High-performance
Team and laboratory dedicated to the conception of your high-performance materials
SPECIFIC POLYMERS focuses its R&D on the development of high-performance materials and multifunctional coatings for high-value-added applications such as aeronautics or aerospace.
With the increasing level of sophistication expected for materials to achieve desired functionalities in a wide range of applications, the production of high-performance materials has become crucial. With this in mind, at SPECIFIC POLYMERS, our research efforts are strongly concentrated on the development of tomorrow’s materials through three main avenues.
HEAT-RESISTANT RESINS
In the current context of global changes, where CO2 emissions are required to be as low as possible, composites appear to be attractive materials since they are their lightweight and easy to manufacture. However, the extreme conditions that materials encounter in aeronautics and automotive applications have, so far, prevented the use of composites which are traditionally made from polyamide, epoxy, vinyl ester, phenolic, polypropylene or unsaturated polyester.
Resins such as bismaleimides, polyimides, cyanate esters, benzoxazines and phthalonitriles are interesting alternatives as they have been made to be able to withstand higher service temperatures. For instance, the PMR polyimides (polymerization of monomeric reactants) exhibit very high thermal stability with a continuous temperature use above 290°C while phthalonitriles show thermal degradation onset above 500°C.
Nevertheless, improvements are still required to extend their thermal resistance and adjust their mechanical properties to the specificity of the application, while containing the product cost.
At SPECIFIC POLYMERS, specific attention is paid to the development of the next generation of cyanate ester resins and their optimization in terms of toughness and the maintenance of mechanical performance after ageing. Different strategies are investigated to bring these new resins up to the high requirements of the aeronautics sector, relying on the synthesis of new precursors and their formulation with suitable additives.
Overview of current heat-resistant resins – the dilemma between excellent mechanical properties and high continuous use temperature
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FUNCTIONAL COATINGS
Through different industrial and collaborative projects, we are involved in the design of tailor-made functional coatings. There are various targeted properties, and the high-performance materials are adjusted as a function of the specifications of each application. One of the main technical challenges relies on the association of multiple functionalities, which are often antagonistic. For instance, super-hydrophobicity is known to be barely compatible with resistance to erosion due to the fragility of the nano/microscopic roughness features.
Hybrid coatings are a promising pathway for responding to such technological challenges and have occupied a more prominent place over the last few decades. Polymers are easy to process, flexible, available at a relatively low cost, lightweight and exhibit an extremely large variety of properties depending on their inherent chemical structure. However, they show some limitations in different high-technology areas where outstanding performance materials are needed, while inorganic components present superior optical, thermal, mechanical, electrical or magnetic properties. Moreover, in hybrid materials, the properties of the plastic and metal are added and synergy is achieved, which leads to unique characteristics. However, reaching this synergetic effect is not a straightforward task, and an accurate control of the interaction between the two counterparts is crucial.
Preparation of a hybrid sol-gel coatings combining classic sol-gel precursors (TEOS) and organosilanes
SOL-GEL COATINGS
The sol-gel chemistry is a suitable route to produce hybrid coatings, as its low processing temperature enables the covalent incorporation of organic components at a nanoscale level into an inorganic network with high mechanical stability. Over the years, SPECIFIC POLYMERS has developed a large range of building blocks and polymers bearing alkoxysilanes that can be covalently reacted into the sol-gel networks by a hydrolysis-condensation mechanism. Organosilanes are largely used in academic and industrial applications thanks to their peculiar feature of bonding organic and inorganic phases, modifying metallic substrates or inorganic nanoparticles or imparting specific properties to sol-gel networks.
A wide range of organosilane compounds are available to meet the specific requirements of applications in various fields.
Coatings, automotive, electronic, energy or biomedical.
For instance, highly stable and efficient water and oil-repellent optical sol-gel coatings have recently been developed. Hydrophobicity and oleophobicity are essential to maintain the durability of a coating (anti-corrosion, anti-fouling), preserve the coating’s optical properties (anti-icing, self-cleaning) or improve fluidic and gas transportations (microfluidic, contamination management). During the development of these coatings, it was demonstrated that with a minimal proportion of fluoroalkylsilanes (SP-02-004) introduced into a sol-gel formulation, similar properties to a classic silanization could be obtained in accordance with a more industry-compliant and straightforward process. This method can be applied to any organosilanes and enables the incorporation of additives of different natures, thus opening up interesting perspectives in the development of multifunctional coatings.
HYBRID MATERIALS AND COATINGS
In addition to sol-gel chemistry, other routes are developed at SPECIFIC POLYMERS to prepare hybrid formulations, such as the intimate mixing of inorganic fillers into polymeric resins or the functionalization of particles according to the “grafting-from” and “grafting-to” techniques.
We have thus addressed multiple subjects in functional coatings going from anti-corrosion coatings in extreme conditions, super-hydrophobic surfaces for self-cleaning, self-healing materials, to conductive or fire-proofing coatings. As an example, the development of a highly conductive paint for lightning protection is on-going. The objective is to find the best combination of metallic and carbon-based particles and polymeric matrices of different chemical natures, to create conductive channels with the lowest number of fillers, while showing excellent weatherability and mechanical properties.
A wide range of phosphorus flame retardants are available to meet the specific requirements of applications in various fields.
SP-3-15-004 > | SP-1P-1-009 > | SP-41-010 > | SP-3-12-001 >
Phosphorus flame retardants that can be covalently linked to various polymeric matrices (epoxy, PU, sol-gel, acrylate) were also designed due to the need for fire-proof materials. These additives act mainly in the solid phase of burning polymeric materials and cause the polymer to char, thus inhibiting the pyrolysis process necessary to feed the flames.
Find all the SPECIFIC POLYMERS products related to functional coatings
Corresponding Scientific Publications
- A. Bouvet-Marchand and al., Distribution of fluoroalkylsilanes in hydrophobic hybrid sol–gel coatings obtained by co-condensation, Journal of Materials Chemistry A, 6, 24899-24910, (2018) >
- C. J. Brinker and G. W. Scherer, Sol-Gel Science: The Physics and Chemistry of Sol–Gel Processing, Book, (1990) >
- A. Bouvet-Marchand and al., Influence of experimental parameters on the side reactions of hydrosilylation of allyl polyethers studied by a fractional factorial design, React. Chem. Eng., 3, 696-706, (2018) >
UV-CURABLE RESINS
When it comes to the production of functional coatings, photopolymerization is undoubtedly the method of choice. Considered a green technology, the photopolymerization reactions are characterized by a solvent-free, low-temperature and rapid cure process. Since the polymerizations can be induced through free-radical, ionic (mostly cationic) mechanisms or both simultaneously, a large range of reactive functions is thereby available.
Thanks to SPECIFIC POLYMERS’ expertise in organic and polymer chemistry, functional monomers and polymers can be developed and tuned according to the specific requirements of the customers. Molecular weight, the nature of the backbone and the location of the functionality can be varied depending on the targeted properties.
UV-CURING METHODS
As we are aware of the current technical challenges related to photopolymerization, SPECIFIC POLYMERS can provide UV-curable monomers and polymers of different natures (acrylate, vinyl ether, epoxies, etc.). We also develop breakthrough innovation R&D products, such as maleimide monomers that can react without photo-initiators, which are often problematic in terms of toxicity and yellowing. In addition, investigations have also been initiated into the UV-curing of hybrid formulations, or thick films in which light penetration can be an issue to achieving sufficient curing of the material.
BIO-BASED UV MONOMERS
Moreover, a range of bio-based UV precursors has been developed to offer “green coatings” by combining the process of photo-polymerization with bio-based monomers. A wide range of Tg, from -20°C to 80°C, was then achieved. Further work aims to extend the range of thermo-mechanical properties with other bio-based molecules of interest.
UV HYBRID MATERIALS
More recently, photopolymerization has been applied to the preparation of hybrid materials. It was demonstrated, for instance, that the generation of functional nanoparticles into UV-cured resin, or the synthesis of sol-gel hybrid films could be achieved in a one-step UV-process. These promising results open up fascinating opportunities in the field of tailor-made high-performance materials.
Platform of UV-reactive functions and examples of SPECIFIC POLYMERS’ R&D products
For instance, SPECIFIC POLYMERS has been involved in the development of hybrid UV-curable formulations for two different applications. One of them is a formulation specially dedicated to the encapsulation of piezoelectric ZnO nanowires (NWs) for pressure-based fingerprint sensors, to meet an increasing need for the highest reliability in biometric identification (Piezomat). The other formulation is a UV-curable resin behaving in a semi-conductor fashion for the embedding of biological living cells, requiring a minimal concentration of heavy-metal salt to display a high contrast at high resolution in volume electron microscopy, while allowing fluorescence preservation during freeze-substitution of a biological sample.
Chemical structures of epoxidized bio-renewable precursors and their related glass transition temperatures after cationic photo-polymerization
Corresponding Scientific Publications
- A. Bouvet-Marchand and al., UV-crosslinked polymeric materials for encapsulation of ZnO nanowires in piezoelectric fingerprint sensors, Procedia Engineering, 168, 1135-1139, (2016) >
- A. Bouvet-Marchand and al., Design of UV-crosslinked polymeric thin layers for encapsulation of piezoelectric ZnO nanowires for pressure-based fingerprint sensors, Journal of Materials Chemistry C, 6(3), 605-613, (2018) >
- P. Garra and al., Photopolymerization processes of thick films and in shadow areas: a review for the access to composites, Polymers Chemistry, 8, 7088-7101, (2017) >
- C. Noè and al., Cationic photopolymerization of bio-renewable epoxidized monomers, Progress in Organic Coatings, 133, 131-138, (2010) >
- C. Belon and al., Combination of Radical and Cationic Photoprocesses for the Single-Step Synthesis of Organic-Inorganic Hybrid Films, Journal of Polymer Science Part A, 48(19), 4150-4158, (2010) >
What a pleasure to hear from you!
Do not hesitate to contact us if you require more information or if you have any questions about our expertise in high-performance materials and coatings.