Original biobased nonisocyanate polyurethanes: solvent- and catalyst-free synthesis, thermal properties and rheological behaviour

Abstract

Novel biobased NonIsocyanate PolyUrethanes (NIPUs) were synthesized from dimer-based diamines and sebacic biscyclocarbonate in bulk, and without catalyst. All synthesized NIPUs present biobased contents around 80%. Biscyclocarbonates and final NIPUs were characterized by FTIR and NMR spectroscopy. A specific study was conducted to determine the best carbonate to amine ratio. The influence on the structures and properties of NIPUs with different average amine functionalities, varying from 2.0 to 2.2, was investigated by DSC, SEC and dynamic rheological analyses. Based on FTIR analyses, it was found that the stoichiometric ratio is optimal for the NIPU synthesis to obtain the highest molar masses with appropriate kinetics. However, the results show that the molar masses (up to 22 000 g mol À1 ) were lower than conventional polyurethanes. A specific structuration due to a higher crosslink degree was observed when the average functionality of the diamine dimer increased. As expected, the glass transition temperature rises in this case. Crosslinked samples were synthesized with an average amine functionality of 2.15 and 2.2. A promising elastomer sample with elongation higher than 600% was then obtained.

Poly(hydroxy urethane)s based on renewable diglycerol dicarbonate

“…Several chemical routes have been developed throughout the years to avoid these issues, yet none of these pathways is currently used for the large scale production of non-isocyanate polyurethanes (NIPU) [2][3][4][5][6][7][8]. Still, the addition reaction between cyclic carbonates and amines to form poly(hydroxy urethane)s (PHU) has recently been highlighted in an increasing number of publications [9][10][11][12][13][14]. The reaction between five-, six-, or seven-membered cyclic carbonates and an amine results in an additional hydroxyl group adjacent to the urethane linkage formed, which may be a primary or a secondary hydroxyl group [15][16][17][18][19][20][21].…”

A novel 2,5-furandicarboxylic acid-based bis(cyclic carbonate) for the synthesis of biobased non-isocyanate polyurethanes

“…In the second step, the maximum degradation rates occurred between 401 C and 455 C, which were associated with weight losses of 65-75%. The rst step of degradation was due to the degradation of the urethane bonds, which are known to decompose starting at approximately 200 C. 10 In this step, the decomposition of urethanes may occur via three possible mechanisms: the degradation to isocyanates and alcohols; the formation of primary amines, CO 2 , and olens; and the formation of secondary amines and CO 2 .…”

“…12 The NIPU prepared via this route is also called poly(hydroxyurethane) (PHU) owing to the formation of hydroxyl groups that result from the opening of cyclic carbonate rings. 10 The hydroxyl groups can form hydrogen bonds to the carbonyl oxygens within the urethane linkages, accounting for a number of characteristics of PHU, such as improved hydrophilicity, reduced crystallinity, and increased resistance to organic solvents.…”

“…4,7,8 Moreover, isocyanates are typically produced from the reactions of amines with phosgene, which can be extremely dangerous to humans. 6,9,10 Environmental and health hazard concerns over the use of isocyanates have led to an increasing demand for the development of environmentally-friendly processes for PU production without using toxic isocyanates. 8 The development of novel non-isocyanate polyurethanes (NIPUs) has received increased attention in recent years.…”

DFT investigation of the reaction mechanism for the guanidine catalysed ring-opening of cyclic carbonates by aromatic and alkyl-amines

“…The most frequently studied and promising route relies on the polyaddition of bis-5-membered cyclic carbonates with diamines, leading to the formation of PolyHydroxyUrethanes (PHUs) [1][2][3][4][5][6][7] that are mainly exploited for coating applications or as crosslinked materials for thermosets or elastomers [8][9][10] or as foamed materials.…”