Solvent-free processes to polyurea elastomers from diamines and diphenyl carbonate

Abstract

Two solvent-free processes without using volatile organic chemical (VOC) for making polyurea elastomers have been successfully developed from diamines and diphenyl carbonate (DPC) to meet stringent public demands for a high standard green alternative Anastas and Eghbali (Chem Soc Rev 39 (1): [301][302][303][304][305][306][307][308][309][310][311][312] 2010). In this new non-isocyanate route (NIR) which is an improvement over our previous process to polyurea elastomers, molten DPC are utilized as the carbonylation agents, where DPC reacts sequentially with 1,6-hexanediamine (HDA), polyether diamines of 2000 molecular weight and short chain diamines such as isophorondiamine (IPDA) or 4,4′-diaminodicyclohexylmethane (H 12 MDA). No solvent was added in the synthesis of these new non-solvent polyurea. Alternatively, the above process was modified with an 3 % addition of a water dispersant such as 3-[(2-aminoethyl)amino]-1-propane sulfonic acid sodium salt (ESA) to make waterborne polyurea elastomers to facilitate the mixing in the preparation and in the film-making steps for the final products. In both solvent-free processes, the longchained polyether diamine and the phenol generated from the displacement reaction of diphenyl carbonate were utilized as diluents to lower the viscosities of the reaction mixtures. Unexpectedly, ultra high molecular weight products were resulted particularly for the waterborne polyurea products measuring in excess of 1,000,000 g/mol in some cases. All samples were characterized by FT-IR, H-NMR, TGA, DSC, AFM and GPC. Since the polymers were prepared under mild conditions in absence of a VOC solvent, the new products were found to mostly exist in highly phase-segregated states, exhibiting high heat-resistant temperatures with T d(5%) of well over 300°C with high elongation (>600 %) for the optimized products. Thus, this solvent-free syntheses and environmentfriendly polyurea products should find usefulness in many practical applications.

New Insights into Segmental Packing, Chain Dynamics and Thermomechanical Performance of Aliphatic Polyurea Composites: Comparison between Silica Oxides and Titanium (III) Oxides

“…In response to these hazards, several solvent-free routes to PU exist in the new literature. [25][26][27] Synthesis of poly(dimethylsiloxane) based-semicrystalline PU with tunable crystalline melting points exhibited high strain at break between 495% and 1180%, as reported by Sirrine et al [25] However, the low HS content (4.0 wt%) led to an ultimate tensile strength of only 1.16 MPa. On the other hand, a non-solvent route using diphenyl carbonates [27] achieved higher stress and elongation at break results of 17 MPa and 681%, respectively.…”

“…[25][26][27] Synthesis of poly(dimethylsiloxane) based-semicrystalline PU with tunable crystalline melting points exhibited high strain at break between 495% and 1180%, as reported by Sirrine et al [25] However, the low HS content (4.0 wt%) led to an ultimate tensile strength of only 1.16 MPa. On the other hand, a non-solvent route using diphenyl carbonates [27] achieved higher stress and elongation at break results of 17 MPa and 681%, respectively. However, multi-step polymerization was used incurring in longer processing time, which is not suitable for an industrial-scale application.…”

Urea and Polyurea Production: An Innovative Solvent- and Catalyst-Free Approach through Catechol Carbonate

“…“CO 2 -based routes”: condensation of CO 2 and amines, , aminolysis of linear aliphatic, , cyclic aliphatic, , and linear aromatic organic carbonates ,, “CO 2 -based routes”: condensation of CO 2 and polyamines, ,,− carbamate metathesis or aminolysis, − aminolysis of both linear aromatic carbonates and inorganic urea. , . …”

Direct synthesis of polyureas from the dehydrogenative coupling of diamines and methanol

“…[2][3][4][5][6][7] Although the use of CO 2 for the synthesis of polyureas is attractive, the use of harsh reaction conditions such as reaction temperature of 170-180 1C, and CO 2 pressure of 40-110 bars, in order to overcome the high thermodynamic barriers, present a bottleneck to utilize this methodology on an industrial level. Another approach is based on the polycondensation of diamines with CO 2 derivatives -organic carbamates, [8][9][10][11][12] organic carbonates [13][14][15] and urea (NH 2 CONH 2 ). 16,17 This methodology also suffers from drawbacks such as the use of expensive reagents or solvents (e.g.…”

“…16,17 This methodology also suffers from drawbacks such as the use of expensive reagents or solvents (e.g. biscarbamate [8][9][10][11][12] or ionic liquids as solvent), poor substrate scope, [14][15][16][17] and low atom-economy. 13 Catalytic dehydrogenation is a green and atom-economic approach in organic synthesis, and several new green protocols based on acceptorless dehydrogenative coupling have been developed in the past.…”