 3c (the adduct of resorcinol and 2 eq butyl