Lignin-derivable non-isocyanate polyurethanes with increased performance and processing

Abstract

Disclosed herein are lignin-derivable non-isocyanate polyurethane polymers, compounds used to create the lignin-derivable non-isocyanate polyurethane polymers, and methods for producing the lignin-derivable non-isocyanate polyurethane polymers.

Description

[0001] -1 -

[0002] LIGNIN-DERIVABLE NON-ISOCYANATE POLYURETHANES WITH INCREASED PERFORMANCE AND PROCESSING

[0003] CROSS-REFERENCE TO RELATED APPLICATION

[0004] This application claims priority to U.S. Provisional Patent Application No. 63 / 568,653 filed on March 22, 2024, the contents of which are incorporated herein by reference in their entirety for all purposes.

[0005] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0006] This invention was made with government support under Grant No. NSF DMR POL 2004682 awarded by the National Science Foundation, and Cooperative Agreement Number W911 NF-22-2-0257 awarded by the Army Research Office. The government has certain rights in the invention.

[0007] FIELD

[0008] The present disclosure relates to lignin-derivable, thermoplastic, nonisocyanate polyurethanes and methods of their production.

[0009] BACKGROUND

[0010] Thermoplastic polyurethanes (PUs) are highly desirable materials for numerous applications (e.g., automotive parts, packaging films, medical materials) because they are readily processable and offer highly tunable chemical structures (e.g., compositions of soft and hard segments) that yield a range of sought-after properties (e.g., toughness, modulus, thermal stability, and adhesion). Conventional thermoplastic PUs are synthesized by reacting diisocyanates with diols (and chain extenders in the case of segmented PUs); however, this route has signifixant health and environmental challenges. For example, isocyanates are synthesized using highly toxic phosgene, and the most common aromatic isocyanates, such as methylene diphenyl diisocyanate (MDI) and toluene diisocyanate (TDI), have been classified as carcinogenic, mutagenic, and reprotoxic compounds. Long-term exposure to isocyanates can also cause respiratory disorders, and the European Union is considering restrictions to isocyanate usage. Apart from the toxicity, phosgene and isocyanates are highly reactive and volatile, and their production / usage / storage / transportation are associated with high environmental risk. For instance, phosgene synthesis requires -2- a large amount of chlorine, and its production generates several chlorine- contaminated waste / by-products.

[0011] An emerging strategy to avoid the various drawbacks associated with isocyanate use in Pll synthesis is to create non-isocyanate polyurethanes (NIPUs), i.e., a class of polymers synthesized via alternative chemistries processes that avoid the use of toxic isocyanates. NIPUs can possess various improvements over their conventional PU counterparts (e.g., increased resistance to chemical degradation and increased wear resistance).

[0012] Although the synthesis of NIPUs can avoid the direct use of isocyanates, several of the alternative chemistry synthetic routes used to produce NIPUs reported in the literature use toxic precursors. For example, NIPU syntheses have been reported that incorporate the rearrangement of acyl azides (i.e., Curtius rearrangement) or employ hydroxamic azides (i.e., Lossen rearrangement). Additionally, NIPUs have been synthesized through the polycondensation of polycarbamoyl chlorides and polyols. These compounds (acyl azides, hydroxamic azides, and polycarbamoyl chlorides) use phosgene or its derivatives as a key building block.

[0013] Hence, a preferred pathway for NIPU synthesis is via a step-growth process involving the polyaddition of cyclic carbonates and diamines, which significantly reduces the use of toxic precursors. One advantage of synthesizing NIPUs via a step-growth process involving the use of cyclic carbonates is improved stability of NIPU reactants. Cyclic carbonates are non-moisture sensitive and, thus, possess superior storage stability relative to isocyanates. Additionally, because CO2 sequestration occurs during the synthesis of the cyclic carbonates, the stepgrowth polyaddition process can also provide environmental benefits. NIPUs synthesized through cyclic carbonate ring opening reaction also possess hydroxyl groups along the polymer chain, which are not assessable in isocyanate-based PUs. The presence of these hydroxyl groups could allow for additional functionalization of the NIPUs.

[0014] Another concern with known PU and NIPU synthesis methods is the reliance on non-renewable feedstocks. Indeed, most of the precursors used in PU / NIPU synthesis methods are derived from petroleum-feedstocks, which are limited in -3- quantity and unevenly distributed globally. Accordingly, there is significant opportunity for new bio-based / bio-derivable building blocks with reduced toxicity and increased sustainability. Most bio-based / bio-derivable NIPU studies have focused on using aliphatic / cycloaliphatic building blocks derived from plant oils and fatty acids, but many polymers derived from such aliphatic / cycloaliphatic sources lack the robust structural features necessary to generate materials with properties competitive to those of similar polymers made from conventional aromatics (e.g., TDI, MDI) in terms of glass transition temperatures [Tgs] and moduli. Though petroleum-derived bisphenol A (BPA) can be used to make aromatic NIPUs, BPA is a suspected endocrine disruptor and the potential of BPA to leach out from bisphenol-derived plastics is implicated in numerous health hazards.

[0015] Lignin is an attractive feedstock for renewable polymer applications as it is the most abundant potential source of natural aromatics and can act as a replacement feedstock for aromatic NIPUs. Bulk lignin is mainly comprised of p- hydroxyphenyls (H; no methoxy groups on the aromatic ring), guaiacyl (G; one methoxy group on the aromatic ring), and syringyl (S; two methoxy groups on the aromatic ring) units. The relative content of these units can vary with the source of the lignin biomass, for example, softwoods include a majority of G units, hardwoods contain a mixture of G and S units, and grasses contain a mixture of H, G, and S units. Unfortunately, materials made from bulk lignin can have inconsistent properties due to lignin’s structural heterogeneity and limited reactivity. To overcome this hurdle, lignin can be broken down by catalytic, enzymatic, or pyrolytic pathways into smaller molecules with several inherent functional groups (e.g., aliphatic / aromatic hydroxyl, methoxy, alkyl, allyl), and many of these functionalities can be used to develop renewable materials, such as polycarbonates, polyesters, epoxy resins, and PUs.

[0016] Thus, to address the foregoing issues with NIPU synthesis methods and the weak structural integrity of known bio-based NIPU, the present disclosure provides novel approaches for using lignin to create more structurally robust NIPUs.

[0017] SUMMARY

[0018] An aspect of the present disclosure is a compound of Formula (I): -4-

[0019] (Formula I) wherein

[0020] R1and R2are either the same or different, and are selected from -H and - CH3; R3and R4are either the same or different, and are selected from -H and -

[0021] OCH3;

[0022] R5and R6are -OCH3; and

[0023] R7and R8are either the same or different, and are selected from -H, wherein R9is selected from a C4 to C10 alkyl group.

[0024] Another aspect of the present disclosure is lignin-derivable NIPU of Formula

[0025] (Formula II) wherein -5-

[0026] R1and R2are either the same or different, and are selected from -H and - CH3;

[0027] R3and R4are either the same or different, and are selected from -H and - OCH3; R5and R6are -OCH3;

[0028] R9is selected from a C4 to C10 alkyl group; and n is an integer representing a degree of polymerization.

[0029] Another aspect of the present disclosure is a method of producing a lignin- derivable NIPU of Formula II, the method including one or more of: isolating guaiacol or syringol from a lignin-containing material or feedstock; reacting the isolated guaiacol or syringol with either vanillyl alcohol or syringy I alcohol to create an intermediate compound of Formula III:

[0030] (Formula III), or reacting the isolated guaiacol or syringol with acetone to create an intermediate compound of Formula IV:

[0031] (Formula IV); reacting the intermediate compound of Formula III or the intermediate compound of Formula IV with epichlorohydrin to create an intermediate compound of Formula V: -6-

[0032] (Formula V); reacting the intermediate compound of Formula V with carbon monoxide and tetrabutylammonium bromide to create an intermediate compound of Formula VI:

[0033] (Formula VI); and reacting the intermediate compound of Formula VI with a diamine.

[0034] BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Other features and advantages of the compositions, devices and methods disclosed herein will be apparent to those skilled in the art reading the following detailed description in conjugation with the exemplary embodiments illustrated in the drawings, wherein:

[0036] FIG. 1 depicts an exemplary synthesis of bisguaiacol F (BGF) and bissyringol F (BSF).

[0037] FIG. 2 depicts an exemplary synthesis of bisguaiacol A (BGA) and bissyringol A (BSA).

[0038] FIG. 3 depicts an exemplary synthesis of diglycidyl ethers.

[0039] FIG. 4 depicts an exemplary synthesis of cyclic carbonates.

[0040] FIG. 5 depicts an exemplary synthesis of a lignin-derivable NIPU.

[0041] FIG. 6 depicts the petroleum-derived NIPUs and exemplary lignin-derivable NIPUs that were examined in Example 2.

[0042] FIG. 7 depicts the differential weight fraction distributions of exemplary NIPUs as a function of molar mass (M) measured via gel permeation chromatography (GPC). Number-average molecular weights (Mns) were determined relative to poly(methyl methacrylate) standards using data from GPC -7- with a refractive index detector [GPC solvent: N,N-Dimethylacetamide (DMAc) + 0.5 wt% lithium bromide (LiBr)].

[0043] FIG. 8 depicts the deconvoluted hydroxyl region of exemplary NIPUs in attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectra. The - OH / -NH absorption bands were fit using two Gaussian distributions: one for hydrogen-bonded -OH / -NH groups and another for free -OH / -NH groups.

[0044] FIG. 9 depicts the engineering tensile stress vs. engineering strain curves, strain for exemplary NIPUs.

[0045] FIG. 10 depicts the strain-at-break vs. number of methoxy groups, the toughness vs. number of methoxy groups, Young’s modulus vs. number of methoxy groups, and ultimate tensile strength vs. number of methoxy groups for exemplary NIPUs.

[0046] FIG. 11 depicts engineering tensile stress vs. engineering strain (from 0% to 18%) curves for exemplary NIPUs.

[0047] FIG. 12 depicts the differential scanning calorimetry (DSC) thermograms (a) and the Tgvs. number of methoxy groups (b) of exemplary NIPUs. The DSC thermograms were acquired with a heating rate of 10 °C / min in an N2 atmosphere (data from the third heating trace and curves were shifted vertically for clarity with Tgvalues marked on the respective curves). Tgas a function of the methoxy-group content from 0 to 4: for unsubstituted bridging carbon- and dimethyl-substituted bridging carbon-based NIPUs. Tgvalues from the second and third heating traces were identical, and the error bars were determined using Tgvalues from the third heating traces of two separate samples for each NIPU.

[0048] FIG. 13 depicts thermogravimetric analysis (TGA) thermograms (a) and the first derivative of the weight remaining (% / °C) as a function of temperature (b) for exemplary NIPUs.

[0049] FIG. 14 depicts the frequency-dependent storage (G1) and loss (G") moduli for (a) unsubstituted bridging carbon- and (b) dimethyl-substituted bridging carbonbased exemplary NIPUs. The master curves were constructed using timetemperature superposition and reported at 150 °C. Lines indicate typical power-law scalings of G' (slope of 2) and G" (slope of 1 ). -8-

[0050] FIG. 15 depicts van Gurp-Palmen representations of the linear viscoelastic spectrum for (a) unsubstituted, bridging-carbon- and (b) dimethyl-substituted, bridging-carbon-based exemplary NIPUs. DETAILED DESCRIPTION

[0051] All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. 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. In case of conflict, the present specification, including definitions, will control.

[0052] One aspect of the present disclosure is a compound of Formula (I):

[0053] (Formula I) wherein R1and R2are either the same or different, and are selected from -H and -

[0054] CH3;

[0055] R3and R4are either the same or different, and are selected from -H and - OCH3;

[0056] R5and R6are -OCH3; and -9-

[0057] R7and R8are either the same or different, and are selected from -H, wherein R9is selected from a C4 to C10 alkyl group.

[0058] As used herein, the term “alkyl group” means a linear or branched saturated hydrocarbon. Examples of possible alkyl groups that can be present in the compounds of Formula I include, but are not limited to, linear or branched hydrocarbon chains having 4 to 10 carbon atoms. Examples of possible alkyl groups include, but are not limited to, 1 -pentyl (n-pentyl, — CH2CH2CH2CH2CH2—), 2-pentyl (— CH(CH3)CH2CH2CH2— ), 3-pentyl (— CH(CH2CH3)(CHCH3) — ), 2-methyl-2-butyl (— C(CH3)2CH2CH2— ), 3-methyl-2-butyl (— CH(CH3)CH(CH3) — ), 3-methyl-1 -butyl (— CH2CH2CH(CH3) — ), 2-methyl-1 - butyl (— CH2CH(CH3)CH2CH2— ), 1 -hexyl (— CH2CH2CH2CH2CH2CH2— ), 2-hexyl (— CH(CH3)CH2CH2CH2CH2— ), 3-hexyl (— CH(CH2CH3)CH2CH2CH2— ), 2-methyl- 2-pentyl ( — C(CH3)2CH2CH2CH2 — ), 3-methyl-2-pentyl ( — CH(CH3)CH(CH3)CH2CH2— ), 4-methyl-2-pentyl (— CH(CH3)CH2CH(CH3)CH2— ), 3- methyl-3-pentyl ( — C(CH3)(CH2CH3)CH2CH2— ), 2-methyl-3-pentyl ( — CH(CH2CH3)CH(CH3)CH2— ), 2,3-dimethyl-2-butyl (— C(CH3)2CH(CH3)CH2— ), 3,3- dimethyl-2-butyl (— CH(CH3)C(CH3)2CH2— ), heptyl (— (CH2)7— ), octyl (— (CH2)8— ), nonyl (— (CH2)9— ), and decyl (— (CH2)IO— ).

[0059] In exemplary embodiments of the compound of Formula I, R9is a C10 alkyl group. -10-

[0060] In exemplary embodiments of the compound of Formula I, R7is

[0061] In exemplary embodiments of the compound of Formula I, R7and R8are both

[0062] In exemplary embodiments of the compound of Formula I, R7and R8are both

[0063] In exemplary embodiments of the compound of Formula I, R1and R2are both -H.

[0064] In exemplary embodiments of the compound of Formula I, R1and R2are both -CH3.

[0065] In exemplary embodiments of the compound of Formula I, R3and R4are both -H.

[0066] In exemplary embodiments of the compound of Formula I, R3and R4are both -OCH3.

[0067] In exemplary embodiments of the compound of Formula I, R7and R8are both -H.

[0068] Another aspect of the present disclosure is a lignin-derivable NIPU of Formula II:

[0069] (Formula II) wherein -11 -

[0070] R1and R2are either the same or different, and are selected from -H and - CH3;

[0071] R3and R4are either the same or different, and are selected from -H and - OCH3;

[0072] R5and R6are -OCH3;

[0073] R9is selected from a C4 to C10 alkyl group; and n is an integer representing a degree of polymerization. The pendent hydroxyl and methoxy groups in the NIPU of Formula II has surprisingly been discovered to offer additional hydrogen-bonding content not accessible in conventional petroleum-derived PUs / NIPUs. Without being bound to a particular theory, the increased hydrogen-bonding content of the NIPU of Formula II allows the NIPU to participate in more hydrogen-bonding interactions and therefore achieve greater thermal, mechanical, and rheological properties than those seen with conventional petroleum-derived PUs / NIPUs. The additional methoxy groups present in the NIPU of Formula II can also potentially mitigate toxicity concerns associated with commercial aromatics such as BPA (e.g., estrogenic activity, genotoxicity, oxidative DNA damage).

[0074] As used herein “a lignin-derivable NIPU” is a NIPU that contains at least one subunit derived from a lignin material. The lignin material can be, but is not limited to, a lignocellulosic biomass derived from com stover, cotton seed hairs, grasses, hardwood stems, leaves, newspaper, nut shells, paper, softwood stems, switchgrass, waste papers from chemical pulps, wheat straw, wood, woody residues, and other sources. The lignin material can also be a lignocellulosic biomass in the form of raw lignocellulosic biomass, i.e., lignocellulosic biomass that has not been processed from its native, unaltered chemical state by any lignocellulosic pretreatments except for mechanical comminution (e.g., chopping, chipping, grinding, milling). The lignin material can also be a lignocellulosic biomass that has been pretreated. A pretreated lignocellulosic biomass can include, but is not limited to, a lignocellulosic biomass that has undergone one or more of microwave irradiation, ultrasound sonication, pyrolysis, pulsed-electric field treatment, acid treatment (e.g., sulfuric acid treatment, dicarboxylic acid treatment) alkali treatment, ozonolysis, organosol treatment, ionic liquid treatment, deep -12- eutectic solvent treatment, natural deep eutectic solvent treatment, steam explosion, liquid hot water treatment, wet oxidation, SPORL (sulfite pretreatment to overcome recalcitrance of lignocellulose) pretreatment, ammonia-based pretreatment (e.g., ammonia fiber explosion (AFEX), ammonia recycle percolation (ARP), soaking aqueous ammonia (SAA)), CO2 explosion, oxidative pretreatment, biological pretreatment (e.g., fungi treatment (e.g., brown-rot fungi treatment, whiterot fungi treatment, soft-rot fungi treatment), bacterial treatment, archaeal treatment, and enzyme treatment (e.g., peroxidase enzyme treatment, laccase enzyme treatment)).

[0075] In exemplary embodiments of the NIPU of Formula II, R9is a C10 alkyl group. In exemplary embodiments of the NIPU of Formula II, R1and R2are both -H. In exemplary embodiments of the NIPU of Formula II, R1and R2are both - CH3.

[0076] In exemplary embodiments of the NIPU of Formula II, R3and R4are both -H.

[0077] In exemplary embodiments of the NIPU of Formula II, R3and R4are both - OCH3.

[0078] In exemplary embodiments of the NIPU of Formula II, n is an integer of at least 20, at least 30, at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, at least 100, at least 200, at least 300, at least 400, or any integer or range of integers falling with the range of 20 to 400.

[0079] In exemplary embodiments, the NIPU of Formula II has a longest relaxation time (TX) ranging from 1 x 10-4to 8 x 10-4seconds, 2 x 10-4to 6 x 10-4seconds, 3 x 10’4to 4 x 10’4seconds, or any longest relaxation time or longest relaxation time range falling within the range of about 1 x 10-4to about 8 x 10-4seconds.

[0080] As used herein, the term “about” refers to a value that is ± 5% of the stated value. In addition, it is understood that reference to a range of a first value to a second value includes the range of the stated values, e.g., a range of about 1 to about 5 also includes the more precise range of 1 to 5. It is also understood that the ranges disclosed herein include any selected subrange within the stated range, e.g., a subrange of about 50 to about 60 is contemplated in a disclosed range of about 1 to about 100. -13-

[0081] In exemplary embodiments, the NIPU of Formula II has a fast relaxation time (TC) ranging from about 4.7 x 10’7to about 2.5 x 10’6s, or any fast relaxation time or range of fast relaxation times falling within the range of about 4.7 x 10’7to about 2.5 x 10’6s.

[0082] In exemplary embodiments, the NIPU of Formula II is free of one or more of processing aids, thermal stabilizers and antioxidants. A processing aid functions to improve the processing characteristics of the NIPU and can include, but is not limited to, lubricants (like metal soaps, hydrocarbon waxes, fatty acids), fluoropolymer-based additives, acrylic copolymers, silicone oils, calcium carbonates, styrenics, amide waxes, fatty alcohols, esters, and certain types of polyethylene. Thermal stabilizers are additives that prevent degradation caused by heat exposure during processing or usage and can include, but are not limited to, organotin catalysts, lead stabilizers, metal deactivators, acid scavengers, poly(vinyl chloride) stabilizers, flame retardants, dibutyl tin maleate and cadmium-barium stearate. Antioxidants are compounds that help prevent unwanted radical reactions from occurring during the processing of the NIPU and can include, but are not limited to, primary antioxidants (e.g., hindered-phenols or hindered-amines, such as butylated hydroxytoluene (BHT)) and secondary antioxidants (e.g., phosphites, such as tris(2,4-di-tert-butylpheny I) phosphite, triphenyl phosphite and diphenyloctyl phosphite).

[0083] In exemplary embodiments, the NIPU of Formula II has a toughness, when in the shape of a 9.5 mm x 2.5 mm x 0.17-0.24 mm (gauge length x width x thickness) film, ranging from 30 to 70 MJ / m3, 40 to 60 MJ / m3or any toughness or range of toughness values falling within about 30 to about 70 MJ / m3.

[0084] In exemplary embodiments, the NIPU of Formula II has an ultimate tensile strength, when in the shape of a 9.5 mm x 2.5 mm x 0.17-0.24 mm (gauge length x width x thickness) film, ranging from 35 to 60 MPa, 40 to 50 MPa, or any ultimate tensile strength or range of ultimate tensile strengths falling within the range of about 35 to about 60 MPa.

[0085] In exemplary embodiments, the NIPU of Formula II has a Young’s modulus, when in the shape of a 9.5 mm x 2.5 mm x 0.17-0.24 mm (gauge length x width x thickness) film, ranging from about 1 .2 to about 1 .4 GPa. -14-

[0086] In exemplary embodiments, the NIPU of Formula II has a relaxation time that is at least about 10 to 20% lower than a relaxation time of a similar NIPU obtained from petroleum-derived analogues and / or a similar NIPU that possesses BPA and / or bisphenol F (BPF) subunits instead of BGF, BSF, BGA and / or BSA subunits.

[0087] In exemplary embodiments, the NIPU of Formula II has an Mn of more than 10 kg / mol or more than 15 kg / mol. In exemplary embodiments, the NIPU of Formula II has a Mn falling within the range of about 10 kg / mol to about 20 kg / mol. In exemplary embodiments, the NIPU of Formula II retains an Mn after high- temperature processing, i.e., after being subjected to processing conditions (e.g., those that involve melting the NIPU of Formula II and / or passing a melted NIPU of Formula II through an extruder, such as during polymer extrusion molding) above 100 °C.

[0088] In exemplary embodiments, the NIPU of Formula II has a dispersity ranging from 2.0 to 3.0, 2.2 to 2.8, 2.4 to 2.6, or any dispersity or range of dispersities falling within the range of about 2.0 to about 3.0. In exemplary embodiments, the NIPU of Formula II retains a dispersity after high-temperature processing, i.e., after being subjected to processing conditions (e.g., those that involve melting the NIPU of Formula II and / or passing a melted NIPU of Formula II through an extruder, such as during polymer extrusion molding) above 100 °C.

[0089] In exemplary embodiments, the NIPU of Formula II has at least about a 40 to 60% higher extent of hydrogen-bonding than a hydrogen-bonding extent of a similar NIPU obtained from petroleum-derived analogues and / or a similar NIPU that possesses BPA and / or BPF subunits instead of BGF, BSF, BGA and / or BSA subunits.

[0090] In exemplary embodiments, the NIPU of Formula II has a toughness, when in the shape of a 9.5 mm x 2.5 mm x 0.17-0.24 mm (gauge length x width x thickness) film, that is at least about 40 to 50% higher than a toughness of a similar NIPU film obtained from petroleum-derived analogues and / or a NIPU film that possesses BPA and / or BPF subunits instead of BGF, BSF, BGA and / or BSA subunits.

[0091] In exemplary embodiments, the NIPU of Formula II has a thermal degradation onset temperature that is substantially similar to a thermal degradation -15- onset temperature of a NIPU obtained from petroleum-derived analogues and / or a NIPU that possesses BPA and / or BPF subunits instead of BGF, BSF, BGA and / or BSA subunits. In exemplary embodiments, the NIPU of Formula II has a thermal degradation onset temperature of 5 percent weight loss at about 280 °C.

[0092] In exemplary embodiments, the NIPU of Formula II has a glass transition temperature in a range of 40 °C to 55 °C, 45 °C to 50 °C, or any Tgor range of Tgs falling within the range of about 40 °C to about 55 °C.

[0093] In exemplary embodiments, the NIPU of Formula II has a Tgthat is at least about 10-20% higher than a Tgof a NIPU obtained from petroleum-derived analogues and / or a NIPU that possesses BPA and / or BPF subunits instead of BGF, BSF, BGA and / or BSA subunits.

[0094] In exemplary embodiments, the NIPU of Formula II, when -OH and -NH are considered hydrogen-bond donors, and urethane carbonyls (-C=O), ether oxygens (-O-), and methoxy groups (-OCH3) are considered hydrogen-bond acceptors, the NIPU of Formula II has about 85% to about 95% of its -OH and -NH hydrogen-bond donors participating in hydrogen-bonding interactions and / or networks.

[0095] In exemplary embodiments, the NIPU of Formula II has an elongation-at- break, when in the shape of a 9.5 mm x 2.5 mm x 0.17-0.24 mm (gauge length x width x thickness) film, of about 125% to about 220%, about 150% to about 200%, about 170% to about 190%, or any elongation-at-break or range of elongation-at- breaks falling within the range of about 125% to about 220%.

[0096] In exemplary embodiments, the NIPU of Formula II has a plateau modulus (GN,O) ranging from about 7.8 x 105to about 8.8 x 105Pa, 8.1 x 105to 8.6 x 105Pa, 8.3 x 105to 8.4 x 105Pa, or any plateau modulus or range of plateau moduli falling within the range of about 7.8 x 105to about 8.8 x 105Pa.

[0097] Another aspect of the present disclosure is a method for producing a NIPU of Formula II, the method including one or more of: isolating guaiacol or syringol from a lignin-containing material; reacting the isolated guaiacol or syringol with either vanillyl alcohol or syringyl alcohol to create an intermediate compound of Formula III: -16-

[0098] (Formula III), or reacting the isolated guaiacol or syringol with acetone to create an intermediate compound of Formula IV:

[0099] (Formula IV); reacting the intermediate compound of Formula III or the intermediate compound of Formula IV with epichlorohydrin to create an intermediate compound of Formula V:

[0100] (Formula V); reacting the intermediate compound of Formula V with carbon monoxide and tetrabutylammonium bromide to create an intermediate compound of Formula VI: (Formula VI); and / or reacting the intermediate compound of Formula VI with a diamine to create the NIPU of Formula II.

[0101] In exemplary embodiments, the reacting of the intermediate compound of

[0102] Formula VI with the diamine to create the NIPU of Formula II includes reacting the intermediate and the diamine under step-growth polyaddition conditions. Stepgrowth polyaddition reactions involving a diamine and cyclic carbonates are well- -17- known in the art (see Kihara, N. and Endo, T. (1993), Synthesis and properties of poly(hydroxyurethane)s. J. Polym. Sci. A Polym. Chem., 31 : 2765-2773; and Cornille, A. et al. (2017), A perspective approach to sustainable routes for nonisocyanate polyurethanes. Ear. Polym. J., 87, 535-552), therefore those of ordinary skill in the art would be readily aware and capable of create the NIPU of Formula II via a step-growth polyaddition reaction between the intermediate compound of Formula VI and a diamine.

[0103] In exemplary embodiments, the reacting of the isolated guaiacol or syringol with either vanillyl alcohol or syringyl alcohol to create the intermediate compound of Formula III occurs at a temperature of about 60°C to about 100°C, about 70°C to about 90°C, about 75 °C, or any temperature or temperature range falling within a range of about 60°C to about 100°C. In exemplary embodiments, the reacting of the isolated guaiacol or syringol with either vanillyl alcohol or syringyl alcohol to create the intermediate compound of Formula III occurs under an inert atmosphere, and / or in a presence of an acidic resin. The acidic resin can be, but is not limited to, an Amberlyst® resin (e.g., Amberlyst® 15(H)) and / or a Dowex® resin (e.g., Dowex® 50W-X8). In exemplary embodiments, the reacting of the isolated guaiacol or syringol with either vanillyl alcohol or syringyl alcohol to create the intermediate compound of Formula III occurs in a presence of hydrochloric acid (HCI) and optionally without a presence of an acidic resin.

[0104] In exemplary embodiments, the reacting of the isolated guaiacol or syringol with acetone to create the intermediate compound of Formula IV occurs at a temperature of about 60°C to about 100°C, about 70°C to about 90°C, about 100 °C, or any temperature or temperature range falling within a range of about 60°C to about 100°C. In exemplary embodiments, the reacting of the isolated guaiacol or syringol with acetone to create the intermediate compound of Formula IV occurs under an inert atmosphere and / or in a presence of an acid. The acid can be, but is not limited to, an acid resin (e.g., Amberlyst® 15(H) and / or Dowex® 50W- X8), an organic acid or an inorganic acid (e.g., HCI).

[0105] In exemplary embodiments, the reacting of the intermediate compound of Formula III or the intermediate compound of Formula IV with epichlorohydrin to create the intermediate compound of Formula V occurs at a temperature of about -18-

[0106] 0 °C to about 50 °C, about 10 °C to about 40 °C, about 20 °C to about 30 °C , about 20 °C, or any temperature or temperature range falling within a range of about 0 °C to about 50 °C. In exemplary embodiments, the reacting of the intermediate compound of Formula III or the intermediate compound of Formula IV with epichlorohydrin to create the intermediate compound of Formula V occurs under an inert atmosphere and / or in a presence of a base and tetrabutylammonium bromide. The base can be, but is not limited to, an inorganic base or an organic base.

[0107] In exemplary embodiments, the reacting of the intermediate compound of Formula V with carbon monoxide and tetrabutylammonium bromide to create the intermediate compound of Formula VI occurs at a temperature of about 100 °C to about 130 °C, about 110 °C to about 120 °C, about 130 °C or any temperature or temperature range falling within a range of about 100 °C to about 130 °C. Other salts besides tetrabutylammonium bromide can be used to create the intermediate compound of Formula V with carbon monoxide such as, without limitation, lithium bromide.

[0108] In exemplary embodiments, the reacting of the intermediate compound of Formula VI with the diamine to create the NIPU of Formula II occurs at a temperature of about 60°C to about 100°C, about 70°C to about 90°C, about 100 °C, or any temperature or temperature range falling within a range of about 60°C to about 100°C. In exemplary embodiments, the reacting of the intermediate compound of Formula VI with the diamine to create the NIPU of Formula II occurs in a presence of a chloride metal salt. In exemplary embodiments, the reacting of the intermediate compound of Formula VI with the diamine to create the NIPU of Formula II occurs in a presence of a catalyst. The catalyst can be, but is not limited to, LiB r or triazabicyclodecene (TBD).

[0109] In exemplary embodiments, the diamine is 1 ,4-diaminobutane, cadaverine, 1 ,6-diaminohexane, 1 ,7-diaminoheptane, 1 ,8-diaminooctane, 1 ,9-diaminononane, or 1 ,10-diaminodecane. The diamine can also be a branched diamine (e.g., 1 ,3- diaminopentane and 2-methyl-1 ,5-diaminopentane). Examples -19-

[0110] The present disclosure will be described in more detail with reference to the following Examples, which shows exemplary embodiments in accordance with the present disclosure. The present disclosure is not limited to these exemplary embodiments.

[0111] Example 1 : Synthesis of Exemplary Lignin-Derivable NIPUs

[0112] Materials used in the Exemplary Synthesis:

[0113] BPA diglycidyl ether (extent of oligomerization = about 0.02, physical form = solid), guaiacol (> 98% food grade), syringol (99%), vanillyl alcohol (>98%), thioglycolic acid (98%), LiBr (>99%), LiCI (>99%), and Amberlyst® 15 hydrogen form (dry) were purchased from Sigma-Aldrich. DA-10 (>99%) was purchased from TCI. Syringyl alcohol (97%), deuterated dimethyl sulfoxide (DMSO-cfe, ^99.5%), DMAc (99.8+%, HPLC grade), DMSO (anhydrous, 99.7% extra dry), tetrabutylammonium bromide (TBAB, 99+%), epichlorohydrin (99%), and deuterated chloroform (CDCh, >99.75%) were purchased from Acres Organics. BPF diglycidyl ether (EPON™ 862, extent of oligomerization = about 0.10, physical form = viscous liquid), a product of Hexion, was purchased from Chemical Marketing Concepts Inc. Acetone (>99.5%), dichloromethane (DCM, >99.5%), N,N- dimethylformamide (DMF, >99.8%), HCI (36.5 to 38.0% [w / w]), NaOH (>97%), magnesium sulfate (anhydrous), sodium bicarbonate (>99.7%), NaCI (>99.5%), tetrahydrofuran (THF, >99%), hexanes (99%), ethyl acetate (>99.5%), and acetonitrile (>99.9%) were purchased from Thermo Fisher Scientific. Ar (grade 5), CO2 (grade 5), and N2 (grade 5) were purchased from Keen Compressed Gas. All chemicals were used as received except acetone, which was passed through a magnesium sulfate column before use.

[0114] Monomer Synthesis and Characterization:

[0115] Synthesis of Lignin-Derivable Bisphenols

[0116] BGF synthesis - BGF was synthesized according to the process disclosed in Nicastro et al. (see K. H. Nicastro, C. J. Kloxin and T. H. Epps, III, ACS Sustainable Chemistry & Engineering, 2018, 6, 14812-14819) (see FIG. 1 ). Briefly, guaiacol (40 g, 0.311 mol) and vanillyl alcohol (12 g, 0.078 mol) were loaded into an oven-dried, single-neck, round-bottom flask (250 mL) equipped with a magnetic stir bar. The solution was heated to 70 °C in a silicone oil bath and sparged with Ar gas for 40 -20- min. Then, under Ar flow, Amberlyst® 15 hydrogen form (dry) (3.6 g, 30 wt% relative to the vanillyl alcohol) was added to the reaction mixture, and the reaction was allowed to proceed for 18 h at 70 °C. Next, the reaction mixture was passively cooled to about 20 °C in air for about 1 .5 h, then dissolved in 15 mL of DCM. The solid catalyst was separated from the crude mixture using a Buchner funnel and the liquid phase was transferred to a separatory funnel and washed with deionized (DI) water (3 times) and a brine solution (2 times). The organic phase was collected, the solvent was removed under reduced pressure, and the product was purified by flash column chromatography (Biotage® Selekt Systems, Biotage® Sfar Silica columns - 60 pm, 100 g) with ethyl acetate (25 v / v%) and hexanes (75 v / v%). The product was dried at 50 °C under vacuum for 24 h, and the dried product was obtained as a white solid (yield = about 50 mol%). Proton (1H) nuclear magnetic resonance (1H NMR) spectra (600 MHz, DMSO-d6) 6 8.68 (s, 2H), 6.80-6.51 (m, 6H), 3.71 (d, J = 4.7 Hz, 8H). Fourier Transform Mass Spectrometry (FTMS) (Electrospray Ionization [ESI]-FTMS, m / z) calculated for C15H16O4 260.1049; found 260.1041.

[0117] BSF synthesis (see FIG. 1 ) - Syringol (40.1 g, 0.26 mol) and syringyl alcohol (12 g, 0.065 mol) were loaded into an oven-dried, single-neck, round-bottom flask (250 mL) equipped with a magnetic stir bar. The solution was heated to 85 °C in a silicone oil bath and sparged with Ar gas for 40 min. Then, Amberlyst® 15 hydrogen form (dry) (3.6 g, 30 wt% relative to the syringyl alcohol) was added to the reaction mixture, and the reaction was allowed to proceed for 18 h. After the designated time, the reaction mixture was allowed to passively cool to about 20 °C in air for about 1 .5 h. The reaction mixture was subsequently dissolved in 15 mL of DCM, and the solid catalyst was separated from the crude mixture using a Buchner funnel. Like in the BGF purification, the liquid phase was washed with DI water (3 times) and a brine solution (2 times) in a separatory funnel. The organic phase was collected, and the excess solvent was removed under reduced pressure. Further, flash column chromatography (Biotage® Selekt Systems, Biotage® Sfar Silica columns - 60 pm, 100 g) with ethyl acetate (25 v / v%) and hexanes (75 v / v%) was used to purify BSF. The product was dried at 50 °C under vacuum for 24 h, and the dried product was obtained as a white solid (yield = about 45 mol%).1H NMR (600 -21 -

[0118] MHz, DMSO-cfe) 5 8.50 (s, 1 H), 8.04 (s, 1 H), 6.69-6.28 (m, 4H), 3.83-3.54 (m, 14H). FTMS (ESI, m / z): calculated for C17H20O6 320.1260; found 320.1321.

[0119] The direct condensation approach used to synthesize BGF and BSF eliminates the use of formaldehyde, a hazardous compound typically employed in the synthesis of BPF.

[0120] BGA synthesis (see FIG. 2) - Guaiacol (40 g, 0.32 mol) and acetone (3.4 mL, 0.046 mol) were charged in an oven-dried, single-neck, round-bottom flask (250 mL) equipped with a condenser and magnetic stirrer. The reaction was conducted in a large excess of guaiacol to minimize the formation of by-products from the self-condensation of acetone. Next, 5 mL of concentrated HCI (6 g, 15 wt% relative to guaiacol) was slowly added to the above reactants, followed by thioglycolic acid (0.2 vol% with respect to the catalyst) as a promoter. The reaction mixture was sparged with Ar gas for 10 min, and the mixture was heated to 100 °C in a silicone oil bath for 24 h. After that, the reaction mixture was allowed to passively cool to about 20 °C in air for about 1 .5 h. The crude mixture was dissolved in 15 mL of DCM, and the organic phase was washed with sodium bicarbonate until the aqueous layer reached neutral pH. The organic phase was washed with DI water (3 times) and a brine solution (2 times). The organic phase was then collected, and the solvent was removed under reduced pressure. The product was purified by flash column chromatography (Biotage® Selekt Systems, Biotage® Sfar Silica columns - 60 pm, 100 g) with ethyl acetate (25% v / v) and hexanes (75% v / v). The product was dried at 50 °C under vacuum for 24 h, and the dried product was obtained as a white solid (yield = about 40 mol%).1H NMR (600 MHz, DMSO-cfe) 6 8.69 (d, J = 5.7 Hz, 2H), 6.88-6.46 (m, 6H), 3.80-3.51 (m, 6H), 1.54 (d, J = 18.2 Hz, 6H). FTMS (ESI, m / z): calculated for C17H20O4 288.1362; found 288.1354.

[0121] BSA synthesis (see FIG. 2)- Syringol (40 g, 0.26 mol) was weighed into an oven-dried, single-neck, round-bottom flask (250 mL) equipped with a condenser and magnetic stirrer. To melt syringol, the round-bottom flask was heated to 85 °C in a silicone oil bath under Ar flow for 30 min. Acetone (2.75 mL, 0.037 mol) and HCI (5 mL, about 15 wt% relative to syringol) were added dropwise to the reaction flask, and the mixture was heated to 100 °C for 24 h. After 24 h, the reaction -22- mixture was allowed to passively cool to about 20 °C in air for about 1.5 h. The reaction mixture was dissolved in 15 mL of DCM and subsequently washed with sodium bicarbonate until the aqueous layer reached neutral pH. The organic phase was then washed with DI water (3 times) and a brine solution (2 times). Next, the excess solvent was removed under reduced pressure from the organic phase, and flash column chromatography (Biotage® Selekt Systems, Biotage® Sfar Silica columns - 60 pm, 100 g) with ethyl acetate (25 v / v%} and hexanes (75 v / v%) was employed to purify BSA. The product was dried at 50 °C under vacuum for 24 h, and the dried product was obtained as a viscous, orangish liquid (yield = about 40 mol%).1H NMR (600 MHz, DMSO-d6) 6 8.25-7.95 (m, 2H), 6.44 (d, J = 0.9 Hz, 3H), 3.68 (s, 12H), 1.56 (d, J = 27.3 Hz, 6H). FTMS (ESI, m / z): calculated for C19H24O6 348.1573; found 348.1643.

[0122] BGA and BSA were synthesized via electrophilic aromatic condensation reactions involving acetone. Given that bio-based acetone is available, these synthesis methods can provide a potentially greener process for NIPU production.

[0123] General Procedure for the Synthesis of Diglycidyl Ethers Bisguaiacol / bissyringol diglycidyl ethers were synthesized per protocols reported in Nicastro et al. (see K. H. Nicastro, C. J. Kloxin and T. H. Epps, III, ACS Sustainable Chemistry & Engineering, 2018, 6, 14812-14819) (see FIG. 3). In brief, bisguaiacol / bissyringol (0.02 mol), epichlorohydrin (0.20 mol), and TBAB (0.002 mol) were transferred into an oven-dried, single-neck, round-bottom flask (25 mL) equipped with a magnetic stir bar. The reaction mixture was sparged with Ar gas for 40 min at about 20 °C under constant stirring. Next, the mixture was heated at 50 °C for 2 h in a silicone oil bath. Subsequently, the reaction flask was immediately transferred into an ice bath maintained at about 0 °C. After 15 min, 40 wt% of aqueous NaOH (0.08 mol) was added dropwise under constant stirring to the cooled reaction flask, and the reaction was continued at 20 °C for 16 h in a water bath. The reaction mixture was then dissolved in 10 mL of DCM, washed with 20 mL of DI water (3 times) in a separation funnel until the aqueous layer reached neutral pH, and then washed with a brine solution (3 times). The organic layer was collected and then purified by automated flash column chromatography (Biotage® Selekt, Sfar Silica column - 60 pm particle size, 100 A pore size, 100 g silica gel) -23- with a step gradient of ethyl acetate (60% v / v) and hexanes (40% v / v) for elution. The solvents were removed from the product using a rotary evaporator, and the concentrated product was dried in an oven under vacuum at 50 °C for 24 h. The yield of the respective bisguaiacol / bissyringol diglycidyl ether varied between about 75-80 mol% after purification (purity >99%).

[0124] BPF diglycidyl ether (purchased) was a viscous, colorless liquid.1H NMR (600 MHz, DMSO-cfe) 6 7.21 -6.71 (m, 9H), 4.39-4.10 (m, 2H), 4.01 -3.69 (m, 4H), 2.94-2.57 (m, 4H). FTMS (ESI, m / z): calculated for C19H20O4 312.1362; found 312.1444.

[0125] BGF diglycidyl ether was isolated as a white solid (purity: >99%, yield = about 85 mol%).1H NMR (600 MHz, DMSO-d6) 6 6.77 (dd, J = 67.3, 8.0 Hz, 6H), 4.22 (d, J = 8.6 Hz, 2H), 3.91-3.62 (m, 10H), 3.28 (d, J = 4.0 Hz, 2H), 2.88-2.77 (m, 2H), 2.67 (t, J = 4.7 Hz, 2H). FTMS (ESI, m / z): calculated for C21 H24O6 372.1573; found 372.1574.

[0126] BSF diglycidyl ether was isolated as a viscous, light-greenish liquid (purity: >99%, yield = about 75 mol%).1H NMR (600 MHz, DMSO-d6) 6 6.87 (d, J = 8.5 Hz, 1 H), 6.74 (d, J = 7.6 Hz, 1 H), 6.49 (s, 2H), 4.20 (d, J = 14.1 Hz, 1 H), 4.03 (d, J = 11 .4 Hz, 1 H), 3.83-3.65 (m, 16H), 3.25 (d, J = 32.8 Hz, 2H), 2.77 (s, 2H), 2.55 (s, 2H). FTMS (ESI, m / z): calculated for C23H28O8 432.1784; found 432.1861.

[0127] BPA diglycidyl ether (purchased) was a white solid.1H NMR (600 MHz, DMSO-cfe) 6 7.22-6.98 (m, 4H), 6.95-6.70 (m, 4H), 4.26 (dd, J= 11.3, 2.8 Hz, 2H), 3.79 (dd, J = 11 .3, 6.5 Hz, 2H), 2.82 (dd, J = 5.1 , 4.3 Hz, 2H), 2.69 (dd, J = 5.1 , 2.7 Hz, 2H), 1.58 (s, 6H). FTMS (ESI, m / z): calculated for C21 H24O4 340.1675; found 340.1744.

[0128] BGA diglycidyl ether was isolated as a viscous, light-yellowish liquid (purity: >99%, yield = about 75 mol%).1H NMR (600 MHz, DMSO-d6) 6 6.94-6.64 (m, 6H), 4.21 (ddd, J = 24.1 , 11 .4, 2.8 Hz, 2H), 3.84-3.61 (m, 8H), 2.80 (ddd, J = 20.0, 5.1 , 4.2 Hz, 2H), 2.66 (ddd, J = 13.9, 5.1 , 2.6 Hz, 2H), 1.60 (d, J = 7.2 Hz, 6H). FTMS (ESI, m / z): calculated for C23H28O6 400.1886; found 400.1951.

[0129] BSA diglycidyl ether was isolated as an orangish solid (purity: >99%, yield = about 80 mol%).1H NMR (600 MHz, CDCI3) 5 6.36 (s, 4H), 4.11 -3.90 (m, 4H), 3.71 (s, 12H), 3.30 (dtd, J = 5.8, 4.1 , 2.6 Hz, 2H), 2.74 (dd, J = 5.0, 4.2 Hz, 2H), 2.56 -24-

[0130] (dd, J = 5.0, 2. 7 Hz, 2H), 1.58 (s, 6H). FTMS (ESI, m / z): calculated for C25H32O8 460.2097; found 460.2172.

[0131] General Procedure for the Synthesis of Cyclic Carbonates

[0132] Cyclic carbonates were synthesized by catalytic carbonation of diglycidyl ethers (see FIG. 4). To serve as an example, BGA cyclic carbonate was synthesized as follows. BGA diglycidyl ether (0.0085 mol, 3.3 g) and TBAB (0.04 g, 1 .5 mol% relative to diglycidyl ether) were added in a 25-mL Teflon™ cylindrical liner equipped with a magnetic stir bar. The liner was sealed in a 25-mL Parr reactor and flushed with CO2 (3 times) at about 20 °C. Next, the reactor was pressurized with about 30 bar CO2 and placed in a heating jacket (ceramic band heater) connected to a proportional-integral-derivative controller. The reaction continued for 24 h at 130 °C under constant stirring. After the designated time, the controller was turned off, and the reactor was allowed to passively cool to about 20 °C in air for about 1 .5 h. The reactor was subsequently depressurized and unsealed to collect the resulting product from the liner. The product was then dissolved in acetone (3 mL) and precipitated in DI water (30 mL) two times. The precipitated solid was dried in an oven under vacuum at 65 °C for 24 h, and the dried product was obtained as an off-white solid (yield = about 85 mol% and purity >99%). The other cyclic carbonates were synthesized similarly with yields of about 85 mol% and purities >99%.

[0133] BPF cyclic carbonate was isolated as a white solid (purity: >99%, yield = about 85 mol%).1H NMR (600 MHz, DMSO-d6) 5 7.21 -6. 71 (m, 9H), 4.39-4.10 (m, 2H), 4.01 -3.69 (m, 4H), 2.94-2.57 (m, 4H). FTMS (ESI, m / z): calculated for C21 H20O8 400.1158; found 400.1243.

[0134] BGF cyclic carbonate was isolated as an off-white solid (purity: >99%, yield = about 85 mol%).1H NMR (600 MHz, DMSO-d6) 6 6.95-6.66 (m, 6H), 5.10 (dddd, J = 8.3, 6.2, 4.2, 2.0 Hz, 2H), 4.61 (t, J = 8.5 Hz, 2H), 4.46-4.31 (m, 2H), 4.29-4.02 (m, 4H), 3.73 (d, J = 6.0 Hz, 8H). FTMS (ESI, m / z): calculated for C23H24O10 460.1369; found 460.1443.

[0135] BSF cyclic carbonate was isolated as an off-white solid (purity: >99%, yield = about 85 mo1 %).1H NMR (600 MHz, DMSO-d6) 6 6.82 (dd, J = 75.1 , 8.6 Hz, 2H), -25-

[0136] 6.50 (s, 2H), 5.11-4.84 (m, 2H), 4.73-4.38 (m, 4H), 4.26-3.87 (m, 4H), 3.82-3.66 (m, 14H). FTMS (ESI, m / z): calculated for C25H28O12 520.1581 ; found 520.1652.

[0137] BPA cyclic carbonate was isolated as a white solid (purity: >99%, yield = about 85 mol%),1H NMR (600 MHz, DMSO-d6) δ 7.21-7.02 (m, 4H), 6.92-6.75 (m, 4H), 5.13 (dtt, J = 8.6, 6.0, 2.6 Hz, 2H), 4.62 (t, J = 8.5 Hz, 2H), 4.37 (dd, J = 8.4, 5.9 Hz, 2H), 4.29-4.11 (m, 4H), 1.58 (s, 6H). FTMS (ESI, m / z): calculated for C23H24O8 428.1471 ; found 428.1536.

[0138] BGA cyclic carbonate was isolated as an off-white solid (purity: >99%, yield = about 85 mol%).1H NMR (600 MHz, DMSO-d6) δ 6.96-6.67 (m, 6H), 5.20-5.02 (m, 2H), 4.60 (dt, J = 13.8, 8.5 Hz, 2H), 4.50-4.31 (m, 2H), 4.31 -4.06 (m, 4H), 3.71 (d, J = 26.7 Hz, 6H), 1 .60 (d, J = 6.6 Hz, 6H). FTMS (ESI, m / z): calculated for C25H28O10 488.1682; found 488.1771.

[0139] BSA cyclic carbonate was isolated as a light-orangish-yellow solid (purity: >99%, yield = about 85 mol%).1H NMR (600 MHz, DMSO-d6) δ 6.51 (s, 4H), 5.08-4.91 (m, 2H), 4.69-4.45 (m, 4H), 4.35-4.08 (m, 2H), 4.05-3.86 (m, 2H), 3.71 (s, 12H), 1.64 (s, 6H). FTMS (ESI, m / z): calculated for C27H32O12 548.1894; found 548.1967.

[0140] 1H NMR spectroscopy

[0141] All NMR samples (except BSA diglycidyl ether) were prepared in DMSO-d6and analyzed on a Broker AVIII 600 Hz spectrometer. The BSA diglycidyl ether sample was prepared in CDCI3 due to its limited solubility in DMSO-d6.1H NMR spectra were analyzed using the MestReNova v1.8 software package. Chemical shifts were reported with respect to the solvent peak at 2.50 ppm for DMSO-d6and at 7.26 ppm for CDCI3.

[0142] Mass spectrometry

[0143] The exact molar masses of the lignin-derivable bisphenols, diglycidyl ethers, and cyclic carbonates were determined by ESI-FTMS using a Q-Exactive Orbitrap (Thermo Fisher Scientific) mass spectrometer. Samples were dissolved in acetonitrile (0.1 mg / mL), and the ESI-FTMS was conducted in positive-ion mode by direct syringe injection of samples in the mass spectrometer.

[0144] Polymer Synthesis and Characterization

[0145] General Procedure for the Synthesis of NIPUs -26-

[0146] NIPUs were synthesized via the step-growth polyaddition of the cyclic carbonates and diamines (FIG. 5). To serve as an example, the method to synthesize BGA-NIPU is provided below.

[0147] BGA cyclic carbonate (0.50 g, 1.02 mmol), DA-10 (0.176 g, 1.02 mmol), LiCI (2.1 mg, 0.05 mmol), and anhydrous DMSO (1 mL, 1 mmol / L) were all added to an oven-dried, single-neck, roundbottom flask (10 mL). The flask was sealed with a rubber septum, and the reaction mixture was sparged with Ar gas (about 15 min). The reaction was continued in a silicone oil bath for 24 h at 100 °C. After the reaction, the mixture was passively cooled to about 20 °C, diluted with 4 mL of THF, and precipitated from DI water (40 mL). The polymer was redissolved in THF (4 mL) and again precipitated from DI water (40 mL). The1H NMR of each of the synthesized polymers are provided below.

[0148] BPF-NIPU:1H NMR (600 MHz, DMSO-d6) δ 7.31 -6.58 (m, 11 H), 5.20 (s, 1 H), 5.03-4.80 (m,1 H), 4.09-3.70 (m, 10H), 3.56 (s, 1 H), 2.93 (q, J = 6.5 Hz, 4H), 1.38-1.12 (m, 16H).

[0149] BGF-NIPU:1H NMR (600 MHz, DMSO-d6) δ 7.14 (d, J = 27.5 Hz, 2H), 6.77 (d, J = 59.6 Hz, 6H), 5.31 -4.70 (m, 3H), 4.10-3.50 (m, 17H), 2.94 (s, 4H), 1.29 (d, J = 58.5 Hz, 16H).

[0150] BSF-NIPU:1H NMR (600 MHz, DMSO-d6) δ 7.06 (s, 2H), 6.77 (d, J = 53.8 Hz, 2H), 6.47 (d, J = 6.0 Hz, 2H), 5.12-4.66 (m, 3H), 4.17-3.53 (m, 23H), 2.93 (s, 4H), 1.29 (d, J = 58.6 Hz, 16H).

[0151] BPA-NIPU:1H NMR (600 MHz, DMSO-d6) δ 7.09 (d, J = 8.5 Hz, 6H), 6.81 (d, J = 8.6 Hz, 4H), 5.20 (d, J = 5.1 Hz, 1 H), 4.95-4.78 (m, 1 H), 4.11-3.79 (m, 8H), 3.56 (s, 1 H), 2.94 (s, 4H), 1 .57 (s, 6H), 1 .29 (d, J = 59.7 Hz, 16H).

[0152] BGA-NIPU:1H NMR (600 MHz, DMSO-d6) δ 7.24-6.99 (m, 2H), 6.92-6.64 (m, 6H), 5.18 (s, 1 H), 4.87 (d, J = 10.6 Hz, 1 H), 4.18-3.48 (m, 15H), 2.94 (s, 4H), 1.59 (s, 6H), 1.29 (d, J= 59.0 Hz, 16H).

[0153] BSA-NIPU:1H NMR (600 MHz, DMSO-d6) δ 7.07 (s, 2H), 6.59 (d, J = 77.9 Hz, 4H), 5.05-4.53 (m, 2H), 4.31-3.45 (m, 21 H), 2.93 (s, 4H), 1.61 (d, J = 19.7 Hz, 6H), 1.24 (d, J = 17.3 Hz, 16H).

[0154] All NIPU NMR samples were prepared in DMSO-d6and analyzed on a Bruker AVIII 600 Hz spectrometer, and1H NMR spectra were analyzed using the -27-

[0155] MestReNova v1 .8 software package. Chemical shifts were reported with respect to the solvent peak at 2.50 ppm for DMSO-c / e.

[0156] Example 2: Characterization and Evaluation of Exemplary Lignin-Derivable NIPUs In this example, exemplary NIPUs synthesized from monomers with varying methoxy-group content on their aromatic rings and substituents on bridging carbons were studied to understand the impact that these structural features have on the thermal, mechanical, and rheological behavior of the resulting polymers. The molecular structures of petroleum-based NIPUs and the exemplary lignin-derivable analogues of these petroleum-based NIPUs are presented in FIG. 6.

[0157] Methods

[0158] ATR-FTIR Spectroscopy

[0159] Hydrogen bonding and NIPU formation were assessed through ATR-FTIR spectroscopy using a Thermo Nicolet NEXUS 870 FTIR (Thermo Fisher Scientific) with a deuterated triglycine sulfate / potassium bromide (DTGS / KBr) detector. All cyclic carbonates and NIPUs were recorded at a resolution of 4 cm-1with 256 scans in the 4000-500 cm-1range. NIPU formation was assessed by examination of the cyclic carbonate carbonyl stretching band at about 1790 cm-1, the urethane carbonyl stretching band at about 1700 cm’1, and the broad hydroxyl stretching band at about 3100-3700 cm’1.

[0160] GPC

[0161] The molar masses of the polymers were determined using an HLC-8420 EcoSEC Elite GPC instrument from TOSOH with a refractive index (Rl) detector and four columns in series (1x TSKgel SuperAW-L guard column, 2x TSKgel SuperAWM-H columns, and 1x TSKgel SuperAW2500 column). The mobile phase was DMAc with 0.5 wt.% of LiBr. The flow rate of the mobile phase was 0.4 mL / min with an injection volume of 80 pL. A calibration curve was made using narrowdispersity poly(methyl methacrylate) [PMMA] standards from Agilent Technologies. The polymer solutions were prepared by dissolving samples in DMAc at about 1 .0 mg / ml (at about 20 °C for 24 h). The samples were then filtered using 0.1 -pm PTFE filters. The differential weight fraction distributions as a function of molar mass for the NIPUs are shown in FIG. 7.

[0162] NIPU Film Fabrication -28-

[0163] Solvent casting was employed for NIPU film preparation. The respective polymer was dissolved in DMF (about 10 w / v%) and stirred at about 20 °C for 24 h before pouring the solution into the mold (Teflon™ petri dish of diameter about 7 cm). The mold was covered with perforated aluminum foil and placed on a hot plate maintained at 60 °C for 2 h. Then, the mold was placed into an oven at 85 °C for 24 h at ambient pressure, followed by 85 °C for 48 h under vacuum. Next, TGA was employed to ensure the complete removal of solvent from the NIPU films.

[0164] Tensile Tests

[0165] The tensile properties, i.e., Young's modulus, ebreak, ultimate tensile strength, toughness (area under the tensile stress-strain curve), were measured using a Zwick / Roell Z 0.5 (500 N zw icki) tensile tester with a 100 N-capacity load cell and a clamp force of 200 N. The specimens with dimensions of 9.5 mm x 2.5 mm x 0.17 - 0.24 mm (gauge length x width x thickness) were subjected to an extension rate of 10 mm / min until film breakage. Five replicates were analyzed, and the average values are reported in this Example. All tests were performed at about 20 °C.

[0166] DSC

[0167] The Tgs of synthesized NIPUs were determined using a Discovery Series DSC 972000.901 instrument (TA Instruments). Samples were loaded into hermetically sealed aluminum pans. The pans were heated from -20 °C to 170 °C at a rate of 10 °C / min under continuous N2 flow (50 mL / min) and held isothermally for 2 min at 170 °C. Then, the pans were cooled to -20 °C at a rate of 10 °C / min under N2 flow. The data from the third heating trace were used for analysis. The Tgwas reported as the midpoint of the inflection in the thermogram from the third heating.

[0168] TGA

[0169] The thermal stability of the polymers and the solvent content of the films were investigated using a Discovery Series Thermogravimetric Analyzer TA Q500 (TA Instruments). About 5 mg of polymer was placed into a 100-pL platinum pan. Under a continuous flow of N2 (50 mL / min) gas, the sample was heated to 200 °C at a rate of 10 °C / min and held at this temperature for 2 min to evaporate any water or solvents that may have been present. Then, the sample was cooled to 30 °C and -29- heated to 700 °C at a rate of 10 °C / min in the N2 atmosphere. The thermal stability (Td5%) was reported as the temperature at which a 5 wt% loss was noted.

[0170] Rheological Analysis

[0171] The rheological response of the polymers was quantified using a strain- controlled, torsional Ares G2 rheometer (TA Instruments). Vacuum-dried films were stacked and loaded into the test geometry (8-mm-diameter parallel plates) that had been preheated to 160 °C. The samples were slowly pressed and trimmed, such that the final thickness was 1 mm. A pre-shear step was then applied at 1 rad / s and 0.2% strain for 60 s to relax any stresses arising from sample loading. A series of frequency sweeps (between 0.1 and 100 rad / s) and temperature ramps were performed to obtain linear viscoelastic responses between 150 °C and 40 °C in 10 °C increments. The strain amplitude remained within the linear viscoelastic regime (as determined by amplitude sweeps) and was selected to be 0.5% and 0.2% for temperatures above and below 90 °C, respectively. All experiments were conducted in a N2 atmosphere.

[0172] Linear viscoelastic spectra at a reference temperature of Tref = 150 °C were constructed using the frequency sweep data via time-temperature superposition. Vertical shift factors of Tref / T were applied, and, subsequently, horizontal shift factors were determined using the algorithm in the TRIOS software (TA Instruments).

[0173] Properties of Exemplary Lignin-Derivable NIPUs

[0174] All the NIPUs evaluated in this Example are provided in Table 1 .

[0175] Table 1 : / Wnand Dispersity Characterization Data of Exemplary NIPUs -30-aDetermined relative to PMMA standards using data from GPC with Rl detectors [GPC solvent: DMAc + 0.5 wt% LiBr].

[0176] All NIPUs exhibited comparable molar masses of about 15-20 kg / mol. Although traditional PUs can be obtained with molar masses >20 kg / mol, most of the NIPUs known in the art possess an Mn of <10 kg / mol due to the lower reactivity of cyclic carbonates vs. isocyanates, along with numerous possible side reactions (e.g., urea formation, amidification reaction, and oxazolidinone formation) that can limit molar mass. Additionally, the five-membered cyclic carbonates are relatively less reactive than six-, seven-, or eight-membered cyclic carbonates because of the ring strain. Notably, in this Example, higher-than-average Mnvalues were achieved, and free-standing films were fabricated, which suggests that the hydrogen-bonding in these polymers improves mechanical robustness even in lower-molar-mass NIPUs. As shown in Table 1 , most of the NIPUs had dispersities (Ds) of about 2.5- 3, except for BPF-NIPU (D of about 4). This exception was likely a result of the higher extent of oligomerization (about 0.10) in the commercial BPF diglycidyl ether vs. the other diglycidyl ethers (about 0.01 - 0.03).

[0177] Determination of Hydrogen-Bonding in NIPUs

[0178] Hydrogen bonding plays a crucial role in the properties (mechanical and rheological) of PUs and NIPUs. The exemplary lignin-derivable NIPUs evaluated in this Example displayed higher percentages of hydrogen-bonded acceptors (attributable to their methoxy moieties) than their petroleum-based analogues. The total number of hydrogen-bond acceptors and donors was calculated from the theoretical structures of the repeat unit in the PUs and NIPUs. In particular, -OH and -NH were considered the hydrogen-bond donors, and urethane carbonyls (- C=O), ether oxygens (-O-), and methoxy groups (-OCH3) were considered the hydrogen-bond acceptors. As shown in Table 2, the hydrogen-bond acceptor count per repeat unit in the exemplary NIPUs increased with the number of methoxy groups (between 0, 2, and 4) in BPF- / BGF- / BSF-NIPUs.

[0179] Table 2: Calculated Hydrogen-bond Donors, Acceptors, and Hydrogen-bonded - OH / -NH Percentage for NIPUs -31 - aEstimated from ATR-FTIR spectroscopy data.

[0180] Semi-quantitative analysis using ATR-FTIR spectroscopy was employed to estimate the amount of hydrogen-bonding in the NIPUs. The -OH / -NH absorption bands (3100-3700 cm’1) of the NIPU samples were deconvoluted using Gaussian distributions. The -OH / -NH absorption bands were fit to two subpeaks because the stretching vibrations of hydrogen-bonded -OH / -NH were at a slightly lower wavenumber (about 3300-3350 cm’1) than the free -OH / -NH vibrations (about 3450- 3550 cm’1), and the relative areas of these two peaks were calculated. Hydrogen bonding can cause the vibrational frequencies to red-shift (i.e., migrate towards lower energy) for the hydrogen-bonding motifs, with stronger bonds precipitating shifts to lower energies. The hydrogen-bonded region includes all self- and transassociations, and the broadness of this region depends upon the number / strength of associations. The presence of additional methoxy groups (hydrogen-bond acceptors) increased the interactions in the hydrogen-bonded region and the broadness of this region. FTIR analysis suggested that increasing the number of methoxy groups from 0 to 2 to 4 in BPF- / BGF- / BSF-NIPUs led to higher percentages of hydrogen-bonded -OH / -NH groups (about 65%, about 85%, and about 95%, respectively). Similar trends were found in the dimethyl-substituted analogues, BPA- / BGA- / BSA-NIPUs (see Table 2 and FIG. 8). This finding demonstrated that the added hydrogen-bonding capability of the monomers directly -32- translated to greater secondary interactions between NIPU chains, which positively influenced the mechanical and rheological properties.

[0181] Mechanical Behavior of NIPUs

[0182] The impacts of both hydrogen bonding and substitutive groups on the solid- state performance of the NIPUs were quantified using tensile testing. The exemplary lignin-derivable NIPUs exhibited improved mechanical properties (ebreak and toughness) over their petroleum-based counterparts without a reduction in Young's modulus or tensile strength (see FIG. 9, FIG. 10, FIG. 11 and Table 3).

[0183] Table 3: Mechanical Property Characterization Summary of the NIPUs

[0184] The ebreak and toughness of NIPUs increased with an increase in the methoxy-group content. For example, in the unsubstituted bridging-group case, BSF-NIPU exhibited the highest ebreak (about 210%) and toughness (about 62 MJ / m3), followed by BGF-NIPU (ebreak of about 185%, toughness of about 58 MJ / m3), and then BPF-NIPU (ebreak of about 140%, toughness of about 42 MJ / m3).

[0185] In the dimethyl-substituted cases, both lignin-derivable versions, BGA-NIPU (ebreak of about 145%, toughness of about 51 MJ / m3) and BSA-NIPU (ebreak of about 120%, -33- toughness of about 44 MJ / m3) exhibited higher ebreak and toughness than petroleum-derived BPA-NIPU (ebreak of about 95%, toughness of about 36 MJ / m3). The increased toughness was attributed to the hydrogen-bonds between chains that acted as physical crosslinks. As the petroleum-derived NIPUs had a fixed number of donors for potential hydrogen-bonding interactions, the methoxy moieties in the lignin-derivable systems could provide additional sites for intra- and inter-molecular hydrogen-bonding in the NIPU matrix. The density of these physical crosslinks possibly increased with an increase in methoxy content, which likely led to higher extensibility.

[0186] The TT-TT stacking interactions are expected to be comparable across all NIPUs as it has been reported that lignin-derivable G and S units can form TT-TT stacking interactions, and these interactions are almost equivalent in softwood and hardwood lignin samples. Thus, the methoxy substituents may not significantly interrupt TT-TT interactions in lignin-derivable-NIPUs (BGF-ZBGA-NIPUs (softwood derivable) and BSF-ZBSA-NIPUs (hardwood derivable)) vs. petroleum-derived- NIPUs (BPF-ZBPA-NIPUs).

[0187] Thermal Properties of NIPUs

[0188] The thermal properties of the exemplary lignin-derivable NIPUs were benchmarked against their petroleum-derived analogues (see FIG. 12). The Tgs of the NIPUs increased with an increase in the methoxy-group content. For example, BPF-NIPU with zero methoxy groups had a Tgof about 36 °C, BGF-NIPU with two methoxy groups had a Tgof about 39 °C, and BSF-NIPU with four methoxy groups had a Tgof about 42 °C. Similarly, BPA-NIPU with zero methoxy groups had a Tgof about 46 °C, BGA-NIPU with two methoxy groups had a Tgof about 50 °C, and BSA-NIPU with four methoxy groups had a Tgof about 55 °C. These results indicated that the presence of side groups (i.e., methoxy moieties) on the polymer backbone could increase Tgby limiting the chain mobility. Additionally, secondary forces, such as hydrogen-bonding and dipole-dipole interactions, between the chains also might be responsible for an increase in Tgdue to greater constraints on segmental mobility imposed by associations.

[0189] The NIPUs based on monomers with dimethyl-substituted bridging carbons exhibited higher Tgs than their unsubstituted analogues. The Tgvalues were BPA- -34-

[0190] NIPU > BPF-NIPU; BGA-NIPU > BGF-NIPU; and BSA-NIPU > BSF-NIPU. This trend was most likely related to the rotational freedom of the aromatic ring around the central carbon, which was lower for the dimethyl group as the dimethyl bridge restricted the free rotation of the polymer backbone (BPA- / BGA- / BSA-NIPUs) and led to a comparably higher Tg(BPF- / BGF- / BSF-NIPUs). This was an unexpected discovery because the art had previously reported that the Tgs of bisguaiacol / bissyringol-based polymers were lower than BPA-based counterparts. In combination with the mechanical responses of the NIPUs, these DSC results demonstrate that hydrogen-bonding contributes to the ability to obtain glassy polymers with tunable extensibility at room temperature.

[0191] The thermal stabilities of the exemplary lignin-derivable NIPUs were equivalent to those of the BPA- / BPF-based NIPUs (Td5% of about 280 °C) (see FIG. 13). The Td5% values for BPF- / BGF- / BSF-NIPU were about 283 °C, 276 °C, and 288 °C, respectively. Similarly, BPA- / BGA- / BSA-NIPUs exhibited Td5% values of About 275 °C, 285 °C, and 283 °C, respectively. The char contents were nearly identical across all NIPUs. Additionally, the most significant degradation event occurred at similar temperatures (about 350 °C) across all NIPUs (see FIG. 13). The comparable thermal stabilities of all NIPUs (7^5% of about 280 °C) were mainly attributed to the initial breakage of the hydroxyurethane linkages, which occurred at about 250-270 °C. Interestingly, the increased methoxy content in the exemplary lignin-derivable NIPUs did not reduce thermal stability. This observation is noteworthy because the art had previously reported that the increased oxygen content in lignin-derivable thermoplastic polymers, such as polycarbonates and polyesters, reduced thermal stability. Surprisingly, the presence and number of methoxy moieties did not strongly impact the thermal decomposition temperature across the different lignin-derivable NIPUs.

[0192] Rheological Behavior of NIPUs

[0193] Thermoplastic PUs are typically melt processed for fabrication of commercial products, and thus their rheological behavior is key to macromolecular design. The addition of hydrogen-bonding groups has been well-established to strongly affect the melt flow in a wide range of polymers (e.g., polyacrylates, polyolefins, polyethers) and in several complex ways (e.g., by increasing terminal relaxation -35- time and by altering slope in the terminal regime). Therefore, the contribution that the additional hydrogen-bonding capabilities in the exemplary lignin-derivable NIPUs had on rheological behavior was investigated. For unsubstituted NIPUs, the rheological behavior in the rubbery and glassy states (i.e., frequencies > 105rad / s) was similar for all polymers (see FIG. 14). A slight trend in the glassy modulus (i.e., the plateau value of storage modulus, G', at high frequencies) was noticed whereby the modulus increased with increasing numbers of methoxy groups. The critical relaxation time (TC) (i.e., the inverse of the frequency at which a crossover of G' and G" occurs) when the transitional and rubbery regimes meet is related to localized, fast relaxations. Interestingly, TCappeared to be non-monotonic with the number of methoxy groups (see Table 4). The value of TCis typically sensitive to intermonomer friction, yet this trend was unexpected given the probable increase in friction with increasing methoxy moieties. This discrepancy could be due to the higher dispersity of BPF-NIPU as result of the extent of oligomerization in comparison to the other NIPUs or relative differences in the frictional contribution of the methoxies subject to their position on the aromatic rings.

[0194] Table 4: Rheological Properties of NIPUs -36-aGiven at the reference temperature of 150 °C.bCalculated as the inverse of the low-frequency crossover.ccalculated as the inverse of the crossover at high frequencies bounded by the rubbery and transitional regimes.dThe value of G' at the minimum of phase angle vs. complex modulus.eApproximated as the frequency in the terminal regime at which phase angle vs. complex modulus went through a maximum.

[0195] Whereas the high-frequency region of the viscoelastic response provides information regarding the motion of monomer units, the intermediate frequencies reveal long-range interactions between chains. Given the evidence that hydrogen bonding was improved for the exemplary lignin-derivable NIPUs studied in this Example, the rubbery response at moderate frequencies was investigated to understand the effect that increased hydrogen-bonding content had on both the viscous and elastic behaviors of the NIPUs. With an increasing number of methoxy groups, a steady increase in the values of the plateau (i.e., rubbery) modulus (GN,O) occurred (see Table 4). The GN,O values for BSF- and BGF-NIPUs were higher (about 8 x 105Pa) than that of BPF-NIPU (about 7x105Pa). This behavior was directly related to the increase in hydrogen-bonding for BSF-NIPU (about 90%) and BGF-NIPU (about 85%) in comparison to that of BPF-NIPU (about 60%) shown by ATR-FTIR spectroscopy. Additionally, as the difference in the hydrogen-bonding between BSF- and BGF NIPUs was not significant, the GN,O values for both the polymers were equivalent. The most prominent differences in the NIPU rheology were seen in the terminal regime. Between the petroleum- and lignin-derivable polymers, there was an order of magnitude decrease in the long relaxation time (TX). Although it would be expected that an increase in hydrogen-bonding content would lead to an increase in this timescale, differences in molar mass and dispersity also impact this relaxation behavior. The BPF-NIPU exhibited a stronger deviation from the classical terminal power-law slopes of G' (slope of 2) and G" (slope of 1) than the BGF- and BSF-NIPUs, indicating a greater strength of association between chains for the former. This behavior was unsurprising considering the associations in BPF-NIPU were primarily between hydroxyls, which typically had a stronger hydrogen-bond energy than between methoxy and hydroxyl groups. Thus, even with a greater number of potential hydrogen-bonding groups, -37- the lignin-derivable NIPUs flowed more easily because these interactions were more easily interrupted.

[0196] The transitional and glassy behavior also were similar in the case of the dimethyl-substituted NIPUs (see FIG. 14); however, there was a lesser dependence of the glassy moduli on methoxy content than for unsubstituted NIPUs. This finding could be related to the presence of the bridging group substituents, thus suggesting that these substituents more prominently control solid viscoelasticity. The TCS followed the same trend as for unsubstituted NIPUs yet were slightly higher in magnitude for BPA-NIPU in comparison to BPF-NIPU, which could be because of the added friction associated with the bridging substituents that was insignificant in the presence of bulkier methoxy substituents on the ring. Although the GN,O values for the dimethyl-substituted, lignin-derivable NIPUs were comparable to their unsubstituted counterparts, BPA-NIPU had a higher value than BPF-NIPU, thus suggesting that the rigidity of dimethyl-substituted NIPUs increases physical crosslinking. This effect, however, had little impact on lignin- derivable NIPUs potentially because the methoxy groups interfere with the hydroxyl-hydroxyl hydrogen bonding. This interference can yield a transient network with more, but weaker, junctions.

[0197] The dimethyl-substituted NIPUs also exhibited additional features related to hydrogen-bonding in the terminal regime. The expected terminal power-law scaling was followed for all the NIPUs (except BSA-NIPU). This finding demonstrated the strength of hydrogen-bonding in BSA-NIPU. Although the impact was small on the plateau modulus, there was a more pronounced influence in the melt state because of the accessibility of hydrogen-bonds once backbone features (e.g., chain segments and entanglements) had relaxed. The trend in TXwas similar to that seen for unsubstituted NIPUs, except for BSA-NIPU. This relationship could be related to the chain flexibility (i.e., persistence length), as well as the hydrogen-bond strength.

[0198] The thermo-rheological responses of the NIPUs were next examined. Timetemperature superposition was performed to construct master curves; however, the quality of the superposition varied. This phenomenon was best visualized using van Gurp-Palmen plots (see Figure 15). For all unsubstituted NIPUs, the data did not -38- superimpose to a single curve around the transitional regime, although only BPF- NIPII was poorly superimposed in the terminal regime, which was likely a consequence of a higher molecular-weight dispersity in comparison to the other NIPUs. The dimethyl-substituted NIPUs showed good superposition across all temperatures, with only a noticeable spread in the data in the terminal regime caused by the noise related to measuring the low moduli. Vertical shift factors were nearly identical between all of the NIPUs, as demonstrated by the general equivalence of the Williams-Landel-Ferry parameters Ci and C2 (see Table 4). The greatest deviation between the NIPUs was noticed at temperatures approaching the glass transition.

[0199] Overall, the exemplary lignin-derivable NIPUs exhibited a similar behavior to their petroleum-derived counterparts in the rubbery and glassy states, yet unexpectedly, the lignin-derivable NIPUs flowed more easily (i.e., exhibited overall lower moduli in the terminal regime) and had faster relaxation times than the petroleum-derived NIPUs. These findings suggest that the added functionalities derived from lignin precursors were not a hindrance to processability, but rather a benefit to modulating the strength of hydrogen-bonding from sustainably manufactured NIPUs. Notably, the methoxy groups in the exemplary lignin- derivable thermoplastic NIPUs increased the extent of hydrogen-bonding in these polymers, which led to increased ebreak and toughness vs. petroleum-based versions. For example, lignin-derivable BGF-NIPU (ebreak of about 185%, toughness of about 58 MJ / m3) and BSF-NIPU (ebreak of about 210%, toughness of about 62 MJ / m3) exhibited higher ebreak and toughness than BPF-NIPU (ebreak of about 140%, toughness of about 42 MJ / m3). Furthermore, the Tgof NIPUs increased with an increase in the methoxy-group content as the side groups and secondary interactions increased due to the methoxy substituents reducing the chain mobility. These increases in ebreak, toughness, and Tgs were obtained without any adverse effect on other polymer properties, such as modulus (about 1 .2-1 .4 GPa), tensile strength (about 40-55 MPa), and thermal stability (about 280 °C). Importantly, the melt rheology of the lignin-derivable NIPUs remained favorable, and these methoxy moieties offered improved processability vs. their non-methoxy- containing, petroleum-derived counterparts. Altogether, the thermomechanical -39- properties of lignin-derivable NIPUs can be readily tuned with careful choice of lignin-derivable building blocks, and the structure-property-processing relationships established in this work can aid the development of sustainable polymeric materials. It will be appreciated by those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the disclosure is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.

Claims

-40-CLAIMS:

1. A compound of Formula I:(Formula I), wherein:R1and R2are either the same or different, and are selected from the group consisting of -H and -CH3;R3and R4are either the same or different, and are selected from the group consisting of -H and -OCH3;R5and R6are -OCH3; andR7and R8are either the same or different, and are selected from the group consistingwherein R9is selected from a C4 to C10 alkyl group.

2. The compound of claim 1, wherein R9is a C10 alkyl group.-41-3. The compound of claim 1, wherein R7is and R8is4. The compound of claim 1, wherein R and R are bothThe compound of claim 1, wherein R7and R8are both6. A lignin-derivable non-isocyanate polyurethane (NIPU) of Formula II:(Formula II), wherein:-42-R1and R2are either the same or different, and are selected from the group consisting of -H and -CH3;R3and R4are either the same or different, and are selected from the group consisting of -H and -OCH3;R5and R6are -OCH3;R9is selected from a C4 to C10 alkyl group; and n is an integer ranging from 20 to 100.

7. The NIPU of claim 6, wherein R9is a C10 alkyl group.

8. The NIPU of claim 6, wherein R1and R2are -CH3.

9. The NIPU of claim 6, wherein R3and R4are -OCH3.

10. The NIPU of claim 6, wherein the NIPU has a relaxation time (TX) ranging from 1 x 10'4to 8 x 10'4seconds.

11. The NIPU of claim 6, wherein the NIPU is free of one or more of processing aids, thermal stabilizers and antioxidants.

12. The NIPU of claim 6, wherein the NIPU has a toughness ranging from 30 to 70-43-13. The NIPU of claim 6, wherein the NIPU has an ultimate tensile strength ranging from 35 to 60 Mpa.

14. The NIPU of claim 6, wherein the NIPU has a Young’ s modulus ranging from 1.2 to 1.4 GPa.

15. A method of producing a lignin-derivable non-isocyanate polyurethane (NIPU) ofFormula II:(Formula II), wherein:R1and R2are either the same or different, and are selected from the group consisting of -H and -CH3;R3and R4are either the same or different, and are selected from the group consisting of -H and -OCH3;R5and R6are -OCH3;R9is selected from a C4 to C10 alkyl group; and n is an integer ranging from 20 to 100, the method comprising:(i) isolating guaiacol or syringol from a lignin-containing material;-44- reacting the isolated guaiacol or syringol with either vanillyl alcohol or syringyl alcohol to create an intermediate compound of Formula III:(Formula III), or reacting the isolated guaiacol or syringol with acetone to create an intermediate compound of Formula IV:(Formula IV);(iii) reacting the intermediate compound of Formula III or the intermediate compound of Formula (IV) with epichlorohydrin to create an intermediate compound ofFormula V:(Formula V);(iv) reacting the intermediate compound of Formula V with carbon monoxide and tetrabutylammonium bromide to create an intermediate compound of Formula VI:-45-(Formula VI); and(v) reacting the intermediate compound of Formula VI with a diamine to create the NIPU of Formula II.

16. The method of claim 15, wherein the reacting the isolated guaiacol or syringol with either vanillyl alcohol or syringyl alcohol to create the intermediate compound of FormulaIII occurs at about 75°C, under an inert atmosphere and in a presence of an acidic resin.

17. The method of claim 15, wherein the reacting of the isolated guaiacol or syringol with acetone to create to intermediate compound of Formula IV occurs at about 100°C, under an inert atmosphere and in a presence of an acid.

18. The method of claim 15, wherein the reacting of the intermediate compound ofFormula III or the intermediate compound of Formula (IV) with epichlorohydrin to create the intermediate compound of Formula V occurs at about 20°C, under an inert atmosphere and in a presence of a base and tetrabutylammonium bromide.

19. The method of claim 15, wherein the reacting of the intermediate compound ofFormula V with carbon monoxide and tetrabutylammonium bromide to create the intermediate compound of Formula VI occurs at about 130°C.-46-20. The method of claim 15, wherein the reacting of the intermediate compound of Formula VI with the diamine to create the NIPU of Formula II occurs at about 100°C in a presence of a chloride metal salt.

21. The method of claim 15, wherein the diamine is 1,10-diaminodecane.

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