Thermoset polyurethane foams incorporating dynamic covalent adaptable networks

Abstract

The present disclosure provides "thermoplastic polyurethane foams incorporating a dynamic covalent adaptable network." A thermoplastic polyurethane foam has a chemical dynamic covalent adaptable network. The foam includes a reaction product of a polyol mixture and an isocyanate mixture. The polyol mixture includes a polyol and a dynamic crosslinker, the dynamic crosslinker being present in an amount between 0.1 wt% and 70 wt%. The dynamic crosslinker forms dynamic crosslinking bonds.

Description

Technical Field

[0001] This disclosure generally relates to polyurethane foams, and more specifically, to thermosetting polyurethane foams. Background Technology

[0002] The statements in this section are provided only as background information in connection with this disclosure and may not constitute prior art.

[0003] Polyurethane (PU) foam is used in a variety of automotive applications because it can be formed into lightweight, flexible, highly resilient, and rigid foams.

[0004] Conventional polyurethane foam is manufactured by reacting a mixture of polyols with a mixture of isocyanates. The reaction of the polyol and isocyanate mixtures forms a thermosetting polymer via two reactions. One is a gelation reaction between the polyol and isocyanate, forming polyurethane bonds; the other is a foaming reaction between water (as a blowing agent) and isocyanate, forming carbon dioxide and polyurea bonds. Due to these permanent cross-linked bonds, polyurethane foam is strong and durable. However, these cross-linked bonds also mean that the foam cannot be easily reprocessed.

[0005] Covalently adaptable networks (CANs) utilize dynamic chemical covalent bonds that undergo exchange reactions upon the application of external stimuli (typically heat or light). In the absence of stimulation, these materials behave as thermosetting materials, exhibiting high chemical resistance and dimensional stability. When stimulation is applied, the dynamic bonds become activated, allowing the network to rearrange its topology at the molecular level. Consequently, these materials undergo deformation, enabling reshaping and reprocessing.

[0006] Research is underway on CAN-containing PU foam as an alternative to conventional foam, which would allow for easier recycling of thermosetting PU foam waste. However, existing methods rely on adding catalysts or using sulfur-containing compounds during reprocessing, which can lead to odor, stability, and durability issues throughout the foam's lifespan.

[0007] This application addresses a problem related to thermosetting polyurethane foam. Summary of the Invention

[0008] This section provides a general overview of this disclosure and is not a full disclosure of its entire scope or all its features.

[0009] In one form, this disclosure provides a thermosetting polyurethane foam having a chemically dynamically covalently adaptable network. The foam comprises the reaction products of a polyol mixture and an isocyanate mixture. The polyol mixture comprises a polyol and a hindered amine, the hindered amine being present in an amount between 0.1% by weight and 70% by weight of the polyol mixture. The hindered amine forms dynamically crosslinked urea bonds.

[0010] In a variation of the method that can be implemented alone or in any combination: 5% to 100% of the crosslinking sites in the foam are formed by dynamic crosslinking bonds; the hindered amine is an oligomer; the hindered amine is a monomer; the content of the hindered amine is between 0.05% by weight and 20.0% by weight of the polyol mixture; the hindered amine is 4,4'-trimethylenedipiperidine; and the hindered amine is diethanolamine.

[0011] This disclosure also provides another thermosetting polyurethane foam having a chemically dynamic covalently adaptable network. The foam comprises the reaction products of a polyol mixture and an isocyanate mixture. The polyol mixture comprises a polyol and phenol, wherein the phenol content is between 0.1% by weight and 70% by weight of the polyol mixture. The phenol forms dynamic crosslinking bonds.

[0012] In variations of the method that can be implemented alone or in any combination: the polyol mixture further includes one or more of an opening agent, a surfactant, a foaming agent, and a catalyst; the phenol is an additive; the phenol additive is solid at room temperature; the phenol additive is one or more of lignin, tannin, and phenolic resin; the phenol additive content is between 0.1% by weight and 40% by weight of the polyol mixture; the phenol content is between 0.40% by weight and 70% by weight of the polyol mixture; the phenol is 4,4'-sulfonyl biphenyl; the phenol content is between 1% by weight and 10% by weight of the polyol mixture; the phenol is one or more of gallic acid, resveratrol, quercetin, hydroquinone, aflatoxin, 4,4'-dihydroxybiphenyl, bisphenol, 4,4'-sulfonyl biphenyl, 4-aminophenol, 2-hydroxybenzyl alcohol, and 4-hydroxybenzyl alcohol; and the crosslinking sites in the foam are formed by dynamic crosslinking bonds at a rate between 5% and 100%.

[0013] In another form, this disclosure provides yet another thermosetting polyurethane foam having a chemically dynamic covalently adaptable network. The foam comprises the reaction products of a polyol mixture and an isocyanate mixture. The polyol mixture comprises a polyol, phenol, and a hindered amine. The phenol and the hindered amine form dynamic crosslinking bonds.

[0014] In a variation of this method, cross-linking sites between 5% and 100% in the foam are formed through dynamic cross-linking bonds.

[0015] Further applicability will become apparent from the description provided herein. It should be understood that the descriptions and specific examples are intended for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0016] To better understand this disclosure, various forms of the disclosure will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 Dynamic bond exchange is shown in a thermosetting PU foam incorporating a dynamic covalently adaptable network (CAN); Figure 2 The chemical structures of several hindered amine compounds according to one aspect of this disclosure are shown; Figure 3 Photographs showing the results of reprocessing according to one aspect of this disclosure are provided. Figure 4 A graph showing relaxation times for several examples according to one aspect of this disclosure is provided; Figure 5 Photographs showing the results of reprocessing according to one aspect of this disclosure are provided. Figure 6 The chemical structures of several monofunctional phenolic compounds according to one aspect of this disclosure are shown; Figure 7 The chemical structures of several bifunctional phenolic compounds according to one aspect of this disclosure are shown; Figure 8 The chemical structures of several trifunctional and polyfunctional phenolic compounds according to one aspect of this disclosure are shown; and Figure 9 Photographs showing the results of reprocessing several examples according to one aspect of this disclosure are provided.

[0017] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way. Detailed Implementation

[0018] The following description is merely exemplary in nature and is not intended to limit this disclosure, its application, or its uses. It should be understood that throughout the drawings, corresponding reference numerals indicate the same or corresponding parts and features.

[0019] This disclosure discloses a thermosetting polyurethane foam having a composition in which a dynamic crosslinking agent generates dynamically crosslinked bonding chemical bonds. These dynamically crosslinked bonds together form a chemically dynamically covalently adaptable network, wherein the crosslinked bonds can be altered and rearranged. As described above, upon application of a stimulus, the dynamically crosslinked bonds undergo an exchange reaction. When a stimulus is applied, the dynamic bonds become activated, thereby enabling the network to rearrange its topology at the molecular level, such as... Figure 1 As shown in the diagram. Therefore, as used herein, a chemically dynamically crosslinked adaptive network is a polymer network possessing reversible covalent crosslinking bonds, which has the ability to adapt to externally applied stimuli. In this disclosure, a novel method for generating chemically dynamically covalently adaptive networks is proposed using dynamic crosslinking agents in thermosetting polyurethane foams.

[0020] Thermosetting polyurethane foam comprises the reaction product of a mixture of isocyanate and polyol, wherein both gelation and foaming reactions occur. The polyol mixture comprises at least one polyol and a dynamic crosslinking agent. The dynamic crosslinking agent comprises at least one of a hindered amine and phenol, each of which will be discussed in more detail below.

[0021] In one form, the cross-linking sites in the foam between 5% and 100% are formed through dynamic cross-linking bonds.

[0022] In one form, the crosslinking agent is an additive to the polyol mixture. In another form, the crosslinking agent replaces a portion of the polyol in the polyol mixture. For example, up to 70% of the polyol can be replaced by hindered amines or phenolic materials. Replacing polyols with hindered amines can improve foam-to-film processability, but limits film-to-film reprocessability. Replacing polyols with phenols can further improve film-to-film reprocessability.

[0023] In one form, the polyol mixture also includes additives such as, but not limited to, cell openers, surfactants, catalysts, and / or blowing agents. Additionally, in some forms, the polyol mixture contains conventional crosslinking agents, such as diethanolamine or triethanolamine. Conventional crosslinking agents are used in foam applications to build robustness, increase catalytic activity, strengthen crosslinked bonding networks, and control foam flexibility and other properties.

[0024] As used herein, "isocyanate" in the context of isocyanate mixtures includes diisocyanates such as aromatic diisocyanates, toluene diisocyanate ("TDI"), and methylene diphenyl diisocyanate ("MDI"), as well as polyisocyanates and mixtures thereof. Non-limiting examples of isocyanates include methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-diisocyanate dicyclohexylmethane (H12MDI), 1,5-naphthalene diisocyanate (NDI), tetramethylxylene diisocyanate (TMXDI), terephthalene diisocyanate (PPDI), 1,4-cyclohexane diisocyanate (CDI), benzyltoluidine diisocyanate (TODI), and combinations thereof. It is contemplated that isocyanates may comprise polymeric materials.

[0025] Polyols include at least one of petroleum-based polyols, bio-based polyols, and CO2 polyols, as well as mixtures thereof.

[0026] As used herein, “petroleum-based polyols” (hereinafter “petroleum polyols”) are polyether polyols that are available in practice and are well-known and widely commercially available. Such polyols are typically compositions or blends of compositions obtained directly or indirectly from non-renewable resources such as crude oil, at least about 80% by weight or more. Non-limiting examples of polyether polyols include polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutene glycol, polytetramethylene glycol, block copolymers such as combinations of polyoxypropylene glycol and polyoxyethylene glycol, poly-1,2-oxybutene glycol and polyoxyethylene glycol, poly-1,4-tetramethylene glycol and polyoxyethylene glycol, and random and block copolymer diols prepared from blends or sequential additions of two or more epoxides. The mechanical properties of the resulting polyurethane foam may determine the consistency of the polyol. More specifically, higher molecular weight polyols generally form more flexible polyurethanes, while lower molecular weight polyols generally form more rigid polyurethanes.

[0027] As used herein, “bio-based polyol” means a composition or blend of compositions that is typically derived directly or indirectly from natural (e.g., animal- or plant-based) oils, at least about 80% by weight or more. In other embodiments, the polyol is typically a composition or blend of compositions that is derived directly or indirectly from natural oils, at least about 85% by weight, at least 90% by weight and / or at least 95% by weight or more. As used herein, natural oils include, but are not limited to, vegetable oils, animal fats, algae oils, tall oils, derivatives of these oils, and combinations of any of these oils. Representative, non-limiting examples of vegetable oils include canola oil, rapeseed oil, coconut oil, corn oil, cottonseed oil, olive oil, palm oil, peanut oil, safflower oil, sesame oil, soybean oil, sunflower oil, flaxseed oil, palm kernel oil, tung oil, jatropha oil, mustard oil, iris oil, shepherd's purse oil, and castor oil. Representative, non-limiting examples of animal fats include lard, tallow, poultry fat, yellow fats, and fish oil, as well as polyols and diacids made from bio-based glycols 1,3-propanediol (PDO) and 1,4-butanediol (BDO), including succinic acid and larger acids such as Elevance's intrinsic C18 octadecanoic acid (ODDA). Representative, non-limiting examples of algal oils include microalgae (such as *Chlorella microphylla*, *Spirulina*, *Chlorella vulgaris*); algae (such as red algae—*Rhodophyta*, red algae, *Malva lataniae*, green algae), etc.; and combinations thereof.

[0028] As used herein, carbon dioxide-based polyols are poly(ether carbonate) polyols (hereinafter referred to as "CO2-polyols"). Non-limiting examples of CO2-polyols include CARDYON® LC-05, which is available from Covestro Deutschland AG.

[0029] Opening agents are used to prepare foam structures that are primarily open-celled, which gives them a high permeability value and include water-soluble emulsifiers.

[0030] Surfactants can be used for cell nucleation and opening in foam applications, and provide foam stabilization. A non-limiting example of a surfactant is TEGOSTAB® B 4690, available from Evonik Degussa, but other nonionic surfactants are envisioned to be suitable for preparing the polyurethane foams disclosed herein.

[0031] Catalysts enhance the processing characteristics and physical properties of polyurethane foams by promoting the fundamental chemical reactions between polyols and isocyanates, the reactions between water and isocyanates, and the reactions of trimerized isocyanates. Catalysts can be selected based on the specific application requirements, for example, to improve the polyether foaming process of various foams, including high-density unfilled foams, filled foams, high-load-bearing flexible foams, low-density foams, and high-resilience molding foams. Other catalysts can be selected to delay the foam formation reaction process, which may result in a more open foam structure. Suitable catalysts according to this disclosure are dibutyltin dilaurate and diluted amine ethers. When water is present in the polyol isocyanate reaction mixture, the use of tertiary amines as catalysts may be desirable because they catalyze the reaction of isocyanates with water to form urea bonds with urethanes.

[0032] Foaming agents facilitate the preparation of foams, and water is the most commonly used foaming agent. Other potential foaming agents include fluorocarbons, hydrochlorocarbons, chlorofluorocarbons, hydrofluorocarbons, and / or hydrocarbons. It is also envisioned that gases can be added directly to polyol isocyanate reaction mixtures to form foams. The specific foaming agent required depends on the desired foam properties for a particular application and the selected isocyanate and polyol mixture. The disclosed foaming agents are merely exemplary, and other foaming agents or gases may be utilized within the scope of this disclosure.

[0033] Other optional additives include buffers, dendritic macromolecules, inorganic particles, other types of polyols not listed herein, polyisocyanates, i.e., flame retardants, deodorants, colorants, chain extenders, fillers, combinations thereof, and other additives known to those skilled in the art, as specified in particular application requirements.

[0034] hindered amines As used herein, a "hindered amine" is a compound containing one or more hindered amine functional groups, in which the nitrogen atom of the amine group is partially shielded by adjacent groups, making it difficult for larger molecules to approach and react with nitrogen. In polyurethane foam, hindered amine functional groups form dynamically crosslinked hindered urea bonds (HUBs) at crosslinking binding sites. Dynamically crosslinked HUBs are a specific type of dynamic crosslinking bond formed by hindered amine functional groups.

[0035] Figure 2The chemical structures of several hindered amines within the scope of this disclosure are shown. However, these are merely exemplary, and the possible materials are not limited to those explicitly listed. In one form, the hindered amine includes at least one selected from 4,4-trimethylenedipiperidine, diethanolamine, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, and epoxy-amine adducts. The hindered amine is an oligomer or a monomer. In one form, the hindered amine is an oligomer, and its content is between 0.1 wt% and 70 wt% of the polyol mixture. In another form, the hindered amine is a monomer, and its content is between 0.05 wt% and 20 wt% of the polyol mixture. The adjacent groups and molecular weight of the hindered amine affect the choice of hindered amine and the hindered amine content in the polyol mixture. The larger the adjacent groups, the slower the hindered amine reacts with the isocyanate, and the greater the content of hindered amine required to replace the polyol. The higher the molecular weight of the hindered amine, the greater the content of hindered amine required to replace the polyol.

[0036] Table 1 below shows three example compositions used to compare the reprocessability of a polyurethane foam containing a hindered amine according to this disclosure with a “control” foam without a dynamic crosslinking agent.

[0037] Table 1. Examples 1 to 3: 4,4'-Trimethylenedipiperidine The hindered amine is 4,4-trimethylenedipiperidine. Diethanolamine provides a small secondary crosslinking effect. Example 1 is a control foam in which the content of 4,4-trimethylenedipiperidine is 0%. Examples 2 and 3 are foams containing 0.5% by weight (0.91 g) and 2.0% by weight (3.65 g) of the hindered amine, respectively.

[0038] like Figure 3 As shown, each of the foams in Examples 1 to 3 (labeled as control, HUB 0.5%, and 2.0%, respectively) was heated to 160°C and pressed at a pressure of 25 MPa for 10 minutes to compress them into a polyurethane film (see Example 3). Figure 3 (A)). Subsequently, the membrane is cut into sheets and reprocessed into membranes again (see...). Figure 3 (B)). Finally, repeat the membrane-to-membrane reprocessing, such as... Figure 3 As shown in (C), the material becomes more brittle with each reprocessing. However, the example containing 4,4'-trimethylenedipiperidine remained functional for a longer period than the control sample.

[0039] Figure 4The relaxation times of each of Examples 1 to 3, measured on membranes produced via a first compression molding process (foam to membrane), are shown. Examples 2 and 3, containing 4,4'-trimethylenedipiperidine, have shorter membrane relaxation times compared to the control of Example 1. Shorter relaxation times indicate that reprocessing will be more efficient. Therefore, the addition of 4,4'-trimethylenedipiperidine facilitates the foam to membrane compression molding process. Furthermore, the relaxation time decreases further as the amount of 4,4'-trimethylenedipiperidine increases.

[0040] Table 2 below shows two other example compositions in which the hindered amine is diethanolamine.

[0041] Table 2. Examples (4 to 5): Diethanolamine Similar to Examples 1 to 3 above, Examples 4 and 5 are also processed from foam into films. Figure 5 A), and then from membrane to membrane ( Figure 5 B). Example 5 ( Figure 5 C) More cohesion was observed after the two reprocessing steps than the control in Example 4.

[0042] phenol As used herein, "phenol" is a compound containing a six-membered aromatic ring directly bonded to a functional group hydroxyl (-OH). The definition includes monofunctional, difunctional, trifunctional, or polyfunctional phenols and mixtures thereof. In various forms, phenols are, for example, monophenols such as 4-hydroxybenzyl alcohol (4-HBA), 2-hydroxybenzyl alcohol (2-HBA), or aminophenol; diphenols such as bisphenol, 3-methylcatechol, dihydroxybiphenyl, or hydroquinone; or trifunctional or polyfunctional phenols such as gallic acid, quercetin, resveratrol, and lignin. Figures 6 to 8 The chemical structures of several of these phenols are shown; however, these are merely exemplary, and possible phenols are not limited to those explicitly listed. In one form, the phenol is one or more of gallic acid, resveratrol, quercetin, hydroquinone, aflatoxin, 4,4'-dihydroxybiphenyl, bisphenol, 4,4'-sulfonylbiphenyl, 4-aminophenol, 2-hydroxybenzyl alcohol, and 4-hydroxybenzyl alcohol. The reactivity, efficiency, and toxicity of phenol compounds guide their selection. The presence of electron-withdrawing groups on the aromatic ring of phenol favors its reactivity with aromatic isocyanates and provides a more efficient dynamic covalent adaptive network. Low-toxicity phenols are advantageous when phenol replaces polyols.

[0043] In one form, the phenol content is between 0.1% by weight and 70% by weight of the polyol mixture.

[0044] In one form, phenol is an additive. In another form, the phenol additive forms a polyol mixture at a concentration of 0.1% to 40.0% by weight. In a variant of this form, the phenol additive is a solid at room temperature. Solid phenol exhibits lower reactivity to isocyanates and has less impact on foam-forming properties compared to liquid phenol. In yet another form, the phenol additive is one or more of lignin, tannin, and phenolic resin. Lignin and tannin are biogenic phenols and have low toxicity. Phenolic resin is a widely available synthetic resin.

[0045] In one form, phenol is 4,4'-sulfonyl biphenol, and the phenol content is between 1% and 10% by weight of the polyol mixture.

[0046] Table 3 below shows two other example compositions containing phenol 4,4'-sulfonylbiphenol (BPS). Example 1 is used as a control composition, as shown in Table 1.

[0047] Table 3. Examples (6 to 7): 4,4'-sulfonylbiphenol Examples 1, 6 and 7 also involve processing foam into membranes, and then from membrane to membrane. Figure 9 The results after five membrane-to-membrane reprocessing steps are shown. Examples 6 and 7 demonstrate greater flexibility than the control in Example 1 after five reprocessing steps.

[0048] In another form of this disclosure, the polyol mixture may include both phenol and hindered amine. In one form, phenol is used to replace a portion of the polyol, while a hindered amine is added as an additional crosslinking agent. Alternatively, smaller amounts of both hindered amine and phenol are included as additives. As in the other forms described above, the hindered amine and phenol form dynamic crosslinking bonds to form a covalently adaptable network. In one form, crosslinking sites between 5% and 100% in the foam are formed via dynamic crosslinking bonds.

[0049] The foams disclosed herein can be used in a variety of applications where foam is desired, such as the automotive industry, including, for example, the furniture industry and the maritime transportation industry. Furthermore, the foams disclosed herein can be used in a variety of automotive applications and vehicle components, including but not limited to seat backs, armrests, seat cushions, headliner applications, headrests, engine hoods, oil pump covers, air conditioning compressor covers, fuel covers, and engine underbody covers, etc. In addition, once reprocessed, the film and molded parts can also be used in a variety of applications.

[0050] It should also be understood that the foam composition includes all incremental values ​​between the minimum and maximum content values ​​of the dynamic crosslinking agent listed above. That is, the minimum content of the dynamic crosslinking agent can be within the range described from the minimum to the maximum value. Similarly, the maximum content of the dynamic crosslinking agent can be within the range shown from the maximum value to the minimum value described. For example, the minimum hindered amine content can be an increment of 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, or 69.99, and any value between these increments.

[0051] Unless otherwise expressly indicated herein, all numerical values ​​indicating mechanical / thermal properties, percentage of composition, dimensions and / or tolerances or other characteristics should be understood as being modified by the words “about” or “approximately” when describing the scope of this disclosure. Such modification is desired for various reasons, including: industrial practice; material, manufacturing and assembly tolerances; and testing capabilities.

[0052] As used herein, the phrases A, B, and C at least one should be interpreted as using the non-exclusive logic "or" to represent logic (A or B or C), and should not be interpreted as meaning "at least one of A, at least one of B, and at least one of C".

[0053] The description in this disclosure is merely exemplary in nature, and therefore, variations thereof are intended to be made within the scope of this disclosure without departing from its spirit. Such variations should not be considered as departing from the spirit and scope of this disclosure.

[0054] According to the present invention, a thermosetting polyurethane foam having a chemically dynamic covalently adaptable network is provided, the thermosetting polyurethane foam having reaction products of a polyol mixture and an isocyanate mixture, wherein the polyol mixture comprises a polyol, phenol and a hindered amine, the phenol and the hindered amine forming a dynamic crosslinking bond.

Claims

1. A thermosetting polyurethane foam having a chemically dynamic covalently adaptable network, said thermosetting polyurethane foam comprising: The reaction products of polyol mixtures and isocyanate mixtures The polyol mixture comprises a polyol and a hindered amine, wherein the content of the hindered amine is between 0.1% by weight and 70% by weight of the polyol mixture, and the hindered amine forms a dynamically crosslinked hindered urea bond.

2. The thermosetting polyurethane foam of claim 1, wherein the crosslinking sites in the thermosetting polyurethane foam between 5% and 100% are formed by dynamically crosslinking hindered urea bonds.

3. The thermosetting polyurethane foam of claim 1, wherein the hindered amine is an oligomer.

4. The thermosetting polyurethane foam of claim 1, wherein the hindered amine is a monomer.

5. The thermosetting polyurethane foam of claim 4, wherein the content of the hindered amine is between 0.05% by weight and 20.0% by weight of the polyol mixture.

6. The thermosetting polyurethane foam of claim 4, wherein the hindered amine is 4,4'-trimethylenedipiperidine.

7. The thermosetting polyurethane foam of claim 4, wherein the hindered amine is diethanolamine.

8. A thermosetting polyurethane foam having a chemically dynamic covalently adaptable network, said thermosetting polyurethane foam comprising: The reaction products of polyol mixtures and isocyanate mixtures The polyol mixture includes polyols and phenol. The content of phenol is between 0.1% by weight and 70% by weight of the polyol mixture, and The phenol forms dynamic cross-linking bonds.

9. The thermosetting polyurethane foam of claim 8, wherein the phenol is an additive.

10. The thermosetting polyurethane foam of claim 8, wherein the phenol additive is solid at room temperature.

11. The thermosetting polyurethane foam of claim 10, wherein the phenol additive is between 0.1% by weight and 40% by weight of the polyol mixture.

12. The thermosetting polyurethane foam of claim 8, wherein the phenol is between 40% and 70% by weight of the polyol mixture.

13. The thermosetting polyurethane foam of claim 8, wherein the phenol is 4,4'-sulfonylbiphenol.

14. The thermosetting polyurethane foam of claim 8, wherein the phenol content is between 1% by weight and 10% by weight of the polyol mixture.

15. The thermosetting polyurethane foam of claim 8, wherein the phenol is one or more of gallic acid, resveratrol, quercetin, hydroquinone, aflatoxin, 4,4'-dihydroxybiphenyl, bisphenol, 4,4'-sulfonylbiphenyl, 4-aminophenol, 2-hydroxybenzyl alcohol, and 4-hydroxybenzyl alcohol.

Images