Room temperature synthesis of non-isocyanate polyurethanes (NIPUs) using highly reactive N-substituted 8-membered cyclic carbonates

Abstract

Non-isocyanate polyurethanes (NIPUs) were prepared via polyaddition of highly reactive 8-membered ‘bis-cyclic’ carbonates and various diamines under catalyst-free and room temperature conditions.

Novel thermoplastic polyhydroxyurethane elastomers as effective damping materials over broad temperature ranges

“…Further studies are needed to investigate the origin of this phenomenon and to improve the MW range attainable in PHU synthesis. Recent work by Sardon and coworkers [12] on PHU synthesis at room temperature using 8-membered ring carbonate achieved M n in excess of 40 kg/mol. Synthesis of segmented PHUs using organic catalyst such as 1,5,7-triazabicyclo[4,4,0] undec-5-ene (TBD) also merits further investigation.…”

“…Cyclic carbonate aminolysis has emerged as one of the most promising chemistries to produce PU-like material without using isocyanate [8][9][10][11][12]. This chemistry relies on the ring opening of five-, six-, seven-, or eight-membered-ring cyclic carbonates by amine moieties to produce polyhydroxyurethane (PHU) that is analogous to PU with the exception of an additional primary or secondary hydroxyl group adjacent to the urethane linkage [2,[8][9][10][11][12].…”

“…This chemistry relies on the ring opening of five-, six-, seven-, or eight-membered-ring cyclic carbonates by amine moieties to produce polyhydroxyurethane (PHU) that is analogous to PU with the exception of an additional primary or secondary hydroxyl group adjacent to the urethane linkage [2,[8][9][10][11][12]. Five-membered-ring cyclic carbonates can be easily obtained from a carbon dioxide insertion reaction into an epoxy ring enabling the generation of carbonate monomers from various epoxy precursors [13].…”

“…For example, Endo and coworkers [14][15][16][17][18][19][20][21][22][23], as well as others [24][25][26][27][28][29], synthesized PHUs from carbonated epoxy resins (such as Bisphenol A diglycidyl ether, hydroquinone diglycidyl ether, and butanediol diglycidyl ether) and small-molecule diamines (such as hexamethylene diamine) resulting in single-phase PHUs [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. The reaction kinetics of five-, six- [17][18][19]51], seven- [20] and eight-membered ring carbonates [12], the influence of substituent on reactivity [21,52], and the effects of catalysts [22,[30][31][32] were also characterized. Renewable resources such as carbonated soybean oil, linseed oil [33][34]…”

“…Renewable resources such as carbonated soybean oil, linseed oil [33][34][35][36], limonene [37], cellulose [38], isosorbide [39], cashew nut shell liquid [40], and glycerol [41] have been used to make crosslinked PHUs [33][34][35][36][37][38][39][40][41][42][43][44]. Other investigators have studied various routes to generate cyclic carbonate monomers for synthesizing single-phase and crosslinked PHUs [44][45][46][47][48][49] as well as the increased reactivity of eight-membered ring carbonates allowing room temperature synthesis without the aid of catalysts [12].…”