Maleimidophenyl isocyanates as postpolymerization modification agents and their applications in the synthesis of block copolymers

Abstract

The maleimide structure is highly reactive, exemplified by thiol–ene click reactions with thiols and Diels–Alder reactions with furans. Although postpolymerization modifications and macromolecular conjugations involving maleimide units have been widely studied, mostly due to their selectivity and high reactivity, little has been reported on the one‐pot postpolymerization introduction of maleimides in polymer chains. Herein, we report p‐maleimidophenyl isocyanate and its derivatives as modification agents to introduce maleimide moieties by reaction with hydroxy groups into polymer chains. The high reactivity of the resulting modification agents and of the corresponding maleimide structures once inserted in the polymer chains was examined by studying their reaction kinetics. Furthermore, these modification agents were successfully applied to the synthesis of macromonomers for graft polymerization and various block copolymers, with, for example, AB‐type, star‐shaped, and H‐shaped architectures. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2396–2406

Characterization of N-phenylmaleimide-terminated poly(ethylene glycol)s and their application to a tetra-arm poly(ethylene glycol) gel

“…Surprisingly, when N-aryl MA was used, the t gel occurred much earlier than when N-alkyl MA was used, indicating a higher reactivity of N-aryl MA PEG compared to that of N-alkyl MA PEG. In our previous work, 42 we found the reactivity of phenyl maleimide terminated PEG toward thiol molecule was as same as that of alkyl maleimide terminated PEG in chloroform with triethylamine as a base catalyst. To our best knowledges, this is first case that a difference in the reactivity of phenyl and alkyl N-substituted maleimide in water has been observed.…”

“…We have recently developed one-pot post-polymerization modification reactions using p-maleimidophenyl isocyanate (PMPI) as a modification reagent to introduce maleimide moieties into polymers with hydroxy groups and studied the polymerization reactions between the introduced N-aryl MA groups and thiol groups. 42 Their high reactivity was corroborated by the kinetics of the addition reactions between the alcohols and isocyanates (-OH and -NCO) and the coupling of the obtained maleimide-terminated polymers with thiolterminated polymers (-MA and -SH). This procedure is very effective for the transformation of typical hydroxy groups in polymer chains into reactive MA groups, as the reaction is quantitative without any side reactions.…”

“…p-Maleimidophenyl isocyanate (PMPI) was synthesized following our previous report. 42 Characterisation 1 H NMR spectra were recorded using a Bruker AVANCE III HD500 spectrometer. Analytical size-exclusion chromatography (SEC) measurements were carried out at 40 1C using a TOSOH HLC-8320 SEC system equipped with a guard column (TOSOH TSK guard column Super H-L), three columns (TOSOH TSK gel SuperH 6000, 4000, and 2500), a differential refractive index detector, and a UV-vis detector.…”

Synthesis of Heat‐resistant Polymers by Thiol–Ene Reaction of N‐Allylmaleimide Copolymers Using Glycoluril Crosslinkers with Rigid Molecular Structures

“…Functional glycoluril derivatives are available as the crosslinkers for the construction of network polymer systems . On the other hand, various compounds containing a reactive maleimide moiety are used for the syntheses of thermally stable copolymers with vinyl monomers by radical chain polymerization, high‐temperature polymer networks by successive addition reactions, and degradable and stimuli‐responsive network polymers by reversible Diels–Alder reactions . We previously reported that N ‐allylmaleimide (AMI) copolymers produced by radical copolymerization were valid as the precursor polymers for thermoset systems with or without crosslinking agents .…”

“…[6][7][8] On the other hand, various compounds containing a reactive maleimide moiety are used for the syntheses of thermally stable copolymers with vinyl monomers by radical chain polymerization, [9][10][11][12][13][14][15][16][17][18] high-temperature polymer networks by successive addition reactions, [19][20][21][22][23][24][25] and degradable and stimuli-responsive network polymers by reversible Diels-Alder reactions. [26][27][28][29][30] We previously reported that Nallylmaleimide (AMI) copolymers produced by radical copolymerization were valid as the precursor polymers for thermoset systems with or without crosslinking agents. [31][32][33][34][35] The maleimide copolymers exhibited a high glass-transition temperature (T g ) and excellent thermal stability, but the cured materials were brittle.…”