Recyclable and malleable thermosets enabled by activating dormant dynamic bonds

Abstract

The invention disclosed herein relates to a novel class of alkyl- and / or aryl-linked crosslinked polymeric compounds and methods for their synthesis from alkoxy-substituted triazines by reacting the alkoxy-substituted triazines with diols. Additionally, a method for synthesizing alkyl-linked polyaryl ether monomers / networks is provided, which comprises reacting an alkoxy-substituted phenyl derivative bearing an electron-withdrawing group with a diol.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This international PCT application claims the benefit of and priority to U.S. Provisional Application No. 63 / 354,754, filed June 23, 2022, the specification, claims, and drawings of which are incorporated herein by reference in their entirety.

[0002] Generally, the inventive technology disclosed herein relates to novel alkyl- and / or aryl-linked polycyanurate compounds and methods for their synthesis. [Background technology]

[0003] Plastics have become an indispensable part of our daily lives. The lightweight, durable, excellent barrier properties, and low cost properties of most plastics have led to significant societal benefits and technological advancements. However, the ever-increasing demand for plastics, the negative environmental impacts of their unregulated disposal, and challenges in recycling have raised concerns about long-term adverse effects on the environment and human health. To achieve a circular economy and environmental sustainability, achieving recyclability for polymeric materials has attracted significant attention. Thermosets, in which monomers are permanently crosslinked by strong covalent bonds, are typically manufactured as unprocessable and unrecyclable plastics by design. To address the recyclability issue, there has been an explosion in the creation of novel thermoset polymers by introducing cleavable or dynamic covalent bonds into monomers or as crosslinkers. Various chemistries, including dynamic imine bonds, transesterification, boronic ester bonds, urethane, and silyl ether bonds, have been explored as cleavable units for preparing these materials. However, little research has focused on achieving the recyclability and malleability of existing thermosets to realize a circular economy. While developing new polymers as "green" alternatives is important, rethinking traditional materials in new ways is crucial and can generate important knowledge that will guide the development of sustainable, high-performance materials. Summary of the Invention [Problem to be solved by the invention]

[0004] Retrosynthetic analysis has long been a standard method for synthetic chemists to evaluate possible cleavage options for target structures and find the most efficient pathways. However, the importance of retrosynthetic analysis in polymer synthesis is often overlooked because polymers are composed of simple repeating units and have limited possible connectivity. Searching backwards can uncover alternative synthetic routes for polymers, which may offer unexpected benefits. For example, poly(phenylene ethynylene)s (PPEs) are typically synthesized via cross-coupling reactions, generally resulting in PPEs with relatively low molecular weights and diyne defects (Figure 1a). However, alkyne metathesis, which forms C≡C bonds instead of C≡C bonds, can yield high-molecular-weight, defect-free PPEs. More importantly, dynamic alkyne metathesis enables the depolymerization of PPEs into small molecules and their potential closed-loop recyclability. Recent studies on chemically recyclable polymers and covalently adaptable networks (CANs) have demonstrated that reversible activation of bonds in polymers may be a key driver of the recyclability and malleability of thermosetting polymers. Therefore, the present inventors sought to discover potentially reversible bonds through retrosynthetic analysis in conventional thermosetting polymers.

[0005] As proof-of-concept, we selected cyanate ester resins as an exemplary model system to demonstrate our strategy of achieving recyclability and malleability by activating dormant dynamic bonds in conventional thermoset resins. Polycyanurate networks (PCNs) are widely adopted in the aerospace and microelectronics industries, with a market expected to reach $338 million by 2022. Cyanate ester resins are traditionally cured via a [2 + 2 + 2] cyclotrimerization reaction of three cyanate groups (Figure 1b) to form polycyanurate networks (PCNs), which exhibit unique properties such as good flame retardancy, high thermal stability, low moisture absorption, low dielectric dissipation factor, excellent compatibility with carbon fiber, and adhesion to metals. Recycling such crosslinked thermoset resins is challenging. Previously, PCNs were decomposed into triazine-based structures and phenols by treatment with various nucleophiles. The resulting products were obtained as mixtures and could be further used in polyurethane synthesis. However, closed-loop recycling of PCNs back into clean, reusable building blocks (e.g., triazine-based monomers for repolymerization) has not been achieved to date. Furthermore, because alkyl-OC≡N monomers undergo isomerization at high temperatures, the [2 + 2 + 2] cyclotrimerization reaction is an irreversible reaction that limits the substrate scope to aromatic aryl-OC≡N monomers, generally resulting in very brittle PCNs. The introduction of alkyl groups into PCNs is uncontrollable by conventional trimerization methods, and the synthesis of alkyl-linked PCNs is challenging, making it an underexplored area. [Means for solving the problem]

[0006] By performing retrosynthetic analysis and reconsidering possible alternative pathways, we have demonstrated that nucleophilic aromatic substitution (S N We hypothesize that PCNs can also be constructed by forming a single bond between the triazine carbon and oxygen via the reaction with Ar. Here, instead of the irreversible cyclotrimerization reaction, a reversible S NWe demonstrate that the dynamic bonds in dormant PCNs can be activated by employing Ar chemistry. Thus, recyclable and malleable PCNs can be prepared from two simple building blocks, enabling conventional aryl PCNs to be upcycled into reusable monomers for alkyl PCN synthesis. This new synthetic route eliminates the need for aryl linkers in PCN synthesis and offers unprecedented variability in PCN properties, which has proven technically challenging using conventional cyclotrimerization methods. Alkyl PCNs exhibit excellent film properties, chemical resistance, and recyclability. Used PCNs in mixed plastic waste streams can be selectively decomposed back to the starting monomers, which can then be separated and directly reused in the next production cycle, achieving closed-loop polymer-to-polymer recycling.

[0007] In one aspect, the present invention comprises novel thermosetting polymer compositions. In a preferred embodiment, the thermosetting polymers of the present invention comprise one or more novel alkyl- and / or aryl-linked polycyanurate network (PCN) compositions. In one aspect, the alkyl-linked PCN monomer compounds of the present invention are capable of reversible S-bonding between alcohols and cyanurates. N The alkyl-linked PCN can be synthesized by the Ar reaction. Alternatively, the alkyl-linked PCN can be converted to the monomer by refluxing in an alcohol, preferably ethanol. In this embodiment, potassium carbonate can be used as a base to deprotonate the ethanol and facilitate the conversion.

[0008] In a preferred embodiment, the thermosetting polymer of the present invention contains one or more novel polyarylether (PAE) compositions. In this embodiment, the PAE monomer compounds of the present invention are capable of forming reversible S-type bonds between alcohols and di / triarylethers having two or more cyano, aldehyde, and / or halogen groups. NThe PAE can be synthesized by the Ar reaction. Alternatively, the PAE can be converted to the monomer by refluxing in an alcohol, preferably methanol. In this embodiment, potassium carbonate may be used as a base to deprotonate the ethanol and facilitate the conversion.

[0009] In another aspect, the present invention includes a novel system and method for the synthesis of novel thermosetting polymer compositions. In a preferred embodiment, the present invention provides a method for the synthesis of novel alkyl- and / or aryl-linked PCNs by reversible nucleophilic aromatic substitution (S N This includes the use of Ar.

[0010] In a preferred embodiment, the present invention involves the synthesis of aryl-linked PCNs formed by substituting ethoxy groups on a cyanurate structure with bisphenol A (BPA).

[0011] In a preferred embodiment, the present invention involves the synthesis of alkyl-linked PCNs formed by substituting an alkyl diol for the ethoxy group on the cyanurate structure. In a preferred aspect, the alkyl diol can be selected from 1,4-butanediol (DO-4), 1,6-hexanediol (DO-6), and 1,12-dodecanediol (DO-12), which can be used in the synthesis of S-PCNs as described herein. N It can act as a linker via Ar reaction.

[0012] Additional aspects of the present invention include methods for upcycling conventional aryl-PCNs into reusable monomers for alkyl-PCN synthesis. In a preferred embodiment, spent aryl-PCN materials can be converted to cyanurate structures in which the ethoxy groups are substituted with one or more alkyl diols to form novel alkyl (PCNs).

[0013] An additional embodiment of the present invention includes a method for converting alkyl-backed PCN to its monomer subunits, preferably by refluxing the PCN in ethanol in the presence of potassium carbonate catalyst.

[0014] Additional aspects of the present invention will become apparent based on the following specification and drawings. [Brief explanation of the drawings]

[0015] [Figure 1] Polymer synthesis strategies are shown. a) Poly(phenyleneethynylene) (PPE) can be prepared by either the cross-coupling of aryl halides with terminal alkynes (blue) or alkyne metathesis polymerization (red). b) Polycyanurate networks (PCNs) can be prepared by the [2 + 2 + 2]-cyclotrimerization reaction of cyanate esters (blue) or the dynamic SNAr reaction between alkoxyl triazines and alcohols (red). The [2 + 2 + 2]-cyclotrimerization reaction is irreversible, limiting this method to the synthesis of aryl PCNs. In contrast, the reversibility of the SNAr reaction can be activated under certain conditions, allowing for the malleability and recyclability of polycyanurate networks. Both aryl PCNs and alkyl PCNs are accessible via the SNAr reaction. [Figure 2] SNAr in the cyanurate exchange reaction. a) Upon addition of 6 mol% TBD, the exchange reaction between TETA and methanol occurred and reached equilibrium within 40 h at 60 °C. Three new triazines substituted with one, two, or three methoxy groups were formed. b) The relative concentration of TETA (% of TETA remaining) versus time was plotted to obtain the kinetic profile of the SNAr reaction at different temperatures. c) Arrhenius plot and its linear fitting of the small molecule analog reaction. The activation energy was determined to be 62.5 kJ / mol. [Figure 3]Preparation and characterization of PCNs are shown. a) TETA monomer can be obtained by depolymerization of spent aryl-PCNs prepared by conventional trimerization or synthesized from commercially available cyanuric chloride. Alkyl-PCNs were synthesized by the SNAr reaction between TETA and various diols in anisole. b) Representative stress-strain curves of PCNs. c) Tan δ-temperature curves obtained by DMA testing of PCNs. d) Gel fraction testing of PCNs. e) Comparative FT-IR spectra of PCN-A6 after 48 hours of treatment with different solutions. f) Transparent films of PCN-A6 can be used as chemical-resistant films. After elution with different solvents (acetone, dichloromethane, and ethanol), PCN-A6 maintained the same transparency, while the polystyrene was significantly damaged. [Figure 4] Chemical recycling of PCN is shown. a) Closed-loop recycling of PCN. PCN can be depolymerized to form monomers, which can then be repolymerized to form recycled PCN with nearly identical chemical, thermal, and mechanical properties. Thus, the reversible SNAr reaction enables closed-loop polymer-polymer recycling of PCN. b) Photograph showing the selective recycling procedure for PCN-A6 from plastic waste containing HDPE, PP, and PS. PCN-A6 was cleanly converted to soluble monomers, while other plastics remained solid. Recycled TETA was reused to form PCN-A6. c) Comparison of 1H-NMR spectra of recycled TETA and newly synthesized TETA. The recycled TETA exhibited the same NMR proton signals as the newly synthesized TETA. d) The mechanical properties of virgin and recycled PCN are very similar. e) The recycled PCN exhibited nearly the same glass transition temperature as virgin PCN. [Figure 5]Closed-loop recycling of PCNs by kinetic SNAr is demonstrated. PCNs can be produced by the polymerization of diols and substituted triazine monomers. Treatment with monoalcohols or monophenols converts the PCNs to a monomer mixture, which can be further separated and purified if necessary. Because alkyl-OCNs undergo rapid isomerization under the reaction conditions, the traditional irreversible trimerization method is only applicable to aryl-PCNs. [Figure 6] Small molecule studies of cyanurate exchange are shown. a) Without TBD catalyst, no reaction between TETA and methanol was observed. b) When deuterated methanol was used as the solvent, the first step of the exchange reaction between TETA and deuterated methanol can be considered an irreversible pseudo-first-order reaction. [Figure 7] Figure 1 shows a comparison of FTIR spectra: a) FTIR spectra of PCN-A4 film and the corresponding monomers; b) FTIR spectra of PCN-A6 film and the corresponding monomers; c) FTIR spectra of PCN-A12 film and the corresponding monomers. [Figure 8] Chemical resistance tests of PCN films are shown. a) Chemical resistance test of PCN-A4 film. b) Chemical resistance test of PCN-A6 film. c) Chemical resistance test of PCN-A12 film. PCN films were cut into rectangles and immersed in different solutions (1M HCl, 1M NaOH, 30% H2O2, and 1M NaBH4). The upper, middle, and lower photographs were taken before immersion, after 48 hours of immersion, and after drying, respectively. No changes in appearance were observed in any of the PCN films. [Figure 9] Chemical recycling of PCN-A12 is shown. a) 1H-NMR spectra show clean film decomposition in ethanol (using TMB, 1,3,5-trimethoxybenzene as an internal standard) and high purity of recycled DO-12 and TETA. b) Nearly identical loss factors for the original and recycled PCN-A12 samples. c) Nearly identical FTIR spectra for the original and recycled PCN-A12 samples. [Figure 10]Chemical recycling of PCN-A4 is shown. a) 1H-NMR spectrum shows clean film decomposition in ethanol (using TMB as internal standard) and high purity of recycled TETA. b) Nearly identical loss factors for the original and recycled PCN-A4 samples. c) Nearly identical FTIR spectra for the original and recycled PCN-A4 samples. [Figure 11] Chemical recycling of PCN-A6 is shown. a) 1H-NMR spectrum shows clean film decomposition in ethanol (using TMB as internal standard) and high purity of recycled TETA. b) Nearly identical loss factors for the original and recycled PCN-A6 samples. c) Nearly identical FTIR spectra for the original and recycled PCN-A6 samples. [Figure 12] Kinetic study of cyanurate exchange in the solid state. a) In the presence of 23 mol% excess diol monomer and 10 mol% TBD, the bond exchange reaction can be induced under heating. b) Stress relaxation test of PCN-A6-m at various temperatures. c) Arrhenius plot and its linear fitting. The activation energy was calculated to be 76.7 kJ / mol. [Figure 13] 1H-NMR spectrum of TETA. [Figure 14] 13C-NMR spectrum of TETA. [Figure 15] 1 shows the 1H-NMR spectrum of TPhTA prepared by phenol exchange. [Figure 16] The 1H-NMR spectrum of the residue is shown. [Figure 17] The 1H-NMR spectrum of the mixture after stirring at 100°C for 16 hours is shown. [Figure 18] FT-IR spectra of DCBPA and PCN-DCBPA are shown. [Figure 19]H-NMR spectra of (a) the crude reaction mixture from PCN-DCPBA depolymerization, (b) TETA recovered from PCN-DCBPA upcycle, and (c) bisphenol A recovered from PCN-DCBPA upcycle. [Figure 20A] (a) 1H-NMR spectrum of the mixture in the kinetic test at 20°C. [Figure 20B] (b) 1H-NMR spectrum of the mixture in the kinetic test at 35°C. [Figure 20C] (c) 1H-NMR spectrum of the mixture in the kinetic test at 40°C. [Figure 20D] (d) 1H-NMR spectrum of the mixture in the kinetic test at 45°C. [Figure 20E] (e) 1H-NMR spectrum of the mixture in the kinetic test at 50°C. [Figure 21] 1 shows ln([C] / [C]) vs. t plots of cyanurate exchange at (a) 35°C, 40°C, 45°C, and 50°C, and (b) 20°C. [Figure 22] (a) Reaction of TETA with 3 equivalents of methanol. (b) GC-MS spectra of pure TETA (top) and the reaction mixture from (a) (bottom). [Figure 23] (a) Reaction of TETA in deuterated methanol (as solvent). (b) GC-MS spectra of pure TETA (top) and the reaction mixture from (a) (bottom). [Figure 24] The CP / MAS NMR spectra of PCNs are shown (the Teflon signal from the NMR vessel was observed at 116 ppm). The proportion of unreacted -OEt groups was estimated to be less than 10 mol% for PCN-A4, PCN-A6, and PCN-A12 from the relative peak intensities, which was consistent with the mass calculations above. [Figure 25] The tensile test curve of PCN is shown. [Figure 26] Storage modulus and tan delta curves of PCNs: (a) PCN-A4, (b) PCN-A6, and (c) PCN-A12. [Figure 27] DSC results show that the Tgs (onset) are 63°C, 44°C and -3°C for PCN-A4, PCN-A6 and PCN-A12, respectively. [Figure 28] FTIR spectra of PCNs before (light gray) and after (bottom) treatment: (a) PCN-A4, (b) PCN-A12. [Figure 29] UV-Vis spectra of PCN-A6, PS, and PSU. (a) Transmittance measurement before solvent drainage. (b) Transmittance measurement after solvent drainage. [Figure 30] TGA of PCN shows a mass loss of <4 wt% below 300 °C. [Figure 31] Characterization of PCN-BPA: (a) gel fraction test, (b) FT-IR spectrum. [Figure 32] The 1H-NMR spectrum of the decomposed PCN-A4 mixture shows approximately a 2:3 molar ratio of TETA and DO-4. [Figure 33] The 1H-NMR spectrum of the decomposed PCN-A6 mixture shows approximately a 2:3 molar ratio of TETA and DO-6. [Figure 34] The 1H-NMR spectrum of the decomposed PCN-A12 mixture is shown. The TETA and DO-12 are in a molar ratio of approximately 2:3. [Figure 35] Figure 1 shows the H-NMR spectrum of TETA recycled from PCN-A6 using a plastic waste stream. [Figure 36] Figure 1 shows the tensile test curve of recycled PCN. [Figure 37] Storage modulus and tan delta curves of recycled PCNs: (a) PCN-A4, (b) PCN-A6, and (c) PCN-A12. [Figure 38]Reprocessing of PCN-A6-m. (a) Image of forming PCN-A6-m platelets from polymer platelets. (b) FTIR spectra of original PCN-A6-m, reprocessed PCN-A6-m, and PCN-A6. (c) Tensile test curve of PCN-A6-m. (d) Storage modulus and tan delta curves of PCN-A6-m (solid line: original, dashed line: reprocessed). DETAILED DESCRIPTION OF THE INVENTION

[0016] As mentioned above, polymer reuse is considered crucial for improving the circular economy and environmental sustainability of plastics. Chemical recycling, with its ability to decompose polymers into precursors and building blocks, has attracted growing interest due to its potential for use as feedstocks, similar to petroleum-derived chemicals. While several approaches have been developed to create novel recyclable polymers by introducing cleavable or dynamic linkers, existing thermoset polymers have been widely overlooked because they are considered permanently bonded materials. Here, we performed a retrosynthetic analysis of conventional polycyanurate-based thermosets, changing the synthetic route from the conventional irreversible cyanate trimerization to the construction of C-O bonds via reversible nucleophilic aromatic substitution between alkoxyl triazines and alcohols. This approach to polycyanurate synthesis overcomes many limitations of the conventional trimerization method, including the limited substrate range to only aryl monomers, the high reaction temperature, and the difficulty of reshaping, repair, and recycling. Alkyl polycyanurate-based thermosets have been successfully prepared, exhibiting previously unattainable film properties with high chemical resistance under a variety of conditions and polymer-to-polymer closed-loop recyclability. The results described in this work demonstrate the potential for discovering "apparently dormant" dynamic bonds by retrosynthetic reversion to the chemical structures of traditional thermoset polymers. By harnessing these dynamic bonds to construct the same types of polymer networks, the scope of monomers can be significantly expanded, enabling previously unrecyclable materials to achieve sustainable properties without sacrificing their physical properties.

[0017] In one embodiment, the present invention comprises an alkyl- and / or aryl-linked crosslinked polymeric compound according to Formula (I), wherein the alkyl- and / or aryl-linked crosslinked polymeric compound according to Formula (I) is: [ka] (In the formula, X is independently N or C, and when all X are N, R 2 does not exist and all Xs are C, then R 2 exists, R 1 are independently CH, halogen, alkyl, or a diol selected from alkyl diols or aryl diols; R 1 at least two of which are independently alkyl diols or aryl diols; R 2 are independently H, CH, or an electron-withdrawing group; R 2 at least two of are independently electron-withdrawing groups; R 1 and R 2 optionally joined together to form one or more aromatic rings or one or more heterocyclic rings, one or more rings optionally substituted with at least one electron-withdrawing group, one or more rings of the compound further forming an electron-deficient cyclic core; The dashed lines represent possible double bond positions according to the configuration where X is N or C, including double bond positions that form an aromatic ring.

[0018] In another embodiment, the compound according to formula (I) is R 1 can comprise a compound selected from polyols, polythiols, bisphenol A, polyamines, 1,4-butanediol, 1,6-hexanediol, and 1,12-dodecanediol, or combinations thereof. In another embodiment, R of the compound of formula (I) can comprise a compound selected from polyols, polythiols, bisphenol A, polyamines, 1,4-butanediol, 1,6-hexanediol, and 1,12-dodecanediol, or combinations thereof. 1 may be selected from the following: [ka] (Wherein R is C 4~12 a linear alkyl, aromatic diol, polyol, polythiol or polyamine; n is greater than 1).

[0019] In another embodiment, the compound according to formula (I) is selected from the group consisting of NO, CN, CHO, halogen, COR 3 ,CONR3 , CH=NR 3 , (C=S)OR 3 , (C=O)SR 3 , CS2R 3 , SO2R 3 , SO2NR 3 , SO3R 3 , P(O)(OR 3 )2, P(O)(R 3 )2, or B(OR 3 )3, wherein R 3 is alkyl, aryl, or H. In a preferred embodiment, the compound according to formula (I) may include an electron withdrawing group selected from CN, CHO, or halogen.

[0020] As indicated above, in a preferred embodiment, the core of the compound of formula (I) is an aromatic ring, which can be represented by R 1 and R 2 and an additional ring structure formed between: In particular, in this embodiment, the core aromatic ring is electron-deficient. By way of example, compounds according to Formula I can include the following exemplary compounds having an electron-deficient core aromatic ring structure: [ka]

[0021] In one embodiment, the present invention comprises a compound comprising an alkyl-linked polyaryl ether network (PAE) formed by a plurality of alkyl-linked polyether compounds according to formula (III): [ka] wherein R is independently alkyl or aryl; 2 are independently electron-withdrawing groups. In another embodiment, R is C 4~12 It is a straight chain alkyl, and the electron-withdrawing groups are NO2, CN, CHO, halogen, and CO2R. 3 ,CONR 3 , CH=NR 3 , (C=S)OR3 , (C=O)SR 3 , CS2R 3 , SO2R 3 , SO2NR 3 , SO3R 3 , P(O)(OR 3 )2, P(O)(R 3 )2, or B(OR 3 ) 3 type (wherein R 3 is an alkyl, aryl, or hydrogen atom). In a preferred embodiment, the compound according to formula (III) can include an electron withdrawing group selected from CN, CHO, or halogen. In another preferred embodiment, the compound of formula (II) can form monomer units that can form alkyl-linked polyaryl ether networks (PAEs) as generally described herein.

[0022] Additional embodiments include methods of synthesizing alkyl-linked polyarylether monomers / networks comprising steps according to the following scheme: [ka] wherein R is independently alkyl or aryl; 2 are independently electron-withdrawing groups as described herein).

[0023] Additional embodiments of the present invention further include methods of synthesizing polyaryl ethers, comprising reacting a di / triaryl ether with two / three cyano groups and an alcohol by a nucleophilic aromatic substitution (SNAr) reaction. Additional embodiments of the present invention further include methods of synthesizing polyaryl ethers, comprising reacting a di / triaryl ether with two / three aldehyde groups and an alcohol by a nucleophilic aromatic substitution (SNAr) reaction. Additional embodiments of the present invention further include methods of synthesizing polyaryl ethers, comprising reacting a di / triaryl ether with two / three halogen groups and an alcohol by a nucleophilic aromatic substitution (SNAr) reaction.

[0024] In another preferred embodiment, the present invention provides: [ka] , (In the formula, R 1 is an alkyl or aryl diol). In a preferred embodiment, the alkyl diol of the compound of formula IA is: [ka] (Wherein R is C 4~12 In an alternative preferred embodiment, the alkyl diol of formula IA is selected from the group consisting of 1,4-butanediol, 1,6-hexanediol, and 1,12-dodecanediol.

[0025] In another embodiment, the present invention may include an alkyl-linked polycyanurate network (PCN formed by a plurality of alkyl-linked polycyanurate compounds according to Formula II): [ka]

[0026] In this preferred embodiment, n in formula II can be between 2 and 6.

[0027] Additional embodiments of the present invention include methods of synthesizing alkyl-linked polycyanurate monomers / networks, comprising steps according to the following scheme: [ka]

[0028] In this preferred embodiment, n in the above method can be between 2 and 6.

[0029] An additional embodiment of the present invention includes a method for synthesizing an alkyl-linked polycyanurate from an aryl polycyanurate, the method comprising steps according to the following scheme: [ka]

[0030] In this preferred embodiment, n in the above method can be between 2 and 6.

[0031] An additional embodiment of the present invention includes a method for synthesizing alkyl-linked polycyanurates, comprising forming a single bond between a triazine carbon and an oxygen by a nucleophilic aromatic substitution (SNAr) reaction.

[0032] An additional embodiment of the present invention includes a method of synthesizing an alkyl-linked polycyanurate, comprising reacting an alkyl cyanurate with an alcohol via a nucleophilic aromatic substitution (SNAr) reaction.

[0033] An additional embodiment of the present invention includes a method for synthesizing alkyl-linked polycyanurates, comprising reacting 2,4,6-triethoxy-1,3,5-triazine (TETA) with an alcohol in the presence of triazabicyclodecene (TBD).

[0034] An additional embodiment of the present invention includes a method for converting alkyl-backed PCN to its monomer subunits, the method comprising steps according to the following scheme: [ka]

[0035] Additional embodiments of the present invention include methods for upcycling aryl-PCN to TETA and bisphenol A (BPA) by the following scheme: [ka]

[0036] Section 1. Materials and equipment Acetone (99.5%), dichloromethane (99.5%), ethanol (200 prof), methanol (99.8%), hexane (98.5%), hydrogen peroxide (30%), hydrochloric acid (99.7%), sodium hydroxide (97.0%), tetrahydrofuran (99.9%), phenol (99%), and anhydrous potassium carbonate (99.0%) were purchased from Fisher Chemical. Cyanuric chloride (99%), 1,4-butanenaiol (99%), bisphenol A (99%), 1,4-dimethoxybenzene (99%), 1,12-dodecanediol (99%), sodium borohydride (97%), and 1,3,5-trimethoxybenzene (99.0%) were purchased from Sigma-Aldrich. Anisole (99.0%) and 1,6-hexanediol (97.0%) were purchased from TCI. Triazabicyclodecene (98%) and dicycanatobisphenol A (98%) were purchased from Combi-Blocks. p-Cresol (98%) was purchased from Alfa Aesar. Deuterated chloroform (99.8%), deuterated methanol (99.8%), and deuterated benzene (99.5%) were purchased from Cambridge Isotope Laboratories. All chemicals were used directly without further purification. Polyethylene samples were obtained from Caplugs WW-9, polypropylene samples from Thermo Scientific centrifuge tube racks, polystyrene samples from Sigma-Aldrich polystyrene Petri dishes, and polysulfone samples from Cambro polysulfone containers.

[0037] 1 H-NMR and 13C-NMR spectra were obtained on a Bruker Avance-III 300M NMR spectrometer. The chemical shifts of residual solvent signals, C6H6, CHCl3, or MeOH, were used as reference. Solid-state cross-polarization magic-angle spinning (CP / MAS) NMR spectra were recorded on a Varian INOVA 400 NMR spectrometer. Fourier transform infrared (FT-IR) spectra were obtained on an Agilent Cary 630 FTIR spectrometer. High-resolution mass spectra were obtained on a Waters SYNAPT G2 High Definition Mass Spectrometry System. Gas chromatography-mass spectrometry (GC-MS) was acquired on an Agilent 6890 Single Quad GC-Mass Spectrometer equipped with an Agilent VF-5-MS 30 m × 0.25 mm × 0.25 μm column. Dynamic mechanical analysis (DMA) studies were performed on a TA Instruments Q800. Differential scanning calorimetry (DSC) was performed on a Mettler Toledo DSC823. Ultraviolet-visible spectroscopy (UV-Vis) was measured on an Agilent Cary 5000 UV-Vis-NIR. Elastic modulus was measured from uniaxial tensile tests using an Instron 5965. Thermogravimetric analysis (TGA) was performed on a TA Instruments Thermogravimetric Analysis Q500.

[0038] Section 2. Monomer synthesis and characterization [ka] Preparation of 2,4,6-triethoxy-1,3,5-triazine (TETA) A suspension of cyanuric chloride (1.84 g, 10.0 mmol) and potassium carbonate (5.52 g, 40.0 mmol) in ethanol (40 mL) was heated with stirring at 100 °C under a nitrogen atmosphere in a Schlenk tube for 16 h. After the suspension was cooled to room temperature, the ethanol was removed by rotary evaporation. Hexane (60 mL) was added to the residue to dissolve the crude product. The mixture was filtered, and the solid was washed with hexane (40 mL). The combined filtrate was washed with water (2 × 50 mL) and brine (50 mL) and dried over anhydrous NaSO. After evaporation of the volatiles, the product was obtained as white crystals (1.79 g, 84.0%). 1 H-NMR (300MHz, CDCl3) δ4.41(q, J=7.0Hz, 2H), 1.37(t, J=7.1Hz, 3H); 13 C-NMR(75MHz, CDCl3)δ173.05, 64.35, 14.34;C9H 15 N3O3[M+H] + ESI-TOF MS calculated value: 214.1192, observed value: 214.1178. [ka]

[0039] Preparation of 2,4,6-triphenoxy-1,3,5-triazine (TPhTA) A suspension of cyanuric chloride (1.84 g, 10.0 mmol), phenol (4.70 g, 50.0 mmol), and potassium carbonate (6.90 g, 50.0 mmol) in acetone (40 mL) was heated with stirring at 60 °C under a nitrogen atmosphere in a Schlenk tube for 16 h. After cooling to room temperature, the acetone was removed by rotary evaporation. The resulting solid was stirred with 1 M aqueous potassium carbonate (100 mL) for 10 min. The yellowish suspension was filtered, and the off-white solid was washed with excess water and methanol and dried in a vacuum oven at 60 °C to give pure TPhTA as a white solid (3.25 g, 91.0%). 1 H-NMR (300 MHz, CDCl3) δ 7.43-7.29 (m, 6H), 7.25-7.19 (m, 3H), 7.17-7.08 (m, 6H). The data are consistent with previous literature reports.1 . [ka]

[0040] Preparation of 2,4,6-tris(p-tolyloxy)-1,3,5-triazine A suspension of cyanuric chloride (300 mg, 1.63 mmol), p-cresol (880 mg, 8.15 mmol), and potassium carbonate (1.12 g, 8.15 mmol) in acetone (15 mL) was heated with stirring at 60 °C under nitrogen in a Schlenk tube for 16 h. After cooling to room temperature, the acetone was removed by rotary evaporation. The resulting solid was stirred with 1 M aqueous potassium carbonate (20 mL) for 10 min. The yellowish suspension was filtered, and the off-white solid was washed with excess water and methanol and dried in a vacuum oven at 60 °C to give pure 2,4,6-tris(p-tolyloxy)-1,3,5-triazine as a white solid (3.25 g, 91.0%). 1 H-NMR (300 MHz, CDCl3) δ 7.17-7.12 (m, 6H), 7.04-6.98 (m, 6H), 2.34 (s, 9H). The data are consistent with previous literature reports. 2 . [ka]

[0041] Conversion of 2,4,6-tris(p-tolyloxy)-1,3,5-triazine to TPhTA A suspension of 2,4,6-tris(p-tolyloxy)-1,3,5-triazine (40 mg, 0.100 mmol) and potassium carbonate (1.0 mg, 7.2 μmol) in ethanol (1.0 g) was heated with stirring at 100°C for 24 hours in a 4 mL vial. The mixture was cooled to room temperature and stirred in 1 M aqueous potassium carbonate solution (20 mL) for 10 minutes. The suspension was filtered, and the off-white solid was washed with excess 1 M aqueous potassium carbonate solution, water, and methanol, then dried in a vacuum oven at 60°C to give TPhTA (32 mg, 90%). [ka]

[0042] Conversion of TPhTA to TETA A suspension of TPhTA (107 mg, 0.300 mmol) and potassium carbonate (5.0 mg, 36 μmol) in ethanol (5.0 mL) was heated with stirring at 90 °C for 16 h. The ethanol was then removed by rotary evaporation. An aliquot of the resulting concentrate was dissolved in 0.5 mL of CDCl 1 Analysis by H-NMR spectroscopy showed almost complete conversion of TPhTA to TETA and phenol. [ka]

[0043] Reaction of TETA with phenol TETA (107 mg, 0.500 mmol), potassium carbonate (5.0 mg, 36 μmol), and phenol (94.1 mg, 1.00 mmol) were stirred at 90° C. for 16 hours. 1 H-NMR spectrum showed that no reaction had occurred. [ka]

[0044] Preparation of commercially available aryl PCNs To investigate the possibility of upcycling PCN waste into TETA monomer, the commercially available cyanate resin dicycanatobisphenol A (DCBPA) was chosen as a model system. DCBPA (2.0 g, 7.2 mmol) was weighed into an ampoule. The ampoule was cooled to 77 K and sealed under vacuum (100 mTorr). After warming to room temperature, the monomer was cured at 180 °C for 1 h, 200 °C for 1 h, 220 °C for 1 h, and 250 °C for 2 h, according to the literature. 3The product was obtained as a translucent yellow solid. The FT-IR spectrum was consistent with literature reports, supporting the formation of PCN-DCBPA. c The resulting PCN-DCBPA was mechanically disintegrated to a powdery solid before upcycling. A suspension of PCN-DCBPA (100 mg) and potassium carbonate (10.0 mg, 72.5 μmol) in ethanol (10 mL) was stirred at 100 °C for 16 h. After cooling to room temperature, the ethanol was removed by rotary evaporation. 0.1 M NaOH solution (20 mL) and hexane (20 mL) were added, and the mixture was sonicated for 5 min. The organic solution was separated, and the aqueous solution was extracted twice with hexane (20 mL each). The organic solutions were combined, washed with brine, and then dried over anhydrous Na2SO4. After evaporation of the volatiles, TETA was obtained as white crystals (36.6 mg, 71%) (Figure 19b). The aqueous phase was neutralized with 12 M HCl and then extracted with ethyl acetate (3 × 20 mL). The organic solutions were combined, washed with brine, and then dried over anhydrous NaSO. After evaporation of the volatiles, bisphenol A was obtained as a pale yellow solid (72.3 mg, 88%) (Figure 19c).

[0045] Item 3. Small molecule model reactions [ka]

[0046] Thermodynamic equilibrium test of the kinetic cyanurate exchange reaction. TETA (128 mg, 0.601 mmol), methanol (58 mg, 1.80 mmol), and deuterated benzene (3.0 mL) were weighed into a 10 mL vial. The mixture was stirred at room temperature for 10 minutes. 1 mL of the above solution was added to NMR tube A. 1 mL of the above solution was added to NMR tube B along with TBD (1.7 mg, 12 μmol). The two NMR tubes were sealed and kept in the same oil bath at 60 °C. The reaction in the two NMR tubes was 1 The reaction was monitored by H NMR spectroscopy. No exchange reaction was observed in tube A over 24 hours. The reaction in NMR tube B gradually reached equilibrium after 40 hours.

[0047] Kinetic studies using small molecules To deuterated methanol (3.96 g) was added TBD (41.2 mg, 29.6 μmol) and 1,3,5-trimethoxybenzene (8.4 mg, 50 μmol). The mixture was sealed and stirred at room temperature until a clear solution was obtained. TETA (63.9 mg, 0.300 mmol) was added to the solution. The mixture was then sealed and stirred at room temperature for several minutes to completely dissolve the TETA. The resulting solution was transferred to five NMR tubes (Trt, T35, T40, T45, and T50) and stored in an ice bath to freeze the exchange reaction. Trt 1 After H-NMR measurement, T35, T40, T45, and T50 were simultaneously heated at 35°C, 40°C, 45°C, and 50°C, respectively. After 180 seconds, T35, T40, T45, and T50 were removed from the oil bath and cooled in an ice bath. 1 This process was repeated to obtain H-NMR spectra of T35, T40, T45, and T50. 1 H-NMR spectra were obtained at 180, 360, 660, and 1260 seconds. 1 The recording times for the H-NMR spectra were 1553, 3300, 5121, and 7300 seconds. The temperature of the NMR equipment was 20 °C. Due to a slight decrease in the electron-donating effect of the methoxy group, the -CH2- on the remaining ethoxy group showed a slightly higher chemical shift. Even though the -CH2- signals of different species overlap, the amount of unreacted TETA can be quantified using the integration of the rightmost peak of the TETA quartet (4.41 ppm) and the methoxy peak of 1,3,5-trimethoxybenzene (3.73 ppm).

[0048] S N Ar is formulated as a second-order reaction, as shown in Equation S1. MeOH-d4 is present in large excess, and proton exchange proceeds as S N Since the reaction rate of MeOH-d4 is much faster than that of Ar, the concentration of MeOH-d4 was assumed to be constant. Equation S1 can then be simplified to equation S2, where the experimental rate constant k exp is equal to the rate constant times the methanol concentration. If the initial concentration of TETA is [C]0, then equation S2 can be further rewritten as equation S3.

number

number

number

[0049] The experimental rate constants at different temperatures were calculated by plotting ln([C] / [C]) versus time and are listed in Table 1. [Table 1]

[0050] Reaction activation energy (E a The Arrhenius equation (Equation S4) and its equivalent form (Equation S5) were used to calculate E (where A and B are fitting parameters, and R is the gas constant, 8.31 J / (mol K)). By fitting to the experimental data in Figure 2c, E a was calculated to be 62.7 kJ / mol.

number

number

[0051] GC-MS measurement GC-MS experiments were carried out under a nitrogen flow at a rate of 1 mL / min. The temperature was held at 60°C for 1.5 min, then increased to 325°C at 15°C / min and held at 325°C for 1 min. 1To confirm the H-NMR analysis, three samples were analyzed by GC-MS, and four different alkoxy-substituted triazines were observed to be formed when reacted with 3 equivalents of methanol for 40 hours. These were assigned to 3M-TA, 2M-TA, M-TA, and TETA by mass spectrometry, as shown in Figure 22. When TETA was reacted with a large excess of methanol, only one major peak was observed by GC. The mass spectrum, as shown in Figure 23, indicates that all of the TETA was converted to 3MD-TA. Therefore, the GC-MS results are consistent with the above. 1 This is consistent with the H-NMR results.

[0052] Preparation of sample TETA: TETA was dissolved in acetonitrile (1 mg / mL).

[0053] Preparation of samples from thermodynamic equilibrium tests: After 40 hours of reaction, the solution was removed from tube B, the solvent was evaporated under high vacuum, and then diluted with acetonitrile (1 mg / mL). Preparation of samples from kinetic tests: A solution of T50 was heated overnight and then diluted directly with acetonitrile (1 mg / mL).

[0054] Section 4. Polymer synthesis and characterization Preparation of PCN-A4 films A mixture of TETA (853 mg, 4.00 mmol), 1,4-butanediol (DO-4) (541 mg, 6.00 mmol), and TBD (33.5 mg, 0.24 mmol) in anisole (3 mL) was stirred at 100 °C. After 15 min of stirring, the mixture became a homogeneous solution. The solution was then poured into a Petri dish (5 cm diameter). The solvent was slowly evaporated at 120 °C for 14 h, yielding a transparent, defect-free polycyanurate film. The film was further cured using a heat press at 130 °C for 4 h under atmospheric pressure. A transparent film (926 mg) was obtained. Approximately 9.4% of the ethoxy groups remained unreacted.

[0055] Preparation of PCN-A6 films A mixture of TETA (853 mg, 4.00 mmol), 1,6-hexanediol (DO-6) (709 mg, 6.00 mmol), and TBD (33.5 mg, 0.24 mmol) in anisole (3 mL) was stirred at 100 °C. After 5 min of stirring, the mixture became a homogeneous solution. The solution was then poured into a Petri dish (5 cm diameter). The solvent was slowly evaporated at 120 °C for 14 h, yielding a transparent, defect-free PCN film. The film was further cured using a heat press at 130 °C for 4 h under atmospheric pressure. A transparent film (1.106 g) was obtained. Approximately 5.4% of the ethoxy groups remained unreacted.

[0056] Preparation of PCN-A12 films A mixture of TETA (569 mg, 2.67 mmol), 1,12-dodecanediol (DO-12) (809 mg, 4.00 mmol), and TBD (22.2 mg, 0.16 mmol) in anisole (3 mL) was stirred at 100 °C. After 5 min of stirring, the mixture became a homogeneous solution. The solution was then poured into a Petri dish (5 cm diameter) and placed in an oven. The solvent was slowly evaporated at 120 °C for 8 h, yielding a transparent, defect-free polycyanurate film. The film was further cured using a heat press at 130 °C for 4 h under atmospheric pressure. A transparent film (1.049 g) was obtained. Approximately 4.3% of the ethoxy groups remained unreacted.

[0057] Tensile test The specimens were cut into small pieces of approximately 3.5 mm x 0.3 mm x 20 mm from the original pad of PCN. Tensile tests were performed at room temperature with a strain rate of 2.5% / min until fracture.

[0058] Dynamic Mechanical Analysis (DMA) Testing The samples were cut into small pieces of approximately 3 mm × 0.3 mm × 10 mm from the original pad of PCN. The samples were equilibrated at -50°C for 5 minutes. Then, they were heated to 120°C for PCN-A4 and to 90°C for PCN-A6 and PCN-12 at a frequency of 1 Hz and a rate of 2°C / min.

[0059] Differential Scanning Calorimetry (DSC) Testing Samples were placed in TZero aluminum pans and scanned against an empty reference pan. After equilibration at -50°C, the temperature was increased at 10°C / min to 160°C.

[0060] Gel fraction test The PCN was cut into small pieces and immersed in various solvents (tetrahydrofuran, acetone, dichloromethane, and ethanol, 2 mL). After 48 hours at room temperature, the solvent was decanted, and the residue was washed five times with the same amount of solvent and then dried in a vacuum oven at 60 °C for 4 hours. The weights before and after the test were recorded (Table 2). [Table 2]

[0061] Chemical Resistance Test The PCN was cut into rectangular pieces (approximately 30 mg) and immersed in various solutions (2 mL of 1 N HCl, 1 N NaOH, 30% H2O2, and 1 M NaBH4 in THF). After 48 h at room temperature, the solution was decanted, and the residue was washed five times with excess water and three times with acetone before being dried in an oven at 120 °C for 4 h. The weights before and after the test were recorded (Table 3). Optical images before and after the test were recorded in Extended Data Figure 3. FT-IR spectra before and after the test are shown in Figure 3e and Figure 25. [Table 3]

[0062] Solvent spill test PCN-A6, polystyrene (PS), and polysulfone (PSU) were cut into rectangles (40 mm x 30 mm) and their UV-Vis transmittance was measured. Then, 0.5 mL of acetone, dichloromethane, and ethanol were poured into the plastics, followed by UV-Vis transmittance measurements. As shown in Figure 29, virgin PCN-A6 and PS both exhibited transmittances greater than 90% in the visible light range (400–800 nm). PSU exhibited fair transparency in the longer wavelength range but significant absorption below 550 nm, consistent with its amber color. Upon solvent bleed, no significant change was observed for PCN-A6 and PSU, while PS exhibited a sharp drop in transmittance. These results clearly demonstrate the excellent solvent resistance of PCN, which is similar to that of commercially available PSU.

[0063] Thermogravimetric Analysis (TGA) Testing Samples (approximately 3 mg) were tested at a temperature ramp rate of 10°C / min under a constant flow of nitrogen gas.

[0064] Synthesis of PCN-BPA A mixture of TPhTA (715 mg, 2.00 mmol), bisphenol A (685 mg, 3.00 mmol), and TBD (17 mg, 0.12 mmol) in 1,4-dimethoxybenzene (4.0 g) was stirred at 100 °C. After 15 min, the mixture became a homogeneous solution. The solution was then poured into a Petri dish (5 cm diameter). The solvent was slowly evaporated at 150 °C for 4 h, 180 °C for 2 h, 200 °C for 2 h, 220 °C for 2 h, and 250 °C for 2 h, yielding a yellowish, transparent, defect-free polycyanurate film. The appearance of aliphatic CH absorption and the disappearance of -OH absorption indicate the formation of PCN-BPA. 4 .

[0065] Section 5. Chemical recycling of PCN Decomposition of PCN-A4 PCN-A4 (57.4 mg), potassium carbonate (3.0 mg, 22 μmol), and 1,3,5-trimethoxybenzene (TMB) (49.0 mg, 0.291 mmol) were weighed into a 10 mL vial. Ethanol (3 mL) was added. The mixture was treated as described in the method for the decomposition procedure of PCN. 1 The H-NMR spectrum indicates a 2:3 molar ratio of TETA to diol. The original polymer contains approximately 8.9 mol% of unreacted -OEt groups, calculated based on the mass of TMB.

[0066] Chemical recycling of TETA from PCN-A4 PCN-A4 (469 mg) and potassium carbonate (32.0 mg, 0.232 mmol) in ethanol (25 mL) were stirred at 90 °C for 16 h. After the mixture was cooled to room temperature, the solid was filtered and washed with additional ethanol. Most of the ethanol was removed by rotary evaporation, but not to dryness to prevent repolymerization. Residual ethanol was then removed by high vacuum at room temperature. Hexane (10 mL) was added, and the mixture was sonicated for 5 min. The hexane solution was separated, and the DO-4 layer was washed twice more with hexane (5 mL). The combined hexane filtrate was washed with brine, dried over anhydrous NaSO, and concentrated to give TETA as off-white crystals (385 mg, 81% recovery).

[0067] Decomposition of PCN-A6 PCN-A6 (52.7 mg), potassium carbonate (3.0 mg, 22 μmol), and 1,3,5-trimethoxybenzene (TMB) (37.7 mg, 0.224 mmol) were weighed into a 10 mL vial. Ethanol (3 mL) was added. The mixture was treated as described in the method for the decomposition procedure of PCN. 1 The H-NMR spectrum indicates a 2:3 molar ratio of TETA to diol. The original polymer contains approximately 5.8 mol% of unreacted -OEt groups, calculated based on the mass of TMB.

[0068] Chemical recycling of TETA from PCN-A6 PCN-A6 (524 mg) and potassium carbonate (30.0 mg, 0.217 mmol) were stirred in ethanol (25 mL) at 90 °C for 16 h. The mixture was treated as described above for the chemical recycling procedure of PCN-A4. TETA was recovered as white crystals (381 mg, 86% recovery yield).

[0069] Decomposition of PCN-A12 PCN-A12 (66.5 mg), potassium carbonate (3.0 mg, 22 μmol), and 1,3,5-trimethoxybenzene (TMB) (31.4 mg, 0.187 mmol) were weighed into a 10 mL vial. Ethanol (3 mL) was added. The mixture was treated as described in the method for the decomposition procedure of PCN. 1 The H-NMR spectrum indicates a 2:3 molar ratio of TETA to diol. The original polymer contains approximately 5.2 mol% of unreacted -OEt groups, calculated based on the mass of TMB.

[0070] Chemical recycling of DO-12 and TETA from PCN-A12 PCN-A12 (506 mg) and potassium carbonate (25.0 mg, 0.181 mmol) were stirred in ethanol (25 mL) at 90 °C for 16 h. After the mixture was cooled to room temperature, the solid was filtered and washed with additional ethanol. Most of the ethanol was removed by rotary evaporation, but not to dryness to prevent repolymerization. High vacuum was then applied at room temperature to remove the remaining ethanol. Hexane (10 mL) was added, and the mixture was sonicated for 5 min. A white solid precipitated, which was then filtered and washed with an additional 20 mL of hexane and water. The resulting white solid was dried under high vacuum to give DO-12 as a white powder (385 mg, 95% recovery). The filtrate was transferred to a vial, and all volatiles were removed by rotary evaporation to give TETA as off-white crystals (246 mg, 87% recovery).

[0071] Modification of PCN The procedure was the same as for the synthesis of PCN, but using recycled monomers. Defect-free, transparent PCN was obtained.

[0072] Characterization of modified PCN Tensile and DMA tests were performed, and as shown in Figures 36-37, no obvious changes in chemical and mechanical properties were observed compared to the original PCN. [Table 4]

[0073] Item 6. Dynamic Test of PCN-A6-m Synthesis of PCN-A6-m The preparation of PCN-A6-m was the same as PCN-A6, except that 824 mg (3.86 mmol) of DO-6 and 201 mg (1.44 mmol) of TBD were used. In this case, the ratio between alkoxy and free hydroxyl groups was approximately 3:0.7. The catalyst amount was 10 mol% relative to the alkoxy group. FTIR spectra showed a -OH at 3400 cm -1 There is a clear bump nearby.

[0074] Reworking PCN-A6-m Approximately 300 mg of PCN-A6-m was cut into small pieces and used to fill a rectangular Teflon mold. The mold was heat-pressed under conditions of 300 kPa and 120°C for 3 hours to obtain a defect-free film from recycled PCN-A6-m. The recycled film had very similar FT-IR spectra, tensile strength, and T values ​​to virgin PCN-A6-m. g The results are shown in Figure 38 and Table 5. [Table 5]

[0075] Stress relaxation test The PCN-A6-m specimen was cut into small pieces measuring approximately 3.5 mm x 0.3 mm x 6 mm. After equilibrating at the set temperature for 30 minutes, the specimen was tensioned to a strain of 5%. The specimen was allowed to relax to approximately 37% of its original relaxed modulus (1 / e) at each temperature (110°C, 120°C, 130°C, and 140°C).

[0076] Unless otherwise stated, a structure depicted herein is also meant to include all isomeric (e.g., enantiomeric, diastereomeric, and geometric (or conformational)) forms of that structure, such as the R and S configurations of each asymmetric center, Z and E double bond isomers, and Z and E conformers. Accordingly, single stereochemical isomers as well as enantiomeric, diastereomeric, and geometric (or conformational) mixtures of the present compounds are within the scope of the invention. Unless otherwise stated, all tautomeric forms of the present compounds are within the scope of the invention. Additionally, unless otherwise stated, structures depicted herein are also intended to include compounds that differ only in the presence of one or more isotopically enriched atoms. For example, compounds having the present structures containing the replacement of hydrogen with deuterium or tritium, or the replacement of a carbon with a C- or C-enriched carbon are within the scope of the invention. Such compounds are useful, for example, as analytical tools, probes in biological assays, or as therapeutic agents according to the present invention. The term "stereoisomer" refers to a molecule that is an enantiomer, diastereomer, or geometric isomer of a molecule. Stereoisomers differ from structural isomers in that they differ not with regard to the number or kinds of atoms in the molecule's structure, but with regard to the spatial arrangement of the molecule's atoms. Examples of stereoisomers are the (+) and (-) forms of an optically active molecule.

[0077] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a compound" includes a plurality of such compounds, reference to "the method" includes reference to one or more methods, method steps, and equivalents thereof known to those skilled in the art, and so forth.

[0078] Similarly, the word "or" is intended to include "and" unless the context clearly dictates otherwise. Thus, "including A or B" means including A, or B, or A and B. Furthermore, use of the term "including" and other related forms such as "includes" and "included" is not limiting.

[0079] As used herein, the term "about" is a flexible term, similar in meaning to "approximately" or "nearly." The term "about" indicates that precision is not required, but rather that variation is intended. Thus, as used herein, the term "about" means within one or two standard deviations from a specifically stated value, or within a range of ± up to 20%, up to 15%, up to 10%, up to 5%, or up to 4%, 3%, 2%, or 1% relative to a specifically stated value.

[0080] As used herein, the term "electron-withdrawing group" means a functional group that has the ability to attract electrons, especially when it is a substituent of an aromatic group, such as a group of the type NO, CN, CHO, halogen, COR, CONR, CH=NR, (C=S)OR, (C=O)SR, CS,R, SO, SONR, SO,R, P(O)(OR), P(O)(R), or B(OR), where R is an alkyl, aryl, or hydrogen atom, among others.

[0081] The term "alkyl" refers to a saturated linear monovalent hydrocarbon moiety having 1 to 20, typically 1 to 15, and often 1 to 10 carbon atoms, or a saturated branched monovalent hydrocarbon moiety having 3 to 20, typically 3 to 15, and often 3 to 10 carbon atoms. Exemplary alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, 2-propyl, tert-butyl, pentyl, iso-pentyl, hexyl, and the like.

[0082] As used herein, the term "aryl" or "aromatic moiety" refers to an aromatic ring system that may further contain one or more non-carbon atoms. These are typically 5- or 6-membered isolated rings or 8- or 10-membered bicyclic groups, which may be substituted. Thus, contemplated aryl groups include (e.g., phenyl, naphthyl, etc.) and pyridyl. Additionally, contemplated aryl groups may be fused (i.e., covalently bonded to two atoms on the first aromatic ring) with one or two 5- or 6-membered aryl or heterocyclic groups, and thus referred to as "fused aryl" or "fused aromatic."

[0083] Aromatic groups containing one or more heteroatoms (typically N, O, or S) as ring members can be referred to as heteroaryl or heteroaromatic groups. Typical heteroaromatic groups include monocyclic C5-C6 aromatic groups such as pyridyl, pyrimidyl, pyrazinyl, thienyl, furanyl, pyrrolyl, pyrazolyl, thiazolyl, oxazolyl, isothiazolyl, isoxazolyl, and imidazolyl, and fused bicyclic moieties formed by fusing one of these monocyclic groups with either a phenyl ring or a heteroaromatic monocyclic group to form C8-C10 bicyclic groups such as indolyl, benzimidazolyl, indazolyl, benzotriazolyl, isoquinolyl, quinolyl, benzothiazolyl, benzofuranyl, pyrazolopyridyl, pyrazolopyrimidyl, quinazolinyl, quinoxalinyl, cinnolinyl, and the like. Any monocyclic or fused-ring bicyclic system with aromatic character, with electrons distributed throughout the ring system, is included within this definition. Also included are bicyclic groups in which at least the ring directly attached to the rest of the molecule is aromatic in character.Typically, the ring systems contain from 5 to 12 ring atoms.

[0084] As used herein, the terms "heterocycle," "cycloheteroalkyl," and "heterocyclic moiety" are used interchangeably herein and refer to any compound in which multiple atoms form a ring through multiple covalent bonds, and the ring contains at least one atom other than a carbon atom as a ring member. Particularly contemplated heterocycles include five- and six-membered rings having nitrogen, sulfur, or oxygen as the non-carbon atom (e.g., imidazole, pyrrole, triazole, dihydropyrimidine, indole, pyridine, thiazole, tetrazole, etc.). Typically, these rings contain zero to one oxygen or sulfur atom, at least one, typically two to three carbon atoms, and up to four nitrogen atoms as ring members. Furthermore, contemplated heterocycles may be fused (i.e., covalently bonded to two atoms on the first heterocycle) to one or two carbocyclic or heterocyclic rings, and thus, as used herein, are referred to as "fused heterocycles" or "fused heterocyclic rings" or "fused heterocyclic moieties." When the rings are aromatic, they may be referred to herein as "heteroaryl" or heteroaromatic groups.

[0085] As used herein, "alcohol" or "alcohols" refers to compounds having the general formula R-OH, where R is any organic moiety (such as an alkyl group, an aryl group, a silyl group, etc.), including those with heteroatom-containing substituents. In certain embodiments, R represents an alkyl group, an alkenyl group, an aryl group, or an alcohol group. In certain embodiments, the term "alcohol" or "alcohols" may refer to a group of compounds having the general formula above and varying carbon lengths. As used herein, the term "alkanol" refers to an alcohol where R is an alkyl group. In one preferred embodiment, alkyl PCNs are S N By Ar reaction, it can be prepared using alcohols such as 1,4-butanediol (DO-4), 1,6-hexanediol (DO-6), and 1,12-dodecanediol (DO-12) as linkers (Figure 3a).

[0086] As used herein, the term "alkoxy" refers to a hydrocarbon group linked via an oxygen atom, e.g., -O-Hc, where the hydrocarbon portion Hc may have any number of carbon atoms, typically 1 to 10 carbon atoms, may further include double or triple bonds, may contain one or two oxygen, sulfur, or nitrogen atoms in the alkyl chain, and may be substituted with aryl, heteroaryl, cycloalkyl, and / or heterocyclyl groups. For example, suitable alkoxy groups include methoxy, ethoxy, propyloxy, isopropoxy, methoxyethoxy, benzyloxy, allyloxy, and the like.

[0087] By "cyanate ester resin" is meant a bisphenol or polyphenol, such as a novolak derivative, in which the hydrogen atom of the phenolic OH group has been replaced with a cyano group, resulting in an --OCN group. Examples include bisphenol A dicyanate esters, such as Lonza's Primaset® BADCy or Huntsman's AroCy® B-10, and other Primaset® or AroCy® types, such as bis(3,5-dimethyl-4-cyanatophenyl)methane (AroCy® M-10), 1,1-bis(4-cyanatophenyl)ethane (AroCy® L-10), 2,2-bis(4-cyanatophenyl)-1,1,1,3,3,3-hexafluoropropane (AroCy® F-10), 1,3-bis(1-(4-cyanatophenyl)-1-methylethylidene)benzene (AroCy® XU-366), di(4-cyanatophenyl)thioether (AroCy® XU-366), and bis(4-cyanatophenyl)-1-methylethylidene-2-methylpropane (AroCy® XU-366). Examples of suitable bis(4-cyanatophenyl) ether include, but are not limited to, those commercially available as bis(4-cyanatophenyl)dichloromethylidenemethane (AroCy® RDX-80371, AroCy® T-10), bis(4-cyanatophenyl)dichloromethylidenemethane (AroCy® RD98-228), bis(4-cyanatophenyl)octahydro-4,7-methanoindene (AroCy® XU-71787.02L), as well as bis(4-cyanatophenyl)methane, bis(3-methyl-4-cyanatophenyl)methane, bis(3-ethyl-4-cyanatophenyl)methane, di(4-cyanatophenyl)ether, 4,4-dicyanatobiphenyl, 1,4-bis(1-(4-cyanatophenyl)-1-methylethylidene)benzene, and resorcinol dicyanate. See also, for example, US Pat. No. 10,233,139 to Evonik Technochemie GmbH.

[0088] As used herein, "triazine" refers to a nitrogen-containing heterocycle. More specifically, "triazine" refers to a six-membered ring having three carbon atoms and three nitrogen atoms as ring members. "Triazine" is intended to include substituted triazines or triazine derivatives, with melamine or aminoplast being particularly preferred triazines for use as the first monomer in the polymers of the present invention.

[0089] As used herein, the term "diol" refers to a compound containing two hydroxyl groups (-OH groups).

[0090] As used herein, the term "thermoset" refers to a polymer obtained by irreversibly solidifying ("curing") a soft, solid, or viscous liquid prepolymer (resin).

[0091] As used herein, the term "substituted" refers to the replacement of a non-substituent hydrogen atom with a functional group; specifically contemplated functional groups include nucleophilic groups (e.g., -NH, -OH, -SH, -CN, etc.), electrophilic groups (e.g., C(O)OR, C(X)OH, etc.), polar groups (e.g., -OH), non-polar groups (e.g., heterocycle, aryl, alkyl, alkenyl, alkynyl, etc.), ionizable groups (e.g., -NH), halogens (e.g., -F, -Cl), NHCOR, NHCONH, OCHCOOH, OCHCONH, OCHCONHR, NHCHCOOH, NHCHCONH, NHSOR, OCH-heterocycle, POH, SOH, amino acids, and all chemically reasonable combinations thereof. Moreover, the term "substituted" includes multiple degrees of substitution, and where multiple substituents are disclosed or claimed, the substituted compound may be independently substituted with one or more of the disclosed or claimed substituent moieties.

[0092] Further to the disclosure herein, in certain embodiments, a substituted group has 1, 2, 3, or 4 substituents, 1, 2, or 3 substituents, 1 or 2 substituents, or 1 substituent. It is understood that compounds arrived at by defining a substituent having a further substituent thereon in all of the above-defined substituents (e.g., a substituted aryl having a substituted aryl group as a substituent that is itself substituted with a substituted aryl group that is further substituted with a substituted aryl group) are not intended to be included herein. In such cases, the maximum number of such substitutions is 3. For example, the sequential substitution of substituted aryl groups specifically contemplated herein is limited to substituted aryl-(substituted aryl)-substituted aryl.

[0093] The invention, having generally been described above, will be more readily understood by reference to the following examples, which are included solely for purposes of illustrating specific embodiments of the invention. The examples are not intended to limit the invention, as one skilled in the art will recognize from the above teachings and the following examples that other techniques and methods may be employed without departing from the scope of the claimed invention. Indeed, while the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention as encompassed by the appended claims. [Example]

[0094] Example 1: Dynamic nucleophilic aromatic substitution studies on small molecule model compounds. S for heterocyclic substrates such as pyridines, pyrimidines, and triazines N Nucleophilic aromatic substitution (Ar) has been widely performed in medicinal chemistry. However, the application of such reactions to polymer synthesis has not been extensively explored. Bond exchange between phenols and aryloxy-substituted triazines has been previously demonstrated, but dynamic S-type reactions between alcohols and cyanurates have not been demonstrated. NIn this context, the present study is the first to report the S-Ar reaction between alkyl cyanurates and alcohols. N 2,4,6-Triethoxy-1,3,5-triazine (TETA) and methanol were used as model compounds to test the reversibility of Ar. We first demonstrated the thermodynamic equilibrium of the cyanurate exchange reaction (Fig. 2a). In the absence of a catalyst, the exchange reaction between TETA and methanol does not occur at 60 °C (Fig. 6). In contrast, the addition of a catalytic amount of triazabicyclodecene (TBD) immediately led to the exchange of ethoxy and methoxy groups, demonstrating the reversibility of such a S. N The reversibility of the Ar reaction was demonstrated. After heating a diluted solution of TETA and methanol in a 1:3 molar ratio at 60 °C for 40 h, four triazines were obtained in a molar ratio of approximately 1:3:3:1, with up to three ethoxy groups replaced by methoxy groups. This result indicates that all three ethoxy groups are reactive and the exchange reaction reaches equilibrium.

[0095] The kinetics of cyanurate exchange was investigated at various reaction temperatures (Figure 6). 1 The decrease in the intensity of the TETA proton signal in the H-NMR spectrum was monitored over time. N We tested the Ar reaction and proposed a concerted second-order exchange mechanism. Considering the large excess of methanol and the fast proton transfer between the alcohol and TBD, we assumed the reaction to be an irreversible pseudo-first-order reaction and calculated the experimental rate constant from the decrease in TETA concentration (Figure 2b and Table 1). Using the rate constants measured at different temperatures, an Arrhenius plot and its linear fitting calculated the activation energy of the exchange reaction to be 62.5 kJ / mol (Figure 2c).

[0096] Example 2: Synthesis and characterization of PCNs. Unlike well-known aryl PCNs, alkyl PCNs have not been feasible under conventional [2 + 2 + 2] trimerization conditions due to the undesired isomerization of alkyl cyanate monomers to isocyanates. Alkyl PCNs have higher impact toughness than conventional aryl PCNs, but until now, no effective synthetic method has been available. The present inventors hypothesized that the method of the present invention could provide alkyl PCNs with a variety of thermal and mechanical properties that are difficult to achieve using conventional cyclotrimerization methods.

[0097] Therefore, the dynamic S of triazine and various diols N We attempted to synthesize alkyl PCNs using the Ar reaction. 1,4-butanediol (DO-4), 1,6-hexanediol (DO-6), and 1,12-dodecanediol (DO-12) were used as linkers, and S N Various alkyl PCNs were prepared by Ar reaction (Figure 3a). TBD (2 mol% relative to the cyanurate group) was added as a catalyst. The Fourier transform infrared (FT-IR) spectrum of the PCNs showed a peak at 1130 cm -1 COC elastic band, 815cm -1 and 1550cm -1 The presence of a triazine band at 725 cm -1 The methyl rock band disappeared (Figure 7), supporting the cyanurate structure in which the ethoxy groups were substituted with alkyldiols. Solid-state cross-polarization magic-angle spinning (CP / MAS) NMR spectra indicated that only a small amount (4-10 mol%) of the ethoxy groups remained unreacted. Thermogravimetric analysis (TGA) showed a mass loss of <4 wt% below 300 °C, indicating the polymer's high thermal stability and the absence of volatile low-molecular-weight residues.

[0098] The mechanical properties of PCN were measured using uniaxial tension. PCN-A4 exhibited a fracture elongation of over 45%, a tensile strength of 45 MPa, and a Young's modulus of 1.1 GPa, making it extremely ductile compared to typical brittle aryl PCNs (approximately 5%, 90 MPa, and 3.1 GPa, respectively). As the structural flexibility of the hydrocarbon chains between the triazine nodes increases, the PCN becomes softer and more ductile (Figure 3b). The glass transition temperature (T g The gel fractions of all three PCNs in various solvents measured by solvent extraction were approximately 99% (Fig. 3d and Table 2), supporting a highly cross-linked structure (Fig. 3d and Table 2).

[0099] Chemical resistance tests were also performed. Even after 48 hours under acidic (1N HCl), basic (1N NaOH), oxidative (30% H2O2), and reductive (1M NaBH4 in THF) conditions, the PCNs retained nearly the same appearance, weight, and chemical structure, as evidenced by their FT-IR spectra, demonstrating their high resistance to various chemical attacks (Figures 3e and 8). Thus, alkyl PCNs can be used as protective panels with high transparency and solvent / chemical resistance. Transparent PCN-A6 was cut into a rectangle and used to cover a digital display (Figure 3f). Direct contact with common organic solvents (e.g., acetone, dichloromethane, ethanol, etc.) did not alter the film's shape or transparency, similar to that of polysulfone. In contrast, transparent polystyrene films were severely attacked. Such S N It should be noted that the Ar approach can also provide aryl PCNs. As an example, PCN-DCBPA was successfully prepared by the condensation of 2,4,6-triphenoxy-1,3,5-triazine with bisphenol A (BPA).

[0100] Example 3: Closed-loop recycling. Next, we investigated the recyclability of this material and found that these PCNs could be efficiently converted back to monomers when refluxed in ethanol (Figure 4a). For example, PCN-A6 could be slowly decomposed in refluxing ethanol over two days. Adding 5 wt% potassium carbonate as a base to deprotonate the ethanol accelerated the process, and PCN was decomposed in ethanol within 16 hours and converted to monomers almost quantitatively. Both diol and TETA monomers could be easily recovered from the mixture after removing ethanol in approximately 90% isolated yield. Long-chain diols (e.g., 1,12-dodecanediol) precipitated from the mixture upon addition of hexane, yielding clean diols as solids. TETA could be recovered in high purity from the hexane solution (Figures 9–11) and could be reused directly. Short-chain diols (e.g., 1,4-butanediol) could be separated from TETA by liquid-liquid extraction with hexane to yield highly concentrated crude products that could be further purified by distillation.

[0101] To demonstrate the feasibility of selectively recycling PCN in mixed plastic waste streams, we used a sample containing equal amounts of PCN-A6, PP (polypropylene), HDPE (high-density polyethylene), and PS (polystyrene) mixed plastics. After refluxing the plastic mixture with potassium carbonate (5 wt%) in ethanol, PCN-A6 was completely depolymerized to TETA and 1,6-hexanediol, which could be separated from the other plastics by filtration and extraction (Figure 4b). High-purity TETA (Figure 4c) was recovered by simple evaporation and extraction. Recycled PCN (PCN-Ax-Re) (x = 4, 6, or 12) prepared using the recovered TETA exhibited the same FT-IR absorption as virgin PCN (Figures 9-11). The mechanical properties and T of the recycled PCN were analyzed. g The yields of the PCNs were also comparable to those of the original PCNs (Figures 4d, 4e, and Table 4). A similar recycling method was also used to depolymerize conventional aryl polycyanurate wastes such as PCN-DCBPA to form high-purity TETA (Figure 3a). These results are consistent with the results of S NWe clearly demonstrate that our strategy utilizing Ar reactions is generally applicable to a wide range of PCNs and offers convenient closed-loop recyclability of this important class of thermosets.

[0102] Example 4: Materials and Methods. General procedure for PCN film synthesis: TETA (1.0 equiv.), diol (1.5 equiv.), and TBD catalyst (0.06 equiv.) were stirred in anisole at 100 °C for 15–30 min. The resulting homogeneous solution was then poured into a glass Petri dish. The solvent was slowly evaporated in an oven at 120 °C for 14 h, yielding a transparent, defect-free PCN film. The film was further cured in a heat press at 130 °C under atmospheric pressure for 4 h.

[0103] Gel fraction and chemical resistance tests: PCN films were cut into rectangular pieces and immersed in various organic solvents or solutions. The mixtures were kept at room temperature for 48 hours without disturbance. Afterwards, the solutions were decanted. For the gel fraction test, the residue was washed five times with excess solvent. For the chemical resistance test, the residue was washed three times with water and acetone. The remaining solid was dried in an oven at 120°C for four hours and weighed. The weight difference between the samples before and after treatment was calculated.

[0104] Decomposition of PCN: PCN film, potassium carbonate (5 wt. % relative to the PCN film), and internal standard (1,3,5-trimethoxybenzene) were stirred in ethanol (approximately 400 wt. % relative to the PCN film) at 90 °C for 16 h. After the mixture was cooled to room temperature, an aliquot of the mixture was dried under high vacuum for 10 min. The progress of decomposition was 1 The decomposition was monitored by H-NMR spectroscopy. The decomposition was clean and complete after 16 hours. 1 The amounts and ratios of the two monomers were also determined by comparing the proton resonance signals in the 1 H-NMR spectra.

[0105] General procedure for chemical recycling of TETA: PCN film chips and potassium carbonate (approximately 5 wt.% relative to the PCN film) were stirred in ethanol (approximately 400 wt.% relative to the PCN film) at 90 °C for 16 h. After the mixture was cooled to room temperature, the solid was filtered and washed with additional ethanol. Most of the ethanol was removed by rotary evaporation, but not to dryness to prevent repolymerization. High vacuum was then applied at room temperature to remove the remaining ethanol. Hexane (approximately 200 wt.% relative to the original PCN film) was added. Diols can be separated from the solution due to their low solubility in hexane. The mixture was sonicated for 5 min. For recycling of PCN-A12, the resulting suspension was filtered, and the solid residue was washed with additional hexane and water to obtain recycled DO-12. The filtrate was transferred to a vial and all volatiles were removed by rotary evaporation, yielding TETA as off-white crystals. For recycling of PCN-A4 and PCN-A6, the mixture was washed twice more with fresh hexane to completely extract TETA. The combined hexane filtrate was washed with brine, dried over anhydrous Na2SO4, and concentrated to give TETA as off-white crystals.

[0106] Chemical recycling of TETA from plastic mixtures: High-density polyethylene (410 mg) from a flask cap, polypropylene (410 mg) from a tape case, polystyrene (581 mg) from a centrifuge tube, PCN-A6 (539 mg), and potassium carbonate (27 mg) were weighed into a 40 mL vial. Ethanol (20 mL) was added, and the mixture was stirred at 90 °C for 16 h. After cooling to room temperature, the mixture was filtered. The remaining solid was washed with an additional 5 mL of ethanol. The filtrate was treated as described above for PCN recycling. TETA was recovered as off-white crystals (387 mg, 85%).

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Claims

1. Alkyl and / or aryl bond crosslinked polymeric compounds according to formula (I) 【Chemical 1】 (In the formula, X is independently N or C, and when all X are N, R ２ does not exist and all X are C, then R ２ exists, R １ are independently CH, halogen, alkyl, or a diol selected from alkyl diols or aryl diols; R １ at least two of which are independently an alkyl diol or an aryl diol; R ２ are independently H, CH, or an electron-withdrawing group; R ２ at least two of are independently electron-withdrawing groups; R １ and R ２ optionally joined together to form one or more aromatic rings or one or more heterocyclic rings, one or more rings optionally substituted with at least one electron-withdrawing group, one or more rings of the compound further forming an electron-deficient cyclic core; The dashed lines represent possible double bond positions according to the configuration where X is N or C, and the double bond positions form an aromatic ring. A composition comprising:

2. R １ The compound of claim 1 , wherein is selected from polyols, polythiols, bisphenol A, polyamines, 1,4-butanediol, 1,6-hexanediol, and 1,12-dodecanediol, or combinations thereof.

3. R １ but, 【Chemistry 2】 (In the formula, R is C ４～１２ a linear alkyl, aromatic diol, polyol, polythiol or polyamine; n is greater than 1) 2. The compound of claim 1 selected from:

4. The electron withdrawing group is NO ２ , CN, CHO, halogen, CO ２ R ３ , C.O.R. ３ , CH═NR ３ , (C=S) OR ３ , (C=O)SR ３ , C.S. ２ R ３ , S.O. ２ R ３ , S.O. ２ NR ３ , S.O. ３ R ３ , P(O)(OR ３ ) ２ , P(O)(R ３ ) ２ , or B(OR ３ ) ３ (In the formula, R ３ is alkyl, aryl, or H.

5. 2. The compound of claim 1, wherein the electron withdrawing group is selected from CN, CHO, or halogen.

6. The compound is 【Chemistry 3】 2. The compound of claim 1 selected from:

7. A compound comprising an alkyl-linked polycyanurate network (PCN) formed by a plurality of alkyl-linked polycyanurate compounds according to formula (II): 【Chemistry 4】 where n is greater than 1.

8. 8. The compound of claim 7, wherein n is between 2 and 6.

9. An alkyl-linked polycyanurate network (PCN) formed by the monomer unit compounds according to claims 7 and 8.

10. A compound comprising an alkyl-linked polyaryl ether network (PAE) formed by a plurality of alkyl-linked polyether compounds according to formula (III): 【Chemistry 5】 (In the formula, R is independently alkyl or aryl; R ２ are independently electron-withdrawing groups).

11. R is C ４～１２ 11. The compound of claim 10, which is a straight chain alkyl.

12. The electron withdrawing group is NO ２ , CN, CHO, halogen, CO ２ R ３ , C.O.R. ３ , CH═NR ３ , (C=S) OR ３ , (C=O)SR ３ , C.S. ２ R ３ , S.O. ２ R ３ , S.O. ２ NR ３ , S.O. ３ R ３ , P(O)(OR ３ ) ２ , P(O)(R ３ ) ２ , or B(OR ３ ) ３ type (wherein R ３ is an alkyl, aryl, or hydrogen atom.

13. 11. The compound of claim 10, wherein the electron withdrawing group is selected from CN, CHO, or halogen.

14. An alkyl-linked polyaryl ether network (PAE) formed by the monomer unit compounds of claims 10 to 13.

15. A method for synthesizing alkyl-linked polyaryl ether monomers / networks, comprising the steps according to the following scheme: 【Chemistry 6】 (In the formula, R is independently alkyl or aryl; R ２ are independently electron-withdrawing groups).

16. A method for synthesizing polyaryl ethers, comprising reacting a di / triaryl ether with two / three cyano groups and an alcohol via a nucleophilic aromatic substitution (SNAr) reaction.

17. A method for synthesizing polyaryl ethers, comprising reacting a di / triaryl ether with two / three aldehyde groups and an alcohol via a nucleophilic aromatic substitution (SNAr) reaction.

18. A method for synthesizing polyaryl ethers, comprising reacting a di / triaryl ether with two / three halogen groups and an alcohol via a nucleophilic aromatic substitution (SNAr) reaction.

19. 【Chemical 7】 (In the formula, R １ is an alkyl or aryl diol) Alkyl or aryl linked polycyanurate compounds according to formula (IA) comprising:

20. R １ but, 【Chemistry 8】 wherein R is a straight chain alkyl.

20. The compound of claim 19, comprising:

21. R is C ４～１２ 21. The compound of claim 20, which is a straight chain alkyl.

22. R １ comprises bisphenol A.

23. The R １ The compound of claim 19, wherein is selected from 1,4-butanediol, 1,6-hexanediol, and 1,12-dodecanediol.

24. A method for synthesizing alkyl-linked polycyanurates, comprising steps according to the following scheme: 【Chemistry 9】

25. 25. The method of claim 24, wherein n is between 2 and 6.

26. A method for synthesizing an alkyl-linked polycyanurate from an aryl polycyanurate, comprising the steps according to the following scheme: 【Chemistry 10】

27. 27. The method of claim 26, wherein n is between 2 and 6.

28. A method for synthesizing alkyl-linked polycyanurates, comprising forming a single bond between a triazine carbon and an oxygen by a nucleophilic aromatic substitution (SNAr) reaction.

29. A method for synthesizing alkyl-linked polycyanurates, comprising reacting an alkyl cyanurate with an alcohol via a nucleophilic aromatic substitution (SNAr) reaction.

30. A method for synthesizing alkyl-linked polycyanurates, comprising the step of reacting 2,4,6-triethoxy-1,3,5-triazine (TETA) with an alcohol in the presence of triazabicyclodecene (TBD).

31. A method for converting alkyl-backed PCN to its monomer subunits according to the following scheme: 【Chemistry 11】

32. A method for upcycling aryl-PCN to TETA and bisphenol A (BPA) according to the following scheme: 【Chemistry 12】

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