Photoinitiator Influence on the Photo-crosslink Property in Polyurea Microcapsules

摘要

To respond the outer optical stimuli at confined dimension,1.4(j,m sized microcapsule has been synthesized,with photoinitiators TPO,1173 or 651 as well as TMPTA resin encapsulated as core optical-responding ingredients. The microcapsule shell formation process is detected and the interfacial polycondensation reaction is accelerated with temperature rises. The C=C bonds cleavage and photo-crosslinking process in microcapsule cells are observed by FT-IR analysis. The photopolymerization degree in microcapsules is heightened during UV-exposure,and achieves stable photocrosslinking percentage of 8% after 40s for 651 photoinitiated microcapsule,which is lower in comparison with 25% after exposed for 250s for 1173 photoinitiated sample. While for TPO,the photocrosslinking extent in microcapsule can obtain at 37% after exposed for 30s. The photoinitiator influence on photopolymerization extent in microcapsules is ascribed to the different irradiation energy utilizing efficiency of the three photoinitiators,and TPO has highest efficiency to absorb UV irradiation in microcapsules. Also,the polyurea microcapsule shell has strong UV absorption below the wavelength of 307nm,which further attenuates the total irradiation energy exposed into the microcapsules.