STUDY ON MICROCAPSULES FOR SELF-HEALING POLYMER COMPOSITES

摘要

Self-healing polymer composites is a kind of novel smart material. Autonomic healing the microcracks of composites in time with microcapsules is a new research field. The microcapsules for self-repairing polymer composites were studied in this paper. The microcapsules, consisting of dicyclopentadiene (DCPD) core coated by urea-formaldehyde, were prepared by in-situ polymerization method. The effect of processing parameters on the microcapsule's performance was analyzed. The temperature, heated rate, and mass ratio of monomer of wall and core materials were determined. The influence of pH on the system was investigated at the same time. With using OP-10 as emulsifier and styrene/maleic anhydride copolymer or polyacrylic acid as dispersant(5～10%),the desirable microcapsules were successfully fabricated. The prepared microcapsules were characterized by using optics microscope, scanning electronic microscopy SEM, fourier transfer infrared spectroscopy (FT-IR)and thermal gravity analysis (TGA). The mean size is 210μm under agitation rate of 500 rpm. The SEM images showed that the surface smoother as the diameter is small, the reason also was analyzed. The shell wall thickness what was measured by SEM was 1.8～5 μm. The formation of shell wall was verified by analyzing microcapsules with the IR spectra. The TGA analysis of microcapsules confirmed that the core had been coated by urea-formaldehyde.