We encounter thermosetting resins throughout our daily lives in insulating foams, mattresses, coatings, adhesives, shoe soles, flooring, and electrical insulators to name only a few applications. They are used in nearly every industry imaginable. The pervasiveness of these materials and the fact that many are derived from crude oil is pushing scientists to find alternative and greener chemical feedstocks for these resins.
Polyphenols make up one possible organic chemical class that might have the needed properties to replace petroleum products in thermoset resins. To probe this, Navy researchers have investigated resveratrol tricyanate and its hydrogenated derivative–dihydroresveratrol tricyanate–as bio-based thermosetting resins. The novel process includes extracting and isolating polyphenol compounds, in this case resveratrol, from plants, chemically treating them to produce cyanate esters and polymerizing the cyanate esters with heat to produce thermoset resins.
In comparison to a commercial cyanate ester, dihydroresveratrol tricyanate exhibited a better processing window, superior thermo-mechanical performance under mild cure conditions, and only marginal loss in thermo-chemical stability. Since the glass transition point of this novel resin was approximately the same as a commercial cyanate ester, resveratrol could be a renewable feedstock for this class of thermosetting material offering not only equivalent thermomechanical performance, but significantly improved thermochemical performance.
This patented technology is related to the following:
8,921,614 –Selective deoxygenation of hydroxybenzaldehydes. The effective utilization of multifunctional benzaldehydes requires selective deoxygenation methods. This invention teaches how to remove the hydroxyl groups of syringaldehyde and vanillin to give 3,5-dimethoxybenzaldehyde or 3-methoxybenzaldehyde, respectively. The latter is useful as a starting material for the manufacture of many other products including resveratrol, a natural product that has potential as an anticancer compound.
Three benefits of the process:
- The process starts from a cheap and renewable phenol (syringaldehyde) that can be isolated from various biomass sources, and obtained as a byproduct of paper production or conversion of lignocellulosic feedstocks to biofuels
- The process is selective for the trans-isomer
- The decarboxylation does not require a copper catalyst
8,993,689 – Polyphenols and high-performance resins from syringaldehyde. The patent focuses on making resins from syringaldehydes comprising: reductively coupling syringaldehyde with an additional molecule of syringaldehyde or at least one aromatic aldehyde having a hydroxy group, or methoxy group. Derived polyphenols are reacted with a base to yield cyanogen halides or pseudohalides to produce cyanate ester resins.
9,018,314 – Polyphenols and high performance resins from syringaldehyde. This patent starts with the method from ‘689 but reacts the polyphenols with a reagent such as phosgene, triphosgene, carbonates, sulfones or aldehydes to produce thermoplastics such as polysulfones, polyesters, polyester-styrene, polycarbonates, and others.
9,051,414 – Polyphenols and high performance resins from syringaldehyde. This patent starts with the method from ‘689 but converts the polyphenols to thermosetting resins such as epoxy, benzoxazine, phenolic bismaleimide, polyphenylene, phthalonitrile endcapped, phenylethynyl, and other resins.
9,127,115 – Polyphenols and high performance resins from syringaldehyde. This patent starts with the method from the ‘688 patent but converts the polyphenols to thermosetting resins selected from the group consisting of epoxy, benzoxazine, phenolic, bismaleimide and polyphenylene resins as well as phthalonitrile endcapped, phenylethynyl endcapped, and other endcapped resins.
9,187,591 – Polyphenols and high performance resins from syringaldehyde. This patent starts with the method from the ‘688 patent but converts the polyphenols by reaction with reagents selected from the group consisting of phosgene, triphosgene, diphenylcarbonate, other carbonates, bis(4-chlorophenyl)sulfone, other functionalized sulfones, diacid chlorides, phthalic acids, formaldehyde, other aldehydes, and epichlorohydrin to produce thermoplastics selected from the group consisting of polysulfones, polyesters, polyester-styrene polymers, polyarylates, polycarbonates, and any combination thereof.
- Family of 8 patents including 6 as continuations-in-part address production of starting material and the manufacture of various resins and thermoplastics
- High-temperature, thermo-chemical stability with high strength-to-weight ratio
- Derived from renewable sources, has low toxicity, processed and cured at moderate temperatures
- Resistance to high-energy radiation
- US patent 8,853,343 and related processes available for license
- Potential for collaboration with Navy researchers