Synthesis and characterization of isocyanate-free polyureas,Green Chemistry

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Synthesis and characterization of isocyanate-free polyureas
Green Chemistry ( IF 9.3 ) Pub Date : 2017-11-29 00:00:00 , DOI: 10.1039/c7gc02996a
Joseph M. Dennis _{1,

2,

3,

4,

5} , Limor I. Steinberg _{1,

2,

3,

4,

5} , Allison M. Pekkanen _{1,

2,

3,

4,

5} , Jon Maiz _{6,

7,

8,

9} , Maruti Hegde _{1,

2,

3,

4,

5} , Alejandro J. Müller _{6,

7,

8,

9,

10} , Timothy E. Long _{1,

2,

3,

4,

5}

Affiliation

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. ¹H 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.

中文翻译：

不含异氰酸酯的聚脲的合成与表征

由于围绕异氰酸酯的健康和安全问题持续存在，获得含尿素聚合物的替代合成途径受到了广泛关注。尿素与二胺的熔融缩聚可在不存在催化剂或溶剂的情况下获得聚脲。^1个1 H NMR光谱和热重分析分别确认了目标组成和热稳定性。差示扫描量热法和动态力学分析提供了对共聚物的热和形态行为的了解。与非氢键键合的共聚物形成鲜明对比的是，在整个组合物范围内，熔融温度的稳定提高表明不同重复单元的共结晶。此外，可调节的熔体温度和机械性能说明了这些共聚物在高性能应用中的多功能性。最后，使用天然存在的土壤酶（脲酶）进行的初步生物降解研究表明，在4周内稳定降解，释放出氨作为农业应用的潜在氮源。

更新日期：2018-01-02

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