Study On Preparation And Performance Of Microcapsule Composite Materials For Self-healing

Epoxy resin matrix composite materials which are easily destroyed in themacroscopic and microscopic use process have broad applications in aviation andspaceflight. Especially when micro cracks appear in the microscopic, themechanical properties of materials will be influenced. Self-Healing compositematerials are important aspects of intelligent bionic materials research. Intelligentbionic self-healing composite materials repairing micro cracks provides a newmethod for preventing potential structure fracture harm.In this experiment, the self-healing microcapsules are synthesized by in-situpolymerization with dicyclopentadiene (DCPD) as capsule core and urea-formaldehyderesin as shell material. This self-healing system mainly adopt ring-opening metathesispolymerization between DCPD and Grubbs catalyst. The terminal of polymerizationreactions chain is activated, and the monomer can make the chain grow for many times,which can provide the guarantee for the self-healing. Through a series of experiments todetermine the optimum conditions: the microcapsules with compact and smoothsurfaces, uniform particle size distribution and good dispersion were obtained under thefollowing conditions: the material quantity of urea and formaldehyde is1:2, the terminalpH value is3, and the emulsifier concentration is0.5%. Moreover, the results of thestudy show that the grain diameter of microcapsule reduced with the increased stirringrate. The wide range of microcapsule particle size can be controlled by changing thestirring rate. Analysis results of the thermostability of microcapsules indicated that thethermostability is excellent and the heat stable temperature is260℃.Mechanical properties of the self-healing polymeric materials were measured bytensile test and through finite element method to analyze the fracture mechanism. Theresults show that healing was triggered by crack propagation through the microcapsules,which then initiate polymerization and healing of the crack inside the composites. So itis feasible that microcapsules with cementing agent inside can make epoxy resin and itsstructure produce healing function. Through the Multiple Linear Regression method,quantitative structure-property relationship (QSPR) model set by SPSS statisticalanalysis tool software for self-healing system lay the foundation of finding the newself-healing system.