title: Polyureas from diamines and carbon dioxide: synthesis, structures and properties.
abstract: Polyureas were synthesized from diamines and carbon dioxide in the absence of any catalyst or solvent, analogous to the synthesis of urea from condensation of ammonia with carbon dioxide. The method used carbon dioxide as a carbonyl source to substitute highly toxic isocyanates for the synthesis of polyureas. FTIR and DFT calculations confirmed that strong bidentate hydrogen bonds were formed between urea motifs, and XRD patterns showed that the PUas were highly crystalline and formed a network structure through hydrogen bonds, which served as physical cross-links. The long chain PUas presented a microphase separated morphology as characterized by SAXS and showed a high melting temperature above 200 °C. The PUas showed high resistance to solvents and excellent thermal stability, which benefitted from their special network structures. The PUas synthesized by this method are a new kind of functional material and could serve some areas where their analogues with similar functional groups could not be applied.
authors: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, P R China.
authors: Chaoyong
authors: C
authors: Wu
authors: Jinyao
authors: J
authors: Wang
authors: Pingjing
authors: P
authors: Chang
authors: Haiyang
authors: H
authors: Cheng
authors: Yancun
authors: Y
authors: Yu
authors: Zhijian
authors: Z
authors: Wu
authors: Dewen
authors: D
authors: Dong
authors: Fengyu
authors: F
authors: Zhao