Isocyanate- and solvent-free synthesis of melt processible polyurea elastomers derived from urea as a monomer

White, B. Tyler; Migliore, John M.; Mapesa, Emmanuel Urandu; Wolfgang, Josh D.; Sangoro, Joshua; Long, Timothy Edward

doi:10.1039/d0ra02369h

Cited by 22 publications

(24 citation statements)

References 29 publications

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“…This can be explained by the fact that initiation of segmental relaxation of the soft segment due to the temperature increases. 27–29 Moreover, the presence of a plateau modulus after the storage modulus (E ′ ) sudden drop around 60°C suggests their crosslinked nature 1 and microphase separation, 30 and this is due to the physical crosslinking of the hard segment. At temperature higher than 160°C, the drop of E ′ is related to the hard segment disintegrate.…”

Section: Resultsmentioning

confidence: 99%

Crosslink density and mechanical property evolution during the curing of polyurethane-urea/sodium silicate hybrid composites

Sun

Liang

et al. 2021

High Performance Polymers

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In order to understand the evolution of the structure–property relationship between the crosslink density and mechanical properties of polyurethane-urea/sodium silicate (PU/SS) hybrid composites, a series of PU/SS composites with 2.5 wt% organofunctional silanes and pure PU/SS composites are investigated at different curing time. Mechanical properties, the fracture surface morphology, and thermo-mechanical properties of these PU/SS composites are characterized by electron omnipotence experiment machine, scanning electron microscope, and dynamic mechanical analysis (DMA), respectively. The mechanical test results show the strength and fracture toughness of the PU/SS composites first increase and then stabilize during cure, and the modification leads to PU/SS composites with significantly higher mechanical properties. Further, the morphology of fractured samples also reveals that the longer curing time and the modification of the PU/SS composites means a higher curing degree. Moreover, the increase in the crosslink density calculated from the DMA tests quantitatively confirmed the positive influence of the curing time and the modification in enhancing mechanical properties. In addition, it is also found that the mechanical properties of the PU/SS composites not only depend on the crosslink density but also on the well-dispersed hybrid PU/SS system.

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Section: Resultsmentioning

confidence: 99%

Crosslink density and mechanical property evolution during the curing of polyurethane-urea/sodium silicate hybrid composites

Sun

Liang

et al. 2021

High Performance Polymers

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“…23 CO 2 is reacted with appropriate reagents and catalysts to produce polyureas. [24][25][26][27][28][29][30][31][32][33][34][35][36] CO 2 -derived monomers such as cyclic carbonate, [37][38][39][40] carbamate, 41,42 and urea [43][44][45] are used to synthesize polyurethanes and polyureas. To date, a few types of self-healing and recyclable CO 2 -based polymeric materials have been reported.…”

Section: Introductionmentioning

confidence: 99%

A self-healing and recyclable polyurethane-urea Diels–Alder adduct synthesized from carbon dioxide and furfuryl amine

et al. 2021

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“…This urea method comes back to the vision of researchers only in recent years 26 . Long and coworkers used aminopropyl‐terminated poly(dimethyl siloxane)s, 27 jeffamine, 28 or ether amine, 29 to react with urea and to prepare many PUr elastomers or plastics. These plastics do not show competitive mechanical properties to the commercially available plastics.…”

Section: Introductionmentioning

confidence: 99%

High‐performance thermoplastic polyureas via a non‐isocyanate route from urea and aliphatic diamines

Lin

Xie

Tang

2022

J of Applied Polymer Sci

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Polyureas (PUrs) with excellent properties have been applied widely in many fields. These days attention has been turned to non-isocyanate routes for PUr preparation due to the toxicity and the high cost of isocyanates. Urea is a green chemcial which can be either from urine or from recycled carbon dioxide and ammonia. Here we introduce a urea-based route to prepare PUrs, by melt polycondensation of urea and 1,10-diaminodecane (DA-10) or/and 1,6-diaminohexane (DA-6) without catalyst, solvent, and high pressure. It is difficult to synthesize such thermoplastic PUrs from diisocyanate without any solvent since the melting point of PUr is normally higher than 170 C at which isocyanate is able to react with urea group to form biuret. The thermoplastic PUrs obtained in this study exhibit excellent mechanical and thermal properties. Furthermore, the properties can be adjusted by changing the feed ratio of diamines (DA-6/DA-10). The compression-molded PUrs show even better mechanical properties than ultra-high molecular weight polyethylene (UHMWPE). The values of Young's modulus, strength at break and elongation at break are found to be 230-300 MPa, 40-60 MPa and 200%-400%, respectively (except for PUr-6). Therefore, this facile, non-isocyanate approach provides a viable alternative to the current industrial process for highperformance PUrs.

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Isocyanate- and solvent-free synthesis of melt processible polyurea elastomers derived from urea as a monomer

Abstract: Polyurea elastomers derived in part from a bio-sourced feedstock and synthesized using an isocyanate-, solvent-, and catalyst-free approach exhibit elastomeric properties while maintaining melt-processibility.

Cited by 22 publications

References 29 publications

Crosslink density and mechanical property evolution during the curing of polyurethane-urea/sodium silicate hybrid composites

Crosslink density and mechanical property evolution during the curing of polyurethane-urea/sodium silicate hybrid composites

A self-healing and recyclable polyurethane-urea Diels–Alder adduct synthesized from carbon dioxide and furfuryl amine

High‐performance thermoplastic polyureas via a non‐isocyanate route from urea and aliphatic diamines

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