Preparation And Characyteriszation Of Microcapsules Containg Anionic Ca-Talyst Fro Self-Healing Epoxy System

Due to external factors such as forces, chemical factors, heat and ultraviolet effects,polymer composites are easy to produce cracks inside structural materials, which resultin reduction of mechanical properties and service life. When the internal microcracksappears inside of self-healing material, the healing agent and curing agent would flowout and repair the microcracks timely. The researchers focus on self-healing materialssystem which can fulfill healing function on the condition of room temperature. Somemicroencapsulated curing agents have been prepared as microcapsules, such asmercaptans, boron trifluoride diethyl ether and the active amine curing agents. But theanion curing agent has not been investigated. Anionic catalyst can fulfill fast-curing andmore efficient at room temperature, which has important significance in engineeringapplication.In this article, anionic catalyst curing agen 2,4,6 - (dimethyl amino methyl) phenol(DMP-30) as the core material is protected through the porous materials andmicrocapsules, which make up the dual self-healing system with epoxy resinmicrocapsules in polymer composites.The research is based on the synthesis of DMP-30-containing microcapsules.Through duplicate-latices methods, the microcapsules are prepared with polystyrene(PS) as wall material, anionic catalyst DMP-30 as core material. Based on theexploratory experiments, the study is completed about exploration of the emulsifier typeon the stability of double emulsion film, and then on the synthesis of microcapsulesmorphology. It is concluded that the optimized synthesizing method is a material ratio(core to wall in weight) of 6:1, agitating rate of 250 r·min-1 of primary with 30min,stirring rate of 300 rpm in double emulsion, Span 80 and DBS as the internal aqueousphase emulsifier, SDS and gum arabic as the external phase emulsifier.In order to demonstrate the morphologies and properties of microcapsules, Opticalmicroscopy (OM) , scanning electron microscopy (SEM) , infrared spectroscopy (FTIR)are also applied in the experiments, the results show that the microcapsulese withdense surface, less clustering and the core content of 56.3% . The size distribution ofmicrocapsulse is 10 ~ 30μm, and the average size is 17μm, wall thickness of 1.5 ~ 3μm.The thermal stability of microcapsulese is obtained by thermal gravimetric (TG) anddifferential scanning calorimetry (DSC), Also the releasing properties of microcapsulesare investigated.Anionic catalyst DMP-30– loaded porous materials were studied. Flax fiber as acarrier can adsorb anionic catalyst DMP-30 for self-healing materials, which is coated by polystyrene film. Infrared spectroscopy (FTIR) analysis proves that core material isloaded by flax fiber successfully, Morphology of the fibers are studied through opticalmicroscopy (OM) and scanning electron microscopy (SEM) , the releasing properties ofthe fiber is obtained after experiment at room temperature.In comparison with properties and applications of the two media (microcapsules,flax fiber) for curing agent case, the best way to supply the material is microcapsules forself-healing materials.