Self-Healing EPDM Rubbers with Highly Stable and Mechanically-Enhanced Urea-Formaldehyde (UF) Microcapsules Prepared by Multi-Step In Situ Polymerization

Polymers

Hyunchul Ku¹  KyungWha Oh²  YongJun Chang³  JaeWoo Chung³  Hyung-Min Choi³  KunWon Kim³  Hyeong-Jun Jeoung³  YongChae Jung⁴ 

[1] Department of Electronic and Communication Engineering, Konkuk University, Seoul 05029, Korea;Department of Fashion, Chung-Ang University, 4726 Seodongdae-ro, Daedeok-myeon, Anseong-si, Gyeonggi-do 17546, Korea;Department of Organic Materials and Fiber Engineering, Soongsil University, 369 Sangdo-ro, Dongjak-gu, Seoul 156-743, Korea;Institute of Advanced Composite Materials, Korea Institute of Science and Technology (KIST), 92 Chudong-ro, Bongdong-eup, Wanju-gun, Jeonbuk 55324, Korea;

关键词: dicyclopentadiene (DCPD), ethylene-propylene-diene-monomer (EPDM) rubber;    in situ polymerization;    microcapsules;    self-healing;   

DOI  :  10.3390/polym12091918

来源: DOAJ

【 摘 要 】

The mechanically-enhanced urea-formaldehyde (UF) microcapsules are developed through a multi-step in situ polymerization method. Optical microscope (OM) and field emission scanning electron microscope (FE-SEM) prove that the microcapsules, 147.4 μm in diameter with a shell thickness of 600 nm, are well-formed. From ¹H-nuclear magnetic resonance (¹H-NMR) analysis, we found that dicyclopentadiene (DCPD), a self-healing agent encapsulated by the microcapsules, occupies ca. 40.3 %(v/v) of the internal volume of a single capsule. These microcapsules are mixed with EPDM (ethylene-propylene-diene-monomer) and Grubbs’ catalyst via a solution mixing method, and universal testing machine (UTM) tests show that the composites with mechanically-enhanced microcapsules has ca. 47% higher toughness than the composites with conventionally prepared UF microcapsules, which is attributed to the improved mechanical stability of the microcapsule. When the EPDM/microcapsule rubber composites are notched, Fourier-transform infrared (FT-IR) spectroscopy shows that DCPD leaks from the broken microcapsule to the damaged site and flows to fill the notched valley, and self-heals as it is cured by Grubbs’ catalyst. The self-healing efficiency depends on the capsule concentration in the EPDM matrix. However, the self-healed EPDM/microcapsule rubber composite with over 15 wt% microcapsule shows an almost full recovery of the mechanical strength and 100% healing efficiency.

【 授权许可】

Unknown