Benzoxazine Derivatives Vitrimers

Abstract

Disulfide-containing benzoxazine monomers of formula I

##STR00001##

Also a process for synthesizing a disulfide-containing benzoxazine monomer of formula I comprises the following steps consisting of providing a mixture comprising an amino disulfide compound:H.sub.2N—R—NH.sub.2, wherein R is as defined for the monomer of formula I, an aldehyde derivative; phenolic derivatives, stirring the mixture under a temperature of from 50° C. to 130° C. for 1 h to 48 h, for obtaining the monomer of formula I; wherein the respective stoichiometry of the amino disulfide compound: aldehyde derivative:phenolic derivatives is 1:4: x.sub.1+x.sub.2, with x.sub.1+x.sub.2=2 and 0<x.sub.1;x.sub.2<2. Also a process for preparing a polybenzoxazine derivative vitrimer comprising a polymerization of the benzoxazine monomer at temperatures within the range of from 100° C. to 250° C. for 1 h to 24 h, for obtaining the polybenzoxazine derivatives vitrimer. Also polybenzoxazine derivative vitrimers, presenting at least one of the following characteristics of Tg values of from 0° C. to 250° C.; and relaxation temperature values, above the Tg values, of from 0° C. to 250° C.

Claims

1.-20. (canceled)

21. A disulfide-containing benzoxazine monomer of formula I ##STR00023## wherein R is: ##STR00024## wherein, in formula (II), X and X′ are, independently, at least one of: one of a substituted and an unsubstituted aliphatic C.sub.1-C.sub.20 alkyl group; at least one of a substituted and an unsubstituted aliphatic C.sub.2-C.sub.20 alkenyl group; at least one of a substituted and an unsubstituted C.sub.6-C.sub.20 aryl group; at least one of a substituted and an unsubstituted C.sub.6-C.sub.20 heteroaryl group; at least one of a substituted and an unsubstituted C.sub.6-C.sub.20 heterocyclic group; and at least one of a substituted and an unsubstituted C.sub.3-C.sub.8 cycloalkyl group, and wherein a combination of R.sub.1, R.sub.2, R.sub.3, R.sub.4 substituents is selected from the group of the combinations consisting of R.sub.1=R.sub.2=R.sub.3=R.sub.4=H, R.sub.1=OCH.sub.3, R.sub.2=R.sub.3=R.sub.4=H, R.sub.1=OCH.sub.3, R.sub.2=R.sub.4=R.sub.3=alkyl group of C.sub.1-C.sub.15, R.sub.1=OCH.sub.3, R.sub.2=R.sub.4=H, R.sub.3=CHO, R.sub.1=OCH.sub.3, R.sub.2=R.sub.4=H, R.sub.3=(CH.sub.2).sub.n:1-15COOH, R.sub.1=OCH.sub.3, R.sub.2=R.sub.4=H, R.sub.3=(CH.sub.2).sub.n:1-15CH═CH.sub.2, R.sub.1=OCH.sub.3, R.sub.2=R.sub.4=H, R.sub.3=CH═CHCH.sub.3, R.sub.1=R.sub.2=R.sub.4=H, R.sub.3=(CH.sub.2).sub.n:1-15COOH, R.sub.1=R.sub.2=R.sub.4=H, R.sub.3=CH═CHCOOH, R.sub.1=OCH.sub.3, R.sub.2=R.sub.4=H, R.sub.3=CH═CHCOOH, at least one of R.sub.1, R.sub.2, R.sub.3, R.sub.4 is an aliphatic alkyl group of C.sub.1-C.sub.15, the rest being H, R.sub.1=R.sub.3=R.sub.4=H, and ##STR00025## R.sub.3=R.sub.4=H, R.sub.1=COOH ##STR00026## R.sub.1=H, R.sub.2=OH, R.sub.3=H, and ##STR00027## R.sub.1=H, R.sub.3=OH, R.sub.4=H and ##STR00028## R.sub.1=CH.sub.3, R.sub.2=OH, R.sub.3=H, ##STR00029## R.sub.3=R.sub.4=H, R.sub.1=OH and ##STR00030## R.sub.2=R.sub.3=R.sub.4=H and R.sub.1=(CH.sub.2).sub.n:1-15CH═CH.sub.2, R.sub.1=R.sub.3=R.sub.4=H and R.sub.2=(CH.sub.2).sub.n:1-15CH═CH.sub.2, R.sub.1=R.sub.2=R.sub.4=H and R.sub.3=(CH.sub.2).sub.n:1-15CH═CH.sub.2, R.sub.1=R.sub.3=R.sub.4=H and R.sub.2= ##STR00031## and R.sub.1=R.sub.2=R.sub.4=H and R.sub.3= ##STR00032## or mixture thereof wherein a combination of R.sub.1′, R.sub.2′, R.sub.3′, R.sub.4′, substituents is as defined for the combination of R.sub.1, R.sub.2, R.sub.3, R.sub.4, substituents and is independent thereof, the compound: N,N′-(disulfanediylbis(methylene))bis(6-(2H-benzo[e][1,3] oxazin-3(4H)-yl)hexan-1-amine being excluded.

22. The disulfide-containing benzoxazine monomer of formula (I) according to claim 21, wherein, in formula (II), X and X′ are, independently, at least one of: one of a substituted and an unsubstituted aliphatic C.sub.1-C.sub.15 alkyl group; at least one of a substituted and an unsubstituted aliphatic C.sub.2-C.sub.15 alkenyl group; at least one of a substituted and an unsubstituted C.sub.6-C.sub.15 aryl group; at least one of a substituted and an unsubstituted C.sub.6-C.sub.15 heteroaryl group; at least one of a substituted and an unsubstituted C.sub.6-C.sub.15 heterocyclic group; and at least one of a substituted and an unsubstituted C.sub.3-C.sub.6 cycloalkyl group.

23. The disulfide-containing benzoxazine monomer of formula (I) according to claim 21, wherein R is selected from the group of moieties consisting of ##STR00033## and, independently, the combination of R.sub.1, R.sub.2, R.sub.3, R.sub.4 substituents and R.sub.1′, R.sub.2′, R.sub.3′, R.sub.4′, substituents being as defined for the combination of R.sub.1, R.sub.2, R.sub.3, R.sub.4 substituents and being independent thereof, is selected from the group of the combinations consisting of: R.sub.1=OCH.sub.3, R.sub.2=R.sub.4=H, R.sub.3=alkyl group of C.sub.1-C.sub.15, R.sub.1=OCH.sub.3, R.sub.2=R.sub.4=H, R.sub.3=(CH.sub.2).sub.n:1-15COOH, R.sub.1=OCH.sub.3, R.sub.2=R.sub.4=H, R.sub.3=(CH.sub.2).sub.n:1-15CH═CH.sub.2, R.sub.1=R.sub.2=R.sub.4=H, R.sub.3=(CH.sub.2).sub.n:1-15COOH, at least one of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is an aliphatic alkyl group of C.sub.1-C.sub.15, the rest being H, R.sub.1=R.sub.3=R.sub.4=H, and at least one of: ##STR00034## R.sub.3=R.sub.4=H, R.sub.1=COOH ##STR00035## R.sub.1=H, R.sub.2=OH, R.sub.3=H, and ##STR00036## R.sub.1=H, R.sub.3=OH, R.sub.4=H and ##STR00037## R.sub.1=CH.sub.3, R.sub.2=OH, R.sub.3=H, ##STR00038## R.sub.3=R.sub.4=H, R.sub.1=OH and ##STR00039## R.sub.2=R.sub.3=R.sub.4=H and R.sub.1=(CH.sub.2).sub.n:1-15CH═CH.sub.2, R.sub.1=R.sub.3=R.sub.4=H and R.sub.2=(CH.sub.2).sub.n:1-15CH═CF.sub.12, R.sub.1=R.sub.2=R.sub.4=H and R.sub.3=(CH.sub.2).sub.n:1-15CH═CH.sub.12, R.sub.1=R.sub.3=R.sub.4=H and R.sub.2= ##STR00040## and R.sub.1=R.sub.2=R.sub.4=H and R.sub.3= ##STR00041##

24. The disulfide-containing benzoxazine monomer according to claim 21, wherein the combinations of R.sub.1, R.sub.2, R.sub.3, R.sub.4 substituents and R.sub.1′, R.sub.2′, R.sub.3′, R.sub.4′ substituents are bearing methylene chains (CH.sub.2).sub.n, wherein n values are within a range of from 2 to 15, and alkyl groups of C.sub.2-C.sub.15.

25. A process for synthesizing a disulfide-containing benzoxazine monomer of formula (I) as defined in claim 21 comprises the following steps consisting of: a) providing a mixture comprising: an amino disulfide compound of formula (III): H.sub.2N—R—NH.sub.2 wherein R is as defined for the monomer of formula (I),  an aldehyde derivative, selected from the group consisting of formaldehyde and paraformaldehyde, or mixtures thereof, and phenolic derivatives of formulae (IV) and (V) ##STR00042## wherein combinations of R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.1′, R.sub.2′, R.sub.3′, R.sub.4′ substituents are independently as defined in claim 1, and wherein R.sub.5 and R.sub.5′, independently, are H. b) stirring the mixture under a temperature of from 50° C. to 130° C. for 1 h to 48 h, for obtaining the monomer of formula (I); wherein the respective stoichiometry of the amino disulfide compound: aldehyde derivative:phenolic derivatives is 1:4: x.sub.1+x.sub.2, with x.sub.1+x.sub.2=2 and 0<x.sub.1;x.sub.2<2.

26. The process according to claim 25, wherein the phenolic derivatives, independently, are at least one of those selected from the group consisting of phenol, guaiacol, creosol, vanillin, vanillic acid, eugenol, iso-eugenol, phloretic acid, coumaric acid, ferulic acid, dihydroferrulic acid, cresols (o-, m- and/or p-), phenols substituted by moieties including at least one of 2 to 15 carbon atoms, cardanol derivatives, anacardic acid, cardol, 2-methylcardol, urushiol, o-allylphenol, m-allylphenol, p-allylphenol, 3-(furan-2-yl)phenol and 1-(4-hydroxyphenyl)-1H-pyrrole-2,5-dione.

27. The process according to claim 25, wherein the temperature of the mixture is of from 60° C. to 130° C., the reaction duration (step b)) is of from 1 h to 48 h.

28. The process according to claim 25, wherein, where the process is carried out without any solvent, the reaction temperature is in the range of values of from 60° C. to 120° C., reaction duration is then of from 1 h to 24 h.

29. The process according to claim 25, wherein, where the process is carried out with a solvent, the reaction temperature is in the range of values of from 70° C. to 130° C., reaction duration is then of from 5 h to 24 h.

30. A process for preparing polybenzoxazine derivative vitrimers comprising executing the process of claim 25 at temperatures within the range of from 100° C. to 250° C. for 1 h to 24 h, for obtaining polybenzoxazine derivatives vitrimers.

31. The process according to claim 30, wherein the curing temperature is of from 150° C. to 200° C.

32. A polybenzoxazine derivative vitrimer, obtainable by the process according to claim 30, presenting at least one of the following characteristics: (i) Tg values of from 0° C. to 250° C.; and (ii) Relaxation temperature values, above the Tg values, of from 0° C. to 250° C.

33. The vitrimer according to claim 32, wherein the vitrimer exhibits at least one of the following characteristics selected from the group consisting of: a relaxation time of from 0.1 s to 2 h, preferably of from 1 s to 1 h, the relaxation time being defined as the time needed at a predetermined temperature for the vitrimer to relax of 50% after the appliance of a strain; the activation energy related to relaxation times of from 10 kJ/mol to 300 kJ/mol; and the reprocessing temperature of from 50° C. to 200° C.

34. The vitrimer according to claim 33, wherein the vitrimer exhibits the characteristics of behaving at least one of as a thermoset and an insolubility in solvents, and swelling properties are as an extent of from 0 to 500% of the initial weight thereof.

35. The vitrimer according to claim 33, wherein the vitrimer constitutes an intermediate layer between at least two substrates.

36. The process according to claim 31, wherein the curing temperature is of from 170° C. to 190° C., the latter range providing curing duration of from 1 h to 3 h.

37. The disulfide-containing benzoxazine monomer according to claim 21, wherein, in formula (II), X and X′ are, independently, at least one of: one of a substituted and an unsubstituted aliphatic C.sub.1-C.sub.20 alkyl group containing heteroatoms; at least one of a substituted and an unsubstituted aliphatic C.sub.2-C.sub.20 alkenyl group containing heteroatoms; wherein the heteroatoms being selected from the groups consisting of N, O and S.

Description

DRAWINGS

[0078] Other features and advantages of the present invention will be readily understood from the following detailed description and drawings among them:

[0079] FIG. 1 shows a synthesis reaction of a benzoxazine monomer from cardanol as a phenolic derivative, in accordance with various embodiments of the present invention.

[0080] FIG. 2 shows a network for a vitrimer obtained through the curing of the cardanol benzoxazine monomer (schematized form), in accordance with various embodiments of the present invention.

[0081] FIG. 3 is a NMR spectrum of the cardanol benzoxazine monomer, in accordance with various embodiments of the present invention.

[0082] FIG. 4 is a FTIR spectrum of cardanol derivatives benzoxazine monomer, in accordance with various embodiments of the present invention.

[0083] FIG. 5 displays the DSC curve of cardanol benzoxazine monomer[[;]], in accordance with various embodiments of the present invention.

[0084] FIG. 6 displays a rheogram of the cardanol derivatives benzoxazine monomer—Evolution of the complex viscosity upon heating at 170° C.; in accordance with various embodiments of the present invention.

[0085] FIG. 7 shows the evolution of the relaxation modulus of a vitrimer obtained through the curing of the cardanol benzoxazine monomer, in accordance with various embodiments of the present invention.

[0086] FIG. 8 show the evolution of the relaxation time t* as a function of 1000/T, in accordance with various embodiments of the present invention.

[0087] FIG. 9 is a schematic view of the ability of recycling/reprocessing of a vitrimer obtained through the curing of the cardanol benzoxazine monomer, in accordance with various embodiments of the present invention.

[0088] FIG. 10 shows the evolution of the adhesive strength of a vitrimer of the Example 2 used to glue two steel blocks as a function of the number of breakage cycles, in accordance with various embodiments of the present invention.

[0089] FIG. 11 shows a synthesis of a benzoxazine monomer from 3-pentadecylphenol as a phenolic derivative, in accordance with various embodiments of the present invention.

[0090] FIG. 12 shows a NMR spectrum of 3-pentadecylphenol benzoxazine monomer, in accordance with various embodiments of the present invention.

[0091] FIG. 13 displays the DSC curve of 3-pentadecylphenol benzoxazine monomer, in accordance with various embodiments of the present invention.

[0092] FIG. 14 shows a synthesis of a benzoxazine monomer from phloretic acid as a phenolic derivative, in accordance with various embodiments of the present invention.

[0093] FIG. 15 shows a synthesis of a benzoxazine monomer from eugenol as a phenolic derivative, in accordance with various embodiments of the present invention.

DETAILED DESCRIPTION

Example 1: Synthesis of a Benzoxazine Monomer from Cardanol as a Phenolic Derivative

[0094] Synthesis of disulfide-containing benzoxazine monomer was carried out with a mixture of cardanol (CAR) and 4-aminophenyl disulfide (4apds) and paraformaldehyde (PFA) reactants (FIG. 1).

[0095] Cardanol (5.97 g, 2 eq, 0.02 mol), 4-apds (2.48 g, 1 eq, 0.01 mol) and paraformaldehyde (1.20 g, 4 eq, 0.04 mol) were added at room temperature in a 100 ml round bottom flask. The flask was heated with an oil bath at 70° C. during 7 h and the reaction media was stirred with a mechanical stirrer. The reaction product was a yellow wax and was used without further purifications for the elaboration of vitrimer materials.

[0096] The FIG. 3 is displaying the NMR spectrum (AVANCE III HD Bruker spectrometer) of cardanol derivatives benzoxazine monomer with various n values, as showed in FIG. 1.

[0097] FIG. 4 is showing an FTIR spectrum (Bruker TENSOR 27) of cardanol derivatives benzoxazine monomer with various n values.

[0098] The DSC results (FIG. 5) were obtained using an apparatus (Netzsch DSC 204 F1 Phoenix apparatus) with 10° C./min in an inert atmosphere. The DSC curve shows an exothermic peak starting at a temperature of 130° C., with a maximum located at 194° C., corresponding to the ring opening of the benzoxazine moiety upon heating.

[0099] The rheogram of the cardanol derivatives benzoxazine monomer is showed in FIG. 6.

[0100] The rheogram is performed under the following conditions: 1 Hz, with linear amplitude from 1 to 0.1%; 25 mm plates. The test is performed following a heating ramp from 100° C. to 170° C. at 10° C./min followed by an isothermal measurement at 170° C.

[0101] The test is showing the evolution of the complex viscosity as a function of time. The monomer is first softening as attested by the decrease of its complex viscosity, reaching a value of 100 mPa.Math.s, meaning it can be easily processed by typical processing tool like infusion, etc.

[0102] After 15 minutes, the complex viscosity is increasing to 3.10.sup.4 mPa.Math.s due to the benzoxazine ring opening and the first step of reaction. A second gelation is observed after 50 minutes as the crosslinking process is being achieved.

Example 2: Synthesis of a Vitrimer Obtained Through the Curing of the Cardanol Derivatives Benzoxazine Monomer

[0103] The benzoxazine monomer obtained in Example 1 was polymerized in a Teflon mold at 170° C. during 1 h, followed by a post cure of 30 minutes at 190° C., for the obtention of a cardanol derivatives polybenzoxazine vitrimer material (FIG. 2).

[0104] Pieces of the samples were immersed in DMF, toluene and water to measure their ability to swell. In toluene and DMF, the samples swell of 430% and 300%, respectively. In water, it does not swell.

[0105] The Tg of the material, defined as the maximum of the loss modulus measured by rheological measurement, is 50° C.

[0106] The FIG. 7 is showing the evolution of the relaxation modulus of the cardanol derivatives benzoxazine vitrimer at different temperatures as evidence of the vitrimer behavior. The drop of relaxation modulus is representative of the shape changes of the material. At 80° C., it takes 89 s for the material to lose 50% of its modulus. At 120° C., it takes 11 seconds. The relaxation temperature of the material is comprised between 50 and 150° C.

[0107] The evolution of relaxation time, defined as the time needed at a defined temperature for the material to relax of 50% of its initial modulus, is reported on FIG. 8, as a function of 1000/T. The evolution of ln(t*) as a function of 1000/T is linear, and is following an Arrhenius law, which is evidence of the associative behaviour of the vitrimer. The activation energy of the material can be calculated from the slope of the trendline, and is 65 kJ/mol.

[0108] The reprocessing temperature of the material is between 80° C. and 120° C.

[0109] FIG. 9 shows an example of the vitrimer of the Example 2 that has undergone a torsion at 80° C., then a grinding step and reshape and reprocess steps.

[0110] FIG. 10 shows the evolution of the adhesive strength of the vitrimer of the Example 2 used to glue two steel blocks. A scheme is reported onto the figure for the sake of clarity of the test. After each tensile test leading to the break of the assembly, the two blocks were re-assembled together by heating them and the vitrimer of the Example 2 at 120° C. for 10 minutes under a pressure of 1 bar. Initially the adhesion strength was measured to be equal to 1.08 MPa, without showing any significant decrease after 3 break/healing steps. After that the third breakage, the assembly was rebonded by heating at 120° C. for 2 minutes and pressing at under 8 bars, leading to a clear increase of the adhesion strength (5 kN). After the breakage the assembly was reformed and retested 3 times, showing the rebonding ability. At the end of the 6th cycle, it was possible to disassembly the vitrimer from the cube by heating at 120° C. for 5 minutes and by pulling the steel cubes. After its cooling, it was possible to still use the vitrimer to bond the metal cubes.

Example 3: Synthesis of a Benzoxazine Monomer from 3-Pentadecylphenol as a Phenolic Derivative

[0111] Synthesis of disulfide-containing benzoxazine monomer was carried out with a mixture of 3-pentadecylphenol (3-PDP) and 4-aminophenyl disulfide (4apds) and paraformaldehyde (PFA) reactants (FIG. 11).

[0112] 3-pentadecylphenol (6.09 g, 2 eq, 0.02 mol), 4-apds (2.48 g, 1 eq, 0.01 mol) and paraformaldehyde (1.20 g, 4 eq, 0.04 mol) were added at room temperature in a 100 ml round bottom flask. The flask was heated with an oil bath at 85° C. during 7 h and the reaction media was stirred with a mechanical stirrer. The reaction product was a light yellow wax and was used without further purifications for the elaboration of vitrimer materials.

[0113] The FIG. 12 is displaying the NMR spectrum (AVANCE III HD Bruker spectrometer) of 3-pentadecylphenol derivatives benzoxazine monomer.

[0114] The DSC results (FIG. 13) were obtained using an apparatus (Netzsch DSC 204 F1 Phoenix apparatus) with 10° C./min in an inert atmosphere. The DSC curve shows a broad exothermic peak starting at a temperature of 170° C., with a maximum located at 232° C., corresponding to the ring opening of the benzoxazine moiety upon heating.

[0115] The curing of the 3-pentadecylphenol derivatives benzoxazine monomer was monitored by rheological measurement.

[0116] The rheogram is performed under the following conditions: 1 Hz, with linear amplitude from 1 to 0.1%; 25 mm plates. The test is performed following a heating ramp from 100° C. to 200° C. at 10° C./min followed by an isothermal measurement at 200° C.

[0117] The complex viscosity is recorded as a function of time. The monomer is first softening as attested by the decrease of its complex viscosity, reaching a value of 100 mPa.Math.s, meaning it can be easily processed by typical processing tool like infusion, etc.

[0118] After 200 minutes, the complex viscosity is increasing to 10.sup.4 mPa.Math.s due to the benzoxazine ring opening.

Example 4: Synthesis of a Vitrimer Obtained Through the Curing of the 3-Pentadecylphenol Benzoxazine Monomer

[0119] The benzoxazine monomer obtained in Example 3 was polymerized in a Teflon mold at 200° C. during 2 h, followed by a post cure of 2 h minutes at 220° C., for the obtention of a 3-pentadecylphenol polybenzoxazine vitrimer material.

[0120] Pieces of the samples were immersed in DMF, toluene and water to measure their ability to swell. In toluene and DMF, the samples swell of 800% and 600%, respectively. In water, it does not swell.

[0121] The Tg of the material, defined as the maximum of the loss modulus measured by rheological measurement, is 18° C.

[0122] The evolution of the relaxation modulus of the 3-pentadecylphenol benzoxazine vitrimer was followed by rheology at different temperatures as an evidence of the vitrimer behavior. The drop of relaxation modulus is representative of the shape changes of the material. At 80° C., it takes 42 s for the material to lose 50% of its modulus. At 120° C., it takes 6 seconds. The relaxation temperature of the material is comprised between 40° C. and 150° C.

[0123] The reprocessing temperature of the material is between 40° C. and 120° C.

Example 5: Synthesis of a Benzoxazine Monomer from Phloretic Acid as a Phenolic Derivative

[0124] Synthesis of disulfide-containing benzoxazine monomer was carried out with a mixture of phloretic acid (PA) and 4-aminophenyl disulfide (4apds) and paraformaldehyde (PFA) reactants (FIG. 14).

[0125] Phloretic acid (3.32 g, 2 eq, 0.02 mol), 4-apds (2.48 g, 1 eq, 0.01 mol) and paraformaldehyde (1.20 g, 4 eq, 0.04 mol) were added at room temperature in a 100 ml round bottom flask. The flask was heated with an oil bath at 85° C. during 7 h and the reaction media was stirred with a mechanical stirrer. The reaction product was a brown wax and was used without further purifications for the elaboration of vitrimer materials.

[0126] .sup.1H NMR (CDCl.sub.3): [a] 2.5-2.6 ppm; [b] 2.8-2.9 ppm; [4] 4.5 ppm; [5] 5.3 ppm; [1,2] 6.5-6.7 ppm; [d] 6.75 ppm; [6,7] 6.8-6.9 ppm; [3] 7.0 ppm; [c] 7.15 ppm; [8,9] 7.3 ppm; [e] 11.5 ppm.

[0127] The DSC results were obtained using an apparatus (Netzsch DSC 204 F1 Phoenix apparatus) with 10° C./min in an inert atmosphere. The DSC curve shows a broad exothermic peak starting at a temperature of 130° C., with a maximum located at 176° C., corresponding to the ring opening of the benzoxazine moiety upon heating.

[0128] The curing of the phloretic acid benzoxazine monomer was monitored by rheological measurement.

[0129] The rheogram is performed under the following conditions: 1 Hz, with linear amplitude from 1 to 0.1%; 25 mm plates. The test is performed following a heating ramp from 100° C. to 170° C. at 10° C./min followed by an isothermal measurement at 170° C.

[0130] The complex viscosity is recorded as a function of time. The monomer is first softening as attested by the decrease of its complex viscosity, reaching a value of 100 mPa.Math.s, meaning it can be easily processed by typical processing tool like infusion, etc.

[0131] After 10 minutes, the complex viscosity is increasing to 4.10.sup.4 mPa.Math.s due to the benzoxazine ring opening.

Example 6: Synthesis of a Vitrimer Obtained Through the Curing of the Phloretic Acid Benzoxazine Monomer

[0132] The benzoxazine monomer obtained in Example 5 was polymerized in a Teflon mold at 170° C. during 2 h, followed by a post cure of 30 minutes at 190° C., for the obtention of a phloretic acid polybenzoxazine vitrimer material.

[0133] The evolution of the relaxation modulus of the phloretic acid benzoxazine vitrimer was followed by rheology at different temperatures as an evidence of the vitrimer behavior. The drop of relaxation modulus is representative of the shape changes of the material. At 150° C., it takes 95 minutes for the material to lose 50% of its modulus. The relaxation temperature of the material is comprised between 120 and 190° C.

[0134] The reprocessing temperature of the material is between 80° C. and 120° C.

Example 7: Synthesis of a Benzoxazine Monomer from Eugenol as a Phenolic Derivative

[0135] Synthesis of disulfide-containing benzoxazine monomer was carried out with a mixture of eugenol (EUG) and 4-aminophenyl disulfide (4apds) and paraformaldehyde (PFA) reactants (FIG. 15).

[0136] Eugenol (3.28 g, 2 eq, 0.02 mol), 4-apds (2.48 g, 1 eq, 0.01 mol) and paraformaldehyde (1.20 g, 4 eq, 0.04 mol) were added at room temperature in a 100 ml round bottom flask. The flask was heated with an oil bath at 85° C. during 7 h and the reaction media was stirred with a mechanical stirrer. The reaction product was a brown wax and was used without further purifications for the elaboration of vitrimer materials.

[0137] .sup.1H NMR (CDCl.sub.3): [c] 3.4 ppm; [f] 3.8-3.9; [4] 4.5 ppm; [a] 5.1-5.2 ppm; [5] 5.3 ppm; [b] 5.9 ppm; [d,e] 6.4-6.6 ppm; [1,2] 6.5-6.7 ppm; [6,7] 6.8-6.9 ppm; [3] 7.0 ppm; [8,9] 7.3 ppm.

[0138] The DSC results were obtained using an apparatus (Netzsch DSC 204 F1 Phoenix apparatus) with 10° C./min in an inert atmosphere. The DSC curve shows a broad exothermic peak starting at a temperature of 125° C., with a maximum located at 200° C., corresponding to the ring opening of the benzoxazine moiety upon heating.

[0139] The curing of the eugenol benzoxazine monomer was monitored by rheological measurement.

[0140] The rheogram is performed under the following conditions: 1 Hz, with linear amplitude from 1 to 0.1%; 25 mm plates. The test is performed following a heating ramp from 100° C. to 170° C. at 10° C./min followed by an isothermal measurement at 170° C.

[0141] The complex viscosity is recorded as a function of time. The monomer is first softening as attested by the decrease of its complex viscosity, reaching a value of 100 mPa.Math.s, meaning it can be easily processed by typical processing tool like infusion, etc.

[0142] After 45 minutes, the complex viscosity is increasing to 2.10.sup.4 mPa.Math.s due to the benzoxazine ring opening.

Example 8: Synthesis of a Vitrimer Obtained Through the Curing of the Eugenol Benzoxazine Monomer

[0143] The benzoxazine monomer obtained in Example 7 was polymerized in a Teflon mold at 170° C. during 2 h, followed by a post cure of 30 minutes at 190° C., for the obtention of a eugenol derivatives polybenzoxazine vitrimer material.

[0144] The evolution of the relaxation modulus of the phloretic acid benzoxazine vitrimer was followed by rheology at different temperatures as an evidence of the vitrimer behavior. The drop of relaxation modulus is representative of the shape changes of the material. At 120° C., it takes 7 minutes for the material to lose 50% of its modulus. The relaxation temperature of the material is comprised between 50 and 150° C.

[0145] The reprocessing temperature of the material is between 120° C. and 180° C.