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Phenalkamine curing agents for epoxy resin: characterization and structure property relationship

Kunal Wazarkar (Department of Polymer and Surface Engineering, Institute of Chemical Technology, Mumbai, India)
Anagha S. Sabnis (Department of Polymer and Surface Engineering, Institute of Chemical Technology, Mumbai, India)

Pigment & Resin Technology

ISSN: 0369-9420

Article publication date: 6 August 2018

Issue publication date: 22 August 2018

361

Abstract

Purpose

The purpose of this study is to synthesize structurally different phenalkamines based on cardanol, a renewable material obtained from cashew nut shell liquid, and to evaluate their effect on performance properties of the coatings.

Design/methodology/approach

For this purpose, the Mannich reaction between cardanol, formaldehyde and various diamines such as diaminodiphenyl methane (DDM), hexamethylene diamine, Jeffamine D400 and Jeffamine T403 were carried out to produce novel phenalkamines. Resultant phenalkamines were used as curing agents for commercial DGEBPA epoxy resin and were evaluated for performance properties.

Findings

The mechanical, optical, chemical, thermal and anticorrosive properties were evaluated and compared with those of commercial phenalkamine AG141. It was observed that anticorrosive properties evaluated using a salt spray test and electrochemical impedance spectroscopy revealed significant improvement in anticorrosive performance of coatings cured with synthesized phenalkamines based on DDM and T403 as compared to the coatings based on commercial phenalkamine AG141.

Research limitations/implications

To obtain optimum performance properties of the coatings, a combination of phenalkamines can be used.

Practical implications

Curing time and gel times of all the phenalkamines can be further studied under wet and humid conditions. In addition, the variation in coating properties under humid conditions can be investigated.

Originality/value

In this study, newer phenalkamines were synthesized and used as curing agents for epoxy coatings. So far, there have been no reports indicating the synthesis and application of phenalkamines based on polyetheramines, namely, Jeffamine D400 and Jeffamine T403, in coating applications.

Keywords

Acknowledgements

The authors are grateful to Cardolite Specialty Chemicals, India, Grauer and Weil Ltd., India, and Huntsman International Ltd., India, for providing samples of cardanol (NC-700), commercial phenalkamine (AG141) and commercial epoxy resin (GY-250), respectively. The authors would like to thank Mr Ajit Patil for performing thermogravimetric analysis of samples. The authors would also like to thank UGC-BSR-[F.25-1/2014-15 (BSR)/No. F.7-314/2010(BSR)] for funding the project.

Citation

Wazarkar, K. and Sabnis, A.S. (2018), "Phenalkamine curing agents for epoxy resin: characterization and structure property relationship", Pigment & Resin Technology, Vol. 47 No. 4, pp. 281-289. https://doi.org/10.1108/PRT-08-2017-0071

Publisher

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Emerald Publishing Limited

Copyright © 2018, Emerald Publishing Limited

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