SPECIFIC POLYMERS (SP – www.specificpolymers.fr) is a SME with 20 employees acting as R&D service provider and scale up producer in the field of functional building-blocks, polymers and materials with high specificity. The main goal of the innovative product developed by SPECIFIC POLYMERS is to validate proof of concepts and develop tomorrow’s materials. In this context, green material chemistry biomass valorization and circular economy are the main aspect of SP research and development activities.
- Many industrial and collaborative projects are ongoing to find bio-based breakthrough alternatives to fossil resources having an industrial viability. In this scope, SP research effort is mainly dedicated to
Biobased alternative building-blocks (Figure 1) to substitute toxic and petro-based precursors (Bisphenol-A, Formophenolic, Isocyanates, etc.) in thermoset resins and composites and
- The end-of-life phase of corresponding thermoset materials that suffer from a lack of reprocessability, reparability and recyclability.
Among thermosetting materials, epoxy polymers are used in many industrial fields such as construction industry, automotive, smart coatings or aerospace for instance. This is mainly due to their good adhesion to many substrates, good chemical resistance, and excellent thermal and mechanical properties. Currently, 75% of the epoxy polymers worldwide are prepared from the DiGlycidylEther of Bisphenol A (DGEBA). However, its manufacturing is based on Bisphenol A, a reprotoxic substance that is under close monitoring and which use might be restricted in certain applications in the future. The bio-sourcing of epoxy polymers could thus have the double positive effect of Bisphenol A replacement and renewable and non-harmful epoxy monomers is a hot topic and a challenge that needs to be addressed. For these reasons, the bio-sourcing of epoxy polymers received a great deal of attention.
ECOXY H2020 project (www.ecoxy.eu) is an integral part of this innovation work. Indeed, in this project, innovative bio-based epoxy resins have been synthesized and studied in order to substitutes DGEBA in the applications targeted by the project (automotive and construction sectors). Two kinds of products were developed were evaluated in parallel :
- Aromatic Biobased Precursors: First strategy was to achieve the synthesis of aromatic resins bearing multi-functional glycidyl ether moieties. In this case, the study was based on the chemical modification of vanillin alcohol or phloroglucinol. Vanillin alcohol can be extracted from Lignin and Phloroglucinol can be extracted from Algae. Both products were synthesized successfully in the scope of the project and are now sell for R&D purpose by SPECIFIC POLYMERS:
- SP-9S-5-003: PHloroglucinol Triglycidyl Ether (PHTE) Download SP-9S-5-003-TDS
- SP-9S-5-005: Vanillin Alcohol DiGlycidyl Ether (DGEVA) Download SP-9S-5-005-TDS
- Epoxidation of vegetable oils: Second strategy concern the epoxidation of unsaturated vegetable oils. To do so, a benchmark of all available vegetable oils was achieved. Most interesting oils were deeply analyzed in order to determine their unsaturation content to adapt the epoxidation modification accordingly. It was finally possible to synthesized a wide range of epoxidized vegetable oils exhibiting a epoxy content from 2.5 méq/g to 7.0 méq/g. These epoxidized vegetable oils are now commercialized by SPECIFIC POLYMERS for R&D purpose under the references SP-3S-30-005 and SP-3S-30-006.
- SP-3S-30-005 corresponds to epoxidized castor oil and differs from the other oils because of the hydroxyl groups in β-position to the epoxy rings. Download SP-3S-30-005-TDS
- SP-3S-30-006 corresponds to epoxidized vegetable oils of similar chemical structure but varying from their content of epoxy functions. They are obtained from various vegetable oils such as Saint John’s Wort oil or Rapeseed oil for instance. As much as possible, non-edible oils were favored in the selection of the vegetable oil precursors. Download SP-3S-30-006-TDS
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All these epoxy resins were evaluated and used in the preparation of epoxy-amine materials. The selection of the most promising resins for the project was based on both processes specification and final materials properties. Thus, both the viscosity and the glass transition temperature (Tg) of the cured resins were defined as the most representative parameters for the definition of the most promising resins to further developed for the applications of the project. On one hand, Epoxidized vegetable oils allow to reach Tg in between 15°C and 90°C using the reference hardener. Resins formulated on the basis of DGEVA and PHTE allow to reach Tg in between 90°C to 180°C. Thus, from both these biobased precursors, it was possible to find a sustainable alternative to DGEBA in epoxy resin formulations.
As a consequence, DGEVA and PHTE was retained as the most promising materials for ECOXY project. An in-depth development work was achieved to enhance the synthetic protocols of both these epoxy precursors and SPECIFIC POLYMERS is now working in close collaboration with its toll-manufacturer to scale up the production of these resins to 25 kg by the end of 2019 and 50 kg of biobased resin by the end of the project. Even if they were not retained in the scope of the project, epoxidized vegetable oils provided very interesting results and are being evaluated in other applications such as smart coatings for instance.
More, these products allow to prepare new sustainable thermoset materials exhibiting reparability, reprocessability and recyclability properties (3R). The 3R functionalities are achieved by combining aforementioned SP bio-based epoxy building-blocks with suitable dynamic hardeners. Compatibilization with flax fibers or PLA fibers is currently being studied to prepare corresponding 3R composite materials.
- M. Fache, B. Boutevin and S. Caillol, Epoxy thermosets from model mixtures of the lignin-to-vanillin process, Green Chem., 2016, 18, 712
- J. Ding, O. ur Rahman, W. Peng, H. Dou and H. Yu, A novel hydroxyl epoxy phosphate monomer enhancing the anticorrosive performance of waterborne Graphene/Epoxy coatings, Applied Surface Science 427 (2018) 981–991
- A. Ruiz de Luzuriaga, R. Martin, N. Markaide, A. Rekondo, G. Cabañero, J. Rodríguez and I. Odriozola, Epoxy resin with exchangeable disulfide crosslinks to obtain reprocessable, repairable and recyclable fiber-reinforced thermoset composites, Mater. Horiz., 2016, 3, 241-247