Chemical Research in Chinese Universities ›› 2014, Vol. 30 ›› Issue (3): 431-436.doi: 10.1007/s40242-014-3344-3

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Preparation and Characterization of SiO2-coated 2,4-Hexadiyn-1,6-bis(ethylurea) Microcapsules

CHENG Huan, ZHU Guangming   

  1. Department of Applied Chemistry, Northwestern Polytechnical University, Xi'an 710129, P. R. China
  • Received:2013-08-14 Revised:2013-09-18 Online:2014-06-01 Published:2014-05-24
  • Contact: ZHU Guangming E-mail:gmzhu@nwpu.edu.cn
  • Supported by:

    Supported by the Northwestern Polytechnical University Graduate Venture Seed Fund Project, China(No.Z2013165).

Abstract:

A novel kind of time-temperature indicator, SiO2-coated 2,4-hexadiyn-1,6-bis(ethylurea) microcapsules, has been fabricated by coating SiO2 on 2,4-hexadiyn-1,6-bis(ethylurea). This kind of microcapsules is a model hydrophilic indicator, its stability is improved. And temperature-induced color change is irreversible even under varying irradiation. The influences of ammonia, tetraethyl orthosilicate(TEOS) and temperature on the product have been investigated. 2,4-Hexadiyn-1,6-bis(ethylurea) and the coated particles have been characterized by means of elemental analysis, mass spectrum, FTIR and Raman spectra and DSC, SEM, TEM and DLS analyses. The results indicate that 2,4-hexadiyn-1,6-bis(ethylurea)/SiO2 ratios, ammonia concentration and temperature could modulate the monodispersity and size of the microcapsules. The experiments indicate that when the molar ratio of 2,4-hexadiyn- 1,6-bis(ethylurea)/SiO2/ammonia is 1:3:3.5 and temperature is 40 ℃, the obtained microcapsules are well coated with the best monodispersity. Such sustained-release and hydrophilic microcapsules have very good prospects as a novel time-temperature chromatic indicator.

Key words: 2,4-Hexadiyn-1,6-bis(ethylurea), SiO2, 2,4-Hexadiyn-1,6-bis(ethylurea)/SiO2 microcapsule