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Synthesis and Characterization of a Polyurethane Phase Separated to Nano Size in an Epoxy Polymer

The Center for Chemical Industry Development, Korea Research Institute of Chemical Technology, 45, Jongga-ro, Yugok-dong, Jung-gu, Ulsan 44412, Korea
Authors to whom correspondence should be addressed.
Coatings 2019, 9(5), 319;
Received: 2 April 2019 / Revised: 22 April 2019 / Accepted: 7 May 2019 / Published: 13 May 2019
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Epoxy resins are widely applicable in the aircraft, automobile, coating, and adhesive industries because of their good chemical resistance and excellent mechanical and thermal properties. However, upon external impact, the crack propagation of epoxy polymers weakens the overall impact resistance of these materials. Therefore, many impact modifiers have been developed to reduce the brittleness of epoxy polymers. Polyurethanes, as impact modifiers, can improve the toughness of polymers. Although it is well known that polyurethanes (PUs) are phase-separated in the polymer matrix after curing, connecting PUs to the polymer matrix for enhancing the mechanical properties of polymers has proven to be challenging. In this study, we introduced epoxy functional groups into polyol backbones, which is different from other studies that focused on modifying capping agents to achieve a network structure between the polymer matrix and PU. We confirmed the molecular weight of the prepared PU via gel permeation chromatography. Moreover, the prepared material was added to the epoxies and the resulting mechanical and thermal properties of the materials were evaluated. Furthermore, we conducted tensile, flexural strength, and impact resistance measurements. The addition of PU to the epoxy compositions enhanced their impact strength and maintained their mechanical strength up to 10 phr of PU. Furthermore, the morphologies observed with field emission scanning electron microscopy and transmission electron microscopy proved that the PU was phase separated in the epoxy matrix. View Full-Text
Keywords: epoxy resin; polyurethane; physical properties epoxy resin; polyurethane; physical properties

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Kim, T.H.; Kim, M.; Lee, W.; Kim, H.-G.; Lim, C.-S.; Seo, B. Synthesis and Characterization of a Polyurethane Phase Separated to Nano Size in an Epoxy Polymer. Coatings 2019, 9, 319.

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