Application of a series of novel chain-extended ureas as latent-curing agents and toughening modifiers for epoxy resin
✍ Scribed by Bao-Long Zhang; Hui-Qi Zhang; Ying-Cai You; Zong-Jie Du; Pei-Yuan Ding; Tao Wang; Ji-Fu Huang
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 359 KB
- Volume
- 69
- Category
- Article
- ISSN
- 0021-8995
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✦ Synopsis
A series of novel chain-extended ureas ( U i ) containing poly(ethylene glycol) (PEG) spacers with different molecular weights were synthesized and the reactive mechanism, reactive activity, impact strength, dynamic mechanical behavior, morphology, and storage properties of the epoxy resin/chain-extended urea system were studied. Experimental results revealed that the impact strength of the epoxy resin modified with chain-extended urea containing a PEG flexible spacer with molecular weight of 1000 is 9.5 times higher than that of the epoxy resin/dicyandiamide system. Results also show that the molecular weight of PEG in chain-extended ureas hardly has any influence on the reactive activity of the chain-extended ureas. The storage life of the epoxy resin / U i system can be delayed to 38 h at 50ЊC.