Benzoxazine derivative vitrimer

Abstract

The present invention relates to ester-containing benzoxazine monomers, processes for synthesizing the monomers, and vitrimers obtained by polymerization of the ester-containing benzoxazine monomers. The present invention also relates to the use of vitrimers as reversible adhesives, sealants, coatings, or encapsulation systems for substrates selected from the group consisting of metals, polymers, glasses, and ceramic materials.

Description

[Technical Field]

[0001] The present invention relates to the field of ester-containing benzoxazine derivative vitrimers, and processes for their preparation and use in various applications. [Background technology]

[0002] Composites are almost always made from thermosetting resins, which are the materials of choice for many applications due to their dimensional stability, mechanical properties, and creep / chemical resistance. However, as a result of their permanent molecular structure, they cannot be recycled or reprocessed and end up in landfills.

[0003] A chemical approach to address this drawback is the introduction of exchangeable chemical bonds, resulting in dynamic crosslinks. Polymer networks containing such exchangeable bonds are also known as covalent adaptive networks (CANs) (W. Denissen et al. - Wim Denissen, Johan M. Winne, and Filip E. Du Prez, Chem. Sci., 2016, 7, 30-38). CANs can be further classified into two groups, either dissociative or conjugated, depending on the exchange mechanism. First, chemical bonds are first broken and then reformed in a different location. The Diels-Alder reaction is the most common mechanism for dissociative CANs. Second, polymer networks are characterized by a fixed crosslink density that does not depolymerize upon heating. Because covalent bonds are broken only when new bonds are formed, these networks are permanent and dynamic. The first reported conjugated CANs (2005) were based on a light-mediated reaction using, for example, allyl sulfide. Later, a similar exchange mechanism was introduced using trithiocarbonates and alternative radical generators. In 2011, Leibler et al. (D. Montarnal, M. Capelot, F. Tournilhac, and L. Leibler, Science, 2011, 334, 965-968) expanded the field of bonded CANs by adding a suitable transesterification catalyst to epoxy / acid or epoxy / anhydride polyester-based networks, resulting in persistent polyester / polyol networks that exhibited a slow decrease in viscosity upon heating. This unique feature of fused silica had not previously been observed in organic polymeric materials. Therefore, the inventors introduced the term vitrimers to these materials.

[0004] Vitrimers represent a third class of polymeric materials due to their exceptional functionality. The dynamic nature of this covalent network results from reversible chemical bonds, allowing the material to be repaired, recycled, and reprocessed like a thermoplastic. These exchange reactions are triggered by an external stimulus, most frequently temperature. The viscosity of vitrimers gradually decreases upon heating, relieving internal stresses while making the network malleable. Network integrity across a full range of applications ensures mechanical and solvent resistance.

[0005] Dynamic transesterification reactions, following the prototype vitrimer developed by Leibler et al. (cited above) in 2011, have shown great importance over the past decade. These high-temperature-induced chemical exchanges between ester bonds and hydroxyl groups are responsible for topological rearrangements. The transesterification mechanism has been implemented in crosslinked networks to engineer self-repairable, recyclable, and reprocessable materials with tunable properties.

[0006] Demongeot et al. (A. Demongeot, R. Groote, H. Goossens, T. Hoeks, F. Tournilhac, and L. Leibler, Macromolecules, 2017, 50(16), 6117-6127) adapted the vitrimer concept to commercially available thermoplastics. Crosslinked polybutylene terephthalate (PBT) vitrimers based on transesterification were prepared by reactive extrusion. In addition to improving manufacturing techniques and the potential scope of these networks, the global environmental situation is urging the scientific community to promote sustainable polymers derived from naturally occurring raw materials. Altuna et al. (FI Altuna, V. Pettarin, and R. Williams, Green Chem., 2013, 15, 3360-3366) attempted to generate a fully biobased polyester exhibiting properties reminiscent of vitrimers, starting from epoxidized soybean oil and aqueous citric acid. Furthermore, Legrand et al. (A. Legrand and C. Soulie-Ziakovic, Macromolecules, 2016, 49, 5893-5902) developed silica-reinforced epoxy vitrimer nanocomposites with enhanced properties, enabling an expansion of the application scale of vitrimer networks.

[0007] Polybenzoxazines are a new class of thermosetting resins with excellent mechanical and thermal properties. Like many other thermosetting resins, they cannot be remolded, reprocessed, or recycled. Some examples showing reasonable levels of healing ability have been reported (L. Zhang, Z. Zhao, Z. Dai, L. Xu, F. Fu, T. Endo, X. Liu, ACS Macro. Lett. 2019, 8, 5, 506-511; and Arslan M., Kiskan B., Y. Yagci, Sci. Rep. 2017, 7, 5207). However, polybenzoxazines remain a high-performance material class even when they do not exhibit any vitrimer capabilities. Such sustainable vitrimers could expand the use of polybenzoxazines toward smart coatings, reversible adhesives, and even recyclable matrix resins for composites. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] Wim Denissen and two others, "Vitrimers: permanent organic networks with glass-like fluidity," Chemical Science, (UK), Royal Society of Chemistry, January 2016, Vol. 7, No. 1, pp. 30-38 [Non-patent document 2] Ludwik Leibler and three others, "Silica-Like Malleable Materials from Permanent Organic Networks," Science (USA), American Association for the Advancement of Science, November 2011, Vol. 334, No. 6058, pp. 965-968 [Non-patent document 3] Adrien Demongeot and five others, "Cross-Linking of Poly(butylene terephthalate) by Reactive Extrusion Using Zn(II)Epoxy-Vitrimer Chemistry," Macromolecules, American Chemical Society, August 2017, Vol. 50, No. 16, pp. 6117-6127 [Non-patent document 4] Facundo I. Altuna and two others, "Self-healable polymer networks based on the cross-linking of epoxidised soybean oil by an aqueous citric acid solution," Green Chemistry, (UK), Royal Society of Chemistry, January 2013, Vol. 15, No. 12, pp. 3360-3366 [Non-Patent Document 5] Aurelie Legrand and 1 other author, "Silica-Epoxy Vitrimer Nanocomposites," Macromolecules (USA), American Chemical Society, August 2016, Vol. 49, No. 16, pp. 5893-5902 [Non-patent document 6] Lei Zhang and six others, "Unexpected Healability of an Ortho-Blocked Polybenzoxazine Resin," Macro Letters (USA), American Chemical Society, May 2019, Vol. 8, No. 5, pp. 506-511 [Non-Patent Document 7] Mustafa Arslan and two others, "Recycling and Self-Healing of Polybenzoxazines with Dynamic Sulfide Linkages," Scientific Reports (UK), Nature Research, July 2017, Vol. 7, No. 5207, pp. 1-11 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has the technical problem of providing a solution to at least one of the drawbacks of the prior art cited above. [Means for solving the problem]

[0010] To this end, the present invention relates to ester-containing benzoxazine monomers of formula (I):

[0011] [ka]

[0012] wherein, independently, -At least one R * groups are present in the benzoxazine ring and are selected from the group consisting of H, an aliphatic C1-C6 alkyl group, OH, an aliphatic C1-C6 alkoxy group, an aliphatic C2-C6 alkenyl group, an aliphatic C1-C6 alkyl or alkoxy substituted or unsubstituted phenyl group,

[0013] [ka] selected from the group consisting of: -R is an aliphatic C1-C6 alkyl group, an aliphatic C1-C6 alkyl or alkoxy substituted or unsubstituted phenyl group, a C2-C6 alkenyl group, -(CH2) n3 - (wherein n3 is an integer of 1 to 10), -CH (an aliphatic C1-C6 alkyl group), -CH (an aliphatic C1-C6 alkyl or alkoxy substituted or unsubstituted phenyl group), or R is omitted; -R' is H, -(CH2) n3 -OH, and

[0014] [ka] is selected from the group consisting of (wherein n = n1 = n2, and each R is independently an integer of 1 to 3; at least one R * and n3 is as defined above); -R'' is an aliphatic C1-C6 alkyl group; -p is an integer from 1 to 50.

[0015] The ester-containing benzoxazine monomers of the present invention are advantageously suitable for obtaining polybenzoxazine derivative vitrimers, which undergo polymerization with benzoxazine ring-opening and self-polymerization under heating to form polybenzoxazine derivative vitrimers. Depending on the specific monomer starting product, the vitrimers of the present invention exhibit self-repair, reshapeability, reworkability, and recyclability. In the remainder of this specification, benzoxazine vitrimers always refer to the polymerized form of the ester-linked benzoxazine monomer. "Derivative" means any compound derived from the benzoxazine structure and may have several different moieties or groups that do not modify the basic structure.

[0016] The properties of the polybenzoxazine derivative vitrimers are closely related to the properties of the ester-containing benzoxazine monomers.

[0017] As can be seen from formula (I), the monomer contains benzoxazine ring moieties that allow the monomer to crosslink upon heating, and the exchangeable ester bonds formed after crosslinking facilitate reprocessing of the resulting benzoxazine vitrimers. Benzoxazines impart thermoset properties such as high temperature and flammability capabilities, high strength, thermal stability, low water absorption, chemical resistance, low melt viscosity, and near-zero shrinkage.

[0018] The presence of ester linkages and free aliphatic hydroxyl groups is essential for the formation of a dynamic and reversible network of benzoxazine derivative vitrimers, allowing for recycling, reshaping, and reprocessing of the material. Hydroxyl-terminated amines close the oxazine ring, enabling transesterification. Therefore, the essential characteristics of the monomers of the present invention depend on the benzoxazine-containing moieties, ester linkages, and free aliphatic hydroxyl groups. The Tg of such polybenzoxazines can range from 25°C to 300°C.

[0019] Preferably, the integer p can range from 1 to 30, more preferably from 1 to 20, and most preferably from 1 to 10, these ranges being independently selected for fine tuning the processing temperature and relaxation of the benzoxazine vitrimers obtained by polymerization of the above monomers, and for better mechanical and thermal properties of the vitrimers.

[0020] In the context of this invention, an "aliphatic" group is a straight-chain or branched group.

[0021] At least one R * group, more preferably 1 to 3 R * groups may be present in the benzoxazine ring, R * The group may be H, an aliphatic C1-C4 alkyl group, OH, an aliphatic C1-C4 alkoxy group,

[0022] [ka] is selected from the group consisting of R is an aliphatic C1-C3 alkyl group, an aliphatic C1-C3 alkyl or alkoxy substituted or unsubstituted phenyl group, a C2-C4 alkenyl group, -(CH2) n3 - (wherein n3 is an integer of 1 to 6), -CH (an aliphatic C1-C3 alkyl group), -CH (an aliphatic C1-C3 alkyl or alkoxy substituted or unsubstituted phenyl group), or R may be omitted; R' is H, -(CH2) n3 -OH, and

[0023] [ka] (wherein n=n1=n2, each independently represents an integer of 1 to 3, more preferably 1 or 2; R, R * and n3 are as defined above).

[0024] The present invention also relates to a process for synthesizing an ester-containing benzoxazine monomer of formula (I), the process comprising: a) synthesizing at least one R * a phenolic acid derivative of formula (II) containing a group

[0025] [ka] a polyfunctional molecule or oligomer of formula (III)

[0026] [ka] reacting in the presence of a Bronsted acid type catalyst at a temperature of 25°C to 200°C for 1 hour to 72 hours to produce a phenol-terminated oligomer or molecule of formula (IV);

[0027] [ka] b) reacting a compound of formula (IV) with an amino alcohol bifunctional derivative of formula (V)

[0028] [ka] and a mixture of aldehyde derivatives, reacting the compound (R, R', R'', at least one R) at a temperature ranging from 25°C to 100°C for 0.5 hours to 48 hours; * , n, n1, n2, p are independently at least one R of the phenolic acid derivative; * is in the ortho position relative to the -OH group, R * is as defined above, with the proviso that

[0029] The ester-containing benzoxazine monomer of the present invention is advantageously suitable for obtaining a polybenzoxazine derivative vitrimer by polymerization accompanied by benzoxazine ring-opening and self-polymerization under heating.

[0030] Applicants have shown that certain starting reactants provide ester-containing benzoxazine monomers which, after polymerization, give polybenzoxazine derivative vitrimers containing polymerized benzoxazine.

[0031] The term "derivative" in the expressions "phenolic acid derivative", "amino alcohol bifunctional derivative" and "aldehyde derivative" means any compound having / retaining the phenolic acid, amino alcohol bifunctional and aldehyde base structure, respectively.

[0032] The benzoxazine rings, resulting from the reaction of certain derivatives (formulas (II)-(V)), allow the material to crosslink (process) upon heating, and the exchangeable and reversible ester bonds and free aliphatic hydroxyl groups aid in reprocessing. The benzoxazine ring moiety imparts thermosetting properties such as high temperature and flammability performance, high strength, thermal stability, low water absorption, chemical resistance, low melt viscosity, and near-zero shrinkage.

[0033] Thus, the first step (step a)) of the synthesis of ester-containing benzoxazine monomers typically corresponds to a Fischer esterification between an aliphatic hydroxyl-terminated polyfunctional molecule or oligomer (ditelechelic) of formula (III) and a phenolic acid derivative of formula (II) in the presence of a Bronsted acid-type catalyst, which may be introduced in catalytic amounts.

[0034] The phenolic acid derivative (formula (II)) has at least one, more preferably 1 to 3 R * The R group may be related to the nature of the bridge between the ester bond and the phenol ring.

[0035] The phenolic acid derivative (formula (II)) is preferably an R-substituted phenolic acid derivative that does not interfere with the ortho position of the phenol to avoid steric hindrance that may adversely affect the kinetics of step a) or the oxazine ring closure of step b). * It is advantageous to retain the R * The group is an R *may be a short chain group, provided that is H.

[0036] In some embodiments, there may be two phenolic ortho positions, each of which is R * It is H for the group.

[0037] The phenolic acid derivative may preferably be an aliphatic or aromatic phenolic acid, or a combination thereof.

[0038] The phenolic acid derivatives may more preferably be selected from the group consisting of mono-, di-, and tri-hydroxybenzoic acid derivatives, anacardic acid derivatives, hydroxycinnamic acid derivatives, aliphatic X-hydroxyphenyl acid derivatives (X is 2 to 4), aliphatic diphenolic acid derivatives, and triphenolic acid derivatives, or mixtures thereof, although triphenolic acids are less preferred due to steric hindrance.

[0039] The most preferred aliphatic mono-, di-, tri-hydroxybenzoic acid derivatives may be of formula (VI):

[0040] [ka] (In the formula, R is omitted, and at least one of R1 to R5 is R * wherein at least one of R1-R5 is selected from the group consisting of 1, 2, and 3 hydroxyl groups, at least one H is in the ortho position of the phenol, and the remainder are H and at least one of an aliphatic alkyl group C1-C6).

[0041] In particular, in formula (VI), at least one combination of R1 to R5 may be selected from the group consisting of: R1=OH, R2=H, R3=R4=R5=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2, R2=OH, R1=R3=H, R4=R5=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2, R3=OH, R2=R4=H, R1=R5=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2, R4=OH, R3=R5=H, R1=R2=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2, R1=R2=OH, R3=H, R4=R5=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2, R1=R3=OH, R2=R4=H, R5=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2, R1=R4=OH, R2=R3=R5=H, R1=R5=OH, R2=R4=H, R3=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2, R2=R3=OH, R1=R4=H, R5=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2, R2=R4=OH, R1=R3=R5=H, R1=R3=R5=OH, R2=R4=H, and R2=R3=R4=OH, R1=R5=H.

[0042] The most preferred anacardic acid derivatives may be of formula (VII) where R = R * and

[0043] [ka] R is omitted, and R6 is

[0044] [ka] (It is).

[0045] The most preferred hydroxycinnamic acid derivatives may be of formula (VIII):

[0046] [ka] (wherein at least one of R1 to R5 is R * wherein at least one of R1-R5 may be selected from the group consisting of 1 and 2 hydroxyl groups, at least one H is in the ortho position of the phenol, and the remainder are H and at least one of an aliphatic alkyl group or an alkoxy group C1-C6).

[0047] In particular, in formula (VIII), at least one combination of R1 to R5 may be selected from the group consisting of: R5=OH, R4=H, R1=R2=R3=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2, R4=OH, R3=R5=H, R1=R2=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2, R3=OH, R2=R4=H, R1=R5=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2, R3 = OH, R2 = O (C1-C6 alkyl group), R1 = R4 = R5 = H, and R2=R3=OH, R1=R4=H, R5=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2.

[0048] The most preferred aliphatic X-hydroxyphenyl acid derivatives may be selected from the group consisting of aliphatic di-hydroxyphenyl acids (X=2), aliphatic tri-hydroxyphenyl acids (X=3) and aliphatic tetra-hydroxyphenyl acids (X=4) of formula (IX), or mixtures thereof;

[0049] [ka] (In the formula, -R7 corresponds to R and is (CH2) regardless of the nature of the X-hydroxyphenyl fatty acid derivative. n4 , CH(CH2) n5 -(aliphatic C1-C6 alkyl or alkoxyalkyl or alkoxy substituted or unsubstituted phenyl group), n4 is an integer of 1 to 12, preferably 1 to 10, n5 is an integer of 0 to 12, preferably 0 to 10), CH(CH2) n5 (CH), CH(CH(CH)), C(CH), CH(aliphatic C-C alkyl or alkoxyalkyl or alkoxy substituted or unsubstituted phenyl groups); -R in the ring * The number of R depends on the number of hydroxyl groups in the ring, and at least one R * , preferably 1 to 3 are H toward the ortho position of the phenol, and independently (CH) n4 CH3, (CH2) n4 -(aliphatic C1-C6 aliphatic alkyl or alkoxy substituted or unsubstituted phenyl group) (wherein n4 is an integer of 1 to 12, preferably 1 to 10, more preferably 1 to 6), and (CH2) n4 (CH(CH3)2); -The integer q is comprised between 1 and 3).

[0050] When n5 is 0, the (CH2) group is omitted.

[0051] The most preferred diphenolic acid derivatives are those of formula (X):

[0052] [ka] (In the formula, In each phenol ring, at least one (preferably 1 to 3) R * is H towards the ortho position of the phenol, otherwise R *and R2 is independently (CH2) n4 CH3, (CH2) n4 -(aliphatic C1-C6 aliphatic alkyl or alkoxy substituted or unsubstituted phenyl group), and (CH2)n4(CH(CH3)2), where n4 is an integer from 1 to 12, preferably from 1 to 10, more preferably from 1 to 6; R1 is (CH2) n5 (wherein n5 is an integer from 1 to 3), CH(CH2) n5 (CH), CH(CH(CH)), and C(CH), (CH) n5 is most preferred in order to reduce steric hindrance.

[0053] In the above diphenolic acid derivatives, R=-R1-C-R2- moiety. 4,4-bis(4-hydroxyphenyl)valeric acid (VA) is most preferred.

[0054] The polyfunctional molecule or oligomeric compound of formula (III) is important for selecting the processing temperature of the benzoxazine polymer.

[0055] The compound of formula (III) may advantageously have a p value of 1 to 30, more preferably 1 to 20, especially 1 to 10, and more preferably, when R'=H, may represent a polyethylene glycol (PEG) having a molecular weight (MW) ranging from 4 MW of C2H4O units to 50 MW of C2H4O units (the MW of a C2H4O unit is classically about 44.05 g / mol). Due to their availability, it is preferred to use commercially available PEGs, such as PEG200 to PEG2200.

[0056] In compounds of formula (III), when R'=H, the value of p can be from 1 (ethylene glycol) to 3 (triethylene glycol - TEG).

[0057] In some other embodiments, the compound of formula (III) can be glycerol (R' = CH2OH).

[0058] Bronsted acid catalysts are commonly used in Fischer esterification, including paratoluenesulfonic acid (APTS), anhydrous hydrochloric acid (HCl), phosphoric acid (HP0), methanoic acid (CH-COH), sulfuric acid, tosylic acid, and Lewis acids such as scandium(III) triflate. The catalyst content is 0.5% to 2% by weight.

[0059] Step a) may be advantageously carried out at a temperature ranging from 60°C to 150°C, most preferably from 100°C to 140°C, for the best synthesis yields of more than 95%, the temperature chosen depending on the nature of the reactants, i.e. the melting temperature of the reactant medium.

[0060] Advantageously, step a) is carried out for 12 to 48 hours to obtain a maximum yield of at least 95%, the duration being based on the reaction rate.

[0061] The stoichiometric ratio of the starting reactants, phenolic acid derivative:polyfunctional molecule or oligomer, in step a) may preferably be 1.0-3.0 equivalents:1.0 equivalent, resulting in 1.0 equivalent of phenol-terminated oligomer or molecule.

[0062] The second step of the process, step b), corresponds to a Mannich condensation type reaction of the phenol-terminated oligomer or molecule (formula IV) of step a) with an amino alcohol bifunctional derivative (formula (V)) and an aldehyde derivative, optionally in the presence of a catalyst. Therefore, step b) does not use a catalyst, making it easier to carry out.

[0063] Advantageously, the amino alcohol bifunctional derivative of formula (V) comprises a linear amino alcohol derivative having a primary amine moiety and an aliphatic hydroxyl moiety in order to obtain an oxazine ring in the highest yield and under the best reaction conditions.

[0064] The aminoalcohol bifunctional derivative of formula (V) may more preferably be selected from the group consisting of 2-aminoethanol, 2-amino-2-methylpropanol, 5-aminopentan-1-ol, heptaminol and diglycolamine.

[0065] Preferably, the aldehyde derivative is formaldehyde,

[0066] [ka] (wherein m is an integer of 8 to 100), Acetaldehyde, propionaldehyde, butyraldehyde, polyoxymethylene, and substituted or unsubstituted aliphatic C-C alkyl esters of the general formula R9CHO, where R9 is a substituted or unsubstituted aliphatic C1-C alkyl ester optionally containing heteroatoms. 20 The alkyl group is an aldehyde, or a mixture thereof.

[0067] In the aldehyde derivatives, R is preferably a substituted or unsubstituted aliphatic C-C alkyl group optionally containing heteroatoms such as N, O, S, etc. 15 alkyl group, more preferably R' can be a substituted or unsubstituted aliphatic C1-C8 alkyl group optionally containing an optional heteroatom.

[0068] The temperature range of step b) may be preferably 75°C to 100°C, more preferably 75°C to 95°C, which can provide a maximum conversion yield of at least 95%.

[0069] Advantageously, step b) is carried out for a period of between 1 hour and 12 hours, most preferably between 2 hours and 4 hours, for a maximum yield of at least 95%.

[0070] One advantage of the present invention is that step b) is carried out without any catalyst. However, several catalysts can be used to catalyze the transesterification reaction (step b), such as Zn(II) (R 10 )2(wherein, R 10preferentially Cl - , CH3CO2 - , CH3-C(=O)-O - , CH3COCHCOCH3 - , CH3(CH2) r:1-15 CH2CO2 - The catalyst may be selected from the group consisting of triazobicyclodecane (TBD); triphenylphosphine (PPh3) and paratoluenesulfonic acid (APTS). It should be noted that the presence of the catalyst slightly improves the char yield (flame retardancy) of the resulting benzoxazine monomer. This increased char yield may be 15% to 30%. The catalyst content may be 0.5% to 2% by weight.

[0071] The stoichiometric ratio of the starting reactants in step b), phenol-terminated oligomer or molecule, aminoalcohol bifunctional derivative, and aldehyde derivative, respectively, can be preferably 1.0 equivalent:1.0-18.0 equivalents:2.0-36.0 equivalents, resulting in 1.0 equivalent of ester-containing benzoxazine monomer.

[0072] The particular range of stoichiometric ratios depends on the respective degrees of functionality of the amino alcohol bifunctional derivative and the aldehyde derivative. Furthermore, the selected stoichiometric ratio ranges of both the amino alcohol bifunctional derivative and the aldehyde derivative preferably avoid the formation of any linear and / or aliphatic reaction by-products, such as oxazolidines, triaza derivatives, or condensed derivatives.

[0073] Preferentially, the entire process is carried out with bio-based reactants.

[0074] The monomer synthesis may most preferably be solvent-free, although solvents may be added to dissolve the starting reactants. This process comprises one-step synthesis, which is one of the advantages of the present invention.

[0075] Advantageously, the overall synthesis may generally not require further monomer purification in order to practice the invention, although, if necessary, purification of the monomers may be carried out by any known technique (vacuum, distillation, etc.).

[0076] The reaction mixture of both steps a) and b) is stirred using a classical mechanical stirrer or any non-limiting means.

[0077] This process can be carried out by any known means known to those skilled in the art using suitable vessels on either a laboratory or industrial scale.

[0078] The present invention also relates to a process for preparing a polybenzoxazine derivative vitrimer, which comprises polymerizing an ester-containing benzoxazine monomer of the present invention or as obtained by the above process at a temperature in the range of 100°C to 250°C for 1 hour to 24 hours to obtain a polybenzoxazine derivative vitrimer.

[0079] According to the process for preparing vitrimers of the present invention, the polymerization step, which is the curing step, opens the benzoxazine rings, allowing them to react with themselves to form a three-dimensional network. Once cooled, the material retains its shape for several months, typically 2-4 months. Reheating to at least 100°C for a few minutes exchanges the ester bonds with aliphatic hydroxyl groups, allowing the material to be reshaped, recycled, or reprocessed while maintaining structural integrity and covalent bond count. Considering that the Mannich condensation reaction is quantitative, nearly two hydroxyl groups can react with each ester bonded by transesterification (even after curing). The behavior of vitrimers is characterized by the vitrimer's glass transition (T), which can also be considered the temperature at which transesterification reactions significantly increase. V The behavior of the vitrimer was demonstrated through several experiments. After the curing step, the vitrimer was VBy heating to higher temperatures, the initial shape of the vitrimer can be engineered into other original shapes. For example, the vitrimer can be crushed into a powder and reshaped or reprocessed at 150°C in a few minutes. However, the shape remains stable at room temperature.

[0080] The polymerization time depends on the curing temperature and / or the nature of the ester-containing benzoxazine monomer. The polymerization temperature is selected for a given monomer so that it is higher than the temperature required to synthesize the monomer. Generally, the higher the polymerization temperature, the shorter the curing time. For example, if the polymerization temperature is 250°C, the curing time will be at least 1 hour, and if the polymerization temperature is 100°C, the curing time may be 24 hours or less. Preferably, the curing temperature is 140°C to 200°C, more preferably 140°C to 180°C, and in the range of 140°C to 180°C, the curing time will be 1.5 to 3 hours, preferably 1.5 to 2.5 hours. Polymerization can be carried out by any known heating means, such as laser light and infrared radiation.

[0081] The process may include a post-polymerization step consisting of a heating step which may preferably be carried out at a higher temperature than the polymerization heating step.

[0082] The present invention also relates to polybenzoxazine derivative vitrimers obtainable by the above process, which exhibit at least one of the following characteristics: (i) a Tv value of 120°C to 220°C; preferably 150°C to 200°C, more preferably 150°C to 170°C; (ii) T of 120°C to 270°C, preferably 150°C to 200°C, more preferably 150°C to 180°C V Relaxation temperature value above the value.

[0083] Vitrimer T V The value generally depends on the nature and content of the catalyst of step b), if present.

[0084] The relaxation temperature typically corresponds to the relaxation temperature of the vitrimer after physical deformation such as strain, eg twisting, is applied without any observed decomposition of the vitrimer.

[0085] Advantageously, the vitrimers may also exhibit at least one of the following characteristics selected from the group consisting of: The relaxation time is between 0.5 seconds and 2 hours, preferably between 1 second and 1 hour, and more preferably between 5 seconds and 50 minutes. The relaxation time is conventionally defined as the time it takes for a sample to relax to a value corresponding to 1 / e (0.37) of the original modulus of elasticity. Generally, the higher the temperature, the shorter the relaxation time. For example, at temperatures between 120°C and 150°C, the relaxation time is about 5 minutes to 20 seconds, and at temperatures between 150°C and 200°C, the relaxation time is 20 seconds or less, preferably between 5 and 20 seconds. In some embodiments, the vitrimer can be deformed by 0.1% to 100% of its initial size. the activation energy associated with the relaxation time may be between 50 kJ / mol and 200 kJ / mol, preferably between 70 kJ / mol and 170 kJ / mol, more preferably between 100 kJ / mol and 160 kJ / mol; The processing temperature may be between 100°C and 250°C, preferably between 130°C and 250°C, more preferably between 150°C and 200°C, and most preferably between 150°C and 170°C.

[0086] The vitrimers of the present invention also exhibit the highly advantageous characteristic of being thermosetting and / or insoluble in many solvents, including, but not limited to, water, CHCl3, CHCl2, DMF, THF, aromatic solvents such as toluene and / or xylene, ketones, alcohols, or carboxylic acids. Swelling is observed in the range of 0 to 500% of the initial weight. To evaluate the formation of a crosslinked network, swelling experiments can be performed in various solvents, such as acetone, chloroform, and water. Among these, chloroform is one of the solvents in which the vitrimers can exhibit the highest swelling rate of approximately 100%. In acetone and water, some vitrimers swell by 40% to 50% and 20% to 30%, respectively. Other vitrimers can exhibit swelling properties of 150% to 230% in water.

[0087] The vitrimers of the present invention exhibit self-healing, reshapeable, reworkable, recyclable and reversible adhesive properties.

[0088] The vitrimer can form an interlayer between at least two substrates, such as metals, polymers, glass, and ceramic materials. The resulting composite can be prepared by placing at least one ester-containing benzoxazine monomer between the two substrates and then curing at a temperature that provides the vitrimer without altering the integrity of the substrates. Each substrate can be different from the others.

[0089] The metal substrate can be, but is not limited to, aluminum, iron, steel, and the like.

[0090] The polymer substrate can be polycarbonate, acrylic, polyamide, polyethylene, or terephthalate.

[0091] The benzoxazine vitrimers can then be advantageously used in a variety of technical fields, including but not limited to, electronics, aerospace, defense, and automotive fields.

[0092] The present invention also relates to a composition A comprising: a) an ester-containing benzoxazine monomer of formula (I), and b) at least one or more additional compounds of the organic molecule type, which may or may not contain a benzoxazine moiety.

[0093] Preferably, the organic molecule type may be a polymer with or without benzoxazine moieties.

[0094] The additional compounds may be used to improve the properties (ie, viscosity, mechanical and thermal properties) of either the monomer or the vitrimer, or both.

[0095] The polymer may be an epoxy resin, a bismaleimide resin, a phenolic or benzoxazine resin, a polyurethane, a polyamide, a polyolefin, a polyester, or a rubber. The ester-containing benzoxazine derivative of Formula I may be used in a weight ratio of 0.1 to 80% of the final composition.

[0096] The compounds of formula I can be used to impart vitrimer properties (self-healing, reworkability, etc.) to the polymers described above.

[0097] The present invention also relates to a composition B comprising: a) an ester-containing benzoxazine monomer of formula (I), and b) A material selected from the group consisting of fillers, fibers, pigments, dyes, and plasticizers.

[0098] The additional compounds may be used to improve the properties (ie, viscosity, mechanical and thermal properties) of either the monomer or the vitrimer, or both.

[0099] The additional compound can be carbon fiber, glass fiber, clay, carbon black, silica, carbon nanotubes, graphene, any known means for thermal or mechanical reinforcement of composites.

[0100] The present invention also relates to the use of vitrimers according to the invention as reversible adhesives, sealants, coatings or encapsulation systems for substrates selected from the group consisting of metals, polymers, glasses, and ceramic materials.

[0101] Preferably, the metal and polymer are as defined above.

[0102] The present invention also relates to the use of the vitrimers according to the invention in 3D printing processes or additive manufacturing processes.

[0103] Other features and advantages of the present invention will be readily apparent from the following detailed description and drawings. [Brief explanation of the drawings]

[0104] [Figure 1] FIG. 1 shows a synthesis reaction of an ester-containing benzoxazine monomer from 4,4-bis(4-hydroxyphenyl)valeric acid (DPA), a phenolic acid derivative. [Figure 2] FIG. 1 shows (in schematic form) a vitrimer network obtained by curing benzoxazine valerate monomers. [Figure 3] FIG. 1 shows the NMR spectrum of a valeric acid-derived benzoxazine monomer (PEG-DPA-mea). [Figure 4a] FIG. 1 shows a DSC curve. [Figure 4b] FIG. 1 shows a TGA of benzoxazine valerate monomer. [Figure 5] FIG. 3 illustrates the ability of the vitrimers of FIG. 2 to be reshaped and reprocessed. [Figure 6a] Figure 1 shows the expansion curves (dL / L (%) vs. temperature) of vitrimers obtained by curing benzoxazine valerate monomer without any catalyst or with 2% Zn(OAc) catalyst in step b). [Figure 6b] FIG. 1 shows the mechanical properties of vitrimers. [Figure 7a] Figure 1 shows a shear stress relaxation experiment: normalized relaxation modulus versus time from 120°C to 170°C. [Figure 7b] FIG. 3 shows an Arrhenius plot of the relaxation times measured for the vitrimer of FIG. 2. [Figure 8a] FIG. 1 shows the NMR spectrum of benzoxazine valerate monomer (PEG200-DPA-mea). [Figure 8b] FIG. 1 shows the NMR spectrum of benzoxazine valerate monomer (PEG2000-DPA-mea). [Figure 9] FIG. 1 shows DSC curves of PEGn-DPA-mea ester-containing benzoxazine monomers (n=200 and 2000). [Figure 10] FIG. 1 shows the results of isothermal rheology observation of PEGn-DPA-mea ester-containing benzoxazine monomers (n=200 and 2000). [Figure 11] FIG. 1 shows the expansion curves of PEGn-DPA-mea ester-containing benzoxazine monomers (n=200 and 2000). [Figure 12a] FIG. 1 shows the stress relaxation curve of poly(PEG200-DPA-mea) ester-containing benzoxazine vitrimer. [Figure 12b] FIG. 1 shows the stress relaxation curve of poly(PEG2000-DPA-mea) ester-containing benzoxazine vitrimer. [Figure 13] FIG. 1 shows an Arrhenius plot of poly(PEGn-PA-mea) ester-containing benzoxazine vitrimers. [Figure 14] FIG. 1 shows the NMR spectrum of PEG400-PA-mea ester-containing benzoxazine monomer (PA: phloretic acid). [Figure 15] FIG. 1 shows the DSC curve of PEG400-PA-mea ester-containing benzoxazine monomer (PA: phloretic acid). [Figure 16]FIG. 1 shows the results of isothermal rheological observation of PEG400-PA-mea ester-containing benzoxazine monomer (PA: phloretic acid). [Figure 17a] FIG. 1 shows the stress relaxation curve of poly(PEG400-PA-mea) ester-containing benzoxazine vitrimer (PA: phloretic acid). [Figure 17b] FIG. 1 shows an Arrhenius plot of poly(PEG400-PA-mea) ester-containing benzoxazine vitrimer (PA: phloretic acid). DETAILED DESCRIPTION OF THE INVENTION

[0105] Example 1: Synthesis of ester-containing benzoxazine monomers from 4,4-bis(4-hydroxyphenylvaleric acid (DPA)) as a phenolic acid derivative The ester-containing benzoxazine monomers were synthesized in two steps (Figure 1).

[0106] The first step, step a), is the synthesis of polyethylene glycol (PEG) (M) in the presence of p-toluenesulfonic acid (pTSA) introduced in a catalytic amount (1 wt%). n = 400 g.mol ー1 This corresponds to a Fischer esterification between PEG (p = 8-9, 1 equivalent, 10 g) and 4,4-bis(4-hydroxyphenyl)valeric acid (DPA) (2 equivalents, 14.32 g). PEG, DPA, and pTSA were reacted together in the melt at 130 °C and mechanically stirred for 24 h to yield 4,4-bis(4-hydroxyphenyl)valerate-terminated polyethylene glycol (PEG-DPA).

[0107] The second step, step b), corresponds to a Mannich condensation between 4,4-bis(4-hydroxyphenyl)valerate-terminated polyethylene glycol (PEG-DPA) (1 equivalent, 22.8 g), ethanolamine (mea) (4 equivalents, 5.95 g), and paraformaldehyde (PFA) (8 equivalents, 5.84 g). In some examples, step b) is carried out in the presence of 2 wt. % Zn(OAc) catalyst. All these reactants were reacted together in the melt at 85 °C and stirred with mechanical stirring for 2 hours to obtain an ester-containing benzoxazine monomer designated PEG-DPA-mea.

[0108] FIG. 3 shows the NMR spectrum (AVANCE III HD Bruker spectrometer) of the PEG-DPA-mea ester-containing benzoxazine monomer synthesized in step b) in the presence of 2 wt % Zn(OAc) 2 catalyst.

[0109] Figures 4a) and 4b) show the DSC and TGA curves, respectively, of the PEG-DPA-mea monomer in the presence (solid line) or absence (dashed line) of the Zn(OAc)2 catalyst. Conditions: 10 °C.min -1 , N2 atmosphere.

[0110] The DSC curve (Figure 4a) (Netzsch DSC 204 F1 Phoenix instrument) shows an exothermic peak starting at a temperature of 105 °C, with a maximum at 174 °C. This peak corresponds to the opening of the benzoxazine ring upon heating. The second peak corresponds to the thermal decomposition of the ester bond, confirmed by TGA experiments (Figure 4b) (mass loss <6%). The second decomposition stage is very similar for both samples, with a weight loss of 46.7% and a maximum decomposition temperature of about T = 379 °C. However, it should be noted that the presence of the catalyst slightly improved the char yield (25.1%). Therefore, at this stage, the material is expected to be heated to at least 250 °C (T d5% ) is considered thermally stable.

[0111] Example 2: Synthesis of vitrimers obtained by curing PEG-DPA-mea monomers The benzoxazine monomer obtained in Example 1 was polymerized in a Teflon mold at 150°C for 1 hour, opening the benzoxazine ring and allowing it to react with itself to form a 3D network vitrimer (Figure 2). Once cooled, the material retains its shape even after several months. Reheating to at least 100°C for several minutes exchanges the ester bonds with aliphatic hydroxyl groups, allowing the material to be reshaped, recycled, or reprocessed while maintaining structural integrity and covalent bond count. Considering that the Mannich condensation reaction is quantitative, approximately two hydroxyl groups can react with each ester bonded by transesterification (even after curing). The behavior of the vitrimer is characterized by the glass transition (T) of the vitrimer, which can also be considered the temperature at which transesterification reactions significantly increase. V The vitrimer behavior of these samples was demonstrated by several experiments. After the curing step, the material was v By heating to higher temperatures, the initial rod shape of the material can be engineered into other original shapes. Finally, the material can be ground into powder and reshaped or reprocessed at 150 °C in a few minutes. However, the shape remains stable at room temperature, as reported in Figure 5.

[0112] Swelling experiments were carried out in acetone, chloroform, and water to evaluate the formation of a crosslinked network of the vitrimer obtained by curing the PEG-DPA-mea monomer. Chloroform was the best solvent in which the vitrimer showed the highest swelling ratio (approximately 100%). In acetone and water, the vitrimer samples swelled by 40% and 20%, respectively.

[0113] This material reacted with acetic acid to form an orange, cloudy suspension.The chemical decomposition of thermoset resins is an interesting recycling process.

[0114] Dilatometry experiments were performed to determine the glass transition (T g ) and vitrimer glass-like transition (Tv ) is a classical method for clarifying

[0115] The device used was 2°C.min -1 The experimental conditions were a Netzsch DIL 402C apparatus with a N2 atmosphere.

[0116] Two vitrimer samples were used: one obtained by curing the PEG-DPA-mea monomer without any catalyst in step b) (dashed line), and the second obtained using a 2% Zn(OAc)2 catalyst in step b) (solid line), and the results are shown in Figure 6. The plateau observed in the catalytic system corresponds to the glass-like T v This is a characteristic of

[0117] The mechanical properties were determined by rheological measurements recorded on an Anton Paar Physica MCR 302 rheometer in the right-angle torsion mode under the experimental conditions of γ = 0.1% constant deformation and f = 1 Hz. The T determined from the maximum value of the loss modulus (G") and the maximum value of the loss factor (tan δ) g are 59°C and 93°C, respectively.

[0118] The viscoelastic properties of the PEG-DPA-mea vitrimer were investigated by stress relaxation experiments (Figure 7a). The relaxation time of the polymer was clearly significant and proportionally shortened upon heating from 120 °C (320 min) to 170 °C (94 s).

[0119] The temperature dependence of the relaxation time is plotted in Figure 7b), following the Arrhenius law. The trend line of this plot fits the thermal activation behavior of the relaxation time. A high correlation coefficient (R 2 = 0.987), which means that these data fit perfectly to the Arrhenius law. The activation energy from the Arrhenius equation was extracted using the slope of the trend line. The activation energy obtained from stress relaxation of the PEG-DPA-mea vitrimer was 155 kJ.mol -1 is.

[0120] Example 3: Synthesis of ester-containing benzoxazine monomers from 4,4-bis(4-hydroxyphenylvaleric acid (DPA)) as a phenolic acid derivative and polyethylene glycol (PEG) solutions of different molecular weights The first step, step a), is the synthesis of polyethylene glycol (PEG) in the presence of p-toluenesulfonic acid (pTSA) introduced in a catalytic amount (1 wt%). n )(M n = 200 or 2000 g.mol -1 , p=4-5 or 45-46, 1 equivalent, 10 g) and 4,4-bis(4-hydroxyphenyl)valeric acid (DPA) (2 equivalents, PEG 200 and PEG 2000 , 28.63 g and 2.86 g, respectively), corresponding to a Fisher esterification of PEG. n DPA and pTSA were reacted together in the melt at 130°C and stirred with mechanical stirring for 24 hours to produce 4,4-bis(4-hydroxyphenyl)valeric acid terminated polyethylene glycol (PEG n -DPA, n=200 or 2000).

[0121] The second step, step b), is the synthesis of 4,4-bis(4-hydroxyphenyl)valerate-terminated polyethylene glycol (PEG n -DPA) (1 eq., 25 mmol, PEG 200 and PEG 2000 This corresponds to a Mannich condensation between PEG (18.2 or 63.1 g, respectively), ethanolamine (MEA) (4 equivalents, 100 mmol, 6.11 g), and paraformaldehyde (PFA) (8 equivalents, 200 mmol, 6.0 g). All these reactants were reacted together in the melt at 85°C and stirred by mechanical stirring for 2 hours to give PEG. n The ester-containing benzoxazine monomer, designated as -DPA-mea, was obtained. The reaction product was used without further purification for the assimilation of vitrimer materials.

[0122] Figure 8a) and Figure 8b) show PEG 200 -DPA-mea and PEG2000 1 shows the NMR spectrum (AVANCE III FID Bruker spectrometer) of -DPA-mea ester-containing benzoxazine monomer.

[0123] Figure 9 shows the PEG 200 -DPA-mea and PEG 2000 The DSC curve of DPA-mea monomer is shown. Condition: 10°C.min -1 , N2 atmosphere (Netzsch DSC 204 F1 Phoenix instrument). The DSC curves are 200 -DPA-mea and PEG 2000 For -DPA-mea, an exothermic peak is shown with an onset at temperatures of 105°C and 120°C, respectively. This peak corresponds to the opening of the benzoxazine ring upon heating. A second peak corresponds to the thermal decomposition of the ester bond.

[0124] PEG n The cure of the -DPA-mea ester-containing benzoxazine monomer was monitored by rheological measurements shown in Figure 10 to assess the mechanical behavior of the monomer during the cure process.

[0125] Rheograms are run under the following conditions: 1 Hz, linear amplitude 1-0.1%; 25 mm plate. Tests are performed by heating from 80°C to 140°C at 15°C / min, followed by an isothermal measurement at 140°C. Storage and loss moduli are recorded as a function of time. The term "gel time" is defined as the time at which the storage and loss moduli of the softened monomer increase sharply and transform into a gel. Gelation is defined by the crossover point between the storage and loss moduli. At 140°C, PEG 200 and PEG 2000 The gelation times are reached after 116 and 864 seconds for .

[0126] Example 4: PEG n Synthesis of vitrimers obtained by curing benzoxazine monomers containing -DPA-mea esters PEG nTo obtain the -DPA-mea derivative polybenzoxazine vitrimer materials (n=200 or 2000), the benzoxazine monomer obtained in Example 3 was polymerized in a Teflon mold at 150° C. for 1 hour.

[0127] Swelling experiments were performed in water and PEG n The formation of a crosslinked network of vitrimers obtained by curing the PEG-DPA-mea monomer was evaluated. 200 and PEG 2000 The vitrimer samples swell by 10% and 200%, respectively.

[0128] The dilatometric thermogram of the vitrimer sample is shown in Figure 11. The device used was 2°C.min -1 The experimental conditions are as follows: 1) Netzsch DIL 402C apparatus under N2 atmosphere. The first plateau is the T g The second plateau corresponds to the glass-like T v This is a characteristic of

[0129] Poly(PEG) n The viscoelastic properties of the -DPA-mea) vitrimer were investigated by stress relaxation experiments (Figure 12a): poly(PEG 200 -DPA-mea) vitrimer and Figure 12b): poly(PEG 2000 The relaxation time of the polymer is clearly significant, and the PEG 200 -DPA-mea was heated from 150℃ (814 seconds) to 170℃ (208 seconds), and PEG 2000 For -DPA-mea, the time was shortened proportionally when heated from 130°C (315 seconds) to 150°C (36 seconds).

[0130] The temperature dependence of the relaxation time is plotted in Figure 13, following the Arrhenius law. The trend line fits the thermal activation behavior of the relaxation time. A high correlation coefficient (PEG 200 and PEG 2000 For each, R 2= 0.9996 and 0.9817), which means that these data fit perfectly to the Arrhenius law. The activation energy from the Arrhenius equation was extracted using the slope of the trend line. The activation energy obtained from stress relaxation was 200 -DPA-mea) and poly(PEG 2000 -DPA-mea) vitrimer, 106 and 154 kJ.mol -1 is.

[0131] Example 5: Synthesis of benzoxazine monomers from phloretic acid as a phenolic acid derivative The first step, step a), is the synthesis of polyethylene glycol (PEG) in the presence of p-toluenesulfonic acid (pTSA) introduced in a catalytic amount (1 wt%). 400 )(M n = 400 g.mol ー1 , p = 8-9, corresponds to the Fischer esterification between PEG (1 equiv., 10 g) and fluoroacetic acid (PA) (2 equiv., 8.31 g). 400 The PA and pTSA were reacted together in the melt at 110°C and stirred with mechanical stirring for 24 hours to form fluorescein-terminated polyethylene glycol (PEG 400 -DPA) was obtained.

[0132] The second step, step b), is the synthesis of phloretic acid-terminated polyethylene glycol (PEG 400 This corresponds to a Mannich condensation between PEG-PA (1 equivalent, 17.3 g), ethanolamine (mea) (2 equivalents, 3.04 g), and paraformaldehyde (PFA) (4 equivalents, 2.98 g). All these reactants were reacted together in the melt at 85° C. and stirred by mechanical stirring for 2 hours to give PEG-PA. 400 The ester-containing benzoxazine monomer, designated as -PA-mea, was obtained. The reaction product was used for the assimilation of vitrimer materials without further purification.

[0133] Figure 14 shows the PEG 4001 shows the NMR spectrum (AVANCE III HD Bruker spectrometer) of -PA-mea ester-containing benzoxazine monomer.

[0134] Figure 15 shows the PEG 400 The DSC curve of the PA-mea monomer is shown. Conditions: 10°C.min -1 , N2 atmosphere (Netzsch DSC 204 F1 Phoenix instrument). The DSC curves are 400 Figure 1 shows an exothermic peak beginning at a temperature of 132°C for -PA-mea. This peak corresponds to the opening of the benzoxazine ring upon heating. The second peak corresponds to the thermal decomposition of the ester bond.

[0135] PEG 400 The curing of the -PA-mea ester-containing benzoxazine monomer was monitored by rheological measurements in Figure 16 to assess the mechanical behavior of the monomer during the curing process.

[0136] Rheograms are run under the following conditions: 1 Hz, linear amplitude 1-0.1%; 25 mm plate. Tests are performed by heating from 80°C to 140°C at 15°C / min, followed by an isothermal measurement at 140°C. Storage and loss moduli are recorded as a function of time. The term "gel time" is defined as the time at which the storage and loss moduli of the softened monomer increase sharply and transform into a gel. Gelation is defined by the crossover point between the storage and loss moduli. At 140°C, the gel time is reached after 27 minutes.

[0137] Example 6: PEG 400 Synthesis of vitrimers obtained by curing of -PA-mea ester-containing benzoxazine monomers PEG 400 To obtain the -PA-mea derivative polybenzoxazine vitrimer material, the benzoxazine monomer obtained in Example 5 was polymerized in a Teflon mold at 150° C. for 1 hour.

[0138] Poly(PEG) 400The viscoelastic properties of the (-PA-mea) vitrimer were investigated by stress relaxation experiments (Figure 17a). The relaxation time of the polymer was clearly significant and proportionally shortened upon heating from 120 °C (1131 s) to 170 °C (14 s).

[0139] The temperature dependence of the relaxation time was plotted according to the Arrhenius law (Figure 17b). The trend line fits the thermal activation behavior of the relaxation time. A high correlation coefficient (R 2 =0.9901), which means that these data fit perfectly to the Arrhenius law. The activation energy from the Arrhenius equation was extracted using the slope of the trend line. The activation energy obtained from stress relaxation was 131 kJ.mol -1 is.

Claims

1. Ester-containing benzoxazine monomers of formula (I) 【Chemical 1】 wherein, independently, At least one R ＊ groups are present in the benzoxazine ring, and may include H, aliphatic C １ -C ６ Alkyl group, OH, aliphatic C １ -C ６ Alkoxy group, aliphatic C ２ -C ６ Alkenyl group, aliphatic C １ -C ６ alkyl or alkoxy substituted or unsubstituted phenyl groups; 【Chemistry 2】 is selected from the group consisting of (Wherein R is an aliphatic C １ -C ６ Alkyl group, aliphatic C １ -C ６ alkyl or alkoxy substituted or unsubstituted phenyl group, C ２ -C ６ Alkenyl group, —(CH ２ ) ｎ３ - (in the formula, n ３ is an integer from 1 to 10), —CH(aliphatic C １ -C ６ alkyl group), —CH (aliphatic C １ -C ６ alkyl or alkoxy substituted or unsubstituted phenyl group), or R is omitted; R' is H, -(CH ２ ) ｎ３ -OH, and 【Chemistry 3】 Selected from (In the formula, n=n １ = n ２ and R, R are independently integers from 1 to 3. ＊ and n ３ is as defined above); R'' is an aliphatic C １ -C ６ is an alkyl group; and p is an integer from 1 to 50.

2. At least one R ＊ group is present in the benzoxazine ring, and said R ＊ The group is H, aliphatic C １ -C ４ Alkyl group, OH, aliphatic C １ -C ４ alkoxy groups, 【Chemistry 4】 2. The ester-containing benzoxazine monomer of claim 1, wherein R is an aliphatic C １ -C ３ Alkyl group, aliphatic C １ -C ３ alkyl or alkoxy substituted or unsubstituted phenyl group, C ２ -C ４ Alkenyl group, —(CH ２ ) ｎ３ - (in the formula, n ３ is an integer from 1 to 6), —CH(aliphatic C １ -C ３ alkyl group), —CH (aliphatic C １ -C ３ alkyl or alkoxy substituted or unsubstituted phenyl group), or R is omitted; R' is H, -(CH ２ ) ｎ３ -OH, and 【Chemistry 5】 wherein n=n １ = n ２ and each independently is an integer from 1 to 3; R, at least one R ＊ and n ３ is as defined above).

3. 3. A process for synthesizing an ester-containing benzoxazine monomer of formula (I) according to claim 1 or 2, comprising: a) at least one R ＊ a phenolic acid derivative of formula (II) containing a group 【Chemistry 6】 with a polyfunctional molecule or oligomer of formula (III) 【Chemistry 7】 The reaction is carried out in the presence of a Bronsted acid catalyst at a temperature of 25°C to 200°C for 1 to 72 hours. to produce a phenol-terminated oligomer or molecule of formula (IV); 【Chemistry 8】 b) reacting a compound of formula (IV) - amino alcohol bifunctional derivatives of formula (V): 【Chemistry 9】 and a mixture of aldehyde derivatives, at a temperature ranging from 25°C to 100°C for 0.5 hours to 48 hours (wherein R, R', R'', at least one R ＊ , n, n １ , n ２ , p is independently the at least one R ＊ When the group is in the ortho position relative to the —OH group, R ＊ is as defined above with the proviso that

4. 4. The process of claim 3, wherein the phenolic acid derivative is selected from the group consisting of mono-, di-, tri-hydroxybenzoic acid derivatives, anacardic acid derivatives, hydroxycinnamic acid derivatives, aliphatic X-hydroxyphenyl acid derivatives (X is 2-4), aliphatic diphenolic acid derivatives and triphenolic acid derivatives, or mixtures thereof.

5. 5. The process of claim 4, wherein the aliphatic mono-, di-, trihydroxybenzoic acid derivative is of formula (VI): 【Chemistry 10】 (wherein R is omitted, R １ ~R ５ At least one of ＊ corresponds to R １ ~R ５ at least one of which is selected from the group consisting of 1, 2, and 3 hydroxyl groups, at least one H is in the ortho position of the phenol, and the remainder are H and aliphatic alkyl groups C １ -C ６ at least one of the following:

6. 5. The process of claim 4, wherein the anacardic acid derivative is of formula (VII): 【Chemistry 11】 (In the formula, R ６ =R ＊ where R is omitted and R ６ teeth, 【Chemistry 12】 (It is).

7. 5. The process of claim 4, wherein the hydroxycinnamic acid derivative is of formula (VIII): 【Chemistry 13】 (In the formula, R １ ~R ５ At least one of ＊ corresponds to R １ ~R ５ at least one of which is selected from the group consisting of one and two hydroxyl groups, at least one H is in the ortho position of the phenol, and the remainder are H and an aliphatic alkyl or alkoxy group C １ -C ６ at least one of the following:

8. 5. The process of claim 4, wherein the aliphatic X-hydroxyphenyl acid derivative is selected from the group consisting of aliphatic di-hydroxyphenyl acids (X=2), aliphatic tri-hydroxyphenyl acids (X=3) and aliphatic tetra-hydroxyphenyl acids (X=4) of formula (IX), or mixtures thereof. 【Chemistry 14】 (In the formula, R ７ corresponds to R, and (CH ２ ) ｎ４ , CH(CH ２ ) ｎ５ -(Aliphatic C １ -C ６ alkyl or alkoxy alkyl or alkoxy substituted or unsubstituted phenyl group) (n ４ is an integer from 1 to 12, and n ５ is an integer from 0 to 12), CH(CH ２ ) ｎ５ (CH ３ ), CH(CH(CH ３ ) ２ ), C(CH ３ ) ２ , CH(aliphatic C １ -C ６ alkyl or alkoxy alkyl or alkoxy substituted or unsubstituted phenyl groups; R in the ring ＊ The number of depends on the number of hydroxyl groups in the ring, at least one R* is H toward the ortho position of the phenol, and independently (CH ２ ) ｎ４ CH ３ , (CH ２ ) ｎ４ -(Aliphatic C １ -C ６ aliphatic alkyl or alkoxy substituted or unsubstituted phenyl group, ４ is an integer from 1 to 12), and (CH ２ ) ｎ４ (CH (CH ３ ) ２ ) selected from the group consisting of; The integer q is comprised between 1 and 3).

9. 5. The process of claim 4, wherein the aliphatic diphenolic acid derivative is of formula (X): 【Chemistry 15】 (In the formula, In each phenol ring, at least one R ＊ is H towards the ortho position of the phenol, otherwise R ＊ and R ２ are independently (CH ２ ) ｎ４ CH ３ , (CH ２ ) ｎ４ -(Aliphatic C １ -C ６ aliphatic alkyl or alkoxy substituted or unsubstituted phenyl groups), and (CH ２ ) ｎ４ (CH (CH ３ ) ２ ) (where n ４ is an integer from 1 to 12; R １ is (CH ２ ) ｎ５ (In the formula, n ５ is an integer from 1 to 3), CH(CH ２ ) ｎ５ (CH ３ ), CH(CH(CH ３ ) ２ ) and C(CH ３ ) ２ (selected from the group consisting of:

10. When the compound of formula (III) has a p value of 1 to 30 and R'=H, C ２ H ４ O unit 4MW-C ２ H ４ 10. The process according to any one of claims 3 to 9, wherein the O unit represents a polyethylene glycol (PEG) having a molecular weight (MW) in the range of 50 MW.

11. 11. The process of any one of claims 3 to 10, wherein step a) is carried out at a temperature in the range of from 60°C to 150°C for a period of from 12 hours to 48 hours.

12. 12. The process according to any one of claims 3 to 11, wherein the stoichiometric ratio of the starting reactants phenolic acid derivative:multifunctional molecule or oligomer in step a) is 1.0-3.0 equivalents:1.0 equivalent, resulting in 1.0 equivalent of phenol-terminated oligomer or molecule of formula (IV).

13. 13. The process of any one of claims 3 to 12, wherein the amino alcohol bifunctional derivative of formula (V) comprises a linear amino alcohol derivative having a primary amine moiety and an aliphatic hydroxyl moiety.

14. The aldehyde derivatives include formaldehyde, 【Chemistry 16】 Paraformaldehyde (wherein m is an integer from 8 to 100), acetaldehyde, propionaldehyde, butyraldehyde, polyoxymethylene, and compounds of the general formula R ９ CHO (wherein, R ９ is a substituted or unsubstituted aliphatic C optionally containing heteroatoms １ -C ２０ 14. The process of any one of claims 3 to 13, wherein the alkyl group is selected from the group consisting of aldehydes having a hydroxyl group, ...

15. The process according to any one of claims 3 to 14, wherein step b) is carried out without any catalyst.

16. When step b) comprises at least one catalyst, the at least one catalyst is Zn(II)(R １０ ) ２ (In the formula, R １０ is preferentially Cl － , C.H. ３ CO ２ － , C.H. ３ -C(=O)-O － , C.H. ３ COCHCOCH ３ － , C.H. ３ (CH ２ ) ｒ：１－１５ CH ２ CO ２ － triazobicyclodecane (TBD); triphenylphosphine (PPh ３ 15. The process of any one of claims 3 to 14, wherein the carboxylic acid is selected from the group consisting of paratoluenesulfonic acid (APTS) and paratoluenesulfonic acid (APTS).

17. 17. The process of any one of claims 3 to 16, wherein the stoichiometric ratio of the starting reactants in step b), phenol-terminated oligomer or molecule: aminoalcohol bifunctional derivative: aldehyde derivative, respectively, is 1.0 equivalent: 1.0-18.0 equivalents: 2.0-36.0 equivalents, resulting in 1.0 equivalent of the ester-containing benzoxazine monomer.

18. 18. A process for preparing a polybenzoxazine derivative vitrimer, comprising polymerizing an ester-containing benzoxazine monomer as claimed in claim 1 or 2, or as obtained by the process of any one of claims 3 to 17, at a temperature in the range of 100°C to 250°C for a period of 1 hour to 24 hours.

19. The process of claim 18, wherein the polymerizing step is carried out at a relaxation temperature value of or above a TV value of: (i) the T of 120°C to 220°C Ｖ value, (ii) the T of 120°C to 270°C Ｖ The relaxation temperature value exceeds the value.

20. The process of claim 19, wherein the polymerizing step is performed at the following relaxation times, activation energies or processing temperatures associated with the relaxation times: the relaxation time being between -0.5 seconds and 2 hours; the activation energy is between 50 kJ / mol and 200 kJ / mol; the processing temperature is between 100°C and 250°C;

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