Encapsulation Of Self Healing Function Components To Cement-based Materials

Self-healing components of the cement-based materials such as adhesives, super absorbent polymer, mineralization bacteria are non-traditional ingredients of civil engineering materials. In order to make these functional components play a role in the right time, they need to be encapsulated. In this case, the encapsulation technology provides a solution. In the study, epoxy resin and super absorbent polymer were encapsulated by a series of embedded experiments, in order to isolate epoxy resin from the external environment and prevent super absorbent polymer from water exchanging with the external environment. These encapsulation experiments are spray drying, in-situ polymerization, orifice-bath coagulation and the oil phase separation.Via in-situ polymerization method with urea-formaldehyde resin as shell material and orifice-bath coagulation method with sodium alginate as shell material, epoxy resin embedded experiment was carried out. Epoxy resin embedded products that had a good dispersion were prepared by trying experiments, parameter analysis, process optimization, performance testing. Among them, the microcapsule particles with urea-formaldehyde resin as shell material had an average particle size of 92.1μm and a microstructure of multi-core amorphous morphology; the average particle diameter of ones which were microscopic spherical with sodium alginate as shell material was 889.2μm, and their size swelling rate was 23% at 25 h.Because of the special properties of itself, the super absorbent polymer embedded experiments were divided into two parts. One was under the polymer swollen state, the other part was under its dry state. In the article, seven kinds of shell materials, namely gelatin, urea-formaldehyde resin, sodium alginate, α-cyanide ethyl acrylate, epoxy resins, ethyl cellulose, polyvinyl, were selectively conducted in the above four kinds of experiments. Although some of the products obtained a certain slow absorption function, eventually all arrived completely dry or water-absorbent state because of water getting through shells.