The study on the mechanical properties of PU/MF double shell selfhealing microcapsules

doi:10.1016/j.cjche.2020.03.003

Abstract

Abstract: The self-healing microcapsules can be buried in the coating to improve the anticorrosive ability. In this paper, self-healing microcapsules of polyurea (PU)/melamine resin (MF) double shell were prepared by in-situ polymerization and interfacial polymerization with isocyanate as the core material. Scanning electron microscope was used to observe the microcapsule morphology. The structures of microcapsules prepared with different chain extenders were characterized by Fourier transform infrared spectroscopy. The micromanipulation system was used to loading-holding, loading-unloading and loading to rupture individual microcapsules, so as to explore the mechanical properties of microcapsules. The Young's modulus corresponding to microcapsules was calculated by mathematical model fitting. The self-healing properties of microcapsule coating were characterized by optical microscope. The experimental results showed that the microcapsule shell prepared under optimized conditions had a complete morphology and good mechanical properties. The microcapsule was in the elastic deformation stage under small deformation, and the plastic deformation stage under large deformation. The Young's modulus range of microcapsules was 9.29-14.51 MPa, and the corresponding Young's modulus could be prepared by adjusting the process. The surface crack of the coating containing microcapsule could heal itself after 48 h in a humid environment.

Key words: Microcapsules, Self-healing, Double-layered, Mechanical properties, Young's modulus

摘要： The self-healing microcapsules can be buried in the coating to improve the anticorrosive ability. In this paper, self-healing microcapsules of polyurea (PU)/melamine resin (MF) double shell were prepared by in-situ polymerization and interfacial polymerization with isocyanate as the core material. Scanning electron microscope was used to observe the microcapsule morphology. The structures of microcapsules prepared with different chain extenders were characterized by Fourier transform infrared spectroscopy. The micromanipulation system was used to loading-holding, loading-unloading and loading to rupture individual microcapsules, so as to explore the mechanical properties of microcapsules. The Young's modulus corresponding to microcapsules was calculated by mathematical model fitting. The self-healing properties of microcapsule coating were characterized by optical microscope. The experimental results showed that the microcapsule shell prepared under optimized conditions had a complete morphology and good mechanical properties. The microcapsule was in the elastic deformation stage under small deformation, and the plastic deformation stage under large deformation. The Young's modulus range of microcapsules was 9.29-14.51 MPa, and the corresponding Young's modulus could be prepared by adjusting the process. The surface crack of the coating containing microcapsule could heal itself after 48 h in a humid environment.

关键词: Microcapsules, Self-healing, Double-layered, Mechanical properties, Young's modulus

Guohao Du, Jianfeng Hu, Jianhui Zhou, Guangwu Wang, Shengli Guan, Hailing Liu, Man Geng, Chuang Lü, Yaoqiang Ming, Jinqing Qu. The study on the mechanical properties of PU/MF double shell selfhealing microcapsules[J]. Chinese Journal of Chemical Engineering, 2020, 28(5): 1459-1473.

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