Synthesis and characterization of isocyanate-free polyureas. Issue 1 (6th December 2017)

• Record Type: Journal Article
• Authors: Dennis, Joseph M.; Steinberg, Limor I.; Pekkanen, Allison M.; Maiz, Jon; Hegde, Maruti; Müller, Alejandro J.; Long, Timothy E.
• Is Part Of: Green chemistry. Volume 20:Issue 1(2018)
• Page Start: 243
• Page End: 249
• Publication Date: 2017-12-06
• Subjects: Environmental chemistry -- Industrial applications -- Periodicals; Environmental management -- Periodicals; 660
• DOI: 10.1039/c7gc02996a
• Languages: English
• ISSNs: 1463-9262

Abstract

Abstract : Due to continued health and safety concerns surrounding isocyanates, alternative synthetic routes to obtain urea-containing polymers is gaining much attention. Abstract : Due to continued health and safety concerns surrounding isocyanates, alternative synthetic routes to obtain urea-containing polymers is gaining much attention. Melt polycondensation of urea with diamines achieved polyureas in the absence of catalyst or solvents. 1 H NMR spectroscopy and thermogravimetric analysis confirmed targeted compositions and thermal stability, respectively. Differential scanning calorimetry and dynamic mechanical analysis provided insight into the copolymers' thermal and morphological behavior. A steady increase in the melting temperature across the range of compositions suggested co-crystallization of the different repeating units, in sharp contrast to non-hydrogen bonded copolymers. Furthermore, tunable melt temperatures and mechanical performance illustrated the versatility of these copolymers in high performance applications. Finally, initial biodegradation studies using a naturally occurring, soil enzyme (urease) demonstrated steady degradation over 4 weeks, releasing ammonia as a potential nitrogen source for agricultural applications.