Preparation And Research Of Self-Healing Rubber Material With Microcapsules

The rubber industry is one of the important basic industries of national economy. Not only does it provide people with indispensable light industry rubber products for daily life, but also provide all kinds of rubber material production equipment or rubber parts to the mining, transportation, construction, machinery, electronics and other heavy industries and emerging industries. But at the same time, rubber material are susceptible to damage in the form of microcracks during use, which will lead to mechanical degradation of rubber material and shorten the span-time of life.The material with the ability to autonomically heal cracks can realize self healing. The material incorporates a microencapsulated healing agent that is released upon crack intrusion. Polymerization of the healing agent is triggered by contacting with the embedded catalyst, then bonding the crack faces and prolonging the service life of material.In this paper, microcapsules are prepared by in-situ polymerization technology with poly(urea-formaldehyde) resin (PUF) as the shell material and dicyclopentadiene (DCPD) as the core material. Focusing on the emulsification process and coating process of the preparation of microcapsules during the experiments. Using the method of combining one-step with two-step during the coating process for the first time. And firstly researching the effects of the adding order of the curing agent and pH regulator on the preparation of poly(urea-formaldehyde) microcapsules. The surface morphology of microcapsules are observed by using optical microscope(OM) and scanning electron microscope(SEM). The results indicated that spherical microcapsules which are coated uniformly can be synthesized successfully. And the microcapsules have rough outside surface and smooth inner surface. Besides, the diameter of the microcapsules is during 100～200μm, and the mean wall thickness is about 5μm. Using Fourier transform infrared spectroscopy(FTIR) and Element spectrum analysis(EDS) to characterize and analyze the chemical structure of microcapsules. The results indicated that PUF microcapsules filled with DCPD are synthesized successfully. And the Thermal gravimetric analysis(TGA) results showed that the microcapsules must be used below 200℃.Adding the DCPD-filled microcapsules and Grubbs catalyst into the rubber matrix, then the rubber with the property of self-healing is synthesized successfully. And using a SiO2 needle with a diameter of about 1μm to prick the PUF microcapsules for the first time. The self-healing process was observed under the Optical microscope(OM). The results indicated that the repair agent(DCPD) can flow smoothly from the broken microcapsule, and the DCPD repair agent solidifies by ring-openning metathesis polymerization(ROMP) as soon as it comes in contact with the Grubbs catalyst dispersed in the matrix.