Epoxy Resins Derived from Bio-Based Raw Materials
Epoxy resins can be defined as resins containing multiple oxirane (epoxy) rings. Due to their superior mechanical properties, high adhesion to many surfaces, and good chemical and electrical resistance, they can be used in a wide range of applications such as flooring, electronic materials, metal cans and containers, automotive, marine and white goods coatings. Additionally, they are widely used as adhesives and matrices for fiber-reinforced composites. The global epoxy market size is estimated to reach USD 8.77 billion in 2021 and USD 10.77 billion in 2027. The epoxy market is dominated by reaction products of bisphenol A and epichlorohydrin. The most common epoxy resin is diglycidyl ether of bisphenol A (DGEBA), which accounts for nearly 70% of epoxy resin usage. Others are prepared by epoxidation of unsaturated structures. Bisphenol A has harmful effects on human health and the environment. Additionally, it acts as an endocrine disruptor and is toxic to living organisms. For these reasons, its use in food-related packaging and materials has been banned in many countries [1-6].
Figure 1. Global epoxy application areas and usage rates [4][/caption]In recent years, due to health and environmental concerns and the depletion of fossil raw material sources, research into the use of bio-based materials instead of petroleum-derived raw materials has gained considerable importance. In this direction, bio-based alternatives of epoxy resins have been developed using bio-based raw materials instead of bisphenol A (BPA).
Figure 2. Chemical structure of bisphenol A-based epoxy resin (DGEBA) [5][/caption]In a study, epoxidized soybean oil was synthesized from vegetable oils. Since soybean oil has long aliphatic chains in its chemical structure, coatings prepared using epoxidized soybean oil exhibited low thermal and mechanical properties. Meanwhile, in research on bio-based chemicals similar to bisphenol A, ferulic acid, itaconic acid, eugenol, pine resin, gallic acid, vanillic acid and lignin have been proposed as alternatives to BPA. Finally, using epoxidized vanillin, comparable results were obtained in the physical and chemical properties of the final coatings [7-9].
Figure 3. Chemical structure of lignin and vanillin [9].[/caption]İzel Kimya is conducting research on the production of new epoxy resins prepared by incorporating epoxy groups into bio-based raw materials.
References [1] Clayton May (11 May 2018). Epoxy Resins: Chemistry and Technology (Second ed.).CRC Press. p. 65. ISBN 978-1-351-44995-3. [2]https://en.wikipedia.org/wiki/Epoxy#cite_note-May2018-1. [3] https://www.alliedmarketresearch.com/epoxy-resins-market. [4] Geoff Gibson,Chapter 27 - Epoxy Resins,Editor(s):Marianne Gilbert, Brydson's Plastics Materials (Eighth Edition), Butterworth-Heinemann, 2017, Pages 773-797., [5] https://bilimteknik.tubitak.gov.tr / system/ files / makale / epoksi.pdf. [6] Jaworski C. Capricho, Bronwyn Fox & Nishar Hameed (2020) Multifunctionality in Epoxy Resins, Polymer Reviews, 60:1, 1-41. [7] Sagheer Gul, Ayesha Kausar, Mazhar Mehmood, Bakhtiar Muhammad & Saira Jabeen (2016) Progress on Epoxy/Polyamide and Inorganic Nanofiller-Based Hybrids: Introduction, Application, and Future Potential, Polymer-Plastics Technology and Engineering, 55:17, 1842-1862., [8] Fan-Long Jin, Xiang Li, SooJin Park, Synthesis and application of epoxy resins: A review, Journal of Industrial and Engineering Chemistry, Volume 29, 2015, Pages 1-11., [9] Nikafshar, Saeid, Zabihi, Omid, Hamidi, Susan, Moradi, Yousef, Barzegar, Saeed, Ahmadi, Mojtaba and Naebe, Minoo 2017, A renewable bio-based epoxy resin with improved mechanical performance that can compete with DGEBA, RSC advances, vol. 7, no. 14, pp. 8694-8701.
