Benzoxazine derivative-based glassy polymers

Abstract

The present invention relates to ester-containing benzoxazine monomers and to a process for the synthesis of said monomers, as well as to glassy polymers obtained by polymerization of said ester-containing benzoxazine monomers. The present invention further relates to the use of said glassy polymers 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] This invention relates to the field of ester-containing benzoxazine derivative vitrifiers, as well as methods for their preparation and their use in various applications. Background Technology

[0002] Composite materials are almost all made of thermosetting resins, which are the preferred materials for many applications due to their dimensional stability, mechanical properties, and creep / chemical resistance. However, due to their permanent molecular structure, they cannot be recycled or reprocessed and ultimately end up in landfills.

[0003] A chemical approach to addressing this deficiency has been provided by introducing exchangeable chemical bonds, leading to dynamic crosslinking. Polymer networks containing such exchangeable bonds are also known as covalently adaptive networks (CANs) (W. Denissen et al. - Wim Denissen, Johan M. Winne, and Filip E. Du Prez, Chem. Sci., 2016, 7, 30-38). Depending on their exchange mechanism, CANs can be further classified into two groups: dissociative or associative. In the first case, the chemical bonds break first and then reform at another site. The Diels-Alder reaction is the most common mechanism for dissociative CANs. In the second case, the polymer network does not depolymerize upon heating but is characterized by a fixed crosslinking density. Covalent bonds break only when new covalent bonds are formed, making these networks both permanent and dynamic. The first reported associative CAN (2005) was based on a photo-mediated reaction using, for example, allyl sulfides. Later, a similar exchange mechanism was introduced by using alternative radical generators with trithiocarbonates.

[0004] In 2011, Leibler et al. (D. Montarnal, M. Capelot, F. Tournilhac, and L. Leibler, Science, 2011, 334, 965–968) expanded the field of associative CANs by adding suitable transesterification catalysts to epoxy / acid or epoxy / anhydride-based polyester networks, resulting in permanent polyester / polyol networks exhibiting a gradual decrease in viscosity upon heating. This unique characteristic of vitreous silica has never been observed in organic polymer materials. Therefore, the authors introduced the term "glass-like polymers" for these materials.

[0005] Glass-like polymers are described as a third type of polymer material due to their outstanding characteristics. The dynamic nature of the covalent network formed by reversible chemical bonds allows the material to heal, recycle, and reprocess like thermoplastics. These exchange reactions are triggered by external stimuli, most commonly temperature. The viscosity of glass-like polymers gradually decreases upon heating, thus providing the network with ductility while allowing internal stress relaxation. Network integrity throughout the application range ensures mechanical and solvent resistance.

[0006] Following the development of the prototype glass-like polymer by Leibler et al. in 2011 (mentioned above), dynamic transesterification reactions have shown widespread interest over the past decade. These chemical exchanges induced between ester bonds and hydroxyl groups at elevated temperatures are the cause of topological rearrangements. Implementing transesterification mechanisms in cross-linked networks is aimed at designing self-healing, recyclable, and reprocessable materials with tunable properties.

[0007] Demongeot et al. (A. Demongeot, R. Groote, H. Goossens, T. Hoeks, F. Tournilhac, and L. Leibler, Macromolecules, 2017, 50(16), 6117-6127) applied the concept of glass-like polymers to commercially available thermoplastics. They successfully prepared cross-linked polybutylene terephthalate (PBT) glass-like polymers based on transesterification via reactive extrusion. In addition to improving the potential scope and manufacturing techniques of these networks, the global environmental context has prompted 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) worked to produce a fully bio-based polyester exhibiting properties similar to glass-like polymers, starting from epoxidized soybean oil and an aqueous solution of citric acid. In addition, Legrand et al. (A. Legrand and C. Soulié-Ziakovic, Macromolecules, 2016, 49, 5893-5902) have enabled the scalability of glass-like polymer network applications by developing silica-reinforced epoxy-based glass-like polymer nanocomposites with reinforcing properties.

[0008] Polybenzoxazines are novel thermosetting materials with excellent mechanical and thermal properties. Like many other thermosetting materials, they cannot be reshaped, reprocessed, or recycled. Several examples demonstrating reasonable levels of healability 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 class of high-performance materials without any glass-like polymer capabilities. Such sustainable glass-like polymers would enable polybenzoxazines to be widely used in smart coatings, reversible adhesives, or even as recyclable matrix resins for composites. Summary of the Invention

[0009] Regarding the technical problem, the present invention provides a solution to at least one defect of the prior art cited above.

[0010] Therefore, the present invention relates to ester-containing benzoxazine monomers of formula (I).

[0011]

[0012] Among them, independently,

[0013] - At least one R* group is present in the benzoxazine ring and is selected from H, aliphatic C1-C6 alkyl, OH, aliphatic C1-C6 alkoxy, aliphatic C2-C6 alkenyl, aliphatic C1-C6 alkyl or alkoxy-substituted or unsubstituted phenyl groups.

[0014] -R is selected from aliphatic C1-C6 alkyl, aliphatic C1-C6 alkyl or alkoxy-substituted or unsubstituted phenyl, C2-C6 alkenyl, -(CH2). n3 -, -CH (aliphatic C1-C6 alkyl), -CH (aliphatic C1-C6 alkyl or alkoxy-substituted or unsubstituted phenyl), where n3 is an integer from 1 to 10, or R is omitted;

[0015] -R' is selected from H and -(CH2). n3 -OH and Where n = n1 = n2 and are independent integers from 1 to 3, and R, the at least one R* and n3 are as defined above;

[0016] "-R" represents an aliphatic C1-C6 alkyl group; and

[0017] -p is an integer from 1 to 50.

[0018] The ester-containing benzoxazine monomers of the present invention are advantageously suited for obtaining polybenzoxazine derivative glass polymers by self-polymerization at heat and polymerization involving ring-opening of benzoxazine, resulting in said polybenzoxazine derivative glass polymers. Due to the specific monomeric starting products, the glass polymers of the present invention exhibit self-healing, reshaping, reprocessable, and recyclable properties. For the remainder of this document, benzoxazine glass polymers will always refer to the polymeric form of ester-bonded benzoxazine monomers. "Derivative" means any compound derived from the benzoxazine structure and may have some different parts or groups without altering the basic structure.

[0019] The properties of polybenzoxazine derivative glass polymers are closely related to the properties of ester-containing benzoxazine monomers.

[0020] As can be seen from formula (I), the monomer includes a benzoxazine ring moiety that allows the monomer to crosslink upon heating and facilitates the reprocessing of the obtained benzoxazine glass polymer due to the exchangeable ester bonds formed once crosslinked. Benzoxazine provides thermosetting properties such as high temperature and flammability, high strength, thermal stability, low water absorption, chemical resistance, low melt viscosity, and near-zero shrinkage.

[0021] The presence of a moiety consisting of ester bonds and free aliphatic hydroxyl groups is essential for the formation of dynamic and reversible networks in benzoxazine derivative-type glass polymers, thereby allowing the material to be recycled, reshaped, and reprocessed. Hydroxyl-terminated amines allow for the closure of the oxazine ring and permit transesterification. Therefore, the essential characteristics of the monomers of this invention depend on the benzoxazine-containing moiety, ester bonds, and free aliphatic hydroxyl groups. The Tg of such polybenzoxazines can range from 25°C to 300°C.

[0022] Preferably, the integer p can be selected independently within the range of 1 to 30, more preferably 1 to 20, and most preferably 1 to 10, for fine-tuning the processing temperature and relaxation of the benzoxazine-based glass polymer obtained by polymerization of the monomer, and for better mechanical and thermal properties of the glass polymer.

[0023] In the context of this invention, an "aliphatic" group is a straight-chain or branched group.

[0024] The benzoxazine ring may contain at least one R* group, more preferably 1-3 R* groups, and the R* group is selected from H, aliphatic C1-C4 alkyl, OH, aliphatic C1-C4 alkoxy, ...

[0025]

[0026] R can be selected from aliphatic C1-C3 alkyl, aliphatic C1-C3 alkyl or alkoxy-substituted or unsubstituted phenyl, C2-C4 alkenyl, -(CH2) n3 -, -CH (aliphatic C1-C3 alkyl), -CH (aliphatic C1-C3 alkyl or alkoxy-substituted or unsubstituted phenyl), where n3 is an integer from 1 to 6, or R may be omitted;

[0027] R' is selected from H, -(CH2) n3 -OH and

[0028] Where n = n1 = n2 and are independent integers from 1 to 3, more preferably 1 or 2, and R, R* and n3 are as defined above.

[0029] The present invention also relates to a method for synthesizing an ester-containing benzoxazine monomer of formula (I), the method comprising the following steps:

[0030] a) A phenolic acid derivative of formula (II) containing at least one R* group

[0031]

[0032] With formula (III) multifunctional molecules or oligomers

[0033]

[0034] Reacting at temperatures ranging from 25°C to 200°C for 1 to 72 hours in the presence of a Brønsted acid catalyst yields phenol-terminated oligomers or molecules of formula (IV).

[0035]

[0036] and

[0037] b) React the compound of formula (IV) with the following mixture at a temperature range of 25°C to 100°C for 0.5 hours to 48 hours.

[0038] -Amino alcohol bifunctional derivatives of formula (V):

[0039] and

[0040] -aldehyde derivatives,

[0041] Wherein R, R', R”, at least one R*, n, n1, n2, p are independently as defined above, provided that R* is H when the at least one R* group of the phenolic acid derivative is in the ortho position relative to the -OH group.

[0042] The ester-containing benzoxazine monomers of the present invention are advantageously suited for obtaining polybenzoxazine derivative glass polymers by self-polymerization at heat and polymerization involving ring-opening of benzoxazine.

[0043] The applicant has demonstrated that specific starting reactants provide ester-containing benzoxazine monomers, which, in turn, yield polybenzoxazine derivative-like glass polymers containing polymerized benzoxazine after polymerization.

[0044] The term "derivative" in the expressions "phenolic acid derivatives," "amino alcohol bifunctional derivatives," and "aldehyde derivatives" refers to any compound that has / possesses a phenolic acid, amino alcohol bifunctional, or aldehyde-based structure, respectively.

[0045] The benzoxazine rings obtained from the reaction of specific derivatives (formulas (II)-(V)) (which allow the material to crosslink (process) upon heating) facilitate reprocessing due to their exchangeable and reversible ester bonds and free aliphatic hydroxyl groups. Furthermore, the benzoxazine ring moiety provides thermosetting properties such as high-temperature and flammability, high strength, thermal stability, low water absorption, chemical resistance, low melt viscosity, and near-zero shrinkage (rate).

[0046] Therefore, the first step (step a) in the synthesis of ester-containing benzoxazine monomers typically corresponds to Fischer esterification between aliphatic hydroxyl-terminated polyfunctional molecule or oligomer of formula (III) (ditelechelic) and a phenolic acid derivative of formula (II) in the presence of a Brønsted acid catalyst (which may be introduced in catalytic amounts).

[0047] The phenolic acid derivative (formula (II)) may include at least one R* group associated with the substitution of the phenolic ring, more preferably 1 to 3 R* groups, and an R group associated with the bridging property between the ester bond and the phenolic ring.

[0048] Advantageously, the phenolic acid derivative (formula (II)) contains an R* group, which does not interfere with the ortho position of the phenol to avoid potentially affecting the kinetics of step a) or the steric hindrance of the oxazine ring closure in step b). Therefore, the R* group can be a short-chain group, provided that the R* at the ortho position of the phenol is H.

[0049] In some implementations, there may be two phenolic adjacent positions, each of which has an H R* group.

[0050] Phenolic acid derivatives are preferably aliphatic or aromatic phenolic acids or combinations thereof.

[0051] The phenolic acid derivatives are more preferably selected from mono-, di-, and tri-hydroxybenzoic acid derivatives, ascorbic acid derivatives, hydroxycinnamic acid derivatives, aliphatic X-hydroxyphenyl acid derivatives (where X is 2-4), aliphatic bisphenolic acid derivatives, and triphenolic acid derivatives, or mixtures thereof. However, triphenolic acids are less preferred due to steric hindrance.

[0052] The most preferred aliphatic mono-, di-, and tri-hydroxybenzoic acid derivatives can have formula (VI).

[0053]

[0054] Where R is omitted, and at least one of R1 to R5 corresponds to R*, at least one of R1 to R5 is selected from 1, 2 and 3 hydroxyl groups, then at least one H is located in the ortho position of the phenol, and the remainder is H and at least one of aliphatic C1-C6 alkyl groups.

[0055] Specifically, in formula (VI), at least one combination of R1 to R5 can be selected from:

[0056] R1 = OH, R2 = H, R3 = R4 = R5 = H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2,

[0057] R2=OH, R1=R3=H, R4=R5=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2,

[0058] R3 = OH, R2 = R4 = H, R1 = R5 = H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2.

[0059] R4 = OH, R3 = R5 = H, R1 = R2 = H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2.

[0060] R1 = R2 = OH, R3 = H, R4 = R5 = H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2,

[0061] R1 = R3 = OH, R2 = R4 = H, R5 = H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2,

[0062] R1=R4=OH, R2=R3=R5=H,

[0063] R1 = R5 = OH, R2 = R4 = H, R3 = H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2.

[0064] R2=R3=OH, R1=R4=H, R5=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2,

[0065] R2=R4=OH, R1=R3=R5=H

[0066] R1=R3=R5=OH, R2=R4=H,

[0067] and

[0068] R2=R3=R4=OH, R1=R5=H.

[0069] The most preferred astaxanthin derivative may have formula (VII), where R6 = R*.

[0070]

[0071] R is omitted, and R6 is...

[0072] The most preferred hydroxycinnamic acid derivative can have formula (VIII).

[0073]

[0074] At least one of R1 to R5 corresponds to R*, and at least one of R1 to R5 may be selected from one and two hydroxyl groups and at least one H is located in the ortho position of the phenol, the remainder being at least one of H and C1-C6 aliphatic alkyl or alkoxy groups.

[0075] Specifically, in formula (VIII), at least one combination of R1 to R5 may be selected from:

[0076] R5 = OH, R4 = H, R1 = R2 = R3 = H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2

[0077] R4 = OH, R3 = R5 = H, R1 = R2 = H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2.

[0078] R3 = OH, R2 = R4 = H, R1 = R5 = H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2.

[0079] R3 = OH, R2 = O (C1-C6 alkyl), R1 = R4 = R5 = H, and

[0080] R2=R3=OH, R1=R4=H, R5=H or CH3 or CH2-CH3 or CH2-CH2CH3 or CH2-CH(CH3)2.

[0081] The most preferred aliphatic X-hydroxyphenyl acid derivatives may be selected from aliphatic dihydroxyphenyl acids (X=2), aliphatic trihydroxyphenyl acids (X=3), and aliphatic tetrahydroxyphenyl acids (X=4) of formula (IX), or mixtures thereof.

[0082]

[0083] in

[0084] -R7, corresponding to R, represents properties independent of X-hydroxyphenyl aliphatic acid derivatives, selected from (CH2). n4 CH(CH2) n5 -(aliphatic C1-C6 alkyl or alkoxy-substituted or unsubstituted phenyl), CH(CH2) n5 (CH3), CH(CH(CH3)2), C(CH3)2, CH(aliphatic C1-C6 alkyl or alkoxy substituted or unsubstituted phenyl), wherein n4 is an integer from 1 to 12, preferably from 1 to 10, and n5 is an integer from 0 to 12, preferably from 0 to 10.

[0085] The number of R* in the ring depends on the number of hydroxyl groups in the ring, and at least one R*, preferably one to three R*, is H at the ortho position for phenols and is independently selected from (CH2). n4 CH3, (CH2) n4 -(aliphatic C1-C6 aliphatic alkyl or alkoxy-substituted or unsubstituted phenyl groups) 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; and

[0086] - The integer q is between 1 and 3.

[0087] When n5 is 0, the (CH2) group is omitted.

[0088] The most preferred bisphenolic acid derivative has the formula (X).

[0089]

[0090] in

[0091] On each corresponding phenolic ring, at least one R*, preferably one to three R*, is H at the ortho position of the phenol, and additionally, R* and R2 are independently selected from (CH2). n4 CH3, (CH2) n4 -(aliphatic C1-C6 aliphatic alkyl or alkoxy-substituted or unsubstituted phenyl groups) 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, and

[0092] R1 is selected from (CH2) n5 (where n5 is an integer from 1 to 3), CH(CH2) n5 (CH3), CH(CH(CH3)2), and C(CH3)2, with (CH2) being the most preferred. n5 To reduce spatial steric hindrance.

[0093] In the bisphenolic acid derivatives, R = -R1-C-R2- moiety. The most preferred is 4,4-bis(4-hydroxyphenyl)valeric acid (VA).

[0094] The multifunctional molecules or oligomers of formula (III) are important for selecting the processing temperature of benzoxazine polymers.

[0095] Compounds of formula (III) can advantageously have a p-value of 1-30, more preferably 1-20, and especially 1-10, and when R' = H, can more preferably represent polyethylene glycol (PEG) with a molecular weight (MW) in the range of MW of 4 C2H4O units to MW of 50 C2H4O units, the MW of C2H4O units being classically about 44.05 g / mol. Commercially available PEGs, such as PEG 200 to PEG 2200, are preferred because they are readily available.

[0096] In the compounds of formula (III), when R' = H, the p value can be 1 (ethylene glycol) to 3 (triethylene glycol diethylene glycol-TEG).

[0097] In some other embodiments, the compound of formula (III) can be glycerol (R' = CH2OH).

[0098] Brønsted acid catalysts are those commonly used in Fischer esterification, including p-toluenesulfonic acid (APTS), anhydrous hydrochloric acid (HCl), phosphoric acid (H3PO4), formic acid (CH3-CO2H), sulfuric acid, tosylcacid, and Lewis acids such as scandium(III) trifluoromethanesulfonate. The catalyst content is from 0.5% to 2% by weight.

[0099] Step a) can be advantageously carried out at a temperature in the range of 60°C to 150°C, most preferably 100°C to 140°C, to obtain an optimal synthesis yield of over 95%, the selected temperature depending on the properties of the reactants, i.e., the melting temperature of the reactant medium.

[0100] Advantageously, step a) is carried out for 12 to 48 hours to obtain a maximum yield of at least 95%, and the duration is based on the kinetics of the reaction.

[0101] The phenolic acid derivatives of the starting reactants in step a) are preferably stoichiometric in the form of a multifunctional molecule or oligomer, with a stoichiometry of 1.0-3.0 equivalents: 1.0 equivalents result in 1.0 equivalents of phenol-terminated oligomers or molecules.

[0102] The second step (step b) of the method corresponds to the Mannich condensation 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, since step b) does not use a catalyst, it is carried out in a more convenient manner.

[0103] Advantageously, the amino alcohol bifunctional derivatives of formula (V) include straight-chain amino alcohol derivatives having a primary amine moiety and an aliphatic hydroxyl moiety, for obtaining the oxazine ring in the highest yield and under optimal reaction conditions.

[0104] The amino alcohol bifunctional derivative of formula (V) may be more preferably selected from 2-aminoethanol, 2-amino-2-methylpropanol, 5-aminopent-1-ol, heptaminol (octaminol) and diethylene glycolamine.

[0105] Preferably, the aldehyde derivative is selected from formaldehyde; formula Paraformaldehyde, where m is an integer from 8 to 100; acetaldehyde; propionaldehyde; butyraldehyde; polyoxymethylene; and aldehydes having the general formula R9CHO, where R9 is optionally a substituted or unsubstituted aliphatic C1-C1 aldehyde containing a heteroatom. 20 Alkyl groups; or mixtures thereof.

[0106] In aldehyde derivatives, R9 is preferably an aliphatic C1-C derivative optionally containing substituted or unsubstituted heteroatoms such as N, O, or S. 15 The alkyl group, more preferably R', can be a substituted or unsubstituted aliphatic C1-C8 alkyl group that optionally contains the optional heteroatom.

[0107] The temperature range of step b) is preferably 75°C to 100°C, more preferably 75°C to 95°C, thereby allowing a maximum conversion yield of at least 95%.

[0108] Advantageously, for a maximum yield of at least 95%, step b) is carried out for 1 to 12 hours, preferably 2 to 4 hours.

[0109] One advantage of the present invention is that step b) is carried out without any catalyst.

[0110] However, several catalysts can be used to catalyze the transesterification reaction (step b), said catalyst being selected from Zn(II)(R 10 )2, where R 10 Cl is preferred - CH3CO2 - CH3-C(=O)-O - CH3COCHCOCH3 - CH3(CH2) r:1-15 CH2CO2 - Triazabicyclodecene (TBD); triphenylphosphine (PPh3); and p-toluenesulfonic acid (APTS). It should be noted that the presence of the catalyst slightly improves the char yield (flame retardancy) of the obtained benzoxazine monomer. This improved char yield can be from 15% to 30%. The catalyst content can be from 0.5% to 2% by weight.

[0111] The stoichiometry of the starting reactants in step b)—phenol-terminated oligomers or molecules, amino alcohol bifunctional derivatives, and aldehyde derivatives—is preferably 1.0 equivalent, 1.0-18.0 equivalent, or 2.0-36.0 equivalent, to obtain 1.0 equivalent of ester-containing benzoxazine monomer.

[0112] The specific stoichiometric range depends on the functionality of the amino alcohol bifunctional derivative and the aldehyde derivative, respectively. Furthermore, the selected stoichiometric ranges for both the amino alcohol bifunctional derivative and the aldehyde derivative preferably avoid the formation of linear and / or aliphatic reaction byproducts such as oxazolidines, triaza derivatives, or condensation derivatives.

[0113] Preferably, the entire process is carried out using bio-based reactants.

[0114] Monomer synthesis is preferably solvent-free, even if a solvent can be added to dissolve the starting reactants. This method involves a one-step synthesis, which is one of the advantages of this invention.

[0115] Advantageously, the entire synthesis can generally be carried out without any further monomer purification. However, if desired, monomer purification can be performed using any known technique (vacuum, distillation, etc.).

[0116] Use a classic mechanical stirrer or any non-restrictive means to stir the reaction mixture of steps a) and b).

[0117] This method can be implemented using any known means known to those skilled in the art, using appropriate containers on a laboratory or industrial scale.

[0118] The present invention also relates to a method for preparing polybenzoxazine derivative glass polymers, the method comprising the steps of: polymerizing an ester-containing benzoxazine monomer of the present invention or such that can be obtained by the above method at a temperature in the range of 100°C to 250°C for 1 hour to 24 hours to obtain polybenzoxazine derivative glass polymers.

[0119] According to the method for preparing the glass-like polymer of the present invention, the polymerization step (which is the curing step) allows the benzoxazine ring to open and react on itself to form a 3D network. Once cooled, the shape of the material is retained even after several months, typically 2-4 months. Upon reheating to at least 100°C for several minutes, the ester bonds exchange with the aliphatic hydroxyl groups, thereby allowing the material to be reshaped, recycled, or reprocessed; while maintaining structural integrity and the number of covalent bonds. Considering that the Mannich condensation reaction is quantitative, almost two hydroxyl groups can react with each ester bond via transesterification (even after curing). The behavior of the glass-like polymer is strongly dependent on the glass transition (Tg) of the glass-like polymer. v This temperature is also considered to significantly increase the transesterification reaction. Several experiments demonstrated the behavior of the glass-like polymer. After the curing step, the glass-like polymer was heated to T... v The above allows for the design of glass-like polymers into other original shapes. For example, glass-like polymers can be ground into powder and reshaped or reprocessed within minutes at 150°C. However, their shape remains stable at room temperature.

[0120] The polymerization duration depends on the curing temperature and / or the properties of the ester-containing benzoxazine monomer. For a given monomer, the polymerization temperature is chosen to be higher than the temperature required to synthesize the monomer. Generally, the higher the polymerization temperature, the shorter the curing duration. For example, when the polymerization temperature is 250°C, the curing duration can be at least 1 hour, and for a polymerization temperature of 100°C, the curing duration can not exceed 24 hours. Preferably, the curing temperature can be from 140°C to 200°C, more preferably from 140°C to 180°C, the latter range providing a curing duration of 1.5 hours to 3 hours, preferably 1.5 hours to 2.5 hours. Polymerization can be carried out by any known heating means, such as laser beams and infrared beams.

[0121] The method may further include a post-polymerization step, which consists of a heating step, preferably carried out at a higher temperature than that of the polymerization heating step.

[0122] The present invention also relates to polybenzoxazine derivative glass polymers obtainable by the above method, wherein the polybenzoxazine derivative glass polymers exhibit at least one of the following properties:

[0123] (i) 120°C to 220°C; preferably 150°C to 200°C, more preferably 150°C to 170°C. v Value; and

[0124] (ii) Relaxation temperature value, ≥T v The temperature range is 120°C to 270°C; preferably 150°C to 200°C, more preferably 150°C to 180°C.

[0125] Glass-like polymer T v The value typically depends on the nature and amount of the catalyst (if present) in step b).

[0126] Relaxation temperature typically corresponds to the relaxation temperature of a glass-like polymer after strain (e.g., physical deformation, such as torsion) has been applied without observed degradation of the glass-like polymer.

[0127] Advantageously, the glass-like polymer may also exhibit at least one of the following properties, which are selected from:

[0128] The relaxation time is from -0.5 seconds to 2 hours, preferably from 1 second to 1 hour, and more preferably from 5 seconds to 50 minutes. Relaxation time is generally defined as the time it takes for a sample to relax to a value corresponding to 1 / e(0.37) of its original modulus. Generally, the higher the temperature, the shorter the relaxation time. For example, the relaxation time is approximately 5 minutes to 20 seconds at temperatures between 120°C and 150°C, and ≤20 seconds, preferably 5 seconds to 20 seconds, in the temperature range of 150°C to 200°C.

[0129] In some implementations, the glass-like polymer can be deformed between 0.1% and 100% of its initial size;

[0130] - The activation energy related to the relaxation time can be from 50 kJ / mol to 200 kJ / mol, preferably from 70 kJ / mol to 170 kJ / mol, more preferably from 100 kJ / mol to 160 kJ / mol; and

[0131] - The processing temperature can be from 100°C to 250°C, preferably from 130°C to 250°C, more preferably from 150°C to 200°C, and most preferably from 150°C to 170°C.

[0132] The glass-like polymers according to the invention also very preferably exhibit characteristics of thermosetting materials and / or insolubility in many solvents, such as, but not limited to, water, CHCl3, CH2Cl2, DMF, THF, aromatic solvents such as toluene and / or xylene, ketones, alcohols, or carboxylic acids. Swelling properties are observed to the extent of 0 to 500% of their initial weight. Swelling experiments can be performed in various solvents, such as acetone, chloroform, and water, to evaluate the formation of cross-linked networks. Chloroform is one of the solvents in which the glass-like polymers can exhibit the highest swelling ratio of about 100%. In acetone and water, some glass-like polymers swell by 40%-50% and 20%-30%, respectively. Some other glass-like polymers can exhibit swelling properties of 150% to 230% in water.

[0133] The glass-like polymer of the present invention exhibits self-healing, reshaping, reprocessability, recyclability, and reversible adhesion properties.

[0134] Glass-like polymers can form an intermediate layer between at least two substrates (e.g., metals, polymers, glass, and ceramic materials). The resulting composite material can be prepared by placing at least one ester-containing benzoxazine monomer between two considered substrates, and then curing it at a temperature that provides the glass-like polymer without altering the integrity of the substrates. Each substrate can be different from the others.

[0135] The metal substrate is not limited and can be aluminum, iron, steel, etc.

[0136] The polymer substrate can be polycarbonate, acrylic, polyamide, polyethylene, or terephthalate.

[0137] Therefore, benzoxazine glass polymers can be advantageously used in a variety of non-limiting technical fields, such as electronics, aerospace, defense and automotive.

[0138] The present invention also relates to composition A, which comprises:

[0139] a) an ester-containing benzoxazine monomer of formula (I); and

[0140] (b) At least one or more other organic molecular types of compounds, with or without a benzoxazine moiety.

[0141] Preferably, the organic molecule type can be a polymer with or without a benzoxazine moiety.

[0142] The additional compounds may be used to enhance the properties (i.e., viscosity, mechanical properties, and thermal properties) of the monomer or the glass-like polymer or both.

[0143] The polymer can be epoxy resin, bismaleimide resin, phenolic resin or benzoxazine resin, polyurethane, polyamide, polyolefin, polyester, or rubber. The ester-containing benzoxazine derivative of Formula I can be used at a weight ratio of 0.1 to 80% of the final composition.

[0144] Compounds of Formula I can be used to provide the above polymers with glass-like polymer properties (self-healing, reprocessing, etc.).

[0145] The present invention also relates to composition B, which comprises:

[0146] a) an ester-containing benzoxazine monomer of formula (I); and

[0147] (b) Materials selected from fillers, fibers, pigments, dyes, and plasticizers. The additional compounds may be used to enhance the properties (i.e., viscosity, mechanical properties, and thermal properties) of the monomer or the glass-like polymer, or both.

[0148] The other compound may be carbon fiber, glass fiber, clay, carbon black, silica, carbon nanotubes, graphene, or any known means of thermal or mechanical reinforcement of the composite material.

[0149] The present invention also relates to the use of the glass-like polymer according to the invention as a reversible adhesive, sealant, coating, or encapsulation system for substrates selected from metals, polymers, glass, and ceramic materials. Preferably, the metals and polymers are as defined above.

[0150] The present invention also relates to the use of the glass-like polymer according to the invention in 3D printing processes or in additive manufacturing processes. Attached Figure Description

[0151] Other features and advantages of the invention will be readily understood from the following detailed description and accompanying drawings, wherein:

[0152] - Figure 1 The reaction of synthesizing ester-containing benzoxazine monomers from 4,4-bis(4-hydroxyphenyl)valeric acid (DPA) as a phenolic acid derivative is shown;

[0153] - Figure 2 The network of a glass-like polymer obtained by curing benzoxazine valerate monomer is shown (schematic form);

[0154] - Figure 3 This is the NMR spectrum of the benzoxazine monomer (PEG-DPA-MEA), a valeric acid derivative;

[0155] - Figure 4 a) The DSC curves of the benzoxazine monomer valerate are shown, and Figure 4 b) shows the TGA of the benzoxazine valerate monomer;

[0156] - Figure 5 It shows Figure 2 The ability to reshape and reprocess glass-like polymers;

[0157] - Figure 6 a) shows the dilatation curve (dL / L0 (%) versus temperature) of the glass-like polymer obtained by curing the benzoxazine valerate monomer, which was obtained in step b) either without any catalyst or with 2% Zn(OAc)2 catalyst; and Figure 6 b) The mechanical properties of the glass-like polymer are shown;

[0158] - Figure 7 a) Describes the shear stress relaxation experiment: normalized relaxation modulus as a function of time between 120°C and 170°C. Figure 7 b): Figure 2 Arrhenius plot of the measured relaxation time of glass-like polymers;

[0159] - Figure 8 a) and Figure 8 b) Shows the benzoxazine valerate monomer (PEG) 200 -DPA-mea and PEG 2000 NMR spectrum of -DPA-mea);

[0160] - Figure 9 The ester-containing benzoxazine monomer PEG is shown. n DSC curves for -DPA-mea (n = 200 and 2000);

[0161] - Figure 10 The ester-containing benzoxazine monomer PEG is shown. n Isothermal rheological monitoring of -DPA-mea (n=200 and 2000);

[0162] - Figure 11 The ester-containing benzoxazine monomer PEG is shown. n The expansion curves of -DPA-mea (n = 200 and 2000);

[0163] - Figure 12 a) and 12b) show ester-containing benzoxazine-based glass polymers (PEGs), respectively. 200 -DPA-mea) and poly(PEG) 2000 Stress relaxation curve of -DPA-mea);

[0164] - Figure 13The Arrhenius plot of ester-containing benzoxazine glass polymer (PEGn-PA-mea) is shown;

[0165] - Figure 14 The ester-containing benzoxazine monomer PEG is shown. 400 NMR spectrum of -PA-mea (PA: p-hydroxyphenylpropionic acid);

[0166] - Figure 15 The ester-containing benzoxazine monomer PEG is shown. 400 DSC curve of -PA-mea (PA: p-hydroxyphenylpropionic acid);

[0167] - Figure 16 The ester-containing benzoxazine monomer PEG is shown. 400 Isothermal rheological monitoring of PA-mea (PA: p-hydroxyphenylpropionic acid);

[0168] - Figure 17 a) ester-containing benzoxazine glass polymers (PEG) 400 Stress relaxation curves and Arrhenius plots for (a) PA-mea (PA: p-hydroxyphenylpropionic acid).

[0169] Example 1: Synthesis of ester-containing benzoxazine from 4,4-bis(4-hydroxyphenyl)valeric acid (DPA) as a phenolic acid derivative monomer

[0170] The ester-containing benzoxazine monomer was synthesized in two stages. Figure 1 ).

[0171] The first step (step a) corresponds to polyethylene glycol (PEG) (M n =400g.mol -1 PEG (p=8-9, 1 equivalent, 10 g) and 4,4-bis(4-hydroxyphenyl)valerate (DPA) (2 equivalent, 14.32 g) were Fischer esterified in the presence of p-toluenesulfonic acid (pTSA) introduced in a catalytic amount (1 wt%). PEG, DPA, and pTSA were melt-reacted together at 130 °C and mechanically stirred for 24 hours to provide 4,4-bis(4-hydroxyphenyl)valerate-terminated polyethylene glycol (PEG-DPA).

[0172] The second step (step b) corresponds to the Mannich condensation between 4,4-bis(4-hydroxyphenyl)valerate-terminated polyethylene glycol (PEG-DPA) (1 equivalent, 22.8 g), ethanolamine (mea) (4 equivalent, 5.95 g), and paraformaldehyde (PFA) (8 equivalent, 5.84 g). In some instances, step b) is carried out in the presence of 2% by weight of a Zn(OAc)₂ catalyst. All these reactants are melt-reacted together at 85°C and mechanically stirred for 2 hours to provide an ester-containing benzoxazine monomer named PEG-DPA-mea.

[0173] Figure 3 The NMR spectrum of the ester-containing benzoxazine monomer PEG-DPA-mea synthesized in step b) in the presence of 2% by weight Zn(OAc)2 catalyst is shown (AVANCE III HD Bruker spectrometer).

[0174] Figure 4 a) and 4b) show the DSC and TGA curves of the PEG-DPA-mea monomer in the presence (solid line) and absence (dashed line) of the Zn(OAc)2 catalyst, respectively. Conditions: 10℃ / min -1 N2 atmosphere.

[0175] DSC curve ( Figure 4 a) (Netzsch DSC 204F1 Phoenix instrument) shows an exothermic peak starting at 105 °C, with a maximum value at 174 °C. This peak corresponds to the ring-opening of the benzoxazine ring upon heating. The second peak corresponds to the thermal decomposition of the ester bond, confirmed by TGA experiments. Figure 4 b) (mass loss ≈ 6%). The second degradation stage was very similar for both samples, with a weight loss of 46.7% and a maximum degradation temperature of approximately T = 379 °C. However, it should be noted that the presence of a catalyst slightly improved the char yield (25.1%). Therefore, at this stage, the material is considered to have reached at least 250 °C (T). d5％ All of them are thermally stable.

[0176] Example 2: Synthesis of a glass-like polymer obtained by curing PEG-DPA-mea monomer

[0177] The benzoxazine monomer obtained in Example 1 was used in... Polymerization was carried out in a mold at 150°C for 1 hour, allowing the benzoxazine ring to open and react on itself to form a 3D network-like glass polymer. Figure 2Once cooled, the material retains its shape even after several months. Upon reheating to at least 100°C for several minutes, the ester bonds exchange with the aliphatic hydroxyl groups, allowing the material to be reshaped, recycled, or reprocessed; while maintaining structural integrity and the number of covalent bonds. Given that the Mannich condensation reaction is quantitative, almost both hydroxyl groups can react with each ester bond via transesterification (even after curing). The behavior of glass-like polymers is strongly dependent on the glass transition (Tg) of the glass-like polymer. v This temperature is also considered to significantly increase the transesterification reaction. Several experiments demonstrated the glass-like polymeric behavior of these samples. After the curing step, the material was heated to T... v The above allows for the design of the initial rod shape of the material into other original shapes. Finally, the material can be ground into powder and reshaped or reprocessed within minutes at 150°C. However, as... Figure 5 As shown, its shape remains stable at room temperature.

[0178] Swelling experiments were conducted in acetone, chloroform, and water to evaluate the formation of cross-linked networks in the glass-like polymer obtained by curing the PEG-DPA-mea monomer. Chloroform was the highest solvent in which the glass-like polymer exhibited the highest swelling ratio (≈100%). In acetone and water, the glass-like polymer samples swelled by 40% and 20%, respectively.

[0179] The material reacts with acetic acid to form an orange, turbid suspension. The chemical decomposition of thermosetting materials is an interesting recycling process.

[0180] The expansion experiment is used to reveal the glass transition (T) of glass-like polymers. g ) and glass-like transition (T) of glass-like polymers v (A classic tool.)

[0181] The apparatus used was a Netzsch DIL 402C device, and the experimental conditions were 2℃·min. -1 N2 atmosphere.

[0182] Two types of glassy polymer samples were used, one obtained by curing PEG-DPA-mea monomer without any catalyst in step b) (dashed line), and the second obtained by using 2% Zn(OAc)2 catalyst in step b) (solid line). The results are plotted in... Figure 6 The plateau observed in the catalytic system is T. v The glassy properties are characteristic.

[0183] Mechanical properties were determined by rheological measurements recorded on an Anton Paar Physica MCR 302 rheometer in rectangular torsion mode under experimental conditions of γ = 0.1% constant deformation and f = 1 Hz. T was determined by the maximum values ​​of the loss modulus (G”) and the loss factor (tanδ). g The temperatures were 59℃ and 93℃, respectively.

[0184] The viscoelasticity of PEG-DPA-mea glass polymers was studied through stress relaxation experiments. Figure 7 a)). The relaxation time of the polymer clearly and proportionally decreases when heated from 120°C (320 min) to 170°C (94 s).

[0185] The temperature dependence of relaxation time was plotted according to Arrhenius's law. Figure 7 (b) In this figure, the trend line conforms to the thermal activation behavior of relaxation time. High correlation coefficient (R²) 2 =0.987) means that these data perfectly conform to the Arrhenius law. The activation energy of the Arrhenius equation is extracted using the slope of the trend line. The activation energy obtained from the stress relaxation of PEG-DPA-mea glass polymers is 155 kJ·mol⁻¹. -1 .

[0186] Example 3: 4,4-bis(4-hydroxyphenyl)valeric acid (DPA), a phenolic acid derivative, and poly(hydroxyphenyl)valeric acid of different molecular weights... Synthesis of ester-containing benzoxazine monomers using (ethylene glycol)(PEG) solution

[0187] The first step (step a) corresponds to polyethylene glycol (PEG). n (Mn = 200 or 2000 g.mol) -1 , respectively p = 4-5 or 45-46, 1 equivalent, 10 g) and 4,4-bis(4-hydroxyphenyl)valeric acid (DPA) (2 equivalents, for PEG) 200 and PEG 2000 Fischer esterification was performed in the presence of p-toluenesulfonic acid (pTSA) introduced at a catalytic amount (1 wt%) between 28.63 and 2.86 g respectively. This resulted in PEG. n DPA and pTSA were melt-reacted together at 130°C and mechanically stirred for 24 hours to provide 4,4-bis(4-hydroxyphenyl)valerate-terminated polyethylene glycol (PEG). n -DPA, where n = 200 or 2000).

[0188] The second step (step b) corresponds to 4,4-bis(4-hydroxyphenyl)valerate-terminated polyethylene glycol (PEG). n -DPA)(1 equivalent, 25 mmol, for PEG 200 and PEG2000 Mannich condensation was performed between 18.2 or 63.1 g of ethanolamine (MEA) (4 equivalents, 100 mmol, 6.11 g) and paraformaldehyde (PFA) (8 equivalents, 200 mmol, 6.0 g). All these reactants were melt-reacted together at 85 °C and mechanically stirred for 2 hours to provide a product named PEG. n -DPA-mea contains ester-containing benzoxazine monomers. The reaction product is used for the elaboration of glass-like polymers without further purification.

[0189] Figure 8 a) and Figure 8 b) Shows the ester-containing benzoxazine monomer PEG. 200 -DPA-mea and PEG 2000 -DPA-mea NMR spectrum (Avance III HD Bruker spectrometer).

[0190] Figure 9 PEG was displayed 200 -DPA-mea and PEG 2000 DSC curves of the DPA-mea monomer. Conditions: 10℃·min -1 N2 atmosphere (Netzsch DSC 204F1 Phoenix device). DSC curves show that for PEG... 200 -DPA-mea and PEG 2000 The exothermic peaks of -DPA-mea begin at temperatures of 105 and 120 °C, respectively. This peak corresponds to the ring-opening of the benzoxazine ring upon heating. The second peak corresponds to the thermal decomposition of the ester bond.

[0191] pass Figure 10 The rheological measurements depicted in the figure are used to monitor the ester-containing benzoxazine monomer PEG. n -DPA-mea was cured to evaluate the mechanical behavior of the monomer during the curing process.

[0192] Rheological plots were performed under the following conditions: 1 Hz, linear amplitude of 1 to 0.1%; 25 mm plate. Testing was conducted after a steep increase in temperature from 80 °C to 140 °C at a rate of 15 °C / min, followed by isothermal measurements at 140 °C. Storage modulus and loss modulus were recorded as a function of time. The term "gelation time" was defined as the time it takes for the storage modulus and loss modulus of the softened monomer to suddenly increase in order to transition into a gel. Gelation was defined by the crossover point between the storage modulus and loss modulus. At 140 °C, for PEG... 200 and PEG 2000 The gelation time was reached after 116 seconds and 864 seconds, respectively.

[0193] Example 4: Using ester-containing benzoxazine monomer PEG n -DPA-mea curing yields a glass-like polymer synthesis

[0194] The benzoxazine monomer obtained in Example 3 was polymerized in a Teflon mold at 150°C for 1 hour to obtain PEG. n -DPA-mea derivative polybenzoxazine glass polymer materials (n=200 or 2000).

[0195] Swelling experiments were conducted in water to evaluate the effects of PEG. n The formation of a cross-linked network of a glass-like polymer obtained by curing -DPA-mea monomers. For PEG 200 and PEG 2000 The glass-like polymer samples swelled by 10% and 200%, respectively.

[0196] The thermal expansion spectra of glass-like polymer samples are reported in Figure 11 The apparatus used was a Netzsch DIL 402C device, and the experimental conditions were 2℃·min. -1 N2 atmosphere. The first plateau corresponds to the material's T. g The second platform is T. v The glassy properties are characteristic.

[0197] Through stress relaxation experiments ( Figure 12 a)): Poly(PEG) n -DPA-mea) type glass polymers and Figure 12 b): Poly(PEG) 2000 Research on DPA-mea-type glass polymers (PEG) n The viscoelasticity of PEG-type glass polymers (-DPA-mea). The relaxation time of the polymer is relevant to PEG. 200 -DPA-mea, when heated from 150°C (814 s) to 170°C (208 s) and for PEG 2000 -DPA-mea decreased clearly and proportionally when heated from 130°C (315s) to 150°C (36s).

[0198] The temperature dependence of relaxation time was plotted according to Arrhenius's law. Figure 13 The trend line conforms to the thermal activation behavior of relaxation time. High correlation coefficient (for PEG). 200 and PEG 2000 R respectively 2 =0.9996 and 0.9817) means that these data perfectly conform to the Arrhenius law. The activation energy of the Arrhenius equation is extracted using the slope of the trend line. For poly(PEG) 200-DPA-mea) and poly(PEG) 2000 The activation energies obtained from stress relaxation for DPA-mea-type glass polymers are 106 kJ·mol⁻¹. -1 and 154 kJ·mol -1 .

[0199] Example 5: Synthesis of benzoxazine monomers from p-hydroxyphenylpropionic acid as a phenolic acid derivative

[0200] The first step (step a) corresponds to polyethylene glycol (PEG). 400 (M) n =400g.mol -1 PEG was Fischer-esterified between p-toluenesulfonic acid (pTSA) introduced in the presence of p-toluenesulfonic acid (pTSA) in a catalytic amount (1 wt%), p = 8-9, 1 equivalent, 10 g, and p-hydroxyphenylpropionic acid (PA) (2 equivalent, 8.31 g). 400 PA and pTSA were melt-reacted together at 110°C and mechanically stirred for 24 hours to provide p-hydroxyphenylpropionic acid-terminated polyethylene glycol (PEG). 400 -DPA).

[0201] The second step (step b) corresponds to p-hydroxyphenylpropionic acid-terminated polyethylene glycol (PEG). 400 The Mannich condensation between 1 equivalent of PEG (1 stoichiometric amount, 17.3 g), ethanolamine (MEA) (2 stoichiometric amounts, 3.04 g), and paraformaldehyde (PFA) (4 stoichiometric amounts, 2.98 g) was performed. All these reactants were melt-reacted together at 85°C and mechanically stirred for 2 hours to provide a product named PEG. 400 -PA-mea contains ester-containing benzoxazine monomers. The reaction products are used for the description of glass-like polymers without further purification.

[0202] Figure 14 The ester-containing benzoxazine monomer PEG is shown. 400 - NMR spectrum of PA-mea (AVANCE III HDBruker spectrometer).

[0203] Figure 15 PEG was displayed 400 DSC curves of PA-mea monomer. Conditions: 10℃·min -1 N2 atmosphere (Netzsch DSC 204F1 Phoenix device). DSC curves show that for PEG... 400 The -PA-mea peak is exothermic and begins at 132 °C. This peak corresponds to the ring-opening of the benzoxazine ring upon heating. The second peak corresponds to the thermal decomposition of the ester bond.

[0204] pass Figure 16Rheological measurements were performed to monitor ester-containing benzoxazine monomers PEG. 400 - PA-mea was cured to evaluate the mechanical behavior of the monomer during the curing process.

[0205] Rheological plots were performed under the following conditions: 1 Hz, linear amplitude of 1 to 0.1%; 25 mm plate. Testing was conducted after a rapid increase in temperature from 80 °C to 140 °C at a rate of 15 °C / min, followed by isothermal measurements at 140 °C. Storage modulus and loss modulus were recorded as a function of time. The term "gelation time" was defined as the time it takes for the storage modulus and loss modulus of the softened monomer to suddenly increase in order to transition into a gel. Gelation was defined by the crossover point between the storage modulus and loss modulus. At 140 °C, the gelation time was reached after 27 minutes.

[0206] Example 6: Using ester-containing benzoxazine monomer PEG 400 -The glass-like polymer obtained by curing PA-mea synthesis

[0207] The benzoxazine monomer obtained in Example 5 was polymerized in a Teflon mold at 150°C for 1 hour to obtain PEG. 400 -PA-mea derivative polybenzoxazine glass polymer materials.

[0208] Stress relaxation experiments were conducted to study poly(PEG) 400 -PA-mea) type viscoelasticity of glass polymers ( Figure 17 a)). The relaxation time of the polymer clearly and proportionally decreases when heated from 120°C (1131 seconds) to 170°C (14 seconds).

[0209] Plotting the temperature dependence of relaxation time based on Arrhenius's law ( Figure 17 b) The trend line conforms to the thermal activation behavior of relaxation time. High correlation coefficient (R²) 2 =0.9901) means that these data perfectly conform to the Arrhenius law. The activation energy of the Arrhenius equation is extracted using the slope of the trend line. The activation energy obtained from stress relaxation is 131 kJ·mol⁻¹. -1 .

Claims

1. An ester-containing benzoxazine monomer of formula (I) wherein, independently, at least one R* group is present in the benzoxazine ring and is selected from the group consisting of H, aliphatic Ci-C6alkyl, OH, aliphatic Ci-C6alkoxy, aliphatic C2-C6alkenyl, aliphatic Ci-C6alkyl or aliphatic Ci-C6alkoxy substituted or unsubstituted phenyl, R is selected from aliphatic Ci-C6alkylene, aliphatic Ci-C6alkyl or alkoxy- substituted or unsubstituted phenylene, C2-C6alkenylene, -(CH2) n3 -CH(aliphatic Ci-C6alkyl), -CH(aliphatic Ci-C6alkyl or alkoxy-substituted or unsubstituted phenyl), wherein n3 is an integer from 1 to 10, or R is omitted; R' is selected from the group consisting of H, -(CH2) n3 -OH and wherein n = n1= n2and independently is an integer from 1 to 3, and R, R* and n3are as defined above; R" is an aliphatic Ci-C6alkylene group; and p is an integer from 1 to 50.

2. The ester-containing benzoxazine monomer according to claim 1, wherein: at least one R* group is present in the benzoxazine ring and said R* group is selected from the group consisting of: H; aliphatic C1-C4 alkyl; OH; aliphatic C1-C4 alkoxy; R is selected from aliphatic C1-C3 alkylene, aliphatic C1-C3 alkyl or alkoxy substituted or unsubstituted phenylene, C2-C4 alkenylene, -(CH2) n3 -CH(aliphatic C1-C3 alkyl), -CH(aliphatic C1-C3 alkyl or alkoxy substituted or unsubstituted phenyl), wherein n3 is an integer from 1 to 6, or R is omitted; R' is selected from the group consisting of H, -(CH2) n3 -OH and wherein n = nl = n2 and independently is an integer from 1 to 3, and R, the at least one R* and n3 are as defined in claim 1.

3. The ester-containing benzoxazine monomer according to claim 2, wherein 1-3 R* groups are present in the benzoxazine ring.

4. The ester-containing benzoxazine monomer according to claim 2, wherein the R* groups are selected from: H, the H being located in the ortho position to the phenol; aliphatic Ci-C4alkyl; OH; aliphatic Ci-C4alkoxy; 5. The ester-containing benzoxazine monomer according to claim 2, wherein n = nl = n2 and independently is 1 or 2.

6. A process for the synthesis of the ester-containing benzoxazine monomer according to any one of claims 1 to 5, comprising the steps of: a) reacting a phenolic acid derivative comprising at least one R* group of formula (II) with a multifunctional molecule or oligomer of formula (III) in the presence of a Brønsted acid type catalyst at a temperature from 25°C to 200°C for 1 hour - 72 hours, to give a phenol-terminated oligomer or molecule of formula (IV), and b) reacting the compound of formula (IV) with a mixture of - an aminoalcohol difunctional derivative of formula (V): and - an aldehyde derivative, wherein R, R', R", the at least one R * group, n, n1, n2, p are independently as defined in any one of claims 1-5, with the proviso that when the at least one R* group of the phenolic acid derivative is in the ortho position relative to the -OH group, then R * is H, wherein the aldehyde derivative is selected from formaldehyde; polymethylol aldehyde of the formula wherein m is an integer from 8 to 100; polymethylol aldehyde; or mixtures thereof.

7. The process according to claim 6, wherein the phenolic acid derivative is selected from mono-, di-, tri-hydroxy benzoic acid derivatives; anacardic acid derivatives; hydroxycinnamic acid derivatives; aliphatic X-hydroxyphenyl acid derivatives, wherein X is 2-4; aliphatic bisphenolic acid derivatives and triphenolic acid derivatives; or mixtures thereof.

8. The process according to claim 7, wherein the aliphatic mono-, di-, tri-hydroxy benzoic acid derivatives are of formula (VI) wherein R is omitted, and at least one of R1to R5corresponds to R * and at least one of R1to R5is selected from 1, 2 and 3 hydroxyl groups, then at least one H is located in the ortho position of the phenol, the rest being at least one of H and aliphatic C1-C6alkyl.

9. The method of claim 7, wherein the anacardic acid derivative has the formula (VII), wherein R6 = R * , wherein R is omitted, and R6is 10. The process according to claim 7, wherein the hydroxycinnamic acid derivatives are of formula (VIII) wherein at least one of R1to R5corresponds to R * and at least one of R1to R5is selected from 1 and 2 hydroxyl groups, and at least one H is in the ortho position of the phenol, the rest being H and at least one of C1-C6aliphatic alkyl or alkoxy.

11. The process according to claim 7, wherein the aliphatic X-hydroxyphenyl acid derivatives are selected from aliphatic dihydroxyphenyl acid (X=2), aliphatic trihydroxyphenyl acid (X=3) and aliphatic tetrahydroxyphenyl acid (X=4) of formula (IX) or mixtures thereof wherein R7, corresponding to R, is independently of X -hydroxyphenyl fatty acid derivative of the nature selected from (CH2) n4 , CH(CH2) n5 -(aliphatic C1-C6 alkyl or alkoxy substituted or unsubstituted phenyl), CH(CH2) n5 (CH3), CH(CH(CH3)2), C(CH3)2, CH(aliphatic C1-C6 alkyl or alkoxy substituted or unsubstituted phenyl), wherein n4 is an integer from 1 to 12 and n5 is an integer from 0 to 12; R in the ring * depend on the number of hydroxyl groups in the ring, and at least one R * is H in the ortho position of the phenol and is independently selected from the group consisting of (CH2) n6 CH3, (CH2) n6 -(aliphatic C1-C6 aliphatic alkyl or alkoxy substituted or unsubstituted phenyl) and (CH2) n6 (CH(CH3)2), wherein n6 is an integer from 1 to 12; and the integer q is from 1 to 3.

12. The process according to claim 11, wherein n4 is an integer from 1 to 10.

13. The process according to claim 11, wherein n5 is an integer from 0 to 10.

14. The method of claim 11, wherein 1 to 3 R * H for the ortho position of the phenol.

15. The process according to claim 11, wherein n6 is an integer from 1 to 10.

16. The process according to claim 11, wherein n6 is an integer from 1-6.

17. The process according to claim 7, wherein the aliphatic bisphenolic acid derivatives are of formula (X) wherein at least one R * is H for the ortho position of the phenol and additionally R * and R2are independently selected from the group consisting of (CH2) n4 CH3, (CH2) n4 -(aliphatic C1-C6 aliphatic alkyl or alkoxy substituted or unsubstituted phenyl) and (CH2) n4 (CH(CH3)2), wherein n4 is an integer from 1 to 12, and R1is selected from the group consisting of (CH2) n5 , CH(CH2) n5 (CH3), CH(CH(CH3)2), and C(CH3)2, wherein n5 is an integer from 1 to 3.

18. The method of claim 17, wherein 1 to 3 R * H for the ortho position of the phenol.

19. The process according to claim 17, wherein n4 is an integer from 1 to 10.

20. The process according to claim 17, wherein n4 is an integer from 1 to 6.

21. The method according to any one of claims 6 to 20, wherein the compound of formula (III) has a p value of 1-30 and when R’ = H represents a polyethylene glycol (PEG) having a molecular weight MW in the range of the MW of 4 C2H4O units to the MW of 50 C2H4O units.

22. The method according to claim 21, wherein the compound of formula (III) has a p value of 1-20.

23. The method according to claim 21, wherein the compound of formula (III) has a p value of 1-10.

24. The method according to any one of claims 6 to 20, wherein step a) is carried out at a temperature in the range of 60 °C to 150 °C and for 12 hours to 48 hours.

25. The method according to claim 24, wherein step a) is carried out at a temperature in the range of 100 °C to 140 °C.

26. The method according to any one of claims 6 to 20, wherein the corresponding stoichiometry of the starting reactants phenolic acid derivative: polyfunctional molecule or oligomer of step a) is 1.0-3.0 equivalents: 1.0 equivalent, resulting in 1.0 equivalent of the phenol-terminated oligomer or molecule of formula (IV).

27. The method according to any one of claims 6 to 20, wherein the aminoalcohol difunctional derivative of formula (V) comprises a linear aminoalcohol derivative having a primary amine moiety and an aliphatic hydroxyl moiety.

28. The method according to claim 27, wherein the aminoalcohol difunctional derivative of formula (V) is selected from the group consisting of 2-aminoethanol, 2-amino-2-methylpropanol, 5-aminopentan-1-ol, heptaminol and diglycolamine.

29. The method according to any one of claims 6 to 20, wherein step b) is carried out in the absence of any catalyst.

30. The process according to any one of claims 6 to 20, wherein step b) comprises at least one catalyst selected from the group consisting of Zn(II)(R 10 )2, wherein R 10 is CI - , CH3CO2 - , CH3-C(=0)-0 - , CH3COCHCOCH3 - , CH3(CH2) 1-15 CH2CO2 - ; triazabicyclodecene (TBD); triphenylphosphine (PPh3) and p-toluenesulfonic acid (APTS).

31. The method according to any one of claims 6 to 20, wherein the corresponding stoichiometry of the starting reactants phenol-terminated oligomer or molecule: aminoalcohol difunctional derivative: aldehyde derivative in step b) 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.

32. A method for preparing a polybenzoxazine derivative vitrimer, the method comprising the steps of: polymerizing the ester-containing benzoxazine monomer of any one of claims 1 to 5 or obtained by the method of any one of claims 6-31 at a temperature in the range of 100 °C to 250 °C for 1 hour to 24 hours.

33. The polybenzoxazine derivative vitrimer obtained by the method of claim 32, exhibiting at least one of the following properties: (i) a Tg of 120°C to 220°C v values; and (ii) a relaxation temperature value, > T v a value of 120 °C to 270 °C.

34. The polybenzoxazine derivative vitrimer of claim 33, wherein T v has a value of 150 °C to 200 °C.

35. The polybenzoxazine derivative vitrimer of claim 33, wherein T v has a value of 150 °C to 170 °C.

36. The polybenzoxazine derivative vitrimer of claim 33, wherein the relaxation temperature value is in the range of 150 °C to 200 °C.

37. The polybenzoxazine derivative vitrimer of claim 33, wherein the relaxation temperature value is in the range of 150 °C to 180 °C.

38. The polybenzoxazine derivative vitrimer of claim 33, exhibiting at least one of the following properties selected from the group consisting of: - a relaxation time in the range of 0.5 seconds to 2 hours; - an activation energy related to the relaxation time in the range of 50 kJ / mol to 200 kJ / mol; and - a glass transition temperature in the range of 150 °C to 250 °C. - a processing temperature of 100°C to 250°C.

39. The polybenzoxazine derivative vitrimer polymer of claim 38, wherein the relaxation time is 1 second to 1 hour.

40. The polybenzoxazine derivative vitrimer polymer of claim 38, wherein the relaxation time is 5 seconds to 50 minutes.

41. The polybenzoxazine derivative vitrimer polymer of claim 38, wherein the activation energy associated with the relaxation time is 70 kJ / mol to 170 kJ / mol.

42. The polybenzoxazine derivative vitrimer polymer of claim 38, wherein the activation energy associated with the relaxation time is 100 kJ / mol to 160 kJ / mol.

43. The polybenzoxazine derivative vitrimer polymer of claim 38, wherein the processing temperature is 130°C to 250°C.

44. The polybenzoxazine derivative vitrimer polymer of claim 38, wherein the processing temperature is 150°C to 200°C.

45. The polybenzoxazine derivative vitrimer polymer of claim 38, wherein the processing temperature is 150°C to 170°C.

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