Recyclable and malleable thermoset achieved by activation of dormant dynamic bonds

Abstract

The invention disclosed herein relates to a novel class of alkyl and / or aryl linked cross-linked polymeric polycyanurate compounds and methods of synthesizing the compounds from alkoxy substituted triazines by reacting the alkoxy substituted triazines with glycols. Further provided is a method of synthesizing an alkyl-linked polyarylether monomer / network comprising reacting an alkoxy-substituted phenyl derivative having an electron withdrawing group with a diol.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This International PCT Application claims the benefit of and priority to U.S. Provisional Application No. 63 / 354,754, filed on June 23, 2022. The present specification, claims, and drawings are incorporated herein by reference in their entirety. Technical Field

[0003] Generally, the inventive technology disclosed herein relates to novel alkyl and / or aryl linked polycyanurate compounds and methods for their synthesis. Background Art

[0004] Plastics have become an integral part of our daily lives. The properties of most plastics, such as light weight, durability, excellent barrier properties, and low cost, have brought tremendous social benefits and technological progress. However, the growing demand for plastics, the negative environmental impacts of uncontrolled plastic disposal, and challenges in recycling have raised concerns about the long-term harmful effects of plastics on the environment and human health. Achieving the recyclability of polymer materials to achieve a circular economy and environmental sustainability has attracted great attention. Thermosetting plastics, in which monomers are permanently cross-linked by strong covalent bonds, are usually produced as non-processable and non-recyclable plastics by design. To address their recyclability issues, a surge in the manufacture of new thermosetting polymers has exploded by introducing cleavable or dynamic covalent bonds in monomers or as cross-linking agents. Various chemical substances, such as dynamic imine bonds, transesterification, borate ester bonds, urethane, and silyl ether bonds, have been explored as cleavable units for the preparation of these materials. However, research focused on achieving the recyclability and ductility of existing thermosetting plastics to achieve their circular economy remains scarce. While the development of new polymers as “green” alternatives is important, revisiting traditional materials with the new perspectives introduced is crucial and can generate key knowledge that guides the development of sustainable high-performance materials.

[0005] Retrosynthetic analysis has long been a routine method for synthetic chemists to evaluate possible disconnection options for target structures and find the most efficient pathways. However, the importance of retrosynthetic analysis in polymer synthesis is often overlooked because they are composed of simple repeating units with limited possible connectivity. By searching backwards, alternative synthetic pathways for polymers can be found, which may bring unexpected benefits. For example, poly(phenylene vinylene) (PPE) is usually synthesized by cross-coupling reactions, which usually provide PPEs with relatively low molecular weight and diyne defects (Figure 1a). However, high molecular weight defect-free PPEs can be obtained by forming C≡C bonds instead of CC bonds through alkyne metathesis. More importantly, by adopting dynamic alkyne metathesis, PPEs can be depolymerized into small molecules and their potential closed-loop recyclability is made possible. Recent studies on chemically recyclable polymers and covalent adaptive networks (CANs) have shown that the activation of reversible bond connections in polymers may be a key driver of the recyclability and ductility of thermosetting polymers. Therefore, the inventors attempted to discover potential reversible bonds through retrosynthetic analysis in traditional thermosetting polymers.

[0006] As a proof of concept, cyanate resins were selected as an exemplary model system to demonstrate strategies for achieving recyclability and ductility by activating dormant dynamic bonds of conventional thermosets. Polycyanurate networks (PCNs) have been widely used in the aerospace and microelectronics industries, and their market is expected to reach $338 million in 2022. Cyanate resins are traditionally cured by [2+2+2] cyclotrimerization of three cyanate groups (Figure 1b) to form polycyanurate networks (PCNs), which exhibit unique properties such as good flame retardancy, high thermal stability, low hygroscopicity, low dielectric constant dissipation factor, excellent compatibility with carbon fibers, and adhesion to metals. Recycling such cross-linked thermosets is challenging. Previously, PCNs were degraded into triazine-based structures and phenols by treatment with various nucleophiles. The resulting products were obtained as mixtures that can be further used in polyurethane synthesis. However, closed-loop recycling of PCNs into clean and reusable building blocks (e.g., triazine-based monomers for repolymerization) has never been achieved. In addition, [2+2+2] cyclotrimerization is an irreversible reaction in which the substrate scope is limited to aromatic aryl-OC≡N monomers, which generally provides highly brittle PCNs due to the isomerization of alkyl-OC≡N monomers at high temperatures. Alkyl groups can only be introduced into PCNs uncontrollably through conventional trimerization methods, and thus alkyl-linked PCNs remain unexplored due to the difficulty of synthesis.

[0007] By performing retrosynthetic analysis and rethinking possible alternative routes, the inventors hypothesized that PCN could also be synthesized by nucleophilic aromatic substitution (S NHere, we demonstrate that by using a reversible S N Ar chemistry, rather than irreversible cyclotrimerization, activates dormant dynamic bonds in PCNs. Thus, recyclable and ductile PCNs can be prepared from two simple building blocks, and conventional aryl PCNs can be upcycled into reusable monomers for alkyl PCN synthesis. Through this new synthetic route, the synthesis of PCNs is not limited to only aryl linkers, providing unprecedented tunability in PCN properties, which has proven technically challenging when using conventional cyclotrimerization approaches. Alkyl PCNs show excellent membrane properties, chemical resistance, and recyclability. End-of-life PCNs in mixed plastic waste streams can be selectively degraded back to starting monomers, which can be isolated and directly reused in the next production cycle, achieving polymer-to-polymer closed-loop recycling. Summary of the invention

[0008] In one aspect, the present invention includes novel thermosetting polymer compositions. In a preferred embodiment, the thermosetting polymer of the present invention is 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 can be synthesized by reversible S-linking between alcohol and cyanurate. N Ar reaction synthesis. On the other hand, alkyl-linked PCN can be converted to monomers by refluxing in alcohol, and preferably ethanol. In this regard, potassium carbonate can be used as a base to deprotonate the ethanol and accelerate the conversion.

[0009] In a preferred aspect, the thermosetting polymer of the present invention contains one or more novel polyarylether (PAE) compositions. In this aspect, the PAE monomer compounds of the present invention can be obtained by reversible S-linking between alcohol and di / triarylether having two or more cyano, aldehyde and / or halogen groups. N Ar reaction synthesis. On the other hand, PAE can be converted to monomers by refluxing in an alcohol, and preferably methanol. In this regard, potassium carbonate can be used as a base to deprotonate the ethanol and accelerate the conversion.

[0010] In another aspect, the present invention includes novel systems and methods for synthesizing novel thermosetting polymer compositions. In a preferred embodiment, the present invention includes the use of reversible nucleophilic aromatic substitution (S N Ar) Synthesis of novel alkyl and / or aryl-linked PCNs.

[0011] In a preferred embodiment, the present invention includes the synthesis of aryl-linked PCN formed by replacing the ethoxy group on the cyanurate structure with bisphenol A (BPA).

[0012] In a preferred embodiment, the present invention includes the synthesis of alkyl-linked PCN formed by replacing the ethoxy group on the cyanurate structure with an alkyl diol. 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 prepared by S as described herein. N Ar reacts as a linker.

[0013] Additional aspects of the invention include methods for upgrading and recycling conventional aryl PCNs into reusable monomers for alkyl PCN synthesis. In a preferred embodiment, the used aryl PCN material can be converted into a cyanurate structure in which the ethoxy group is replaced by one or more alkyl diols, thereby forming a novel alkyl (PCN).

[0014] Additional embodiments of the present invention include methods of converting alkyl-lined PCN to its monomeric subunits, preferably by refluxing the PCN in ethanol in the presence of potassium carbonate catalyst.

[0015] Further aspects of the present invention may become apparent from the description and drawings presented hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1A-B .Synthesis strategies of polymers. a. Poly(phenylene vinylene) (PPE) can be prepared by cross-coupling between aryl halides and terminal alkynes (blue) or by metathesis polymerization of alkynes (red). b. Polycyanurate networks (PCN) can be prepared by [2+2+2]-cyclotrimerization of cyanate esters (blue) or by dynamic S-phase polymerization between alkoxy triazines and alcohols. N Ar reaction (red). [2+2+2]-cyclotrimerization is an irreversible reaction, and this method is limited to the synthesis of aromatic PCNs. In contrast, S N The reversibility of the Ar reaction can be activated under certain conditions, thereby achieving the ductility and recyclability of the polycyanurate network. Both aromatic and alkyl PCNs can be synthesized by S N Ar was obtained by reaction.

[0017] Figure 2A-C .S in the cyanurate exchange reaction N Ar. a. When 6 mol% TBD was added, the exchange reaction of TETA and methanol occurred at 60 °C and reached equilibrium within 40 hours. Three new triazines were formed, which were substituted with one, two or three methoxy groups. b. By plotting the relative concentration of TETA (% of remaining TETA) against time, the S N Kinetic curve of Ar reaction. c. Arrhenius plot of small molecule analog reaction and its linear fit. The activation energy was determined to be 62.5 kJ / mol.

[0018] Figure 3A-F . Preparation and characterization of PCN. a. TETA monomer can be obtained from the depolymerization of spent aryl-PCN prepared by conventional trimerization, or it can be synthesized from commercially available cyanuric chloride. Alkyl-PCN is prepared by reacting TETA with various diols in anisole in S N Ar reaction synthesis. b. Representative stress-strain curve of PCN. c. Tanδ-temperature curve obtained by DMA test of PCN. d. Gel fraction test of PCN. e. Comparison of FT-IR spectra of PCN-A6 after 48 hours of treatment with different solutions. f. Transparent film of PCN-A6 can be used as chemical-resistant film. After splashing different solvents (acetone, dichloromethane and ethanol), PCN-A6 maintained the same transparency, while polystyrene was severely damaged.

[0019] Figure 4A-E . Chemical recovery of PCN. a. Closed-loop recovery of PCN. PCN can be depolymerized into monomers, which can be repolymerized to form recovered PCN with almost the same chemical, thermal and mechanical properties. N The Ar reaction enables polymer-polymer closed-loop recycling of PCN. b. Photographs showing the procedure for selective recovery of PCN-A6 from plastic waste containing HDPE, PP, and PS. PCN-A6 is cleanly converted to soluble monomers, while other plastics remain solid. Recovered TETA is reused to form PCN-A6. c. Recycling of recovered and newly prepared TETA 1 Comparison of H-NMR spectra. Recycled TETA shows the same NMR proton signals as freshly synthesized TETA. d. The mechanical properties of native PCN and recycled PCN are highly comparable; e. Recycled PCN shows almost the same glass transition temperature as native PCN.

[0020] Figure 5 .Loop-closure recovery of PCNs via dynamic SNAr. PCNs can be prepared by polymerization of diols and substituted triazine monomers. When treated with monoalcohols or monophenols, PCNs can be converted into a monomer mixture. The monomer mixture can be further separated and purified if necessary. The traditional irreversible trimerization method is only applicable to aromatic PCNs because alkyl-OCNs undergo rapid isomerization under the reaction conditions.

[0021] Figure 6A-B Small molecule study of cyanurate exchange. a. In the absence of TBD catalyst, no reaction between TETA and methanol was observed. b. When deuterated methanol was used as solvent, the first step of the exchange reaction between TETA and deuterated methanol can be considered as an irreversible pseudo-first order reaction.

[0022] Figure 7A-C .FTIR comparison. a. FTIR spectra of PCN-A4 membrane and its corresponding monomer. b. FTIR spectra of PCN-A6 membrane and its corresponding monomer. c. FTIR spectra of PCN-A12 membrane and its corresponding monomer.

[0023] Figure 8A-C .Chemical resistance test of PCN membranes. a. Chemical resistance test of PCN-A4 membrane. b. Chemical resistance test of PCN-A6 membrane. c. Chemical resistance test of PCN-A12 membrane. PCN membranes were cut into rectangles and immersed in different solutions (1M HCl, 1M NaOH, 30% H2O2, and 1M NaBH4); the top, middle, and bottom photos were taken before immersion, after immersion for 48 hours, and after drying, respectively. No changes were observed in the appearance of all PCN membranes.

[0024] Figure 9A-C .Chemical recovery of PCN-A12. a. 1 H-NMR spectra show that the membrane degradation in ethanol is clean (TMB, 1,3,5-trimethoxybenzene, is used as an internal standard) and the recovered DO-12 and TETA are of high purity. b. The loss coefficients of the original and recovered PCN-A12 samples are almost the same. c. The FTIR spectra of the original and recovered PCN-A12 samples are almost the same.

[0025] Figure 10A-C .Chemical recovery of PCN-A4. a. 1H-NMR spectra show that the membrane degradation in ethanol is clean (TMB is used as internal standard). And the recovered TETA is of high purity. b. The loss coefficients of the original and recovered PCN-A4 samples are almost the same. c. The FTIR spectra of the original and recovered PCN-A4 samples are almost the same.

[0026] Figure 11A-C .Chemical recovery of PCN-A6. a. 1 H-NMR spectra show that the film degradation in ethanol is clean (TMB is used as an internal standard) and the recovered TETA is of high purity. b. The loss coefficients of the original and recovered PCN-A6 samples are almost the same. c. The FTIR spectra of the original and recovered PCN-A6 samples are almost the same.

[0027] Figure 12A-C Kinetic study of cyanurate exchange in the solid state. a. The bond exchange reaction can be triggered under heating in the presence of 23 mol% excess diol monomer and 10 mol% TBD. b. Stress relaxation test of PCN-A6-m at various temperatures. c. Arrhenius plot and its linear fit. The activation energy is calculated to be 76.7 kJ / mol.

[0028] Fig.13 .TETA 1 H-NMR spectrum.

[0029] Fig.14 .TETA 13 C-NMR spectroscopy.

[0030] Fig.15 TPhTA prepared by phenol exchange 1 H-NMR spectrum.

[0031] Fig.16 .Residues 1 H-NMR spectrum.

[0032] Fig.17 After stirring at 100°C for 16 hours, the mixture 1 H-NMR spectrum.

[0033] Fig.18 .FT-IR spectra of DCBPA and PCN-DCBPA.

[0034] Figure 19. (a) Crude reaction mixture from depolymerization of PCN-DCPBA, (b) TETA recovered from PCN-DCBPA upcycling, and (c) Bisphenol A recovered from PCN-DCBPA upcycling. 1 H-NMR spectrum.

[0035] Fig. 20A -E. Kinetic study of the mixture at (a) 20°C, (b) 35°C, (c) 40°C, (d) 45°C and (e) 50°C 1 H-NMR spectrum.

[0036] Figure 21A-B . ln([C]0 / [C]) versus t plots for cyanurate exchange at (a) 35°C, 40°C, 45°C, and 50°C and (b) 20°C.

[0037] Figure 22A-B (a) Reaction of TETA with three equivalents of methanol. (b) GC-MS spectra of pure TETA (top) and the reaction mixture from (a) (bottom).

[0038] Figure 23A-B (a) Reaction of TETA in deuterated methanol (as solvent). (b) GC-MS spectra of pure TETA (top) and the reaction mixture from (a) (bottom).

[0039] Fig.24.CP / MAS NMR spectrum of PCN (Teflon signal from NMR vessel observed at 116 ppm). The percentage of unreacted -OEt groups was estimated to be less than 10 mol% based on the relative peak intensities of PCN-A4, PCN-A6, and PCN-A12, which is consistent with the mass calculations above.

[0040] Fig.25 .PCN tensile test curve

[0041] Figure 26A-C Storage modulus and Tanδ curves of PCN. (a) PCN-A4; (b) PCN-A6; (c) PCN-A12.

[0042] Figure 27A-C .DSC results showed that the T g (Starting) were 63°C, 44°C and -3°C respectively.

[0043] Figure 28A-B FTIR spectra of PCNs before (light gray) and after (bottom) treatment: (a) PCN-A4; (b) PCN-A12.

[0044] Figure 29A-B UV-Vis spectra of PCN-A6, PS and PSU. (a) Transmittance measurement before solvent spraying. (b) Transmittance measurement after solvent spraying.

[0045] Fig.30 The TGA of PCN showed a mass loss of <4 wt% below 300 °C.

[0046] Figure 31A-B . Characterization of PCN-BPA. (a) Gel fraction test; (b) FT-IR spectrum.

[0047] Fig.32 . Degraded PCN-A4 mixture 1 H-NMR spectrum. The molar ratio of TETA to DO-4 is approximately 2:3.

[0048] Fig.33 . Degraded PCN-A6 mixture 1 H-NMR spectrum. The molar ratio of TETA to DO-6 is approximately 2:3.

[0049] Fig.34 . Degraded PCN-A12 mixture 1 H-NMR spectrum. The molar ratio of TETA to DO-12 is approximately 2:3.

[0050] Fig.35.TETA recovered from PCN-A6 and plastic waste streams 1 H-NMR spectrum.

[0051] Fig.36 .Tensile test curve of recycled PCN.

[0052] Figure 37A-C Storage modulus and Tanδ curves of recycled PCN. (a) PCN-A4; (b) PCN-A6; (c) PCN-A12.

[0053] Figure 38A-D . Reprocessed PCN-A6-m. (a) Image of PCN-A6-m strips formed by small polymer blocks. (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 Tanδ curves of PCN-A6-m (solid line: original; dashed line: reprocessed). DETAILED DESCRIPTION

[0054] As mentioned above, polymer reuse is considered to be essential for improving the circular economy and environmental sustainability of plastics. Chemical recycling has attracted increasing attention due to its ability to degrade polymers into precursors and building blocks, which can be used as raw materials similar to petroleum-based chemicals. Although there are several methods involving the manufacture of new recyclable polymers by introducing cleavable or dynamic linkers, existing thermosetting polymers are widely overlooked because they are considered to be permanently bound materials. In this article, by performing a retrosynthetic analysis of traditional polycyanurate thermosetting plastics, the inventors shifted the synthetic route from the formation of conventional CN bonds through irreversible cyanate trimerization to the construction of CO bonds through reversible nucleophilic aromatic substitution between alkoxytriazines and alcohols. This polycyanurate synthesis method overcomes many limitations of traditional trimerization methods, including that the substrate range is limited to aromatic monomers, the reaction temperature is high, and it is difficult to reshape, repair and recycle. Previously unavailable alkyl-polycyanurate thermosetting plastics have been successfully prepared, which exhibit excellent film properties and high chemical resistance under various conditions, as well as polymer-to-polymer closed-loop recyclability. The results described in this invention suggest that revisiting the chemical structures of traditional thermosetting polymers with the aid of retrosynthetic analysis may reveal "apparently dormant" dynamic bonds. Exploiting these dynamic bonds to build the same type of polymer networks will significantly expand the monomer range and achieve sustainable features of traditional non-recyclable materials without sacrificing their physical properties.

[0055] In one embodiment, the present invention includes an alkyl and / or aryl linked cross-linked polymeric compound according to formula (I), the cross-linked polymeric compound comprising:

[0056]

[0057] in

[0058] X is independently N or C, and further when all X are N, then R 2 does not exist, and when all X are C, then R 2 exist;

[0059] R 1 are independently CH, halogen, alkyl or a diol selected from an alkyl diol or an aryl diol, and wherein at least two R 1 are independently an alkyl diol or an aryl diol;

[0060] R 2 are independently H, CH or an electron withdrawing group, and at least two R 2 are independently electron withdrawing groups;

[0061] Where R 1 and R 2 Any of the optionally together form one or more aromatic rings or one or more heterocyclic rings, and wherein the one or more rings are optionally substituted with at least one electron withdrawing group, and wherein the one or more rings of the compound further form an electron-deficient ring core; and

[0062] The dotted lines represent possible double bond positions depending on the configuration where X is N or C, wherein the double bond positions form an aromatic ring.

[0063] In another embodiment, the compound according to formula (I) may include a compound wherein R 1 is selected from the group consisting of: polyols, polymercaptans, bisphenol A, polyamines, 1,4-butanediol, 1,6-hexanediol and 1,12-dodecanediol or a combination thereof. In another embodiment, R of the compound of formula (I) 1 Can be selected from:

[0064]

[0065] Where R is C 4-12 Linear alkyl, aromatic diol, polyol, polythiol or polyamine; and

[0066] n is greater than one.

[0067] In another embodiment, the compound according to formula (I) may include an electron withdrawing group selected from the group consisting of NO2, CN, CHO, halogen, CO2R 3 ,CONR 3 、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 )2ORB(OR 3 )3, where R 3 is alkyl, aryl or H. In a preferred embodiment, the compound of formula (I) may include an electron withdrawing group selected from the group consisting of CN, CHO or halogen.

[0068] As shown above, in a preferred embodiment, the core of the compound of formula (I) is an aromatic ring, which may include 1 With R 2 It is worth noting that in this embodiment, the core aromatic ring is electron-deficient. For example, the compound according to Formula I may include the following exemplary compounds having an electron-deficient core aromatic ring structure:

[0069]

[0070] In one embodiment, the present invention includes a compound comprising an alkyl-linked polyarylether network (PAE) formed from a plurality of alkyl-linked polyether compounds according to formula (III):

[0071]

[0072] wherein R is independently alkyl or aryl, and R 2 is independently an electron withdrawing group. In another embodiment, R is C 4-12 A straight chain alkyl group, and the electron withdrawing group is selected from: NO2, CN, CHO, halogen, CO2R 3 ,CONR 3 、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 )2ORB(OR 3 )3 type, of which R 3is an alkyl, aryl or hydrogen atom. In a preferred embodiment, the compound according to formula (III) may include an electron withdrawing group selected from the group consisting of CN, CHO or halogen. In another preferred embodiment, the compound of formula (II) may be used as a monomer unit that can form an alkyl-linked polyarylether network (PAE), as generally described herein.

[0073] Additional embodiments include methods of synthesizing alkyl-linked polyarylether monomers / networks comprising steps according to the following scheme:

[0074]

[0075] wherein R is independently alkyl or aryl, and R 2 is independently an electron withdrawing group as described herein.

[0076] Additional embodiments of the present invention further include methods for synthesizing polyarylethers, the methods comprising the step of reacting a di / triarylether having two / three cyano groups with an alcohol via a nucleophilic aromatic substitution (SNAr) reaction. Additional embodiments of the present invention further include methods for synthesizing polyarylethers, the methods comprising the step of reacting a di / triarylether having two / three aldehyde groups with an alcohol via a nucleophilic aromatic substitution (SNAr) reaction. Additional embodiments of the present invention further include methods for synthesizing polyarylethers, the methods comprising the step of reacting a di / triarylether having two / three halogen groups with an alcohol via a nucleophilic aromatic substitution (SNAr) reaction.

[0077] In another preferred embodiment, the present invention comprises an alkyl and / or aryl linked polycyanurate compound comprising:

[0078]

[0079] Where R 1 is an alkyl or aryl diol. In a preferred embodiment, the alkyl diol of the compound of formula IA comprises:

[0080]

[0081] Where R is C 4-12 Linear alkyl or aromatic diols. In alternative preferred embodiments, the alkyl diol of Formula IA is selected from the group consisting of 1,4-butanediol, 1,6-hexanediol and 1,12-dodecanediol.

[0082] In another embodiment, the present invention may include an alkyl-linked polycyanurate network (PCN) formed from a plurality of alkyl-linked polycyanurate compounds according to Formula II:

[0083]

[0084] In this preferred embodiment, n in Formula II may be between 2-6.

[0085] Additional embodiments of the present invention include methods of synthesizing alkyl-linked polycyanurate monomers / networks comprising steps according to the following scheme:

[0086]

[0087] In this preferred embodiment, n in the above method can be between 2-6.

[0088] Additional embodiments of the present invention include a method for synthesizing an alkyl-linked polycyanurate from an aryl polycyanurate, the method comprising the steps according to the following scheme:

[0089]

[0090] In this preferred embodiment, n in the above method can be between 2-6.

[0091] Additional embodiments of the present invention include methods of synthesizing alkyl-linked polycyanurates comprising the step of forming a single bond between a triazine carbon and an oxygen via a nucleophilic aromatic substitution (SNAr) reaction.

[0092] Additional embodiments of the present invention include methods of synthesizing alkyl-linked polycyanurates comprising the step of reacting an alkyl cyanurate with an alcohol via a nucleophilic aromatic substitution (SNAr) reaction.

[0093] Additional embodiments of the present invention include a method of synthesizing an alkyl-linked polycyanurate comprising the step of reacting 2,4,6-triethoxy-1,3,5-triazine (TETA) with an alcohol in the presence of triazabicyclodecene (TBD).

[0094] Additional embodiments of the present invention include a method of converting an alkyl-lined PCN to its monomeric subunits, the method comprising the steps according to the following scheme:

[0095]

[0096] Additional embodiments of the present invention include methods for upgrading aromatic PCN to TETA and bisphenol A (BPA) according to the following scheme:

[0097]

[0098] Section 1. Materials and Instruments

[0099] Acetone (99.5%), dichloromethane (99.5%, 200prof), 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%),

[0100] 1,4-Butanediol (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 diaminobisphenol 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 were obtained from Thermo Scientific centrifuge tube racks, polystyrene samples were obtained from Sigma-Aldrich polystyrene petri dishes, and polysulfone samples were obtained from Cambro polysulfone containers.

[0101] Acquired on a Bruker Avance-III 300M NMR spectrometer 1 H-NMR and 13C-NMR spectra. The chemical shifts of the residual solvent signals C6H6, CHCl3 or MeOH were used as references. Solid-state cross-polarization magic angle spinning (CP / MAS) NMR spectra were recorded on a Varian INOVA 400NMR spectrometer. Fourier transform infrared (FT-IR) spectra were obtained on an Agilent Cary 630FTIR spectrometer. High-resolution spectra were obtained on a Waters SYNAPT G2 high-resolution mass spectrometer system. Gas chromatography-mass spectrometry (GC-MS) analysis was performed on an Agilent 6890 single quadruple GC mass spectrometer using an Agilent VF-5-MS 30m×0.25mm×0.25μm column. Dynamic mechanical analysis (DMA) tests were performed on the Q800 from TA Instruments. Differential scanning calorimetry (DSC) measurements were performed on a Mettler Toledo DSC823. Ultraviolet-visible spectra (UV-Vis) were measured on an Agilent Cary 5000 UV-Vis-NIR. Modulus was measured by uniaxial tensile testing using an Instron 5965. Thermogravimetric analysis (TGA) was performed on a Thermogravametric Analysis Q500 from TA Instruments.

[0102] Section 2. Monomer synthesis and characterization

[0103]

[0104] Preparation of 2,4,6-triethoxy-1,3,5-triazine (TETA) Under nitrogen, at 100 ° C, 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 in a Schlenk tube under stirring for 16 hours. After the suspension was cooled to room temperature, 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 Na2SO4. After evaporation of the volatiles, the product (1.79 g, 84.0%) was obtained as white crystals: 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; ESI-TOF MS: C9H 15 N3O3[M+H]+ Calculated value, 214.1192; experimental value, 214.1178.

[0105]

[0106] 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 in a Schlenk tube under nitrogen at 60 ° C for 16 hours with stirring. After the suspension was cooled to room temperature, acetone was removed by rotary evaporation. The resulting solid was stirred in 1M potassium carbonate solution (100 mL) for 10 minutes. The pale yellow 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 obtain pure TPhTA (3.25 g, 91.0%) as a white solid: 1 H-NMR (300MHz,CDCl3)δ7.43–7.29(m,6H),7.25–7.19(m,3H),7.17–7.08(m,6H). Data are consistent with previous literature reports 1 Consistent.

[0107]

[0108] 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 in a Schlenk tube under nitrogen at 60 ° C for 16 hours under stirring. After the suspension was cooled to room temperature, acetone was removed by rotary evaporation. The resulting solid was stirred in 1M potassium carbonate solution (20 mL) for 10 minutes. The pale yellow 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 (3.25 g, 91.0%) as a white solid: 1 H-NMR (300MHz,CDCl3)δ7.17–7.12(m,6H),7.04–6.98(m,6H),2.34(s,9H). Data are consistent with previous literature reports 2 Consistent.

[0109]

[0110] 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 in a 4 mL vial under stirring for 24 hours at 100 ° C. The mixture was cooled to room temperature and stirred in 1 M potassium carbonate solution (20 mL) for 10 minutes. The suspension was filtered, and the off-white solid was washed with excess 1 M potassium carbonate solution, water and methanol, and dried in a vacuum oven at 60 ° C to give TPhTA (32 mg, 90%).

[0111]

[0112] 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 under stirring at 90 °C for 16 h. The ethanol was then removed by rotary evaporation. 1 An aliquot of the resulting concentrate was analyzed by H-NMR spectroscopy. Almost complete conversion of TPhTA to TETA and phenol was observed.

[0113]

[0114] 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 spectroscopy showed that no reaction had occurred.

[0115]

[0116] Preparation of Commercially Available Aromatic PCNs Commercially available cyanate resin dicyanobisphenol A (DCBPA) was selected as a model system to study the possibility of upcycling PCN waste into TETA monomers. DCBPA (2.0 g, 7.2 mmol) was weighed in an ampoule. The ampoule was cooled to 77 K and sealed under vacuum (100 mTorr). According to the literature, after warming to room temperature, the monomer was cured at 180 ° C for 1 hour, at 200 ° C for 1 hour, at 220 ° C for 1 hour, and at 250 ° C for 2 hours. 3Obtain the product in the form of a translucent yellow solid. The FT-IR spectrum is consistent with the literature report, supporting the formation of PCN-DCBPA. c Before upgrading and recycling, the obtained PCN-DCBPA is mechanically decomposed into a powdered solid. A suspension of PCN-DCBPA (100 mg) and potassium carbonate (10.0 mg, 72.5 μmol) in ethanol (10 mL) was stirred for 16 hours at 100 ° C. After cooling to room temperature, ethanol was removed by rotary evaporation. 0.1M NaOH solution (20 mL) and hexane (20 mL) were added, and the mixture was sonicated for 5 minutes. The organic solution was separated, and the aqueous solution was extracted twice (20 mL each time) by hexane. The organic solution was combined, washed with brine, and then dried over anhydrous Na2SO4. After evaporating the volatiles, TETA (36.6 mg, 71%) (Figure 19b) was obtained as white crystals. The aqueous phase was neutralized by 12M HCl and then extracted by ethyl acetate (3 × 20 mL). The organic solutions were combined and washed by brine and then dried over anhydrous Na2SO4. After evaporation of the volatiles, bisphenol A (72.3 mg, 88%) was obtained as a light yellow solid (FIG. 19c).

[0117] Section 3. Small molecule model reactions

[0118]

[0119] Scheme S1. Mechanism of the cyanurate exchange reaction.

[0120] Thermodynamic equilibrium study of dynamic cyanurate exchange reaction TETA (128 mg, 0.601 mmol), methanol (58 mg, 1.80 mmol) and deuterated benzene (3.0 mL) were weighed in 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 and TBD (1.7 mg, 12 μmol) were added to NMR tube B. Both NMR tubes were sealed and kept in the same oil bath at 60 ° C. By 1 The reactions in both NMR tubes were monitored by HNMR spectroscopy. No exchange reaction was observed in tube A over a period of 24 hours. The reaction in NMR tube B gradually reached equilibrium after 40 hours.

[0121] Kinetic studies using small molecules TBD (41.2 mg, 29.6 μmol) and 1,3,5-trimethoxybenzene (8.4 mg, 50 μmol) were added to deuterated methanol (3.96 g). 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 a few 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. Once Trt was 1 For H-NMR measurement, T35, T40, T45 and T50 were heated simultaneously at 35°C, 40°C, 45°C and 50°C, respectively. After 180 seconds, T35, T40, T45 and T50 were taken out of the oil bath and cooled in an ice bath, and then subjected to 1 H-NMR spectrum acquisition. This process was repeated to obtain T35, T40, T45 and T50 at 180 seconds, 360 seconds, 660 seconds and 1260 seconds. 1 H-NMR spectrum. 1 The H-NMR spectra were recorded at 1553, 3300, 5121, and 7300 seconds. The temperature of the NMR facility was recorded at 20°C. The -CH2- on the remaining ethoxy groups has a slightly higher chemical shift due to the slightly reduced electron donation effect of the methoxy groups. Even though the -CH2- signals of the different species overlap, the amount of unreacted TETA can still be quantified using the integration of the rightmost peak of the quartet on TETA (at 4.41 ppm) and the methoxy peak of 1,3,5-trimethoxybenzene (at 3.73 ppm).

[0122] S N Ar is formulated as a second order reaction as shown in Equation S1. Since MeOH-d4 is present in large excess and the proton exchange ratio S N Ar is much faster, so the concentration of MeOH-d4 is considered to be constant. Then, Equation S1 can be simplified to Equation S2, where the experimental rate constant k exp = is equal to the rate constant multiplied by the methanol concentration. If the initial concentration of TETA is set to [C]0, Equation S2 can be further rewritten as Equation S3.

[0123]

[0124] The experimental rate constants at different temperatures were calculated by plotting ln([C]0 / [C]) versus time and are shown in Table 1.

[0125] Table 1. Experimental rate constants of cyanurate exchange at different temperatures

[0126]

[0127] The Arrhenius equation (Equation S4) and its equivalent form (Equation S5) are used to calculate the reaction activation energy (E a ), where A and B are fitting parameters, and R is the gas constant 8.31 J / (mol·K). By fitting with the experimental data in Figure 2c, E a It is 62.7kJ / mol.

[0128]

[0129] GC-MS measurements GC-MS tests were performed under a nitrogen flow rate of 1 ml / min. The temperature was maintained at 60 °C for 1.5 min, then increased to 325 °C at 15 °C / min, and then maintained at 325 °C for 1 min. Three samples were analyzed by GC-MS to confirm the small molecule model reaction. 1 H-NMR analysis. It was observed that after 40 h of reaction with three equivalents of methanol, four different alkoxy-substituted triazines were formed. Based on the mass spectrum, they were assigned to 3M-TA, 2M-TA, M-TA and TETA, such as Figure 22A-B When TETA reacted with a large excess of methanol, only one main peak was observed in the GC. The mass spectrum showed that all TETA was converted to 3MD-TA, as shown in Figure 23. Therefore, the GC-MS results are consistent with those shown above. 1 The H-NMR results were consistent. Sample TETA preparation: TETA was dissolved in acetonitrile (1 mg / mL).

[0130] Preparation of samples for thermodynamic equilibrium studies: After 40 hours of reaction, the solution was removed from tube B, the solvent was evaporated under high vacuum, and then diluted in acetonitrile (1 mg / mL). Preparation of samples for kinetic studies: The solution of T50 was heated overnight and then directly diluted in acetonitrile (1 mg / mL).

[0131] Section 4. Polymer synthesis and characterization

[0132] PCN-A4 membrane preparation 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 stirring for 15 minutes, the mixture became a homogeneous solution. The solution was then poured into a petri dish (diameter = 5 cm). The solvent was slowly evaporated at 120 ° C for 14 hours, leaving a transparent, defect-free polycyanurate film. The film was further cured for 4 hours at 130 ° C under ambient pressure using a hot press. A transparent film (926 mg) was obtained. About 9.4% of the ethoxy groups were unreacted.

[0133] PCN-A6 membrane preparation 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 stirring for 5 minutes, the mixture became a homogeneous solution. The solution was then poured into a Petri dish (diameter = 5 cm). The solvent was slowly evaporated at 120 ° C for 14 hours, leaving a transparent defect-free PCN membrane. The membrane was further cured for 4 hours at 130 ° C under ambient pressure using a hot press. A transparent film (1.106 g) was obtained. About 5.4% of the ethoxy groups were unreacted.

[0134] PCN-A12 film preparation 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 stirring for 5 minutes, the mixture became a homogeneous solution. The solution was then poured into a petri dish (diameter = 5 cm) and kept in an oven. The solvent was slowly evaporated at 120 ° C for 8 hours, leaving a transparent, defect-free polycyanurate film. The film was further cured for 4 hours using a hot press at 130 ° C under ambient pressure. A transparent film (1.049 g) was obtained. About 4.3% of the ethoxy groups were unreacted.

[0135] Tensile Testing Samples were cut from pristine mat PCN into strips of approximately 3.5 mm x 0.3 mm x 20 mm. Tensile testing was performed at room temperature at a strain rate of 2.5% / min until fracture.

[0136] Dynamic Mechanical Analysis (DMA) Test The samples were cut from the original mat-like PCN into strips of approximately 3 mm x 0.3 mm x 10 mm. The samples were equilibrated at -50 °C for 5 minutes. Then, the samples were heated at a rate of 2 °C / min with an oscillation frequency of 1 Hz to 120 °C for PCN-A4 and 90 °C for PCN-A6 and PCN-12.

[0137] Differential Scanning Calorimetry (DSC) Tests The samples were loaded into TZero aluminum pans and scanned in an empty reference pan. After equilibration at -50°C, the temperature was increased to 160°C at a rate of 10°C / min.

[0138] Gel fraction test PCN was cut into small pieces and immersed in different solvents (tetrahydrofuran, acetone, dichloromethane and ethanol, 2 mL). After keeping at room temperature for 48 hours, the solvent was decanted and the residue was washed 5 times with an equal amount of solvent and then dried in a vacuum oven at 60°C for 4 hours. The weight before and after the test was recorded (Table 2).

[0139] Table 2. Gel fraction test results of PCN samples.

[0140]

[0141]

[0142] Chemical resistance test PCN was cut into small rectangular pieces (~30 mg) and immersed in different solutions (1N HCl, 1N NaOH, 30% H2O2 and 1M NaBH4 in THF, 2 mL). After keeping at room temperature for 48 hours, the solution was decanted and the residue was washed 5 times with excess water and 3 times with acetone, and then dried in an oven at 120°C for 4 hours. The weight before and after the test was recorded (Table 3). The optical images before and after the test are recorded in Extended Data Figure 3. The FT-IR spectra before and after the test are shown in Figures 3e and Fig.25 shown.

[0143] Table 3. Chemical resistance test results of PCN samples.

[0144]

[0145] Solvent splash test PCN-A6, polystyrene (PS) and polysulfone (PSU) were cut into rectangles (40mm×30mm) and their UV-Vis transmittance was measured. The plastic was then splashed with 0.5mL of acetone, dichloromethane and ethanol, followed by UV-Vis transmittance measurement. As shown in Figure 29, the transmittance of native PCN-A6 and PS in the visible light region (400-800nm) exceeded 90%. PSU showed good transparency in the long wavelength region, but showed obvious absorption below 550nm, which is consistent with its amber color. After solvent splashing, no obvious changes were observed in PCN-A6 and PSU, while the transmittance of PS dropped sharply. These results clearly demonstrate the excellent solvent resistance of PCN, which is similar to the solvent resistance of commercially available PSU.

[0146] Thermogravimetric Analysis (TGA) Tests Samples (~3 mg) were tested at a temperature ramp of 10°C / min with a constant nitrogen flow.

[0147] PCN-BPA Synthesis 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 minutes, the mixture became a homogeneous solution. The solution was then poured into a Petri dish (diameter = 5 cm). The solvent was slowly evaporated at 150 °C for 4 hours, 180 °C for 2 hours, 200 °C for 2 hours, 220 °C for 2 hours, and 250 °C for 2 hours, leaving a light yellow transparent defect-free polycyanurate film. The appearance of aliphatic CH absorption and the disappearance of -OH absorption indicate that PCN-BPA 4 formation.

[0148] Section 5: Chemical Recovery of PCN

[0149] Degradation 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 in a 10 mL vial. Ethanol (3 mL) was added. The mixture was treated as described in the PCN degradation procedure method. 1 H-NMR spectrum indicated that the molar ratio of TETA to diol was 2: 3. The original polymer contained about 8.9 mol% of unreacted -OEt groups, calculated on the mass of TMB.

[0150] Chemical recovery 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 hours. 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 dried to prevent repolymerization. A high vacuum was then applied at room temperature to remove the ethanol residue. Hexane (10 mL) was added and the mixture was sonicated for 5 minutes. 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 Na2SO4, and concentrated to give TETA (385 mg, 81% recovery yield) as off-white crystals.

[0151] Degradation 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 processed as described in the PCN degradation procedure method. 1 H-NMR spectrum indicated that the molar ratio of TETA to diol was 2: 3. The original polymer contained about 5.8 mol% of unreacted -OEt groups, calculated on the mass of TMB.

[0152] Chemical recovery of TETA from PCN-A6 PCN-A6 (524 mg) and potassium carbonate (30.0 mg, 0.217 mmol) in ethanol (25 mL) were stirred at 90° C. for 16 hours. The mixture was treated according to the chemical recovery procedure of PCN-A4 as described above. TETA was recovered as white crystals (381 mg, 86% recovery yield).

[0153] Degradation 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 processed as described in the PCN degradation procedure method. 1 H-NMR spectrum indicated that the molar ratio of TETA to diol was 2: 3. The original polymer contained about 5.2 mol% of unreacted -OEt groups, calculated on the mass of TMB.

[0154] Chemical recovery of DO-12 and TETA from PCN-A12 PCN-A12 (506 mg) and potassium carbonate (25.0 mg, 0.181 mmol) in ethanol (25 mL) were stirred at 90 ° C for 16 hours. 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 dried to prevent repolymerization. High vacuum was then applied at room temperature to remove ethanol residues. Hexane (10 mL) was added and the mixture was ultrasonically treated for 5 minutes. A white solid was precipitated, then filtered and washed with another 20 mL of hexane and water. The resulting white solid was dried under high vacuum to obtain DO-12 (385 mg, 95% recovery yield) in the form of a white powder. The filtrate was transferred to a vial, and all volatiles were removed by rotary evaporation to obtain TETA (246 mg, 87% recovery yield) in the form of off-white crystals.

[0155] The reformation procedure of PCN was the same as PCN synthesis, but using recycled monomers. Defect-free, transparent PCN was obtained.

[0156] The re-formed PCN was characterized by tensile tests and DMA tests. Fig.36 -37, no obvious changes in the chemical and mechanical properties were observed compared with the original PCN.

[0157] Table 4. Mechanical properties and T of original and recycled PCN g Compare

[0158]

[0159] Section 6. Kinetic studies of PCN-A6-m

[0160] Synthesis of PCN-A6-m PCN-A6-m was prepared in the same manner as PCN-A6, but 824 mg (3.86 mmol) of DO-6 and 201 mg (1.44 mmol) of TBD were used. In this case, the ratio between the alkoxy groups and the free hydroxyl groups was about 3:0.7. And the amount of catalyst was 10 mol% of the alkoxy groups. The FTIR spectrum showed that -OH was at about 3400 cm -1 There are obvious bulges.

[0161] Reprocessing of PCN-A6-m About 300 mg of PCN-A6-m was cut into small pieces and used to fill a rectangular Teflon mold. The mold was hot pressed at 300 kPa and 120 °C for 3 hours, and a defect-free film from the recycled PCN-A6-m was obtained. The recycled film showed FT-IR spectra, tensile strength, and T that were very similar to those of the original PCN-A6-m film. g (Figure 38 and Table 5).

[0162] Table 5. Comparison of mechanical properties of pristine and reprocessed PCN-A6-m.

[0163] sample Young's modulus (MPa) Tensile stress (MPa) Elongation(%) <![CDATA[T g (℃)]]> PCN-A6-m 2.93±0.24 2.64±0.04 118±3 27.4 PCN-A6-m-Re 2.66±0.07 2.56±0.06 119±9 28.7

[0164] Stress relaxation test PCN-A6-m samples were cut into strips of approximately 3.5 mm x 0.3 mm x 6 mm. The samples were balanced at a set temperature for 30 minutes and then pulled to 5% strain. At each temperature (110°C, 120°C, 130°C, and 140°C), the samples were relaxed to ~ 37% (1 / e) of their original relaxation modulus.

[0165] Unless otherwise stated, the structures described herein are also meant to include all isomeric (e.g., enantiomers, diastereomers, and geometric (or conformational)) forms of the structure; for example, R and S configurations, Z and E double bond isomers, and Z and E conformational isomers for each asymmetric center. Therefore, single stereochemical isomers of the compounds of the present invention as well as enantiomeric, diastereomeric, and geometric (or conformational) mixtures are within the scope of the present invention. Unless otherwise stated, all tautomeric forms of the compounds of the present invention are within the scope of the present invention. Additionally, unless otherwise stated, the structures depicted herein are also meant to include compounds that differ only in the presence of one or more isotopically enriched atoms. For example, compounds having structures of the present invention that include replacement of hydrogen by deuterium or tritium or replacement of carbon by 13C- or 14C-enriched carbon are within the scope of the present invention. According to the present invention, such compounds can be used, for example, as analytical tools, probes in biological assays, or therapeutic agents. The term "stereoisomer" refers to an enantiomer, diastereomer, or geometric isomer of a molecule. Unlike structural isomers, stereoisomers do not differ in the number and type of atoms in the molecular structure but do differ in the spatial arrangement of the atoms of the molecule. Examples of stereoisomers include (+) and (-) forms of optically active molecules.

[0166] 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, and reference to "the method" includes reference to one or more methods, method steps, and equivalents thereof, and so forth, known to those skilled in the art.

[0167] Similarly, the word "or" is intended to include "and" unless the context clearly indicates otherwise. Thus, "comprising A or B" means including A or B or A and B. In addition, the use of the term "including" and other related forms such as "includes" and "included" is not limiting.

[0168] As used herein, the term "about" is a flexible word with a meaning similar to "approximately" or "close to". The term "about" indicates that precision is not claimed, but rather a variation is contemplated. Thus, as used herein, the term "about" means within 1 or 2 standard deviations, 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% of the specifically cited value.

[0169] As used herein, the term "electron-withdrawing group" means a functional group having the ability to attract electrons, in particular if it is a substituent of an aromatic group, such as, in particular, a group of the NO2, CN, CHO, halogen, CO2R, CONR2, CH═NR, (C═S)OR, (C═O)SR, CS2R, S02R, SO2NR2, S03R, P(O)(OR)2, P(O)(R)2 or B(OR)3 type, in which R is an alkyl group, an aryl group or a hydrogen atom.

[0170] The term "alkyl" refers to a saturated straight chain monovalent hydrocarbon moiety of one to twenty, typically one to fifteen, and usually one to ten carbon atoms, or a saturated branched monovalent hydrocarbon moiety of three to twenty, typically three to fifteen, and usually three to ten carbon atoms. Exemplary alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, 2-propyl, tert-butyl, pentyl, isopentyl, hexyl, and the like.

[0171] As used herein, the term "aryl" or "aromatic moiety" refers to an aromatic ring system that may further include one or more non-carbon atoms. These are typically 5-6 isolated rings, or 8-10 bicyclic groups, and may be substituted. Therefore, envisioned aryl groups include (e.g., phenyl, naphthyl, etc.) and pyridyl. Additional envisioned aryl groups may be fused (i.e., covalently bonded to 2 atoms on the first aromatic ring) to one or two 5- or 6-membered aryl or heterocyclic groups, and are therefore referred to as "fused aryl" or "fused aromatics".

[0172] Aromatic groups containing one or more heteroatoms (usually N, O or S) as ring members may be referred to as heteroaryl or heteroaromatic groups. Typical heteroaromatic groups include monocyclic C5-C6 aromatic groups such as pyridyl, pyrimidinyl, pyrazinyl, thienyl, furanyl, pyrrolyl, pyrazolyl, thiazolyl, oxazolyl, isothiazolyl, isoxazolyl and imidazolyl, as well as fused bicyclic moieties formed by fusing one of these monocyclic groups with a benzene ring or with any heteroaromatic monocyclic group to form a C8-C10 bicyclic group such as indolyl, benzimidazolyl, indazolyl, benzotriazolyl, isoquinolyl, quinolyl, benzothiazolyl, benzofuranyl, pyrazolopyridinyl, pyrazolopyrimidinyl, quinazolinyl, quinoxalinyl, cinnolinyl, etc. Any monocyclic or fused bicyclic ring system having aromatic characteristics in terms of the electron distribution of the entire ring system is included in this definition. It further includes bicyclic groups in which at least the ring directly attached to the remainder of the molecule has aromatic character. Typically, the ring system contains 5-12 ring member atoms.

[0173] As used herein, the terms "heterocycle", "cycloheteroalkyl" and "heterocyclic moiety" are used interchangeably herein and refer to any compound in which a plurality of atoms form a ring by a plurality of covalent bonds, wherein the ring includes at least one atom other than a carbon atom as a ring member. Particularly contemplated heterocycles include 5- and 6-membered rings (e.g., imidazole, pyrrole, triazole, dihydropyrimidine, indole, pyridine, thiazole, tetrazole, etc.) with nitrogen, sulfur or oxygen as non-carbon atoms. Typically, these rings contain 0-1 oxygen or sulfur atoms, at least one carbon atom, and typically 2-3 carbon atoms and up to four nitrogen atoms as ring members. Further contemplated heterocycles can be fused (i.e., covalently bonded to two atoms on the first heterocycle) to one or two carbocyclic or heterocyclic rings, and are therefore referred to as "fused heterocycles" or "fused heterocyclic rings" or "fused heterocyclic moieties", as used herein. When the rings are aromatic, these may be referred to as "heteroaryls" or heteroaromatic groups herein.

[0174] As used herein, "alcohol" or "alcohols" refers to compounds having the following general formula: R-OH, where R represents any organic moiety (such as alkyl, aryl or silyl), including those with heteroatom-containing substituents. In certain embodiments, R represents an alkyl, alkenyl, aryl or alcohol group. In certain embodiments, the term "alcohol" or "alcohols" may refer to a group of compounds having the above general formula, wherein the compounds have different carbon lengths. As used herein, the term "alkanol" refers to an alcohol in which R is an alkyl group. In a preferred embodiment, S N Ar reaction was performed to prepare various alkyl PCNs using alcohols such as 1,4-butanediol (DO-4), 1,6-hexanediol (DO-6), and 1,12-dodecanediol (DO-12) as linkers (Figure 3a).

[0175] As used herein, the term "alkoxy" refers to a hydrocarbon group connected by an oxygen atom, such as -O-Hc, wherein the hydrocarbon portion Hc may have any number of carbon atoms, typically 1-10 carbon atoms, may further include double or triple bonds, and may include one or two oxygen, sulfur or nitrogen atoms in the alkyl chain, and may be substituted with aryl, heteroaryl, cycloalkyl and / or heterocyclic groups. For example, suitable alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, methoxyethoxy, benzyloxy, allyloxy, and the like.

[0176] "Cyanate resin" means a bisphenol or polyphenol, for example, a novolac derivative, in which the hydrogen atom of the phenolic OH group is replaced by a cyano group, thereby forming an -OCN group. Examples include, but are not limited to, bisphenol A dicyanate, commercially available as, for example, CYANOL from Lonza BADCy or from Huntsman B-10, and others or Types, such as bis(3,5-dimethyl-4-cyanophenyl)methane ( M-10), 1,1-bis(4-cyanophenyl)ethane ( L-10), 2,2-bis(4-cyanophenyl)-1,1,1,3,3,3-hexafluoropropane ( F-10), 1,3-bis(1-(4-cyanophenyl)-1-methylethylidene)benzene( XU-366), bis(4-cyanophenyl)sulfide ( RDX-80371; T-10), bis(4-cyanophenyl)dichloromethylenemethane ( RD98-228), bis(4-cyanophenyl)octahydro-4,7-methyleneindene( XU-71787.02L) and bis(4-cyanophenyl)ethane, bis(3-methyl-4-cyanophenyl)methane, bis(3-ethyl-4-cyanophenyl)methane, bis(4-cyanophenyl)ether, 4,4-dicyanodiphenyl, 1,4-bis(1-(4-cyanophenyl)-1-methylethylidene)benzene and resorcinol dicyanate. See also, for example, U.S. Pat. No. 10,233,139 to Evonik Technochemie GmbH.

[0177] 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 aminoplasts being particularly preferred triazines for use as the first monomer in the polymer of the present invention.

[0178] As used herein, the term "diol" refers to a chemical compound containing two hydroxyl groups (—OH groups).

[0179] As used herein, the term "thermoset" refers to a polymer obtained by irreversibly hardening ("curing") a soft solid or viscous liquid prepolymer (resin).

[0180] As used herein, the term "substituted" refers to the replacement of hydrogen atoms of an unsubstituted group by a functional group, and specifically contemplated functional groups include nucleophilic groups (e.g., -NH2, -OH, -SH, -CN, etc.), electrophilic groups (e.g., C(O)OR, C(X)OH, etc.), polar groups (e.g., -OH), nonpolar groups (e.g., heterocycles, aryls, alkyls, alkenyls, alkynyls, etc.), ionic groups (e.g., -NH3+) and halogens (e.g., -F, -Cl), NHCOR, NHCONH2, OCH2COOH, OCH2CONH2, OCH2CONHR, NHCH2COOH, NHCH2CONH2, NHSO2R, OCH2-heterocycles, PO3H, SO3H, amino acids, and all chemically reasonable combinations thereof. In addition, the term "substituted" also includes multiple degrees of substitution, and where multiple substituents are disclosed or claimed, the substituted compounds may be independently partially substituted with one or more disclosed or claimed substituents.

[0181] In addition to the disclosure herein, in certain embodiments, the substituted group has 1, 2, 3 or 4 substituents, 1, 2 or 3 substituents, 1 or 2 substituents or 1 substituent. It should be understood that in all substituted groups defined above, compounds achieved by defining a substituent with an additional substituent as itself (e.g., a substituted aryl having a substituted aryl as a substituent substituted by the substituted aryl itself, the substituted aryl being further substituted by the substituted aryl, etc.) are not intended to be included herein. In such cases, the maximum number of such substitutions is three. For example, the serial substitution of substituted aryls specifically contemplated herein is limited to substituted aryl-(substituted aryl)-substituted aryl.

[0182] The present invention described in general will be more easily understood by reference to the following examples, which are included only for the purpose of illustrating certain embodiments of embodiments of the present invention. As will be appreciated by those skilled in the art from the above teachings and the following examples, other techniques and methods can satisfy the claims and can be adopted without departing from the scope of the present invention claimed, and examples are not intended to limit the present invention. In fact, although the present invention has been specifically shown and described with reference to its preferred embodiments, it will be appreciated by those skilled in the art that different changes in form and detail can be made therein without departing from the scope of the present invention covered by the appended claims.

[0183] Examples

[0184] Example 1: Dynamic nucleophilic aromatic substitution studies in small model compounds.

[0185] For example, S on heterocyclic substrates such as pyridine, pyrimidine, and triazine N Nucleophilic aromatic substitution (AR) has been widely used in medicinal chemistry. However, the application of this type of reaction in polymer synthesis has been less explored. Although bond exchange between phenols and aryloxy-substituted triazines has been demonstrated previously, the dynamic S-linked reaction between alcohols and cyanurates has been widely used in pharmaceutical chemistry. N Ar reaction has never been reported. In this context, firstly, the present invention uses 2,4,6-triethoxy-1,3,5-triazine (TETA) and methanol as model compounds to study the S-Ar reaction between alkyl cyanurate and alcohol. N The present inventors first demonstrated the thermodynamic equilibrium of the cyanurate exchange reaction (Figure 2a). In the absence of any catalyst, TETA and methanol had no exchange reaction at 60 ° C (Figure 6). In contrast, when a catalytic amount of triazabicyclodecene (TBD) was added, the exchange of ethoxy groups with methoxy groups occurred immediately, indicating that this type of S N Reversibility of the Ar reaction. After heating at 60 °C for 40 h, a dilute solution of TETA and methanol in a 1:3 molar ratio provided four triazines in a molar ratio of approximately 1:3:3:1, in which up to three ethoxy groups were replaced by methoxy groups. Such results indicate that all three ethoxy groups are reactive and that the exchange reaction has reached equilibrium.

[0186] The kinetics of cyanurate exchange were studied at different reaction temperatures (Figure 6). 1 The progress of the reaction was monitored by the decrease in the intensity of the TETA proton signal over time in the H-NMR spectrum. NAr reaction, and proposed a coordinated second-order substitution mechanism. Considering the large excess of methanol and the rapid proton transfer between alcohol and TBD, the inventors assumed that the reaction was an irreversible pseudo-first-order reaction, and calculated the experimental rate constant (Fig. 2b and Table 1) based on the TETA concentration reduction. Using the reaction rate constant measured at different temperatures, the activation energy of the exchange reaction calculated according to the Arrhenius diagram and its linear fit is 62.5kJ / mol (Fig. 2c).

[0187] Example 2: PCN synthesis and characterization.

[0188] Unlike the well-known aryl PCNs, alkyl PCNs are not accessible because alkyl cyanate monomers undergo undesirable isomerization to form isocyanates under conventional [2+2+2] trimerization conditions. There is currently no viable synthesis of alkyl PCNs that have high impact toughness compared to conventional aryl PCNs. The inventors envision that the process of the present invention can provide alkyl PCNs with various thermal and mechanical properties that are difficult to achieve using conventional cyclotrimerization methods.

[0189] Therefore, the dynamic S N Ar reaction to synthesize alkyl PCN. N Ar reaction, various alkyl PCNs were prepared using 1,4-butanediol (DO-4), 1,6-hexanediol (DO-6), and 1,12-dodecanediol (DO-12) as linkers (Figure 3a). TBD (2 mol% relative to the cyanurate group) was added as a catalyst. The Fourier transform infrared (FT-IR) spectrum of PCN showed that the -1 There is a COC stretch zone at 815cm -1 and 1550cm -1 There is a triazine band at 725 cm -1 The disappearance of the methyl vibration band at 147°C (Figure 7) supports a cyanurate structure in which the ethoxy group is replaced by an alkyl diol. Solid-state cross-polarization magic angle spinning (CP / MAS) NMR spectroscopy shows that only a small amount (4-10 mol%) of the ethoxy group is unreacted. Thermogravimetric analysis (TGA) shows that below 300°C, the mass loss is <4 wt%, which indicates that the polymer has high thermal stability and the absence of volatile small molecule residues.

[0190] The mechanical properties of PCN were measured by uniaxial tension. PCN-A4 has an elongation at break of over 45%, a tensile strength of 45 MPa, and a Young's modulus of 1.1 GPa, which is very ductile compared to common brittle aromatic PCNs (respectively ~5%, ~90 MPa, and ~3.1 GPa). With the increase in the flexibility of the hydrocarbon chain structure between the triazine nodes, the PCN becomes softer and more ductile (Figure 3b). The glass transition temperature (T g ) ranged widely, from 15.5 °C for PCN-A12 to 54.5 °C and 65.5 °C for PCN-A6 and PCN-A4, respectively (Figure 3c). Alkyl PCNs showed high tolerance to organic solvents. The gel fractions of all three PCNs measured by solvent extraction were ∼99% in various solvents, which supported their highly cross-linked structures (Figure 3d and Table 2).

[0191] Chemical resistance testing was also performed. After 48 hours under acidic (1N HCl), alkaline (1N NaOH), oxidizing (30% H2O2) and reducing (1M NaBH4 in THF) conditions, FT-IR spectroscopy confirmed that PCN retained almost the same appearance, weight and chemical structure, indicating that PCN has high resistance to various chemical attacks (Figures 3e and 8). Therefore, alkyl PCN can be used as a protective panel that provides high transparency and solvent / chemical resistance. Transparent PCN-A6 was cut into rectangles and used to cover digital displays (Figure 3f). After direct contact with common organic solvents (e.g., acetone, dichloromethane and ethanol), there was no change in the shape or transparency of the film, which is similar to polysulfone. In contrast, transparent polystyrene films were severely corroded. It should be noted that this type of S N The Ar method can also provide aromatic PCNs. As an example, PCN-DCBPA was successfully prepared by the condensation reaction between 2,4,6-triphenoxy-1,3,5-triazine and bisphenol A (BPA).

[0192] Example 3: Closed-loop recycling.

[0193] Next, the inventors explored the recyclability of the materials and found that these PCNs can be efficiently converted to monomers when refluxing in ethanol (Figure 4a). For example, PCN-A6 can be slowly degraded in refluxing ethanol for two days. The process was accelerated when 5wt% potassium carbonate was added as a base to deprotonate the ethanol, where the PCN degraded in ethanol within 16 hours and converted almost quantitatively to monomers. After removing the ethanol, both monomers, diols and TETA, can be easily recovered from the mixture with an isolated yield of ~90%. After adding hexane, long-chain diols (e.g., 1,12-dodecanediol) precipitate from the mixture, providing clean diols as solids. TETA can be recovered from the hexane solution with high purity (Figures 9-11) and directly reused. Short-chain diols (e.g., 1,4-butanediol) can be separated from TETA by liquid-liquid extraction with hexane to obtain a highly concentrated crude product, which can be further purified by distillation.

[0194] To demonstrate the possibility of selectively recovering PCN in mixed plastic waste streams, the inventors used samples containing equal amounts of mixed plastics PCN-A6, PP (polypropylene), HDPE (high-density polyethylene) and PS (polystyrene). After refluxing the plastic mixture with potassium carbonate (5 wt%) in ethanol, PCN-A6 was completely depolymerized into TETA and 1,6-hexanediol, which could be separated from other plastics by filtration and extraction ( FIG. 4 b ). High-purity TETA was recovered by simple evaporation and extraction ( FIG. 4 c ). Recycled PCN (PCN-Ax-Re) (x=4, 6 or 12) prepared using recycled TETA showed the same FT-IR absorption as virgin PCN ( FIGS. 9-11 ). Mechanical properties and T of recycled PCN g The mechanical properties are also highly comparable to those of pristine PCN (Figure 4d, Figure 4e and Table 4). A similar recycling approach was also used to depolymerize traditional aromatic polycyanurate wastes, such as PCN-DCBPA, to form high-purity TETA (Figure 3a). These results clearly show that the utilization of S N The Ar-reacted strategy is generally applicable to a wide range of PCNs, thus enabling user-friendly closed-loop recyclability for this important class of thermosets.

[0195] Example 4: Materials and methods.

[0196] General procedure for PCN membrane synthesis: TETA (1.0 eq.), diol (1.5 eq.) and TBD catalyst (0.06 eq.) 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 to obtain a transparent, defect-free PCN membrane. The membrane was further cured using a hot press at 130 °C under ambient pressure for 4 h.

[0197] Gel fraction and chemical resistance testing: PCN membranes were cut into small rectangular pieces and immersed in different organic solvents or solutions. The mixtures were kept undisturbed at room temperature for 48 hours. The solution was then 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 solids were dried in an oven at 120°C for 4 hours and weighed. The weight difference of the sample before and after the treatment was calculated.

[0198] Degradation of PCN: A piece of PCN membrane, potassium carbonate (5 wt% of PCN membrane) and internal standard (1,3,5-trimethoxybenzene) were stirred in ethanol (~400 wt% of PCN membrane) at 90°C for 16 hours. After the mixture was cooled to room temperature, an aliquot of the mixture was dried under high vacuum for 10 minutes. 1 The degradation process was monitored by H-NMR spectroscopy. The degradation was clean and complete after 16 h. 1 The proton resonance signals in the H-NMR spectrum also determined the amounts and ratios of the two monomers.

[0199] General procedure for chemical recovery of TETA: A piece of PCN membrane and potassium carbonate (~5 wt% of PCN membrane) were stirred in ethanol (~400 wt% of PCN membrane) at 90°C for 16 hours. After the mixture was cooled to room temperature, the solids were filtered and washed with additional ethanol. Most of the ethanol was removed by rotary evaporation, but not dried to prevent repolymerization. High vacuum was then applied at room temperature to remove the ethanol residue. Hexane (~200 wt% of the original PCN membrane) was added. The solubility of the diols in hexane is poor and can therefore be separated from the solution. The mixture was sonicated for 5 minutes. For PCN-A12 recovery, the resulting suspension was filtered and the solid residue was washed with additional hexane and water to obtain the recovered DO-12. The filtrate was transferred to a vial and all volatiles were removed by rotary evaporation to obtain TETA as off-white crystals. For PCN-A4 and PCN-A6 recovery, the liquid mixture was washed twice more with fresh hexane to completely extract the TETA. The combined hexane filtrates were washed with brine, dried over anhydrous Na 2 SO 4 , and concentrated to give TETA as off-white crystals.

[0200] Chemical recovery of TETA from plastic mixture: High-density polyethylene (410 mg) from the flask cap, polypropylene (410 mg) from the tape box, polystyrene (581 mg) from the 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 hours. After cooling to room temperature, the mixture was filtered. The remaining solids were washed with an additional 5 mL of ethanol. The filtrate was processed as described above for PCN recovery. TETA was recovered as off-white crystals (387 mg, 85%).

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Claims

1. A composition comprising an alkyl and / or aryl linked cross-linked polymeric compound according to formula (I), the compound comprising: in X is independently N or C, and further when all X are N, then R 2 does not exist, and when all X are C, then R 2 exist; R 1 are independently CH, halogen, alkyl or a diol selected from an alkyl diol or an aryl diol, and wherein at least two R 1 are independently an alkyl diol or an aryl diol; R 2 are independently H, CH or an electron withdrawing group, and at least two R 2 are independently electron withdrawing groups; Where R 1 and R 2 Any of the optionally together form one or more aromatic rings or one or more heterocyclic rings, and wherein the one or more rings are optionally substituted with at least one electron withdrawing group, and wherein the one or more rings of the compound further form an electron-deficient ring core; and The dotted lines represent possible double bond positions depending on the configuration where X is N or C, wherein the double bond positions form an aromatic ring.

2. The compound according to claim 1, wherein R 1 Selected from: polyol, polythiol, bisphenol A, polyamine, 1,4-butanediol, 1,6-hexanediol and 1,12-dodecanediol or a combination thereof.

3. The compound according to claim 1, R 1 Selected from: in R is for C 4-12 Linear alkyl, aromatic diol, polyol, polythiol or polyamine; and n is greater than one.

4. The compound according to claim 1, wherein the electron withdrawing group is selected from: NO2, CN, CHO, halogen, CO2R 3 ,CONR 3 、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 )2ORB(OR 3 )3, where R 3 is alkyl, aryl or H.

5. The compound according to claim 1, wherein the electron withdrawing group is selected from: CN, CHO or halogen.

6. The compound according to claim 1, wherein the compound is selected from:

7. A compound comprising an alkyl-linked polycyanurate network (PCN) formed from a plurality of alkyl-linked polycyanurate compounds according to formula (II): Where n is greater than 1.

8. The compound according to claim 7, wherein n is between 2-6.

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

10. A compound comprising an alkyl-linked polyarylether network (PAE) formed from a plurality of alkyl-linked polyether compounds according to formula (III): in R is independently alkyl or aryl; and R 2 are independently electron withdrawing groups.

11. The compound according to claim 10, wherein R is C 4-12 Straight chain alkyl.

12. The compound according to claim 10, wherein the electron withdrawing group is selected from: NO2, CN, CHO, halogen, CO2R 3 ,CONR 3 、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 )2ORB(OR 3 )3 type, of which R 3 is an alkyl group, an aryl group or a hydrogen atom.

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

14. An alkyl-linked polyarylether network (PAE) formed from the monomer unit compounds according to claims 10 to 13.

15. A method for synthesizing an alkyl-linked polyarylether monomer / network, the method comprising the steps according to the following scheme: in R is independently alkyl or aryl; and R 2 are independently electron withdrawing groups.

16. A method for synthesizing polyarylether, the method comprising the step of reacting a di / triarylether having two / three cyano groups with an alcohol through a nucleophilic aromatic substitution (SNAr) reaction.

17. A method for synthesizing polyarylether, the method comprising the step of reacting a di / triarylether having two / three aldehyde groups with an alcohol through a nucleophilic aromatic substitution (SNAr) reaction.

18. A method for synthesizing polyarylether, the method comprising the step of reacting di / triarylether having two / three halogen groups with alcohol through a nucleophilic aromatic substitution (SNAr) reaction.

19. An alkyl or aryl linked polycyanurate compound according to formula (IA) comprising: Where R 1 is an alkyl or aryl diol.

20. The compound according to claim 19, wherein R 1 Include: wherein R is a straight chain alkyl group.

21. The compound according to claim 20, wherein R is C 4-12 Straight chain alkyl.

22. The compound according to claim 19, wherein R 1 Contains Bisphenol A.

23. The compound according to claim 19, wherein R 1 Selected from: 1,4-butanediol, 1,6-hexanediol and 1,12-dodecanediol.

24. A method for synthesizing an alkyl-linked polycyanurate, the method comprising the steps according to the following scheme:

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, the method comprising the steps according to the following scheme:

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

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

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

30. A method for synthesizing an alkyl-linked polycyanurate, the method 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-lined PCN to its monomeric subunits according to the following scheme:

32. A method for upgrading aryl-PCN to TETA and bisphenol A (BPA) according to the following scheme:

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