TECHNICAL FIELD

The present disclosure relates to an adhesive composition including a polymeric- based adhesive composition and a bio-based reactive diluent.

BACKGROUND ART

There is a continuous need for adhesive materials, which exhibit advantages offered by commercially available materials, while featuring other beneficial properties such as environmental compatibility, potential low toxicity, improved sustainability, and minimal health impact. In addition, there is a need for new additives derivable from bio-based resources. For instance, reactive diluents are added to decrease the viscosity of a polymer based adhesive material. There are several reactive diluents currently commercially available, however, none that are bio-based.

Accordingly, it would be desirable for an improved adhesive that includes a bio-based reactive diluent.

SUMMARY

Various aspects and embodiments contemplated herein may include, but are not limited to one or more of the following.

In a first aspect, an adhesive material includes a polymeric-based adhesive composition and a bio-based reactive diluent, wherein the bio-based reactive diluent includes a hydrocarbon ring structure having at least one pendant epoxy end group or a hydrocarbon non-ring structure having at least two pendant epoxy end groups.

In a second aspect, a method of decreasing the viscosity of an adhesive material includes: providing an adhesive material including a polymeric -based adhesive composition; and adding a bio-based reactive diluent to the adhesive material, wherein the bio-based reactive diluent comprises a hydrocarbon ring structure having at least one pendant epoxy end group or a hydrocarbon non-ring structure having at least two pendant epoxy end groups.

In a third aspect, an adhesive material includes an epoxy-based adhesive composition and an asymmetrical bio-based reactive diluent, wherein the asymmetrical bio-based reactive diluent includes an aromatic ring structure having at least two pendant epoxy groups.

In a fourth aspect, a method of coating a substrate includes applying an adhesive material according to the foregoing first aspect or third aspect to the substrate and curing the adhesive material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description in combination with the figures is provided to assist in understanding the teachings disclosed herein. The following discussion will focus on specific implementations and embodiments of the teachings. This focus is provided to assist in describing the teachings and should not be interpreted as a limitation on the scope or applicability of the teachings.

As used herein, the terms “comprises”, “comprising”, “includes”, “including”, “has”, “having” or any other variation thereof, are open-ended terms and should be interpreted to mean “including, but not limited to. . . .” These terms encompass the more restrictive terms “consisting essentially of’ and “consisting of.” In an embodiment, a method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive-or and not to an exclusive-or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

Also, the use of “a” or “an” is employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise. For example, when a single item is described herein, more than one item may be used in place of a single item. Similarly, where more than one item is described herein, a single item may be substituted for that more than one item.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent not described herein, many details regarding specific materials and processing acts are conventional and may be found in reference books and other sources within the structural arts and corresponding manufacturing arts. Unless indicated otherwise, all measurements are at about 23°C +/- 5°C per ASTM, unless indicated otherwise.

As described above, an adhesive material includes a polymeric -based adhesive composition and a bio-based reactive diluent. “Bio-based” includes any molecule derived from a biological source and includes any subsequent chemical modification of the bio-based molecule. In a particular embodiment, the bio-based reactive diluent covalently incorporates into the chemical structure of the polymer-based adhesive. In an example, the bio-based reactive diluent includes a hydrocarbon ring structure having at least one pendant epoxy end group. A “pendant epoxy end group” as used herein refers to an epoxy end group that is not incorporated within the hydrocarbon ring structure. The inclusion of the bio-based reactive diluent advantageously reduces the viscosity of the polymer-based adhesive composition without having an undesirable reduction in the glass transition temperature (Tg) of the adhesive material.

The adhesive material is typically a composition that, when applied between two substrates and cured, provides adhesive strength between the two substrates. The adhesive material includes any polymeric-based adhesive composition envisioned. For instance, the polymeric-based adhesive composition includes an acrylic-based composition, a urethane- based composition, a silicone-based composition, an epoxy-based composition, or combination thereof. In an embodiment, the polymeric -based adhesive composition includes a pressure sensitive adhesive. In another embodiment, the polymeric-based adhesive composition includes a non-pressure sensitive adhesive. In another embodiment, the polymeric-based adhesive composition includes a structural adhesive.

In a particular embodiment, the polymeric -based adhesive composition includes an epoxy-based composition. In a more particular embodiment, the polymeric-based adhesive composition consists essentially of an epoxy-based composition. As used herein, the phrase "consists essentially of" used in connection with the polymeric -based adhesive composition precludes the presence of monomers and polymers that affect the basic and novel characteristics of the polymeric-based adhesive composition, although, commonly used processing agents and additives such as, for example, a filler, an accelerator, a toughening agent, an adhesion promoter, an impact modifier, a surface modifier, a rheological modifier, bond line control agent, flow control agent, dye, pigment, compatibilizer, hardener, and any combination thereof may be used in the polymeric-based adhesive composition. In an embodiment, the polymeric -based adhesive composition consists of an epoxy-based composition.

In an embodiment, the epoxy-based composition includes a bisphenol A diglycidyl ether. The epoxy-based composition may further include a hardener. Any reasonable hardener is envisioned and includes, for instance, an amine hardener, a thiol hardener, an anhydride hardener, a carboxylic acid hardener, an imidazole hardener, or combination thereof. Any reasonable amine hardener is envisioned and includes, for example, diaminobutane, diethylenetriamine (DETA), triethylenetetramine (TETA), triethyleneglycol diamine, aminopropyl ethylamine (APEA), meta-xylyenediamine (mXDA), metaphenylenediamine (mPDA), 4,7,10-trioxa-l,13- tridecanediamine (TDD), 2,2'- (ethylenedioxy)-bis-(ethylamine) (EDEA), poly(propylene glycol) bis(2-aminopropyl ether), 4,4'-methylenedianiline (MDA), isophoronediamine (IPDA), or a combination thereof. Any reasonable other additives are envisioned. In an example, the polymeric-based adhesive composition further includes one or more additives selected from the group consisting of a filler, an accelerator, a toughening agent, an adhesion promoter, an impact modifier, a surface modifier, a rheological modifier, bond line control agent, flow control agent, dye, pigment, compatibilizer, or a combination thereof.

The polymeric-based adhesive composition provides a matrix in which the bio-based reactive diluent is mixed therein. For instance, the bio-based reactive diluent is homogenously mixed in the polymeric-based adhesive composition. The bio-based reactive diluent typically includes a bio-based molecule having a hydrocarbon ring structure having at least one pendant epoxy end group. The bio-based reactive diluent refers to a molecule derived from a biological source having an average molecular weight (Mw) of less than about 500 grams/mol (g/mol), such as less than about 400 g/mol, or even less than about 265 g/mol.

In an embodiment, the bio-based reactive diluent includes a hydrocarbon ring structure including an aromatic structure, an aliphatic structure, a heterocyclic structure or combination thereof. In a particular embodiment, the hydrocarbon ring structure may have the aromatic ring structure including a benzene ring. In an alternate embodiment, the hydrocarbon ring structure may have a heterocyclic structure including one or more oxygen atoms, one or more nitrogen atoms, or combination thereof. In a more particular embodiment, the heterocyclic structure includes an isosorbide, a furan ring, a pyrazine, a pyrimidine, a pyridine, the like, or combination thereof. In an embodiment, the bio-based reactive diluent includes a hydrocarbon non-ring structure with the proviso that the bio-based reactive diluent has at least two pendant epoxy end groups.

In an embodiment, the bio-based reactive diluent has at least one pendant epoxy end group. In a particular embodiment, the bio-based reactive diluent has two or more pendant epoxy end groups. In an embodiment, the at least one pendant epoxy end group includes a glycidyl ether, a glycidyl amine, or combination thereof. In an embodiment, the bio-based reactive diluent has an epoxide equivalent weight (EEW) of less than 200 g/equivalent, such as less than 150 g/equivalent, or even less than 135 g/equivalent.

The bio-based reactive diluent may be asymmetrical. Any type of asymmetry is envisioned. For instance, the asymmetry may be due to different pendant epoxy end groups on the hydrocarbon ring structure. In an embodiment, the asymmetry is due to unequal substituent chain length off of the hydrocarbon ring. In yet another embodiment, the asymmetry is due to meta-substitution or ortho-substitution on the hydrocarbon ring structure. Any combination of asymmetry is envisioned.

In an example, the bio-based reactive diluent has the following structure: represents a hydrogen atom, glycidyl amine, glycidyl ether, or combination thereof, such as: r combination thereof; where “Y” represents a hydrogen atom, a methyl, an ethyl, a (3-methylbut-2-en-l -yl), an isopentyl, or combination thereof, such as: r combination thereof; where “Z” represents a hydrogen atom, a methyl, a (3-methylbut-2-en-l-yl), an isopentyl, or combination thereof, such as: combination thereof; where “X” represents 2-(methoxymethyl)oxirane, 2-(ethoxymethyl)oxirane, 2- (propoxymethyl)oxirane, N,N-bis(oxiran-2-ylmethyl)methanamine, N,N-bis(oxiran-2- ylmethyl)ethanamine, N,N-bis(oxiran-2-ylmethyl)propan-l-amine, or combination thereof, such as: combination thereof.

In an embodiment, “R” is glycidyl ether, “Y” is a hydrogen atom or a methyl, “Z” is a hydrogen atom or a methyl, and “X” is a 2-(methoxymethyl)oxirane or 2- (ethoxymethyl)oxirane.

In an embodiment, the bio-based reactive diluent is:

In a particular embodiment, the bio-based reactive diluent consists essentially of:

In a more particular embodiment, the bio-based reactive diluent consists essentially of: combination thereof.

Any amount of bio-based reactive diluent is envisioned and depends on the final adhesive material desired. In a particular embodiment, the addition of the bio-based reactive diluent achieves a desirable viscosity reduction without a substantial adverse impact, or reduction, on the glass transition temperature of the adhesive material. In an embodiment, the bio-based reactive diluent is present at an amount of 100 weight % to 0.01 weight %, such as 50 weight % to 1 weight %, or even 20 weight % to 2 weight %, based on the total weight of the adhesive material. In an embodiment, the bio-based reactive diluent reduces the viscosity of the formulation or part by more than 40% at 25°C, such as more than 70% at 25°C, or even more than 75% at 25°C. In a more particular embodiment, when present at an amount of at least 15 weight %, the bio-based reactive diluent has a viscosity reduction effect on a bisphenol-A epoxy resin of 40% or more at 25°C, such as more than 50% at 25°C, or even more than 80% at 25°C.

Further, the bio-based reactive diluent changes the glass transition temperature of the adhesive material by less than 20°C, such as less than 12°C, or even less than 10°C. In an example, the bio-based reactive diluent when present in an adhesive formulation at an amount of 15 parts reactive diluent to 85 parts bisphenol-A epoxy resin cured at 175°C for 2hrs with a polyether- amine used in stoichiometric amounts changes the glass transition temperature of the adhesive material by less than 20°C, such as less than by less than 12°C, or even less than 10°C.

In an embodiment, a method of coating a substrate includes applying the adhesive material to the substrate and curing the adhesive material. Curing the adhesive material includes heating the substrate to at least room temperature (i.e. 25°C). In an embodiment, the cure temperature is from 25°C to 250°C. Any time is envisioned such as at least 15 minutes, or even 15 minutes to 72 hours.

The adhesive material, when cured, has an advantageous lap shear strength. For instance, after curing for at least 70°C for at least 2hrs, the adhesive material has a lap shear strength between a first substrate and a second substrate of at least 10 psi, such as at least 1000 psi, or even at least 3000 psi. Any substrate is envisioned for the first substrate and the second substrate. In an embodiment, the first substrate and the second substrate may be the same material. In another embodiment, the first substrate and the second substrate are different materials. Exemplary materials for the substrate include, but are not limited to, a metal, a polymer, a ceramic, a composite, or combination thereof. Exemplary polymers include, but are not limited to, a polyester, a polyolefin, a polyimide, a polyamide, a polycarbonate, a polyurethane, an acrylic, a reinforced plastic, or combination thereof. Exemplary metal substrates include aluminum and steel carbon-alloy, such as cold rolled steel.

Advantageously, the adhesive material may be used for any applications where the aforementioned adhesive properties are desired. Adhesive films of any thickness are envisioned. In an embodiment, the film has a thickness of up to 200 microns. Adhesive films of the present invention can be applied in a broad spectrum of commercial industry ranging from the optical industry, electronics industry, computer industry, phone industry, automotive industry, aerospace industry, construction industry, telecommunication industry, films for the solar industry, and the like. For instance, an optical stack may include the adhesive material. In an example, the optical stack may include at least one film layer of the adhesive material. In an embodiment, an electronic device may include the adhesive material.

Many different aspects and embodiments are possible. Some of those aspects and embodiments are described herein. After reading this specification, skilled artisans will appreciate that those aspects and embodiments are only illustrative and do not limit the scope of the present invention. Embodiments may be in accordance with any one or more of the items as listed below.

Embodiment 1. An adhesive material includes a polymeric-based adhesive composition and a bio-based reactive diluent, wherein the bio-based reactive diluent includes a hydrocarbon ring structure having at least one pendant epoxy end group or a hydrocarbon non-ring structure having at least two pendant epoxy end groups.

Embodiment 2. A method of decreasing the viscosity of an adhesive material includes: providing an adhesive material including a polymeric -based adhesive composition; and adding a bio-based reactive diluent to the adhesive material, wherein the bio-based reactive diluent comprises a hydrocarbon ring structure having at least one pendant epoxy end group or a hydrocarbon non-ring structure having at least two pendant epoxy end groups.

Embodiment 3. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the hydrocarbon ring structure includes an aromatic structure, an aliphatic structure, a heterocyclic structure, or combination thereof.

Embodiment 4. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with embodiment 3, wherein the aromatic structure includes a benzene ring.

Embodiment 5. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with embodiment 3, wherein the heterocyclic structure includes one or more oxygen atoms, or one or more nitrogen atoms.

Embodiment 6. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with embodiment 5, wherein the heterocyclic structure includes either an isosorbide, a furan ring, a pyrazine, a pyrimidine, or a pyridine. Embodiment 7. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the pendant epoxy end group includes a glycidyl ether, a glycidyl amine, or combination thereof.

Embodiment 8. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with embodiment 7, where the bio-based reactive diluent includes at least two pendant epoxy end groups that are different.

Embodiment 9. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the biobased reactive diluent is asymmetrical.

Embodiment 10. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the biobased reactive diluent has an average molecular weight (Mw) of less than 500 g/mol, such as less than 400 g/mol, or even less than 265 g/mol.

Embodiment 11. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the biobased reactive diluent has an epoxide equivalent weight of less than 200 g/equivalent, such as less than 150 g/equivalent, or even less than 135 g/equivalent.

Embodiment 12. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the biobased reactive diluent reduces the viscosity of the formulation or part by more than 40% at 25°C, such as more than 70% at 25°C, or even more than 75% at 25°C.

Embodiment 13. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the biobased reactive diluent when present at an amount of at least 15 weight % has a viscosity reduction effect on a bisphenol- A epoxy resin of 40% or more at 25 °C, such as more than 50% at 25°C, or even more than 80% at 25°C.

Embodiment 14. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the biobased reactive diluent includes: wherein R represents a hydrogen atom, glycidyl amine, glycidyl ether, or combination thereof; wherein Y represents a hydrogen atom, a methyl, an ethyl, a (3-methylbut-2-en-l-yl), an isopentyl, or combination thereof; wherein Z represents a hydrogen atom, a methyl, a (3-methylbut-2-en-l-yl), an isopentyl, or combination thereof; and wherein X represents 2-(methoxymethyl)oxirane, 2-(ethoxymethyl)oxirane, 2- (propoxymethyl)oxirane, N,N-bis(oxiran-2-tylmethyl)methanamine, N,N-bis(oxiran-2- ylmethyl)ethanamine, N,N-bis(oxiran-2-ylmethyl)propan-l-amine, or combination thereof. Embodiment 15. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the biobased reactive diluent includes:

Embodiment 16. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the bio- based reactive diluent includes:

Embodiment 17. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with embodiment 16, wherein the bio-based reactive diluent consists essentially of:

Embodiment 18. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the biobased reactive diluent is present at an amount of 100 weight % to 0.01 weight %, such as 50 weight % to 1 weight %, or even 20 weight % to 2 weight %, based on the total weight of the adhesive material.

Embodiment 19. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the biobased reactive diluent changes the glass transition temperature of the adhesive material by less than 20°C, such as less than 12°C, or even less than 10°C.

Embodiment 20. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with embodiment 18, wherein the bio-based reactive diluent when present in an adhesive formulation at an amount of 15 parts reactive diluent to 85 parts bisphenol-A epoxy resin cured at 175°C for 2hrs with a polyether- amine used in stoichiometric amounts changes the glass transition temperature of the adhesive material by less than 20°C, such as less than by less than 12°C , or even less than 10°C.

Embodiment 21. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the polymeric-based adhesive composition comprises an acrylic-based composition, a urethane- based composition, a silicone-based composition, an epoxy-based composition, or combination thereof.

Embodiment 22. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with embodiment 21, wherein the polymeric-based adhesive composition comprises the epoxy-based composition. Embodiment 23. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with embodiments 21-22, wherein the epoxy-based composition comprises a bisphenol A diglycidyl ether and an amine hardener, thiol hardener, anhydride hardener, carboxylic acid hardener, or imidazole hardener.

Embodiment 24. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with embodiment 23, wherein the amine hardener is selected from the group consisting of diaminobutane, diethylenetriamine (DETA), triethylenetetramine (TETA), triethyleneglycol diamine, aminopropyl ethylamine (APEA), meta-xylyenediamine (mXDA), meta-phenylenediamine (mPDA), 4,7,10-trioxa-l,13- tridecanediamine (TDD), 2,2'-(ethylenedioxy)-bis-(ethylamine) (EDEA), poly(propylene glycol) bis(2-aminopropyl ether), 4,4'-methylenedianiline (MDA), isophoronediamine (IPDA), or a combination thereof.

Embodiment 25. The adhesive material or the method of decreasing the viscosity of the adhesive material in accordance with any of the preceding embodiments, wherein the polymeric-based adhesive composition further includes one or more additives selected from the group consisting of a filler, an accelerator, a toughening agent, an adhesion promoter, an impact modifier, a surface modifier, a rheological modifier, bond line control agent, flow control agent, or a combination thereof.

Embodiment 26. An adhesive material includes an epoxy-based adhesive composition and an asymmetrical bio-based reactive diluent, wherein the asymmetrical bio-based reactive diluent includes an aromatic ring structure having at least two pendant epoxy groups.

Embodiment 27. The adhesive material in accordance with embodiment 26, wherein the asymmetrical bio-based reactive diluent includes: Embodiment 28. The adhesive material in accordance with embodiment 27, wherein the asymmetrical bio-based reactive diluent consists essentially of: combination thereof.

Embodiment 29. The adhesive material in accordance with embodiments 26-28, wherein the epoxy-based composition includes a bisphenol A diglycidyl ether and an amine hardener.

Embodiment 30. The adhesive material in accordance with embodiment 29, wherein the amine hardener is selected from the group consisting of diaminobutane, diethylenetriamine (DETA), triethylenetetramine (TETA), triethyleneglycol diamine, aminopropyl ethylamine (APEA), meta-xylyenediamine (mXDA), meta-phenylenediamine (mPDA), 4,7,10-trioxa-l,13- tridecanediamine (TDD), 2,2'-(ethylenedioxy)-bis-(ethylamine) (EDEA), polypropylene glycol) bis(2-aminopropyl ether), 4,4'-methylenedianiline (MDA), isophoronediamine (IPDA), or combination thereof.

Embodiment 31. The adhesive material in accordance with embodiments 26-30, wherein the epoxy-based adhesive composition further includes one or more additives selected from the group consisting of a filler, an accelerator, a toughening agent, an adhesion promoter, an impact modifier, a surface modifier, a rheological modifier, bond line control agent, flow control agent, or combination thereof.

Embodiment 32. A method of coating a substrate including: a. applying an adhesive material of any one of embodiments 1-31 to the substrate; and b. curing the adhesive material.

Embodiment 33. The method of coating the substrate in accordance with embodiment

32, wherein the substrate is a metal substrate, a polymer substrate, a ceramic substrate, a composite substrate, or combination thereof.

Embodiment 34. The method of coating the substrate in accordance with embodiment

33, wherein the metal substrate is selected from the group consisting of aluminum and steel carbon-alloy.

Embodiment 35. The method of coating the substrate in accordance with embodiments 32-34, wherein the curing comprises heating the coated substrate to at least room temperature (25°C). Embodiment 36. The method of coating the substrate in accordance with embodiments 32-35, wherein the curing includes heating the coated substrate to from 25°C to 250°C.

Embodiment 37. The method of coating the substrate in accordance with embodiments 32-36, wherein the curing comprises heating the coated substrate for a time period of at least 15 minutes.

Embodiment 38. The method of coating the substrate in accordance with embodiments 32-37, wherein the curing comprises heating the coated substrate for a time period of at least 15 minutes to 72 hours. The following examples are provided to better disclose and teach processes and compositions of the present invention. They are for illustrative purposes only, and it must be acknowledged that minor variations and changes can be made without materially affecting the spirit and scope of the invention as recited in the claims that follow.

EXAMPLES Table 1: Bio-Based Compound Names, Chemical Structures, and Abbreviations:

Reactive diluent synthesis (chemical modification of bio-based molecules)

3HBADGE: 3-(hydroxymethyl)phenol (10 g, 1 Eq, 81 mmol) and benzyltriethylammonium chloride (1.8 g, 0.1 Eq, 8.1 mmol) was added into a 500mL round bottom flask under N2. Then, epichlorohydrin (0.11 kg, 94 mL, 15 Eq, 1.2 mol) was added and reaction was heated at 50°C for 4hr before cooling down to 0°C. Then, a solution of NaOH was added slowly while maintaining the temperature at 0°C. The reaction was stirred at room temperature overnight, then diluted with water and dichloromethane (DCM), extracted and concentrated before silica gel column purification.

HPDGE: 4-(3-hydroxypropyl)phenol (15 g, 1 Eq, 99 mmol) and benzyltriethylammonium chloride (2.2 g, 0.1 Eq, 9.9 mmol) was added into a 500ml round bottom flask under N2. Then, epichlorohydrin (0.14 kg, 0.12 L, 15 Eq, 1.5 mol) was added and the reaction was heated at 50°C for 4hr before cooling down to 0°C. Then, a solution of NaOH was added slowly while maintaining the temperature at 0°C. The reaction was stirred at room temperature overnight, then diluted with water and DCM, and extracted and concentrated before silica gel column purification.

25FDMDGE: To a solution of sodium hydroxide solution (1:2 w/w) was added with furandimethanol (FDM) (10.2 g, 80 mmol) and 10 mol% of tetrabutylammonium hydrogen sulfate (2.7 g, 8.0 mmol). The reaction mixture was cooled to 0°C, epichlorohydrin (32.5 mL, 400 mmol) was added dropwise over 30 min. The mixture was stirred at room temperature for 16 hrs. The reaction was quenched by addition of water (50 mL). The aqueous layer was extracted with pentane (10 mL) to remove excess epichlorohydrin. Then the aqueous layer was extracted with ethyl acetate (4*30 mL). The combined ethyl acetate extracts were washed with water (30 mL) and were allowed to pass through a short pad of silica gel. The solvent was evaporated to obtain a pure yellow 15 oil diepoxy product 2,5-bis((oxiran-2- ylmethoxy)methyl)furan in 18.4 g (76 mmol, 95% yield) and characterized by 1H and 13C NMR.

3MTDGE:

Step 1— » Synthesis of 4-(2-hydroxyethyl)-2-methylphenol

A I M solution of BH3 THF complex in dry THF (4.16 mL, 4.16 mmol, 1.5 eq.) was added with a syringe to a stirred solution of the carboxylic acid (2.76 mmol, 1 eq.) in 10 mL dry THF in a 50 mL two-neck round bottom flask equipped with a calcium chloride drying tube and a rubber septum in an ice/water bath. An exothermic reaction took place after which the ice bath was removed and the mixture was stirred at room temperature for at least Ihr or overnight. The reaction was terminated by careful dropwise addition 0.5 mL cone, hydrochloric acid. After the H2 evolution had ceased, the reaction was stirred for another 15 min art room temperature and was basified with cone, ammonia. The solvent was evaporated on a rotary evaporator and the resulting aqueous mixture diluted with H2O and extracted twice with 50 mL ethyl acetate. The combined organic phases were dried over MgSCL and evaporated on a rotary evaporator. The product was further dried under an oil pump vacuum for several hours. (4-Hydroxyphenyl)-ethanol (0.92 g, 138.17 g/mol, 6.67 mmol, 101 % crude yield, impurities detected by 1H NMR) was obtained after extraction from the reaction mixture with 4 x 20 mL ethyl acetate as water-soluble fine white crystals from 1.00 g (4- hydroxyphenyl)- acetic acid (152.15 g/mol, 6.57 mmol) by general procedure A (BH3) with vigorous stirring of the reaction mix for 2hrs until the gum-like precipitate had disappeared.

Step 2 Synthesis of 3MTDGE

4-(2-hydroxyethyl)-2-methylphenol (9.42 g, 1 Eq, 61.9 mmol) and benzyltriethylammonium chloride (1.41 g, 0.1 Eq, 6.19 mmol) was added into a 500ml round-bottom flask under N2. Then, epichlorohydrin (85.9 g, 72.6 mL, 15 Eq, 928 mmol) was added and reaction was heated at 50°C for 4hrs before cooling down to 0°C. Then, a solution of NaOH was added slowly while maintaining the temperature at 0°C. The reaction was stirred at room temperature overnight. Then dilute with water and DCM, extracted and concentrated before silica gel column purification. Chemical modification of other bio-based reactive diluents not directly stated above followed similar procedures as the above.

Performance Testing

The epoxy equivalent weight (EEW) was measured for each via titration using ASTM DI 652-11. The viscosity reducing effect of each reactive diluent was measured by preparing 85/15wt% mixtures of bisphenol A digycidyl ether monomer/oligomer epoxy resin or Zymergen epoxy resin Compound 2B with each reactive diluent. The viscosity of the mixture was then measured at 25°C using a rheometer in steady-state with 25 mm aluminum parallel plates at 10RPM. The epoxy reactive diluent monomers were also characterized using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) to determine monomer vaporization temperature (T _vap ), melt temperature (T _m ), and glass transition temperature (T _g ).

To evaluate and compare the general performance characteristics provided by each bio-based reactive diluent in an epoxy adhesive, model formulation systems were prepared. The model system formulations included bisphenol A digycidyl ether monomer/oligomer epoxy resin (EPON™ 828) and the reactive diluent at an 85 to 15 weight ratio to one another, along with a diamine hardener. The diamine hardener was 4,7,10-trioxa-l,13- tridecanediamine (TDD) at approximately a ~1:1 equivalent ratio of epoxides to aminehydrogens. Samples in this set were cured at 70°C for Ihr, then post-cured for 2hrs at 175°C. Results from resorcinol diglycidyl ether (RDGE) and cyclohexane dimethanol diglycidyl ether (Heloxy 107) were compared to those from the bio-based reactive diluents. Other more complex formulated systems were also prepared containing additional ingredients for further evaluation.

To evaluate the cure behavior of the uncured formulations, DSC cure profiles were obtained (10°C/min heating rate from -90°C to 250°C).

To evaluate the performance characteristics and properties of the cured material, the glass transition temperature (T _g ) was measured by DSC (using a 20°C/min heating), the decomposition temperature (Tj) by TGA (using a 10°C/min heating), and the room temperature glassy modulus (E’G), rubbery modulus (E’ _R ), and temperature of maximum tan 5 were determined by dynamic mechanical analysis (DMA) using a heating rate of 3°C/min heating, a frequency of 1Hz, 0.01% strain amplitude, and 125% force track ratio in tension mode using a film clamp. Lap shear testing was conducted according to ASTM 1004 on cold rolled steel (36 gauge nichrome wire used to control bondline-thickness). Tensile testing was performed according to ASTM 638. Type V specimens as described in ASTM 638 were used to determine the elongation at break. In some cases, a video extensometer was used to measure elongation at break accurately, and in other cases no extensometer was used (data from prior to extensometer purchase). Note any data collected without an extensometer should be considered directionally telling, but the absolute numbers reported should not be considered accurate.

Table 2: Monomer Characterization Comparison Table: t Viscosity at 25°C of an 85wt%: 15wt% mix of EPON 828 and each reactive diluent.

The viscosity of EPON 828 by itself was -11.2 Pa-s

^Viscosity at 25°C of an 85wt%: 15wt% mix of Zymergen Bio-based epoxy Compound 2B and each reactive diluent. The viscosity of this Compound 2B batch by itself was -280 Pa-s

*EEW of ODGE could not be measured, as it is insoluble in the titration solvent DCM Heloxy 107, 4HBADGE, TDGE, HPDGE, 3MTDGE, 3HBADGE, and 25FDMDGE are all low viscosity liquids at room temperature. 25FDMDGE results show the largest viscosity reducing effect on epoxy resins, followed by 4HBADGE, 3HBADGE, TDGE and HPDGE which all showed similar viscosity reducing effects, then the cyclohexane dimethanol diglycidyl ether and 3MTDGE. RDGE and ODGE are solids at ambient temperature and showed the smallest viscosity reduction. RDGE can be melted and will stay as a liquid for some time (days) following subsequent cooling to room temperature, however with higher viscosity than those stable as liquids at room temperature. Pure RDGE will however eventually crystallize and solidify over the course of several days of holding at room temperature. ODGE seems to behave similarly to RDGE, but with a slightly higher melt temperature and greater propensity to recry stallize/re- solidify more readily and rapidly.

This difference in crystallinity-behavior/form-factor and viscosity between RDGE/ODGE and the others highlights the key differences in the effects of different forms/types of structural asymmetry. 4HBADGE, TDGE, HPDGE, etc. are para-substituted structures, which is the most symmetric substitution pattern, while RDGE/ODGE have meta- substituted structures. However, the two substituent chains (R-groups) off of the aromatic ring in 4HBADGE, TDGE, HPDGE, etc. have unequal lengths, whereas the length of substituent groups on each side of the aromatic ring are the same on each side in RDGE and ODGE. (Unique to this group, 3HBADGE has both a meto-substituted structure and unequal length substituent chains. 3MTDGE has a para-substituted structure and unequal length substituent chains, but also has additional asymmetry created by the presence of the 3-methyl group.)

Formulation Thermal Characterization:

Three Component Model-System

Bisphenol A digycidyl ether monomer/oligomer epoxy resin (85) + epoxy reactive diluent (15) + 4,7,10-trioxa-l,13- tridecanediamine (TDD); epoxy:amine-H ratio = ~1:1

Cure conditions = Ihr at 70°C, 2hrs at 175°C

Note: (DSC ramp cure samples were not subjected to cure condition prior to the experiment).

Table 3:

Based on the DSC cure results (cure peak temperature), RDGE was the most reactive (fastest curing) reactive diluent in the test group. 4HBADGE, EDGE, and 3HBADGE were the next fastest curing, followed then by 3MTDGE, 25FDMDGE, and ODGE. Heloxy 107 was the second slowest/least-reactive, and HPDGE was the slowest/least-reactive in the group.

The only bio-based structure in the tested group that results in a lower Tg formulation than Heloxy 107 across all the measurements shown was 25FDMDGE. 3HBADGE resulted in a slightly higher formulation Tg than Heloxy 107, followed then by HPDGE, TDGE and 3MTDGE. The results were mixed for RDGE and 4HBADGE, so generally they may result in fairly similar Tg formulations. ODGE appeared to result in the highest Tg formulation in the test group.

The TGA data suggests that the aliphatic Heloxy 107 results in a formulation with a slightly lower degradation temperature compared to the aromatic reactive diluents. Generally, the room temperature modulus and crosslink densities were fairly similar for the majority of the different reactive diluent formulations. From very limited results, potentially 3MTDGE, HPDGE, and 3HBADGE may give slightly lower room temperature moduli, which could indicate a propensity for slightly higher flexibility/elongation, whereas potentially 25FDMDGE gives slightly higher room temperature modulus, which could indicate lower flexibility/elongation and higher hardness/rigidity.

Formulation Mechanical and Adhesive Properties:

Table 4: Lap-Shear results Within the range of our measurement error, the lap shear strengths for all formulations with the different reactive diluents seemed very similar, in roughly the range of -3600 - 3800 psi from 3 samples each. HPDGE extended slightly above this range, however the difference was too small to determine whether this was a statistically real performance difference or not given the small sample size and results variability. Formulation Thermal and Mechanical Characterization:

System 2 — Basic Formulation

A bio-based epoxy resin (Zymergen Compound 2B) (85) + epoxy reactive diluent

(15) + 4,7,10-trioxa-l,13- tridecanediamine (TDD) + 1% 3-glycidoxypropyltrimethoxysilane (GLYMO); epoxy:amine-H ratio = -1: 1 prior to addition of GLYMO on top; Cure profile = 2hrs at 70°C. Table 5: t — > elongation measured via video extensometer (absolute value should correct)

Consistent with System 1: Model System results

TDGE showed to be more-reactive/faster-curing than Heloxy 107 (DSC ramp cure peak temp).

TDGE resulted in a higher formulation Tg than Heloxy 107.

Formulation Thermal and Mechanical Characterization:

System 3 — Full/Complex Formulation (A3-F7 vs. A3-F8)

A bio-based epoxy resin (Zymergen Compound 2B) (85) + epoxy reactive diluent (15) + 4,7,10-trioxa-l,13- tridecanediamine (TDD) + 2,4,6-tris(dimethylaminomethyl) phenol

(DMP30) (2 wt% of base) + 1% 3-glycidoxypropyltrimethoxysilane (GEYMO) + 10% amine terminated poly(butadiene-co-acrylonitrile) (ATBN) + 7.5% methacrylate-butadiene- styrene core-shell rubber particles (EXE2691J) + 1% PDMS treated fumed silica (Cabosil); Cure profile = 2hrs at 70°C. Table 6: $ —> elongation measured without an extensometer (relative values in table should be directionally telling, but note that the absolute numbers reported are not directly comparable to those values collected with an extensometer)

4HB ADGE formulation resulted in similar (or potentially just slightly lower) elongation at break to Heloxyl07 formulation (within statistical significance and experimental margin of error).

Consistent with Systems 1: Model System results

4HBADGE showed to be more-reactive/faster-curing than Heloxy 107 (DSC ramp cure peak temp).

4HBADGE resulted in a higher formulation Tg than Heloxy 107.

4HBADGE formulation resulted in similar lap shear strength to Heloxy 107 formulation (within statistical significance and experimental margin of error).

Differentiation

It is surmised that 4HBADGE and TDGE provide a performance advantage compared to commercial incumbent epoxy reactive diluents RDGE and Heloxy 107 when comparing several properties and performance characteristics in combination. For instance, a combination of very low viscosity which is lower than that of either RDGE or Heloxy 107, high/moderate Tg which is higher than Heloxy 107 and similar to RDGE, moderate/fast cure behavior between RDGE and Heloxy 107, and moderate flexibility/toughness similar to RDGE and/or Heloxy 107 can be tailored.

Viscosity (desire low) 25FDMDGE < 4HBADGE « 3HBADGE < TDGE « HPDGE < H107 < 3MTDGE < RDGE < ODGE

Formulation Tg (desire high) ODGE > RDGE > 4HBADGE > TDGE « 3MTDGE > HPDGE > 3HBADGE > H107 > 25FDMDGE

Cure speed (desire fast) RDGE > 4HBADGE « TDGE « 3HBADGE > 25FDMDGE « 3MTDGE « ODGE > H107 > HPDGE

Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed is not necessarily the order in which they are performed.

In the foregoing specification, the concepts have been described with reference to specific embodiments. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of invention.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

After reading the specification, skilled artisans will appreciate that certain features are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. Further, references to values stated in ranges include each and every value within that range.