Thermally stable fluorine-free thermosetting coatings with superior release properties to teflon

Overview

This technology offers a new class of thermosetting coatings based on polybenzoxazine, a polymer that achieves lower surface free energy than Teflon without relying on fluorine chemistry. The unique molecular structure forms a six-membered intramolecular hydrogen bond at the surface, producing a highly hydrophobic yet fluorine-free coating with exceptional thermal stability, mechanical strength, and release properties. The material is durable to 400°F and exhibits thermal stability up to 450°C, making it a strong candidate for industries seeking high-performance, environmentally friendly alternatives to fluoropolymer coatings.

Technical specifications

Key features and benefits:

• Lower surface free energy than Teflon — measured at 15.3 mJ/m² compared to Teflon's 18.5 mJ/m², achieved without fluorine atoms
• High thermal stability — stable up to 450°C with a high char yield of up to 80%
• High glass transition temperature (Tg) — significantly higher than conventional polymers, supporting demanding high-temperature applications
• Superior mechanical properties — modulus approximately twice that of comparable polymers, with potential for much greater scratch resistance than Teflon
• Excellent release properties — driven by a six-membered intramolecular hydrogen-bonded ring structure at the surface
• Hydrophobic surface behavior — despite the hydrophilic appearance of its chemical structure, the intramolecular hydrogen bonding produces a strongly water-repellent surface

How it works:

The polymer's unusual properties arise from a six-membered intramolecular hydrogen bond between electron-rich nitrogen and electron-deficient phenolic hydrogen. High-resolution solid-state 1H NMR spectroscopy confirmed this structure by detecting shared proton signals between oxygen and nitrogen atoms. This intramolecular bonding is responsible for the polymer's high Tg, thermal stability, mechanical strength, and low surface free energy.

Technology readiness level

The polybenzoxazine platform has been studied and validated since its first publication in 1994, with solid evidence of the six-membered intramolecular hydrogen-bonded structure confirmed through high-resolution solid-state NMR. The polymer has demonstrated superior thermal and surface properties relative to Teflon in published research. Future validation efforts will focus on identifying polybenzoxazine formulations with Tg above the required temperature limits, optimizing blend compositions for scratch resistance and ultra-low surface energy, and evaluating the release of any potential toxic gases during processing and use.