Copolymer and its use as a coating

Abstract

Providing a PPM-based copolymer soluble in an organic solvent 【Solution means】The copolymer according to the present invention is a first monomer of formula (I) [Z1 is selected from the group consisting of fluoro, chloro, bromo, iodo, hydroxyl, toluene-4-sulfonyloxy (-O-SO2-C6H4-CH3) and methylsulfonyloxy (-O-SO2-CH3)], and a second monomer of formula (II) [Z2 is selected from the group consisting of fluoro, chloro, bromo, iodo, hydroxyl, toluene-4-sulfonyloxy (-O-SO2-C6H4-CH3) and methylsulfonyloxy (-O-SO2-CH3), and Y is -CH2Z3 (Z3 is selected from the group consisting of fluoro, chloro, bromo, iodo, hydroxyl, toluene-4-sulfonyloxy (-O-SO2-C6H4-CH3) and methylsulfonyloxy), and is composed of (R1, R2, R3 and R4 are disclosed in the specification). 【Chemical formula 1】 TIFF2025523927000014.tif48160

Description

Technical Field

[0001] The present invention relates to a copolymer and its use as a coating.

Background Art

[0002] Protection against corrosion is one of the most important functions of organic coating compositions for metal substrates. On the one hand, the barrier function of the coating composition can be improved in order to keep corrosive substances such as oxygen, water, and ions away from the metal surface. On the other hand, it is possible to employ corrosion-inhibiting pigments that chemically or electrochemically intervene in the corrosion process, for example, by forming insoluble deposits by corrosion products or passivating the metal surface.

[0003] Poly(phenylene methylene) (PPM) is a hydrocarbon polymer of the general formula (C6H4[CH2])n. Structurally, it lies between polyethylene and polyphenylene and consists of an alternating arrangement of phenylene units and methylene units. Surprisingly, it exhibits a rather unique combination of material properties. In addition to high hydrophobicity, it has high thermal stability and fluorescence. This optical property is rare for non-conjugated polymers such as PPM (Non-Patent Document 1: Marco F. D’Elia et al; Poly(phenylene methylene)―Based Coatings for Corrosion Protection: Replacement of Additives by Use of Copolymers, Appl. Sci. 2019, 9, 3551; doi:10.3390 / app917355). PPM has also been shown to be effective for corrosion protection, but is only effective when mixed with rheology additives such as polysiloxane and benzyl butyl phthalate as external plasticizers to prevent surface cracking due to the rigidity of the polymer. To avoid the general problems associated with the use of external plasticizers, the development of PPM-related copolymer systems coatings containing n-octyloxy side chains and their corrosion resistance have been described by D’Elia et al. However, the copolymer has a low molar mass, does not dissolve in any solvent and cannot be processed, and thus its industrial use is naturally limited.

[0004] Nemoto Tadamasa et al (Non-Patent Document 2: “Synthesis and properties of organosoluble poly (phenylenemethylene)s from substituted benzenes or naphthalenes”, polymer Journal, vol.38, no.12, 16 November 2006(2006-11-16), pages 1278-1282, XP093008488) disclose the synthesis of organosoluble substituted benzene or naphthalene-formaldehyde copolymers by addition condensation.

[0005] Patent Document 1 (U.S. Patent No. 3,265,640) discloses a process for forming a shaped cross-linked polymer that includes reacting α,α'-dichloro-p-xylene and a polysubstituted benzene in the presence of a catalytic amount of a Friedel-Crafts catalyst to form a soluble condensation polymer. Brandle et al. (Non-Patent Document 3: Journal of Polymer Science, 2018, 56, 309ff) disclose the synthesis and fractionation of 2,3,5,6-tetramethylbenzyl chloride in bulk polymerization in the presence of the harmful SnCl4 catalyst. However, as a result of the synthesis, an insoluble cross-linked polymer having a glass transition temperature of about room temperature was obtained, and a small soluble fraction of this substance showed a molar mass of less than 800 Da. Furthermore, the solid monomer needs to be preheated at 80 °C, and the polymerization occurs only after heating at 180 °C for 1 hour. Therefore, the said polymer is not suitable for industrial use.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Non-Patent Documents

[0007]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] An object of the present invention was to provide a PPM-based copolymer having a high molar mass and soluble in common organic solvents (i.e., easily processable).

Means for Solving the Problems

[0009] This problem is solved by the copolymer according to claim 1. Further preferred embodiments are the subject of the dependent claims.

[0010] The copolymer of the present invention containing a first monomer of general formula (I) and a second monomer of general formula (II) was found to be obtained with a molar mass of 100 kDa or more and completely soluble in common organic solvents such as chloroform, dichloromethane or THF. Furthermore, this copolymer has a combination of excellent material properties such as high thermal stability, resistance to oxidizing agents and good barrier properties. Furthermore, the fluorescence of the copolymer of the present invention facilitates the detection of defects in coatings during corrosion or any other barrier / coating applications.

[0011] Furthermore, the copolymer according to the present invention is thermoplastic. This enables the copolymer to be processed using all the measures employed for other thermoplastic polymers. For example, in corrosion prevention, almost all commercially available coating agents are thermosetting resins, which represents a great advantage for industrial applications. In addition, the reversible thermoplastic behavior of the copolymer according to the present invention enables the recovery of the structure after thermal shock (e.g., it can be utilized for self-healing).

[0012] Furthermore, the complete substitution of the phenylene ring in the monomer of general formula (II) does not allow reactions on the aromatic backbone, prevents the formation of a complex three-dimensional network, and provides a completely soluble thermoplastic copolymer with material properties enhanced by side-chain insertion.

[0013] The copolymer of the present invention is a first monomer of general formula (I),

Chemical formula

Chemical formula

[0014] As used herein, "C1-C 30 alkyl" means a linear or branched aliphatic hydrocarbon group containing 1 to 30 carbon atoms in the chain. "Branched" means that one or more lower alkyl groups such as methyl, ethyl or propyl are attached to the linear alkyl chain.

[0015] "C2-C 30 alkenyl" means an aliphatic hydrocarbon group containing at least one carbon-carbon double bond, which may be linear or branched and contains 2 to 30 carbon atoms in the chain. "Branched" means that one or more lower alkyl groups such as methyl, ethyl or propyl are attached to a linear alkenyl chain.

[0016] "C2-C 30 "Alkynyl" means an aliphatic hydrocarbon group containing at least one carbon-carbon triple bond, which may be linear or branched and contains 2 to 30 carbon atoms in the chain. "Branched" means that one or more lower alkyl groups such as methyl, ethyl or propyl are attached to a linear alkynyl chain.

[0017] C2-C4-oligo(alkylene glycol) refers to an oligomer consisting of a small number of repeating units of alkene glycols such as oligo(ethylene glycol), oligo(propylene glycol) and oligo(ethylene / propylene glycol). The alkylene repeating unit may be linear or branched and has 2 to 4 carbon atoms. The number of repeating units is between 1 and 10, preferably between 1 and 5. For example, oligo(ethylene glycol) has the formula -(CH2CH2O)p1-H, where p1 is an integer between 1 and 10, preferably an integer between 1 and 5. For example, oligo(propylene glycol) has the formula -(CH(CH3)CH2O)p2-H or -(CH2CH2CH2O)p2-H, where p2 is an integer between 1 and 10, preferably an integer between 1 and 5. Oligo(ethylene / propylene glycol) refers to an oligomer whose repeating unit contains a mixture of ethylene and propylene glycol. The term "monomer" means a low-molecular-weight reactive substance that chemically binds to other molecules, especially other monomers, to form a polymer. In this case, each monomer contains at least one leaving group.

[0018] The term "copolymer" means a compound containing two or more different monomers and containing a plurality of monomers in a linear or branched chain.

[0019] The term "bimodal" means that the claimed compound has at least two polymer or copolymer components with a difference in weight-average molecular weight (Mw) of at least 50,000 g / mol (hereinafter referred to as "ΔMw") as measured by GPC (gel permeation chromatography) described herein, but is not limited to compounds that show two or more visible peaks or humps in the curve generated by the chromatograph. Thus, in the context of the present invention, a monomodal phase containing polymers with molar masses of 100,000 g / mol and 150,000 g / mol is likewise considered to be bimodal.

[0020] The term "Mn: number-average molar mass" means the total mass of all polymer chains in a sample divided by the total number of chains in the sample, and is determined by size-exclusion chromatography (SEC).

[0021] The term "Mw: mass-average molar mass (or weight-average molar mass)" means the average of the molar masses of all chains, weighted by the mass of chains of each length, and is determined by size-exclusion chromatography (SEC).

[0022] The term "PDI" means the polydispersity index and is equivalent to the term "MWD" (molecular weight distribution), which is determined using size-exclusion chromatography (SEC).

[0023] The second monomer in the copolymer of the present invention preferably has the general formula (IIa).

[0024]

Chemical formula

[0025] Due to the presence of the two reactive groups CH2Z2 and -CH2Z3, Z2 and Z3 are preferably the same, and the monomer of general formula (IIa) acts as a co-catalyst. The bifunctionality of said monomer has been shown to significantly increase the yield of copolymers with high molar mass and high PDI values. Furthermore, the presence of the monomer of general formula (II) has been shown not to adversely affect the connectivity along the polymer backbone.

[0026] Z1, Z2 and Z3 act as leaving groups. The leaving group ability generally increases from chloro to bromo and iodine, but chloro is preferred due to its better availability. Suitable sulfonyloxy groups (residue -SO3-), which act as leaving groups for suitable sulfonic acid esters (i.e., sulfonates), are an attractive alternative to halo groups, especially when the residue is electron-withdrawing. Suitable sulfonyloxy groups (residue -SO3-) can be readily prepared from numerous commercially available derivatives, and they exhibit reactivity similar to that of halo groups.

[0027] Examples of suitable sulfonyloxy groups include toluene-4-sulfonyloxy (-O-SO2-C6H4-CH3), i.e., the monomer is p-toluenesulfonate, synonym: tosylate), methylsulfonyloxy (-O-SO2-CH3, i.e., the monomer is methanesulfonic acid, synonym: mesylate) or trifluoromethylsulfonyloxy (-O-SO2-CF3, i.e., the monomer is trifluoromethanesulfonate, synonym: triflate).

[0028] In a preferred embodiment, Z1, Z2 and Z3 in the monomers of general formulas (I) and (II) are the same, resulting in a controllable reaction and facilitating the post-treatment of the crude product and purification from the by-products generated by the elimination of the leaving group.

[0029] When the second monomer of general formula (IIa) has the same R1, R2, R3 and R4, preferably R1, R2, R3 and R4 are methyl, and especially when Z2 and Z3 are chloro groups (α,α - bis(chloromethyl)durene), particularly good results are obtained:

[0030]

Chemical formula

[0031] The presence of α,α-bis(chloromethyl)xylene has been shown not to affect the polymerization initiation temperature below 150 °C. However, at temperatures above 150 °C, α,α-bis(chloromethyl)xylene increases the monomer conversion rate and affects the reaction rate. The increase in the monomer conversion rate increases the viscosity in the reaction batch.

[0032] In another embodiment of the present invention, the copolymer can include one or more additional monomers of general formula (III).

[0033]

Chemical formula

[0034] Such additional monomers can be added, for example, to adjust the rheological properties of the coating.

[0035] Preferably, in the compounds of formulas II and IIa, at least one of R1, R2, R3 and R4 is selected from the group consisting of linear or branched C8-C 30 alkyl, linear or branched C 8~ C 30 alkenyl, linear or branched C8-C 30 alkynyl and -OR9, and R9 is selected from the group consisting of linear or branched C8-C 30 alkyl, linear or branched C8-C 30 alkenyl and linear or branched C8-C 30 alkynyl. In a particularly preferred embodiment, one of R1, R2, R3 and R4 is -OR9, and R9 is selected from the group consisting of linear or branched C8-C 12 alkyl, preferably octyl, and the remaining residues are C1-C5 alkyl, preferably methyl. Such copolymers provide soft materials that can be easily deformed. Such copolymers can be easily processed in different ways and exhibit self-healing properties by utilizing the thermodynamics of corrosion reactions. Furthermore, they are suitable for low-temperature applications.

[0036] In one embodiment of the present invention, the copolymer comprises 0.01-5% (mol / mol), preferably 0.1-1% (mol / mol), and most preferably 0.5% (mol / mol) of the monomer of general formula (II). The molecular weight can be controlled by the concentration of the monomer of general formula (II). However, if the concentration is too high, a highly cross-linked polymer may be obtained. Since the molar ratio of the monomer of formula (II) / the monomer of formula (I) is as low as 0.1-1% (mol / mol), most preferably 0.5% (mol / mol), the molar mass of the copolymer according to the present invention is high.

[0037] Another aspect of the present invention relates to a method for preparing the copolymer according to the present invention. The copolymer is obtained by reacting a monomer of general formula (I) with a monomer of general formula (II) in the presence of a Lewis acid catalyst. As used herein, the term "Lewis acid" is used to refer to a substance capable of accepting an electron pair not shared from other molecules.

[0038] The amount of Lewis acid used depends on the desired reaction time and the concentration of the monomer of general formula (II). Generally, the amount of catalyst added is 0 wt% to 1.5 wt% equivalent of Lewis acid per equivalent of the monomer of general formula (I) in the reaction mixture. The optimal amount of Lewis acid also depends on the catalyst.

[0039] Preferably, the reaction is carried out in the presence of a catalyst selected from the group consisting of bismuth(III)-based catalysts, molybdenum-based catalysts, and tungsten-based catalysts. The catalyst can be shown to be more efficient than the tin catalysts used in the prior art. The catalyst required a shorter reaction time necessary to maximize monomer conversion. Most preferably, the catalyst is selected from the group consisting of WCl4(CNMe)2, WBr2(CO)3(dme), WCl4(THF)2, and MoI2(CO)3(MeCN)2, which exhibit similar catalytic behavior via step-growth polymerization (where CNMe is acetonitrile and dme is dimethoxyethane). For example, when the copolymerization of benzyl chloride catalyzed by WCl4(THF)2 was carried out in the presence of α,α-bis-chloromethyldurene (0.5% mol / mol), a number average molar mass of 230,000 g / mol -1 or more of the copolymer of the present invention was obtained. Despite being of high molecular weight, the copolymer of the present invention is soluble in organic solvents, in contrast to other copolymerization or catalytic strategies reported in the literature where insoluble and thus unprocessable polymers were obtained. Also, the above catalyst exists in a solid state at room temperature, whereas SnCl4 is a toxic liquid that is difficult to handle.

[0040] In one embodiment of the present invention, the copolymer is prepared in the presence of a catalyst throughout the polymerization, and the monomer of general formula (II) is not added before at least 40% by weight of the monomer of general formula (I) has reacted. As the viscosity increases, the Weissenberg effect occurs, which may lead to inefficient mixing. Thus, efficient mixing becomes possible. Due to the thermoplastic behavior of the copolymer according to the present invention, this problem can be overcome by raising the temperature of the reaction.

[0041] Furthermore, monomer I acts as a solvent for monomer II, i.e., the copolymerization reaction can be carried out, of course, in the absence of another solvent which is an economic and ecological benefit.

[0042] The copolymerization reaction preferably occurs at a temperature of 80°C to 180°C. Furthermore, preheating of the monomers is not required. Since benzyl chloride also acts as a solvent for the monomer of formula II, especially BCMD, no pretreatment is necessary.

[0043] BCMD (3,6-bis(chloromethyl)xylene) is preferably added in the range of 0.1% to 1% (mol / mol) relative to benzyl chloride. The rate of the reaction depends on the catalyst used and the concentration of BCMD in the polymerization batch. As a result of this copolymerization, a high molar mass polymer (number average molar mass of 100 kDa or more) can be obtained.

[0044] The copolymer according to the present invention can be used as a coating, particularly for coating metal substrates. The copolymer according to the present invention provides a continuous and essentially crack-free layer. Interestingly, there is no need for additional plasticizers. A coating containing the copolymer according to the present invention creates an excellent barrier between the substrate metal material and the surrounding environment, thereby inhibiting the corrosion process. Such a coating complies with ISO 17463:2014 and is a corrosion protection layer with excellent coating adhesion having very good rheological properties. Furthermore, the rheological behavior of the copolymer according to the present invention enables essential self-healing, perhaps by flow and thus closing pores in the polymer matrix induced or formed after local corrosion events. This behavior gives the coating of the copolymer according to the present invention an enhanced corrosion protection ability that enhances the durability and effectiveness of the coating. The thickness of the coating can be varied and adjusted according to the field of application. Preferably, the thickness of the coating is dimensioned to a value of 5 μm to 600 μm, preferably 5 μm to 50 μm. This coating thickness makes it possible to provide good corrosion protection compliant with ISO 17463:2014 to the metal substrate. These performances were also confirmed by testing a pre-damaged coating (circular damage φ = 0.52 mm) according to the procedure described in ISO 17463:2014. The copolymer according to the present invention can be applied with a coating of a smaller thickness such as 5 μm to 50 μm, whereas epoxy resin coatings typically have a thickness of 200 μm to 600 μm. As the thickness decreases, the material cost decreases and has a favorable impact on the environment.

[0045] Typical materials used for substrates according to this embodiment are aluminum and aluminum alloys, iron and steel (with or without zinc plating), and other examples include copper-based materials and nickel-based materials. The base material can be pretreated, for example, by chemical pretreatment, especially chromate treatment, chromium-free pretreatment, especially phosphate treatment, or anodizing treatment or silane treatment, before the coating is applied. The surface of the steel material may be pre-coated with a metal such as zinc. The shape of the base material can be freely selected, and the base material may be a primary processed product such as a plate material, a bar material, or a pipe material, or a secondary processed product such as a bolt, a nut, a hinge, an engine block, a gasket, and a housing. Examples of processing such secondary processed products include cutting / grinding, press working, bending, machining, casting, forging, etc.

[0046] Preferably, the copolymer according to the present invention can be used as corrosion protection. Corrosive environments are, for example, acidic, alkaline, and saline environments. Such coatings are particularly preferably used for secondary processed parts such as business equipment, electrical equipment, automobiles, ships, bridges, airplanes, and fasteners including bolts and nuts, attachments including clamps and clips, and press-molded products including plates, housings, hinges, and panels. High assembly accuracy is required for these members, and at the same time, since they may be subjected to large shear forces during processing and assembly, a high level of strength and coating adhesion is required.

[0047] The copolymer according to the present invention can be prepared as a powder, whereby it can be easily stored and transported. The powder is heated to a desired temperature and then the molten product is applied to the substrate to be coated. The cooling process cures the molten material to obtain strength and forms a coating on the substrate. Since thermoplastic powder coatings can be reheated multiple times, they can be easily redistributed along the surface. Due to this property, coating defects can be easily repaired with heat.

[0048] Another embodiment of the present invention relates to a paint comprising a copolymer according to the present invention. Such a paint forms a coating that can function simultaneously as a bonding layer, a restraining layer, and a (self-healing) protective layer. The coating formed is strong and self-curing and, under normal environmental conditions, does not require an overcoat of additional protective lacquer / paint and can be used as the topmost paint layer. Further, the coating can be used as a primer because it can be easily overcoated with a wide variety of paints to adjust its final color or to provide additional protection thereto. Such additional protection may be required when the coating is used under severe corrosive environmental conditions, such as when the object to be coated is a duct for corrosive chemicals. Also, the paint comprising the copolymer of the present invention dries rapidly after application and ensures a sufficient pot life, so that it can be used regardless of season or temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0049]

Figure 1a

Figure 1b

Figure 2

Figure 3

Figure 4a

Figure 4b

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0050] Examples [Synthesis of poly(phenylene methylene) catalyzed by a composite based on W and Mo]

[0051] The polymerization of benzyl chloride was carried out for each catalyst with a monomer / catalyst ratio of about 0.1% mol / mol. The polymerization conditions are basically based on the procedure already reported in the literature of Braendle et al. (Journal of Polymer Science, 2018, 56, 309ff). In the catalyst system applied herein, in order to alleviate the increase in viscosity and enable efficient mixing during the reaction, the reaction temperature needs to be changed from room temperature to 80 °C, 120 °C, 160 °C and 180 °C regardless of time constraints. An example of polymerization catalyzed by (WCl4(THF)2) is shown below. The stabilizer propylene oxide present in the starting material was reduced in pressure (10 -2It was removed from benzyl chloride overnight under (a certain pressure). In a 50 mL three-necked flask, under a nitrogen atmosphere, while maintaining a constant gas flow rate of 15 mL / min, 20 g of benzyl chloride (20.8 mL, 0.16 mol) was added to the solid catalyst [WCl4(THF)2] (70 mg, 0.1 mmol). Next, to ensure good mixing of the catalyst and the monomer, the crude reaction product was mechanically stirred for 3 hours. To enable mixing with the increase in viscosity due to the increase in molar mass, the temperature was raised from 25 °C to 180 °C during the reaction. When the reaction was complete, the molten polymer was cooled to room temperature. The polymer was dissolved in 30 mL of chloroform, and the solution was poured into 600 mL of methanol to purify the product. The suspension was vigorously stirred for 3 hours. The obtained PPM powder was filtered through a cellulose filter, and the polymer powder was dried under vacuum (10 -2 bar) overnight. 6.3 g of a pale yellow polymer was obtained (yield 66%). 1 1H NMR (300 MHz, CDCl3, in ppm units): 3.79 (broad, 2H), 7 (broad, 4H), THF (GPC). The molar mass is shown in Table 1, 13 and the 13C NMR spectrum is shown below.

[0052] Synthesis using the catalysts [WCl4(MeCN)2], [WBr2(CO)3(DME)], and [MoI2(CO)3(MeCN)2] was also carried out in the same manner. The yields of the purified PPM polymers reached 68 - 77% and are shown in Table 1 together with the molar mass.

[0053]

Table 1

[0054] [Synthesis of Poly(phenylene methylene) Copolymers Catalyzed by [WCl4(THF)2]] In the presence of 0.5% mol / mol of 1,4-bis(chloromethyl)-2,3,5,6-tetramethylbenzene (3,6-bis(chloromethyl)durene, BCMD), [W2Cl4(THF)2] (75 mg, 0.16 mmol) was used as a catalyst. 172 mg of BCMD (7.4×10−1 mmol) was added to 17 mL of benzyl chloride (148 mmol) to synthesize PPM having durene units in the same manner as above. The color change during the reaction was clear yellowish-brown for the first 1 minute, black at 80 °C, blue at 120 °C, and dark green at 160 °C. As a result of adjusting the sample as described above for PPM, 6.63 g (82%) of a greenish-blue product was obtained. 1H NMR (300 MHz, CDCl3, δ (ppm)): 2.5 (s, 0.12H, CH3), 3.71 (br, 2H, CH2), 7.19 (br, 4H, Ar); GPC (CHCl3): Mn = 3,400 g / mol -1 , weight-average molar mass (Mw) = 211,977 g / mol -1 , Mw / Mn = 55.4; DSC (Tg): 52.0 °C.

[0055] (Fractionation by phase separation) The copolymer (1 g) (Mn = 3,317 g / mol -1 , Mw = 183,600 g / mol -1 ) and 2-butanone (23 mL) were vigorously stirred for 2 hours, and then the suspension was separated into a transparent upper layer containing the low molar mass polymer (F low ) and a turbid oily phase containing the high molar mass polymer (F medium ). The upper layer and the lower layer were separated, the solvent was removed with a rotary evaporator, and then redissolved in 5 mL of chloroform. The solution was precipitated while stirring in 200 mL of methanol, the solid was filtered and dried (as above), and 0.452 g (fractionation yield 45%) of Fmedium (Mn = 33,520 g / mol -1 , Mw = 322,000 g / mol -1 ) was obtained (when the fractionation procedure was repeated twice, a higher molar mass fraction could not be separated). Then, 50 mg of F medium was washed with a 5 mL chloroform / 2-butanone (volume ratio 1:1) mixture to remove the low molar mass fraction, and the polymer fraction Fhigh (23mg, fractionation yield 46%) (Mn=205,300gmol -1 , Mw=777,900gmol -1 ) was obtained.

[0056] (Characterization) The spectrometer was Bruker AV300MHz using CDCl3 as the solvent. 1 H and 13C NMR spectra were recorded. Peak multiplicities are expressed as (BS) for broad signals, (S) for singlets, (d) for doublets, (t) for triplets, and (m) for multiplets. The monomer conversion was determined by withdrawing aliquots of the reaction mixture during the reaction and analyzing the peaks according to the literature. 1 The molar masses were evaluated by analyzing with H NMR spectroscopy. The molar masses were investigated by gel permeation chromatography (GPC) using a Viscotek GPC system with tetrahydrofuran (THF) as the eluent. The GPC module is equipped with a pump and degassing system (GPCmax VE2001, flow rate 1.0 mL / min), a Viscotek 302 TDA as detector, and two columns (2×PLGel Mix-B, dimensions 7.5 mm×300 mm) for the analysis of different molar masses. The thermal characterization was carried out using a TGA / DSC 3+ module (Mettler Toledo). The thermal transitions were investigated from 25 to 360 °C under nitrogen flush (50 mL / min), with the temperature increasing at a rate of 10 °C / min. The onset of decomposition was determined by measuring the temperature with an air flush (50 mL min). ―1 ) in the temperature range of 25℃ to 900℃, with a heating rate of 10℃ min ―1 It was evaluated as follows.

[0057] (Evaluation of catalytic activity in homopolymerization of benzyl chloride) For [WCl4(MeCN)2], [WCl4(THF)2], [WBr2(CO)3(dme)] and [MoI2(CO)3(MeCN)2], screening as bulk polymerization catalysts of benzyl chloride was carried out while maintaining the same molar ratio of catalyst / monomer (0.1% mol / mol) for all compounds. Before starting the reaction by raising the temperature, the catalyst was dissolved in benzyl chloride at room temperature. Since the solubility of each catalyst in benzyl chloride was different, dissolution times in the range of several minutes were observed for [MoI2(CO)3(MeCN)2] and [WBr2(CO)3(dme)], while 4 hours were required for the W(IV)-based catalysts. Next, the reaction temperature was adjusted during the polymerization process to avoid mixing problems (i.e., Weissenberg effect) caused by an increase in viscosity. The temperature required for polymerization and the resulting monomer conversion strongly depended on the compound. In particular, the polymerization in the presence of [MoI2(CO)3(MeCN)2] was already induced at 80 °C, started at 80 °C, and the monomer conversion rate quickly reached about 90% (in 10 minutes). When [WCl4(MeCN)2] was used, the monomer conversion rate increased significantly between 80 °C and 120 °C and leveled off at over 80% after 5 hours at this temperature. Previously reported W(II)-based catalysts also showed catalytic activity below 120 °C. In contrast, the polymerization catalyzed by [WCl4(THF)2] or [WBr2(CO)3(dme)] started only at temperatures above 150 °C.

[0058] The monomer conversion rate of the polymerization by the [WBr2(CO)3(dme)] catalyst reached 100% after 5 hours at 150 °C. Notably, no significant increase in viscosity was observed at this temperature. This is thought to be due to the low molar mass of the resulting polymer. On the other hand, in the polymerization by the [WCl4(THF)2] catalyst, the monomer conversion rate at 150 °C leveled off at 10% or less after 17 hours. An aliquot taken from the reaction mixture 1As is clear from Fig. 1a showing the monomer conversion rate obtained from the 1H NMR spectrum, it was important to raise the temperature to 180 °C to increase the monomer conversion rate and complete the reaction. Fig. 1b shows the GPC chromatograms of aliquots taken after various monomer conversions. These chromatograms show a molar mass distribution represented in two forms with a peak at 15.4 minutes corresponding to a molar mass between 4,500 g / mol -1 and 63,000 g / mol -1 and a small peak at 16.6 minutes (4,480 g / mol -1 or less). After 17 hours at this temperature, the two peaks shifted to lower retention times, 14.3 minutes and 15.4 minutes, and the molar mass range for both was 4,000 g / mol -1 to 500,000 g / mol -1 . These chromatograms showed a tail at 17 minutes corresponding to monomers and oligomers still present in the reaction batch when the monomer conversion was at this level. When the temperature was raised to 180 °C, the increase in the oligomer fraction relative to the high molar mass fraction became faster, as reflected by the rise of the peak at 16.3 minutes and the significant decrease in Mn with the increase in monomer conversion (Fig. 1b). The opposite was observed with other tungsten-based catalysts.

[0059] The presence of a high molar mass at a low monomer conversion rate indicates that a mechanism such as chain growth is involved in the presence of [WCl4(THF)2] (processes such as chain growth have also been reported for other tungsten-based catalysts). In contrast, such an effect was not observed in the polymerizations using [WCl4(MeCN)2], [WBr2(CO)3(dme)], and [MoI2(CO)3(MeCN)2].

[0060] After isolating the polymer by dissolution followed by precipitation, the polymers obtained from the [WCl4(MeCN)2], [WBr2(CO)3(dme)], and [MoI2(CO)3(MeCN)2] catalysts (Fig. 2) had an Mn of 3,100 g / mol -1~4,500 gmol -1 and an Mw of 7,000 gmol -1 ~13,000 gmol -1 showed a single form of molar mass distribution (Table 1). This is within the range of conventional PPM (see "Introduction"). However, the PPM obtained using [WCl4(THF)2] showed a bimodal molar mass distribution (Error! Reference source not found), and consistent with other catalysts, the Mn was 4,090 gmol -1 , but the Mw (63,760 gmol -1 ) was higher, and thus the PDI (15.6) was also significantly higher (Table 1).

[0061]

Table 2

[0062] Among the catalysts investigated, the Mo(II)-based complexes and [WCl4(THF)2] resulted in a Mn that was 25% - 30% higher than that of other tungsten catalysts. However, we regard this result and the higher Mw obtained with [WCl4(THF)2] as the specific effect of the applied compound and do not consider them as general characteristics of molybdenum or W(IV)-based catalysts since the catalysts have different operating temperatures.

[0063] The 13 13C NMR spectrum of the purified PPM is consistent with the PPM spectra reported for other catalysts. Signals in the range of 33 ppm to 44 ppm (Figure 3) are due to the substitution pattern along the PPM backbone, as previously reported (the 13 13C NMR signals in the aromatic region between 125 ppm and 145 ppm are shown in Supplementary Information (SI.1)). 1 In the 1H NMR spectrum [Supplementary Information (SI.2)], for each polymer, a broad peak was observed at 3.7 ppm in the methylene region and a broad peak was observed at 6.5 - 7.25 ppm for the phenylene group, which has also been reported for PPM obtained using SnCl4 or W(II)-based catalysts.

[0064] The obtained polymers were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). All polymers showed high thermal stability with decomposition starting at temperatures above 400 °C. Furthermore, the glass transition temperature was in the range of 58 °C to 63 °C, and no further primary thermal transitions were detected. Thus, the thermal properties of the obtained polymers are in agreement with the reported data for PPMs obtained with other catalysts such as SnCl4 and W(II)-based complexes (Tg 60 °C to 65 °C, decomposition onset temperature above 400 °C).

[0065] (Effect of α,α'-bis(chloromethyl)durene on connectivity) Based on the results obtained with the above catalysts, [WCl4(THF)2] provided the highest Mw, so [WCl4(THF)2] was selected to increase the molar mass by using the difunctional branching agent BCMD as a copolymer. As is clear from Figure 4a, the presence of BCMD (0.5% mol / mol) did not affect the polymerization start temperature (no reaction below 150 °C), but when the temperature reached 150 °C, the reaction became faster than in the case of homopolymerization. In the case of homopolymerization, the monomer conversion did not increase by more than 10% at 150 °C, but at the same temperature, in the presence of BCMD, the monomer conversion reached 70%, accompanied by an increase in viscosity reflected in the observation of the Weissenberg effect. Therefore, to ensure proper mixing within the polymerization batch, the temperature was raised to 180 °C until monomer conversion was complete. The chromatogram shown in Figure 4b again shows the multimodal distribution of molar masses that appears during the polymerization process, with the peaks generally shifted towards the higher molar mass side. In particular, unlike in the case of homopolymerization, in the presence of the branching agent, the intensity of the high molar mass peak at 12 minutes (Mn 914,800 gmol -1 ) increased with the increase in monomer conversion. The overall Mn (3,400 gmol -1 ) did not change significantly, but the Mw (212,000 gmol -1 ) increased fourfold compared to homopolymerization. The product containing BCMD was isolated as the corresponding homopolymer as described above by dissolution followed by precipitation. Compared to the in-situ product, the isolated product had essentially the same Mn (3,400 gmol-1 ) but had an Mw of 187,900 g / mol -1 ) was slightly lower. On the other hand, Mw was 3.8 times that of the product without BCMD, indicating that the proportion of high molar mass products was higher when BCMD was used. To separate the highest molar mass fraction, the resulting polymer was dissolved in 2-butanone, and the low molar mass fraction (F low ) and the high molar mass fraction (F medium ) were spontaneously separated as reported elsewhere for the PPM fraction. Further, using a chloroform:2-butanone 1:1 (volume ratio) mixture, the low mass polymers in the F medium fraction were further extracted to obtain fraction F high . The fractionation results are shown in Table 3. The Mn of F mediu (33,520 g / mol -1 ) differed in order of magnitude from the values before fractionation and those generally obtained by PPM (see "Introduction"). The Mn of fraction F high (205,300 g / mol -1 ) exceeded the highest molar mass of PPM separated so far (167,900 g / mol -1 also obtained by fractionation). From the GPC chart (Figure 5), it can also be seen that the lowest molar mass (F low ) was completely separated from the highest molar mass (F high ) fraction. From Figure 5, it is clear that F high is composed of a molar mass distribution represented in a bimodal form with two peaks, and the two peaks represent molar masses of 872,000 g / mol -1 and 122,200 g / mol -1 (12 minutes and 13.5 minutes in the GPC chart), respectively. However, attempts to separate these two fractions to obtain an ultra-high molar mass fraction failed.

[0066] (Table 3. Number average molar mass (Mn), weight average molar mass (Mw), polydispersity index (PDI), fraction yield, and polymer fraction composition obtained from the polymerization of benzyl chloride with [WCl4(THF)2] catalyst using 0.5% mol / mol of BCMD)

[0067]

Table 3

[0068] 13 The main difference between the products obtained with and without BCMD in the 13C NMR spectrum was the increase in the peak at 16.5 ppm corresponding to the signal of the methyl groups belonging to the durene units (Figure 6), which confirmed that the durene units were incorporated into the polymer chain. The 13C NMR spectrum in the methylene region (30 ppm to 42 ppm) showed a slight difference in the substitution pattern between the copolymer and the homopolymer (Figure 6). Essentially, the relative intensity of the ortho-ortho substitution pattern increased somewhat. 13 In the 1H NMR spectrum, characteristic signals at PPM (broad peaks in the range of 3.7 ppm and 6.8 - 7.2 ppm) and a peak at 2.5 ppm due to the methyl groups of the durene backbone appeared. Integration of the NMR signals revealed that the concentration of durene units relative to phenylene units was about 0.4% mol / mol, which was slightly lower than that of the initial reaction mixture. This may be related to the sample work-up procedure. The thermal properties of PPM-D (Tg 65 °C, decomposition onset temperature at 410 °C) were similar to those of PPM. 1 H NMR spectrum showed characteristic signals at PPM (broad peaks in the range of 3.7 ppm and 6.8 - 7.2 ppm) and a peak at 2.5 ppm due to the methyl groups of the durene backbone. Integration of the NMR signals revealed that the concentration of durene units relative to phenylene units was about 0.4% mol / mol, which was slightly lower than that of the initial reaction mixture. This may be related to the sample work-up procedure. The thermal properties of PPM-D (Tg 65 °C, decomposition onset temperature at 410 °C) were similar to those of PPM.

[0069] (Comparison between 4-octyloxy copolymer and tetramethyl copolymer) The comparison between the coating made from the PPM copolymer containing 4-octyloxy side chains and the coating of the PPM copolymer containing BCMD was carried out according to the ISO 17463:2014 regulation (the procedure reported below). However, since the copolymer disclosed by D’Elia et al. can only be processed by hot pressing (only thicker films can be obtained), the thicknesses of the two types of coatings tested were not equivalent. Thus, while the thickness of the prior art coating is 30 μm, the thickness of the novel coating obtained by spray coating is only 20 μm. In these tests, for the coating containing octyloxy side chains, |Z| 0.01Hz was found to be 10 7 Ωcm 2 during the preliminary EIS cycle. In the next ACET cycle, an increase in |Z| 0.01Hz was observed, and it settled at a value higher than 10 8 Ωcm 2 (Figure 7). Despite the excellent corrosion resistance of this coating, the increase in |Z| 0.01Hz after the preliminary EIS is thought to be due to the gradual saturation of the porosity of the coating surface, reflecting the presence of inhomogeneities within the polymer film. The importance of this type of coating became prominent when a pre-damaged surface was exposed to the ACET test (Figure 8). After damage, the coating shows good corrosion protection (the values of |Z| 0.01Hz are included between 10 7 and 10 8 Ωcm 2 in the first two ACET cycles), but after the third cycle, the coating ceases to function (|Z| 0.01Hz is about 104 Ωcm 2 ), and as a result, corrosion products are generated. In the ACET test performed on the coating surface made from the PPM copolymer obtained using BCMD, there is high corrosion resistance (even though it is one-third thinner than the previous one), and |Z| 8 Ωcm 2 far exceeds 10 0.01Hzshowed a high surface uniformity as reflected in (Fig. 9). As shown in Fig. 10, when ACET was carried out on the pre-damaged surface before damage, it was revealed that this coating had a high protection ability even after damage. This is considered to be due to the improvement of the self-healing ability.

[0070] (Preparation of Coating) Sheets of high-strength aluminum alloy AA2024 (copper 4.3% - 4.5%, magnesium 1.3% - 1.5%, manganese 0.5% - 0.6%, other elements less than 0.5%) with a length of 12 cm, width of 3 cm, and thickness of 4 mm were provided by Aviometal s.p.a (Varese, Italy) and used as substrates. Samples with a length of 4 cm were cut out and subsequently polished with abrasive papers of 300, 500, 800, 1200, and 4000 grit. Immediately after polishing, the samples were immersed in ethanol in an ultrasonic bath (Banderlin, Berlin, Germany) for 5 minutes for cleaning. Next, the AA2024 samples were taken out of the ethanol bath, and the alcohol remaining on the surface was evaporated by nitrogen flushing.

[0071] A layer of benzyltriethoxysilane was applied to the newly cleaned AA2024 samples by spin coating (3500 rpm, 30 s), followed by heating to 100 °C for 1 minute to allow the condensation of benzyltriethoxysilane into respective polysiloxanes.

[0072] The coating of the copolymer was produced by separating the PPM - based polymer from the pressing device using polyether ether ketone (PEEK) foil, pre - treating the AA2024 test piece with silane, and pressing the polymer powder onto it. The octyloxy copolymer (prior art, 13.4% mol / mol) was pressed at a temperature of 120 °C for 30 seconds. The thickness was 30 μm - 50 μm. No rheology additives were added, but the coating appeared extremely uniform and homogeneous. The BCMD copolymer coating (novel) was obtained by dissolving the BCMD copolymer in chloroform to obtain a 0.37 g / mL solution. Next, p - xylene was incorporated into the solution at a ratio of 3.9 mL / mL (p - xylene / polymer solution). This formulation was applied to the surface of AA2024 that had not been pretreated at 120 °C by spray coating at a pressure of 0.5 bar.

[0073] (Electrochemical properties of coated AA2024) The corrosion resistance of the coating was studied by electrochemical techniques, and tests were conducted on AA2024 samples coated with two types of copolymers: octyloxy (prior art: 13.4% mol / mol) and BCMD (novel: 0.4% mol / mol).

[0074] The electrochemical corrosion test was carried out in a naturally aerated near - neutral simulated marine environment prepared by dissolving sodium chloride (≥99.0%, Sigma - Aldrich) of 0.6 mol / L in MilliQ® water. A few drops of 0.2 mol / L -1 sodium hydroxide solution were added to the stock solution to adjust the pH value to 6.7 ± 0.1. Unless otherwise specified, all experiments were carried out at room temperature (24 ± 3 °C, with fluctuations during each run less than 2 °C). In all cases, the operating temperature was below the glass transition temperature of the copolymer according to the present invention. -1 The device used for measurement consisted of a glass cell with a hole (diameter 1 cm) opened in the center of the flat bottom. Through this hole, the coated metal plate (working electrode, exposed area 0.78 cm

[0075] ²) was inserted. 2) Contact with the working solution (0.6 M NaCl) was ensured. Sealing was guaranteed by a double-sided adhesive layer (a2 Soluzioni Adesive, Italy) pressed between the sample and the bottom of the cell. The electrochemical setup also included a platinum coil as the counter electrode and an aqueous saturated calomel electrode as the reference electrode (E SCE = 0.242 V vs. SHE). The latter was inserted into a glass double-junction (filled with the same working solution) ending with a Luggin capillary aimed at minimizing the resistance drop between the working and reference electrodes. No instrumental correction for the remaining resistance drop was made.

[0076] The electrochemical characterization included both the potentiodynamic and potentiostatic methods. The former consisted of an anodic polarization scan with a scan rate of 10 mV min -1 from the OCP to 2.5 V vs. SCE (each run lasted about 5.5 hours). A limiting current density of 4 mA cm -2 was imposed and then the scan was automatically interrupted upon reaching the final potential. In the second characterization, a constant potential was applied to the metal sample and the current flow between the working and counter electrodes was recorded. In our experiments, an oxidation potential of 0 V vs. SCE was applied for 24 hours.

[0077] To ensure the equilibrium of the system at OCP, potentiodynamic and potentiostat curves were recorded after an initial delay time of 600 s. Some potentiodynamic curves were also recorded at a fixed temperature of 35 °C, just above the glass transition temperature of the copolymer according to the present invention. In these experiments, a suitable cell surrounded by a jacket filled with a water flow controlled by a thermostat (Haake CH Fisons coupled to a Haake F3 Fision) was employed.

[0078] In the case of accelerated scanning electrochemical technique (ACET), after conditioning for 10 minutes at open circuit potential (OCP), a pre - controlled electrochemical impedance spectroscopy (EIS) is performed. According to the international standard ISO 17463:2014, the following sequence of deflection - relaxation - EIS is repeated at least 6 times continuously. The EIS analysis is performed in the frequency range from 100 kHz to 0.01 Hz using a sinusoidal voltage of 10 mV as the amplitude at open circuit potential (OCP). The next cathodic polarization step is performed at - 2 V vs. SCE for 20 minutes, and the relaxation process at OCP is continued for 3 hours. Then, a new EIS step is performed using the same parameters. The intrinsic self - healing and corrosion resistance of the PPM copolymer coating are also investigated by applying an artificial circular scratch (hole diameter 0.52 mm, depth corresponding to the coating thickness) during the conditioning time already described using the accelerated cyclic electrochemical technique. The impedance of the coating is obtained by evaluating the impedance coefficient at the lowest frequency of 0.01 Hz (|Z| 0.01Hz ). The high value of |Z| 0.01Hz (>107 Ωcm 2 ) reflects high corrosion protection.

Claims

1. A copolymer comprising: a first monomer of general formula (I), 【Chemical 1】 wherein Z １ is a first monomer selected from the group consisting of fluoro, chloro, bromo, iodo, hydroxyl, toluene-4-sulfonyloxy (-O-SO ２ -C ６ H ４ -CH 3 ), and methylsulfonyloxy (-O-SO ２ -CH 3 ), and a second monomer of general formula (II), [Chemical 2] In the formula, Z ２ is selected from the group consisting of fluoro, chloro, bromo, iodo, hydroxyl, toluene-4-sulfonyloxy (-O-SO ２ -C ６ H ４ -CH 3 ), and methylsulfonyloxy (-O-SO ２ -CH 3 ), Y is -CH ２ Z 3 [Z 3 is selected from the group consisting of fluoro, chloro, bromo, iodo, hydroxyl, toluene-4-sulfonyloxy (-O-SO ２ -C ６ H ４ -CH 3 ), and methylsulfonyloxy (-O-SO ２ -CH 3 ), and is selected from linear or branched C １ -C ３０ alkyl, linear or branched C ２ -C ３０ alkenyl, linear or branched C ２ -C ３０ alkynyl, sulfo (-SO ３ H), nitro, amino, hydroxyl, -NHCOR ５ , -CONHR ６ , -OOCOR ７ , -COOR ８ and -OR ９ and is selected from the group consisting of In the formula, R ５ , R ６ , R ７ , R ８ and R ９ are selected from the group consisting of linear or branched C １ -C ３０ alkyl, linear or branched C ２ -C ３０ alkenyl and linear or branched C ２ -C ３０ alkynyl, R １ 、R ２ 、R ３ and R ４ are, independently of one another, selected from the group consisting of linear or branched C １ -C ３０ alkyl, linear or branched C ２ -C ３０ alkenyl, linear or branched C ２ -C ３０ alkynyl, sulfo (-SO ３ H), nitro, amino, hydroxy, oligo(C ２ -C ４ -alkylene glycol), -NHCOR ５ 、-CONHR ６ 、-OCOR ７ 、-COOR ８ and -OR ９ and the selection is made from the group consisting of In the formula, R ５ , R ６ , R ７ , R ８ and R ９ are a second monomer selected from the group consisting of linear or branched C １ to C ３０ alkyl, linear or branched C ２ to C ３０ alkenyl and linear or branched C ２ to C ３０ alkynyl, and a copolymer containing the same as a constituent element.

2. In the copolymer according to claim 1, wherein the second monomer is of general formula (IIa): 【Chemical 2】 In the formula, Z ２ is selected from the group consisting of fluoro, chloro, bromo, iodo, hydroxyl, toluene-4-sulfonyloxy (—O—SO ２ —C ６ H ４ —CH ３ ), and methylsulfonyloxy (—O—SO ２ —CH ３ ), Z ３ is selected from the group consisting of fluoro, chloro, bromo, iodo, hydroxyl, toluene-4-sulfonyloxy (-O-SO ２ -C ６ H ４ -CH ３ ), and methylsulfonyloxy (-O-SO ２ -CH ３ ), R １ 、 R ２ 、 R ３ and R ４ are each independently selected from the group consisting of linear or branched C １ -C ３０ alkyl, linear or branched C ２ -C 3０ alkenyl, linear or branched C ２ -C ３０ alkynyl, sulfo (-SO 3 H), nitro, amino, hydroxy, oligo (C ２ -C ４ alkylene glycol), -NHCOR ５ 、 -CONHR ６ 、 -O COR ７ 、 -COOR ８ and -OR ９ and are selected from the group consisting of: R ５ 、R ６ 、R ７ 、R ８ and R ９ are copolymers selected from the group consisting of linear or branched C １ -C ３０ alkyl, linear or branched C ２ -C ３０、 alkenyl and linear or branched C ２ -C ３０ alkynyl.

3. In the copolymer according to claim 1 or claim 2, the Z ２ and Z ３ are the same, copolymer.

4. In the copolymer according to any one of claims 1 to 3, the Z １ , Z ２ and Z ３ are the same and are preferably chloro, copolymer.

5. In the copolymer according to any one of claims 1 to 4, R １ , R ２ , R ３ and R ４ are the same, preferably methyl, copolymer.

6. In the copolymer according to any one of claims 1 to 5, wherein the copolymer comprises one or more additional monomers of general formula (III), 【Chemical Formula 3】 In the formula, Z ２ ’ is selected from the group consisting of fluoro, chloro, bromo, iodo, hydroxyl, toluene-4-sulfonyloxy (-O-SO 2 -C 6 H 4 -CH 3 ), and methylsulfonyloxy (-O-SO 2 -CH 3 ), and is selected from the group consisting of Y' is -CH ２ Z ３ '[Z ３ ' is selected from the group consisting of fluoro, chloro, bromo, iodo, hydroxyl, toluene-4-sulfonyloxy (-O-SO 2 -C 6 H 4 -CH 3 ), and methylsulfonyloxy (-O-SO ２ -CH ３ ), and is selected from the group consisting thereof]. Linear or branched C １ ~C ３０ alkyl, linear or branched C ２ ~C ３０ alkenyl, linear or branched C ２ ~C ３０ alkynyl, sulfo (SO ３ H), nitro, amino, hydroxy, -NHCOR ５ ’, -CONHR ６ ’, -OCOR ７ ’, -COOR ８ ’ and -OR ９ ’ selected from the group consisting of, wherein R ５ ’, R ６ ’, R ７ ’, R 8 ’ and R 9 ’ are selected from the group consisting of linear or branched C 1 -C 30 alkyl, linear or branched C ２ -C ３０ alkenyl and linear or branched C ２ -C ３０ alkynyl, R １ ’, R ２ ’’, R ３ ’’’ and R ４ ’ are, independently of one another, linear or branched C 1 ~C 30 alkyl, linear or branched C ２ ~C ３０ alkenyl, linear or branched C ２ ~C ３０ alkynyl, sulfo (-SO ３ H), nitro, amino, hydroxy, oligo(C ２ ~C ４ -alkylene glycol), -NHCOR ５’ , -CONHR ６’ , -OCOR ７’ , -COOR ８’ and -OR ９’ and are selected from the group consisting of, wherein R ５ ’, R ６ ’, R ７ ’, R ８ ’ and R ９ ’ are selected from the group consisting of linear or branched C 1 -C 30 alkyl, linear or branched C ２ -C ３０ alkenyl and linear or branched C ２ -C ３０ alkynyl, wherein the monomers of general formula (III) are different from the monomers of general formula (II).

7. In the copolymer according to any one of claims 1 to 6, In the compounds of formula II and IIa, R １ , R ２ , R ３ and R ４ at least one of which is selected from the group consisting of linear or branched C ８ -C ３０ alkyl, linear or branched C ８ -C ３０ alkenyl, linear or branched C ８ -C ３０ alkynyl and -OR ９ , and R ９ is selected from the group consisting of linear or branched C ８ -C ３０ alkyl, linear or branched C ８ -C ３０ alkenyl, linear or branched C ８ -C ３０ alkynyl, a copolymer.

8. In the copolymer according to any one of claims 1 to 7, the copolymer comprises 0.01 to 5% (mol / mol), preferably 0.1 to 1% (mol / mol), and most preferably 0.5% (mol / mol) of the monomer of general formula (II).

9. In a method for preparing a copolymer according to any one of claims 1 to 8, wherein the monomer of general formula (I) and the monomer of general formula (II) are copolymerized in the presence of a Lewis acid catalyst.

10. In the method according to claim 9, the catalyst is selected from the group consisting of bismuth (III) catalysts, molybdenum catalysts, and tungsten catalysts, preferably WCl ４ (CNMe) ２ , WCl ４ (THF) ２ , WBr ２ (CO) ３ (dme), and MoI ２ (CO) ３ (MeCN) ２ selected from the group consisting of.

11. In the method according to any one of claims 9 and 10, wherein the polymerization of the monomer of general formula (I) is carried out in the presence of the catalyst throughout the polymerization, and the monomer of general formula (II) is added such that at least 40% by weight of the monomer of general formula (I) has not reacted before addition.

12. Use of the copolymer according to any one of claims 1 to 8 as a coating.

13. Use of the copolymer according to any one of claims 1 to 8 as a corrosion inhibitor.

14. A powder or paint comprising the copolymer according to any one of claims 1 to 8.

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