Synthesis of polyurethane by chain-growth copolymerization

Abstract

The present disclosure features materials and methods for the synthesis of polyurethanes by chain-growth copolymerization of a first reactant having an oxirane or thiirane moiety and at least one allene reactant in the presence of a Lewis acid, wherein the first allene reactant is an isocyanate or isothiocyanate. The features also reside in polyurethanes copolymers and terpolymers according to formula (I): (I), wherein An is a halogen atom or a carboxylate or alkoxide moiety; each X and X’ is independently an oxygen or sulfur atom; each R1 and R2 is independently a hydrogen atom or an alkyl group, including straight-chain, branched, saturated, unsaturated, aromatic, cyclic alkyl groups and alkyl groups containing heteroatoms, R3 is an electron-deficient group, m and o are independently selected from integers ≥ 1, and n is 0 or an integer ≥ 1. Both X and X’ can be the same, or X and X’ can be different.

Description

Background Art

[0001] Polyurethane, whose repeating units include urethane bonds, is sometimes also called polycarbamate. As one of the most important industrial polymers, polyurethanes have been widely used in daily life, from soft foams for mattresses to rigid foams for thermal insulation, pigments, coatings, construction, elastomers, and adhesives. Generally, polyurethanes are produced by the addition polymerization between diols and diisocyanates. By using monomers with functionality greater than 2 through one-step addition polymerization or stepwise addition, hyperbranched or dendritic polymer-type polyurethanes can be obtained respectively. Polyurethanes can also be synthesized by polycondensation strategies, and polycondensation between urethanes and alcohols or between carbonates and amines can generate polyurethanes. By wisely designing the structure of monomers, the urethane bonds of the resulting polyurethanes or polycarbamates can be easily broken, and thus once the end-capping terminal groups are removed, the polymers can self-decompose into small organic compounds.

[0002] In addition to these traditional polycondensation processes, ring-opening polymerization of cyclic carbamates is another alternative for polyurethane synthesis. The preparation of polyurethanes by cationic ring-opening polymerization of 6- and 7-membered cyclic carbamates has been reported. Similar to cyclic carbonates, 6-membered cyclic carbamates can also be ring-opened and anionically polymerized. The anionic ring-opening polymerization of 5-membered cyclic carbamates derived from naturally abundant D-glucosamine with hindered substituents has been studied. Recently, the anionic ring-opening polymerization of 5-membered cyclic carbamates using co-initiators commonly used for anionic ring-opening polymerization of lactams has been reported.

[0003] To avoid the use of phosgene and its derivatives, some other synthetic strategies have been proposed. The ring-opening polycondensation of bicyclic carbonates with diamines in a step-growth manner generates so-called poly(hydroxyurethane), where the bicyclic carbonates can be obtained by the coupling reaction of CO2 with epoxides. The direct copolymerization of aziridines with CO2 and the polycondensation of CO2, diamines, and dihalides in the presence of Cs2CO3 can produce polyurethanes without the aid of phosgene and its derivatives.

[0004] Generally, in the presence of metal complexes such as chromium, vanadium, aluminum, or recently through metal-free organic tetraarylphosphonium salts, cyclic carbamate 5-oxazolidinone can be generated by the [2+3] cycloaddition of epoxides and isocyanates; however, the trimerization of isocyanates is a common side reaction that must be suppressed. Recently, the synthesis of low molar mass polyurethanes or poly(urethane ureas) by ring-opening copolymerization of cyclohexene oxide with aryl isocyanates using a dimagnesium catalyst has been reported.

[0005] New synthetic strategies for providing polyurethane copolymers under mild conditions or minimizing side reactions will help meet industrial demands and expand the structural diversity of these polymers. Summary of the Invention

[0006] The present disclosure features materials and methods for synthesizing polyurethanes by chain-growth copolymerization of monomers comprising oxirane or thiirane and monomers comprising isocyanate or isothiocyanate, and polyurethanes copolymers obtainable by these methods. Copolymer synthesis includes contacting a first reactant having an oxirane or thiirane moiety with at least one heteroallene reactant in the presence of a Lewis acid, wherein the first heteroallene reactant is an isocyanate or isothiocyanate.

[0007] The materials and methods of the present disclosure can provide polyurethane or polythiourethane copolymers (i.e., polyurethanes) in the presence of a Lewis acid (including non-metallic Lewis acids), minimizing side reactions while under mild conditions. Copolymerization of epoxides with isocyanates can result in fully alternating polyurethanes. When using electron-deficient isocyanates, trimerization of the isocyanate is negligible and the polyurethane is obtained as the main product. These polymerization conditions can be applied to isothiocyanates and other monomers containing three-membered heterocyclic groups, such as episulfides. The methods described in the present disclosure can also be used to prepare copolymers (random copolymers, gradient copolymers, or block copolymers) by terpolymerization with heteroallene monomers such as carbon dioxide, carbon disulfide, or carbonyl sulfide.

[0008] In a first aspect, embodiments of the present disclosure feature a polyurethane copolymer represented by formula (I):

[0009]

[0010] where An is a halogen atom or a carboxylate or an alkoxide moiety; X and X' are each independently an oxygen or sulfur atom upon each occurrence. R1 and R2 are each independently selected from a hydrogen atom or an alkyl group, including linear, branched, saturated, unsaturated, aromatic, cyclic alkyl groups, and alkyl groups containing heteroatoms; R3 is an electron-deficient group; m and o are each independently selected from integers ≥ 1, and n is 0 or an integer ≥ 1. The An carboxylate and alkoxide can be selected from the group consisting of: monofunctional or polyfunctional carboxylates and monofunctional or polyfunctional alkoxides. Within the same repeating unit or within all repeating units, X and X’ can be the same (i.e., both X and X' are oxygen, or both X and X' are sulfur), or different (i.e., X is oxygen and X' is sulfur, or X' is oxygen and X is sulfur). In some cases, X = X' in all cases in the m repeating units, n repeating units, or all repeating units. In each case in the polymer, each X can be the same. The copolymer can be completely alternating. The value of n can be an integer ≥ 1. When n ≥ 1, the copolymer can be a block copolymer or a gradient copolymer. R1 and R2 can be independently selected from the group consisting of: a hydrogen atom, linear or branched, saturated or unsaturated C1-C 20 alkyl group, C1-C 20 alkyl group having one or more aromatic rings, and linear or branched heteroatom-containing C1-C 20 alkyl group, where the heteroatom includes one or more atoms selected from O, N, S, Si, P, and halogen atoms. R3 can be selected from the group consisting of: phenyl, benzoyl, acetyl, trichloroacetyl, allyl, benzenesulfonyl, p-toluenesulfonyl, 4-chlorobenzenesulfonyl, 4-fluorobenzenesulfonyl, chlorosulfonyl; fluorinated phenyl having one to five fluorine atoms in the ortho, meta, or para positions; phenyl having one or more nitro groups in the ortho, meta, or para positions; phenyl having one or more trifluoromethyl groups in the ortho, meta, or para positions, and phenyl having two or more different substituents selected from the group consisting of: halogen atom, fluorine atom, nitro group, trifluoromethyl group, aromatic group, cyclic alkyl group, and alkyl group containing heteroatoms. The copolymer can have a number average molecular weight (M n ) in the range of about 1,000 to about 300,000 kg / mol. The copolymer can have a dispersity of less than 2 and optionally the dispersity can be in the range of 1 to 1.6. The copolymer can have a structure of formula (II):

[0011]

[0012] Wherein An is a halogen atom or a carboxylate or an alkoxy moiety; X and X' are each independently an oxygen or sulfur atom upon each occurrence; R1 and R2 are each independently selected from a hydrogen atom or an alkyl group, including straight-chain, branched-chain, saturated, unsaturated, aromatic, cyclic alkyl groups, and alkyl groups containing heteroatoms; R3 is an electron-deficient group; and m and n are each independently selected from integers ≥ 1. The An carboxylate and alkoxy can be selected from the group consisting of: monofunctional or polyfunctional carboxylates and monofunctional or polyfunctional alkoxies. Within the same repeating unit, X and X' can be the same (i.e., both X and X' are oxygen, or both X and X' are sulfur), or different (i.e., X is oxygen and X' is sulfur, or X' is oxygen and X is sulfur). In some cases, in all cases within the repeating unit, X = X'. In each case in the polymer, each X can be the same.

[0013] In a second aspect, the present disclosure features a method for preparing a polyurethane copolymer, which includes: contacting a first reactant containing an oxirane or thiirane moiety with one or more additional reactants selected from heterallenes in the presence of a Lewis acid, wherein the first heterallene is selected from the group consisting of isocyanates and isothiocyanates. The Lewis acid can be selected from the group consisting of: Lewis acids based on boranes, aluminum, magnesium, and zinc. The Lewis acid can be an alkyl borane, a trialkyl borane, triethyl borane, triphenyl borane, triisobutyl borane, tris(pentafluorophenyl) borane, an alkyl aluminum, a trialkyl aluminum, trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, triphenyl aluminum, trioctyl aluminum, dimethyl zinc, diethyl zinc, diphenyl zinc, or di-n-butyl magnesium. The first reactant can have the structure of formula (III):

[0014]

[0015] Wherein, X is S or O, and each occurrence of R1 and R2 is independently hydrogen or a hydrocarbyl group selected from the group consisting of: substituted or unsubstituted monovalent alkyl, alkenyl, arenyl, aryl and aralkyl groups and divalent alkylene, alkenylene, arenylene, arylene and aralkylidene groups, wherein one carbon atom of R1 is covalently bonded to the carbon of R2 to form a cycloaliphatic structure. The first reactant can be an epoxide selected from the group consisting of: ethylene oxide (EO), propylene oxide (PO), 1-butene oxide (BO), 1-hexene oxide (HO), 1-octene oxide (OO), glycidyl ether, glycidyl ester, butyl glycidyl ether (BGE), 2-ethylhexyl glycidyl ether (EHGE), phenyl glycidyl ether (PGE), benzyl glycidyl ether (BzGE), glycidyl azide (GA), allyl glycidyl ether (AGE), styrene oxide (SO), epichlorohydrin (ECH), cyclopentene oxide (CPO), cyclohexene oxide (CHO), 4-vinyl-1-cyclohexene 1,2-epoxide (VCHO) and limonene oxide (LO). The first reactant can be a episulfide selected from the group consisting of: ethylene episulfide (EES), propylene episulfide (PES), styrene episulfide (SES), 2-(chloromethyl) episulfide (epithiochlorohydrine, ETCH), 1-butene episulfide (BES), 1-hexene episulfide (HES), 1-octene episulfide (OES), 2-(butoxymethyl) thiirane (BOMT), 2-(allyloxymethyl) thiirane (AOMT), cyclohexene episulfide (CHES), 2-(benzyloxymethyl) thiirane (BzOMT) and 2-(phenoxymethyl) thiirane (PhOMT). The first allene can have the structure of formula (IV):

[0016] R3-N=C=X

[0017] (IV)

[0018] Wherein R3 is an electron-deficient group, and X is an oxygen atom or a sulfur atom. The electron-deficient group can be selected from the group consisting of: phenyl, benzoyl, acetyl, trichloroacetyl, allyl, benzenesulfonyl, p-toluenesulfonyl, 4-chlorobenzenesulfonyl, 4-fluorobenzenesulfonyl, chlorosulfonyl; fluorinated phenyl having one to five fluorine atoms at the ortho, meta or para positions; phenyl having one or more nitro groups at the ortho, meta or para positions; phenyl having one or more trifluoromethyl groups at the ortho, meta or para positions, and phenyl having two or more different substituents selected from the group consisting of: halogen atom, fluorine atom, nitro group, trifluoromethyl group, aromatic group, cyclic alkyl group and heteroatom-containing alkyl group. The first allene can be an isocyanate selected from the group consisting of: trichloroacetyl isocyanate (TCAI), chlorosulfonyl isocyanate (CSI), benzenesulfonyl isocyanate (BSI), p-toluenesulfonyl isocyanate (TSI), 4-chlorobenzenesulfonyl isocyanate (CBSI), 4-nitrophenyl isocyanate (NPI), 4-trifluoromethylphenyl isocyanate (TFMPI), 4-fluorophenyl isocyanate (FPI), pentafluorophenyl isocyanate (PFPI) and 3,5-bis(trifluoromethyl)-phenyl isocyanate (BTFMPI). The first allene can be an isothiocyanate selected from the group consisting of: phenyl isothiocyanate (PIT), benzoyl isothiocyanate (BzIT), 4-fluorophenyl isothiocyanate (FPIT), 4-nitrophenyl isothiocyanate (NPIT), 4-trifluoromethylphenyl isothiocyanate (TFMPIT), allyl isothiocyanate (AIT), acetyl isothiocyanate (AcIT), ethoxycarbonyl isothiocyanate (EOCIT), pentafluorophenyl isothiocyanate (PFPIT) and 3,5-bis(trifluoromethyl)-phenyl isothiocyanate (BTFMPIT). The molar ratio of the first reactant to the additional reactant is in the range of about 1:20 to about 20:1. The method can further include contacting the reactants with an initiator, which is optionally selected from the group consisting of: salts having a halogen root, carboxylate or alkoxide anion and a tetraalkylammonium, tetraalkylphosphonium or phosphazene cation. The initiator can be selected from the group consisting of: tetrabutylammonium chloride (TBACl), bis(triphenylphosphine imide)-ammonium chloride (PPNCl), tetraoctylammonium chloride (TOACl), bis(triphenylphosphine imide)-ammonium acetate (PPNAc), 1,4-dihydroxymethylbenzene / P4-t-Bu (DHMB / P4-t-Bu), tetrabutylammonium butoxide (TBABO), hydroxymethylbenzene / P4-t-Bu (HMB / P4-t-Bu) and tetrabutylammonium succinate (TBAS). The molar ratio of the Lewis acid to the initiator can be in the range of about 0.5:1 to 4:1.One or more additional reactants may further include a second allene selected from the group consisting of carbon dioxide, carbon disulfide, and carbonyl sulfide. The molar ratio of the first reactant to the first allene to the second allene is in the range of about 1-10:1-10:1-10. The contacting step may include adding the first reactant and one or more additional reactants to the reaction vessel simultaneously or sequentially, optionally wherein the first allene and the second allene are added simultaneously or sequentially. The contacting step may be carried out at a temperature in the range of about 0 °C to about 80 °C, optionally about 20 °C to about 60 °C. The contacting step may be carried out for a duration of about 4 hours to about 20 hours, optionally about 12 hours.

[0019] In another aspect, the present disclosure further features a polyurethane copolymer obtained by the method of one or more embodiments described above for the second aspect.

[0020] In another aspect, the present disclosure features a composition for synthesizing a polyurethane by chain growth copolymerization, comprising: a Lewis acid; a first reactant comprising an oxirane or thiirane moiety; and one or more additional reactants selected from allenes, wherein the first allene is selected from the group consisting of isocyanates and isothiocyanates. The Lewis acid, the first reactant, and the one or more additional reactants may be selected from the groups described for the second aspect. For example, the Lewis acid may be a non-metal Lewis acid. The Lewis acid may be selected from the group consisting of Lewis acids based on boranes, aluminum, magnesium, and zinc. The Lewis acid may be an alkyl borane, a trialkyl borane, triethyl borane, triphenyl borane, triisobutyl borane, tris(pentafluorophenyl) borane, an alkyl aluminum, a trialkyl aluminum, trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, triphenyl aluminum, trioctyl aluminum, dimethyl zinc, diethyl zinc, diphenyl zinc, or dibutyl magnesium. The first reactant may have the structure of formula (III):

[0021]

[0022] Wherein, X is S or O, and each occurrence of R1 and R2 is independently hydrogen or a hydrocarbyl group selected from the group consisting of: substituted or unsubstituted monovalent alkyl, alkenyl, arenyl, aryl, and aralkyl groups, and divalent alkylene, alkenylene, arenylene, arylene, and aralkylidene groups, wherein one carbon atom of R1 is covalently bonded to the carbon of R2 to form a cycloaliphatic structure. The first reactant can be an epoxide selected from the group consisting of: ethylene oxide (EO), propylene oxide (PO), 1-butene oxide (BO), 1-hexene oxide (HO), 1-octene oxide (OO), glycidyl ether, glycidyl ester, butyl glycidyl ether (BGE), 2-ethylhexyl glycidyl ether (EHGE), phenyl glycidyl ether (PGE), benzyl glycidyl ether (BzGE), glycidyl azide (GA), allyl glycidyl ether (AGE), styrene oxide (SO), epichlorohydrin (ECH), cyclopentene oxide (CPO), cyclohexene oxide (CHO), 4-vinyl-1-cyclohexene 1,2-epoxide (VCHO), and limonene oxide (LO). The first reactant can be a episulfide selected from the group consisting of: ethylene episulfide (EES), propylene episulfide (PES), styrene episulfide (SES), 2-(chloromethyl) episulfide (epithiochlorohydrine, ETCH), 1-butene episulfide (BES), 1-hexene episulfide (HES), 1-octene episulfide (OES), 2-(butoxymethyl) thiirane (BOMT), 2-(allyloxymethyl) thiirane (AOMT), cyclohexene episulfide (CHES), 2-(benzyloxymethyl) thiirane (BzOMT), and 2-(phenoxymethyl) thiirane (PhOMT). The first allene can be represented by formula (IV):

[0023] R3-N=C=X (IV)

[0024] Wherein R3 is an electron-deficient group, and X is an oxygen atom or a sulfur atom. The electron-deficient group can be selected from the group consisting of: phenyl, benzoyl, acetyl, trichloroacetyl, allyl, benzenesulfonyl, p-toluenesulfonyl, 4-chlorobenzenesulfonyl, 4-fluorobenzenesulfonyl, chlorosulfonyl; fluorinated phenyl having one to five fluorine atoms at the ortho, meta or para positions; phenyl having one or more nitro groups at the ortho, meta or para positions; phenyl having one or more trifluoromethyl groups at the ortho, meta or para positions, and phenyl having two or more different substituents selected from the group consisting of: halogen atom, fluorine atom, nitro group, trifluoromethyl group, aromatic group, cyclic alkyl group and heteroatom-containing alkyl group. The composition can further include a second allene selected from the group consisting of: carbon dioxide, carbon disulfide and carbonyl sulfide. In addition, the composition can further include an initiator, which can be selected from the group consisting of: salts having a halogen root, carboxylate or alkoxide anion and a tetraalkylammonium, tetraalkylphosphonium or phosphazene cation. The initiator can be selected from the group consisting of: tetrabutylammonium chloride (TBACl), bis(triphenylphosphine imide)-ammonium chloride (PPNCl), tetraoctylammonium chloride (TOACl), bis(triphenylphosphine imide)-ammonium acetate (PPNAc), 1,4-dihydroxymethylbenzene / P4-t-Bu (DHMB / P4-t-Bu), tetrabutylammonium butanolate (TBABO), hydroxymethylbenzene / P4-t-Bu (HMB / P4-t-Bu) and tetrabutylammonium succinate (TBAS). The composition can further include a solvent selected from the group consisting of organic solvents: heterocyclic compounds, hydrocarbons, aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, ethers, esters, ketones, hexane, tetrahydrofuran, toluene, dichloromethane, chloroform, 1,2-dichloroethane, propylene carbonate, acetonitrile, dimethylformamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, 1,4-dioxane and 1,3-dioxane.

[0025] Details of one or more examples are set forth in the following description. Other features, objects, and advantages will be apparent from the description and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] This written disclosure describes illustrative embodiments that are non-limiting and non-exhaustive. The drawings generally illustrate various embodiments discussed in this document by way of example and not limitation.

[0027] Referring to the illustrative embodiments depicted in the accompanying drawings, wherein

[0028] Figure 1 is a flow chart of a method 100 for copolymerizing polyurethanes (e.g., polyurethanes and polythiourethanes) according to one or more embodiments of the present disclosure.

[0029] Figure 2 Table 1 is shown, which has representative data for the Lewis acid-assisted copolymerization of epoxides or episulfides with allenes according to one or more embodiments of the present disclosure. a The polymerization reaction was carried out for a period of 12 hours at room temperature. b Calculated by gravimetry. c From the 1 1H NMR of the pure product. d Determined by GPC, using THF as the eluent and calibrated with polystyrene standards.

[0030] Figure 3 Is the gel permeation chromatography (GPC) trace of the polymer (entry 1, Table 1) according to one or more embodiments of the present disclosure in tetrahydrofuran (THF).

[0031] Figure 4 Is the Fourier transform-infrared spectroscopy (FTIR) spectrum of the polymer (entry 1, Table 1) according to one or more embodiments of the present disclosure.

[0032] Figure 5 Is the 1 1H NMR in CDCl3 of the polymer (entry 1, Table 1) according to one or more embodiments of the present disclosure.

[0033] Figure 6 Is the 13 13C NMR in CDCl3 of the polymer (entry 1, Table 1) according to one or more embodiments of the present disclosure.

[0034] Figure 7 Is the GPC trace of the polymer (entry 2, Table 1) in THF according to one or more embodiments of the present disclosure.

[0035] Figure 8 Is the 1 1H NMR in CDCl3 of the polymer (entry 2, Table 1) according to one or more embodiments of the present disclosure.

[0036] Figure 9 Table 2 is shown, which has representative data for the trialkylborane-mediated copolymerization of epoxides with p-toluenesulfonyl isocyanate according to one or more embodiments of the present disclosure. a Unless otherwise stated, the reaction was carried out at 25 °C for 12 hours using THF as the solvent. b From the 1 1H NMR spectrum of the purified polymer. c Yield = weight of the polymer obtained / theoretical weight of the alternating polymer at complete conversion × 100%. dTheoretical molar mass = (58.1 + 197.2) × (E / I) × yield. e Determined by GPC using THF as the solvent and polystyrene standards at 35 °C. f The reaction was carried out at 60 °C. g The polymerization proceeded explosively. h Not detected due to solubility problems.

[0037] Figure 10 It is the FTIR spectrum of the polymer (Entry 2, Table 2) according to one or more embodiments of the present disclosure.

[0038] Figure 11 It is the 1 1H NMR spectrum of the polymer (Entry 2, Table 2) according to one or more embodiments of the present disclosure in CDCl3.

[0039] Figure 12 It is the 13 13C NMR spectrum of the polymer (Entry 2, Table 2) according to one or more embodiments of the present disclosure in CDCl3.

[0040] Figure 13 It is the MALDI-TOF mass spectrum of the polymer (Entry 2, Table 2) according to one or more embodiments of the present disclosure.

[0041] Figure 14 It is the FTIR spectrum of the polymer (Entry 4, Table 2) according to one or more embodiments of the present disclosure.

[0042] Figure 15 It is the GPC trace of the polymer (Entry 4, Table 2) according to one or more embodiments of the present disclosure in THF.

[0043] Figure 16 It is the 1 1H NMR spectrum of the polymer (Entry 4, Table 2) according to one or more embodiments of the present disclosure in CDCl3.

[0044] Figure 17 It is the FTIR spectrum of the polymer (Entry 5, Table 2) according to one or more embodiments of the present disclosure.

[0045] Figure 18 It is the 1 1H NMR spectrum of the polymer (Entry 5, Table 2) according to one or more embodiments of the present disclosure in CDCl3.

[0046] Figure 19 It is the GPC trace of the polymer (Entry 5, Table 2) according to one or more embodiments of the present disclosure in THF.

[0047] Figure 20 is the FTIR spectrum of a polymer (Entry 8, Table 2) according to one or more embodiments of the present disclosure.

[0048] Figure 21 is the 1 HNMR spectrum of a polymer (Entry 8, Table 2) according to one or more embodiments of the present disclosure in CDCl3.

[0049] Figure 22 is the GPC trace of a polymer (Entry 8, Table 2) according to one or more embodiments of the present disclosure in THF.

[0050] Figure 23 is the FTIR spectrum of a polymer (Entry 10, Table 2) according to one or more embodiments of the present disclosure.

[0051] Figure 24 is the FTIR spectrum of a polymer (Entry 11, Table 2) according to one or more embodiments of the present disclosure.

[0052] Figure 25 is the 1 HNMR spectrum of a polymer (Entry 11, Table 2) according to one or more embodiments of the present disclosure in CDCl3.

[0053] Figure 26 is the GPC trace of a polymer (Entry 11, Table 2) according to one or more embodiments of the present disclosure in THF.

[0054] Figure 27 is the FTIR spectrum of a polymer (Entry 12, Table 2) according to one or more embodiments of the present disclosure.

[0055] Figure 28 is the GPC trace of a polymer (Entry 12, Table 2) according to one or more embodiments of the present disclosure in THF.

[0056] Figure 29 Shows Table 3, which has the results of the Lewis acid-assisted terpolymerization of an epoxide or episulfide with two allenes according to one or more embodiments of the present disclosure. a The polymerization reaction was carried out at 60 °C for a period of 12 hours. b Determined from the 1 H NMR spectrum of the pure product. c Determined by GPC, using THF as the eluent and calibrated with polystyrene standards. Detailed Description

[0057] The present disclosure features materials and methods for synthesizing polyurethane copolymers (e.g., polyurethanes and polythiourethanes) by chain-growth copolymerization through contacting an oxirane or thiirane moiety with at least one additional reactant selected from the group consisting of carbodiimides in the presence of a Lewis acid, and copolymers synthesized using these materials and methods.

[0058] Definition

[0059] The following terms, when cited, are defined as described below. All other terms and phrases in the present disclosure shall be construed according to their ordinary meaning as understood by those of ordinary skill in the art.

[0060] "Copolymer" includes a polymer having at least two different repeating units incorporated into the polymer chain. The terms "terpolymer" or "multicomponent polymerization" refer to incorporating three or more types of repeating units into the polymer chain. The properties of an individual polymer chain depend on the type and relative proportion of each repeating unit.

[0061] "Polyurethane" and "polyurethane" are used interchangeably to refer to a polymer having a plurality of urethane groups connected by "urethane" bonds (i.e., a polymer composed of macromolecules containing urethane (urethane) bonds: -NH-CO-O- in the main chain).

[0062] "Chain-growth copolymerization" is different from step-growth polymerization (e.g., condensation) and refers to polymerization that proceeds through a sequence of initiation, growth, and termination, whereby a first reactant is added to a growing chain.

[0063] As used herein, "contacting" means bringing two or more components into proximity, such as physically, chemically, electrically, or a combination thereof. Mixing is an example of contacting.

[0064] As used herein, "ate complex" refers to a salt formed when a Lewis acid obtains a bond by reacting with a base and becomes a negatively charged anion. See Scheme 1. The ate complex can be used to initiate the copolymerization of monomers containing oxirane or thiirane with carbodiimide through urethane bonds.

[0065] As used herein, "initiator" refers to a salt capable of coordinating with a Lewis acid to form an acid root-type complex. Exemplary initiators include tetrabutylammonium chloride (TBACl), bis(triphenylphosphineylidene)ammonium chloride (PPNCl), 1,4-dihydroxymethylbenzene / P4-t-Bu (DHMB / P4-t-Bu), tetrabutylammonium butoxide (TBABO), tetraoctylammonium chloride (TOACl), bis(triphenylphosphineylidene)-ammonium acetate (PPNAc), hydroxymethylbenzene / P4-t-Bu (HMB / P4-t-Bu), and tetrabutylammonium succinate (TBAS), which have the following structures, respectively:

[0066]

[0067] "Ketene" includes compounds having a Y═C═Y' bond in the molecule, where Y is an oxygen atom, a nitrogen atom, or a sulfur atom, and Y' is an oxygen atom, a nitrogen atom, or a sulfur atom. Ketene is: an isocyanate compound when Y is a nitrogen atom and Y' is an oxygen atom; an isothiocyanate compound when Y is a nitrogen atom and Y' is a sulfur atom; carbon dioxide when both Y and Y' are oxygen atoms; carbonyl sulfide when Y is an oxygen atom and Y' is a sulfur atom; and carbon disulfide when both Y and Y' are sulfur atoms. Exemplary ketenes include: trichloroacetyl isocyanate (TCAI), chlorosulfonyl isocyanate (CSI), benzenesulfonyl isocyanate (BSI), p-toluenesulfonyl isocyanate (TSI), 4-chlorobenzenesulfonyl isocyanate (CBSI), 4-nitrophenyl isocyanate (NPI), 4-trifluoromethylphenyl isocyanate (TFMPI), 4-fluorophenyl isocyanate (FPI), pentafluorophenyl isocyanate (PFPI), 3,5-bis(trifluoromethyl)-phenyl isocyanate (BTFMPI), carbon dioxide, carbon disulfide, carbonyl sulfide, phenyl isothiocyanate (PIT), benzoyl isothiocyanate (BzIT), 4-fluorophenyl isothiocyanate (FPIT), 4-nitrophenyl isothiocyanate (NPIT), 4-trifluoromethylphenyl isothiocyanate (TFMPIT), allyl isothiocyanate (AIT), acetyl isothiocyanate (AcIT), ethoxycarbonyl isothiocyanate (EOCIT), pentafluoroisothiocyanate (PFIT), and 3,5-bis(trifluoromethyl)phenyl isothiocyanate (BTFMPIT).

[0068] Figure 1Disclosed is a method 100 for preparing a polyurethane copolymer according to one or more embodiments of the present disclosure. Method 100 includes a contacting step 101, in which a reactant containing oxirane or thiirane is contacted with a reactant containing isocyanate or isothiocyanate in the presence of a Lewis acid. Step 102 includes stirring the reactants at a predetermined temperature for a predetermined duration to initiate the polymerization of the reactants and promote the growth of copolymer chains (i.e., chain-growth copolymerization). Step 103 includes terminating the reaction. In some cases, the method includes a step 104 of purifying the resulting polyurethane copolymer.

[0069] Returning to the contacting step 101, the first reactant having an oxirane or thiirane moiety (i.e., the reactant containing oxirane or thiirane) can be a substituted or unsubstituted epoxide or episulfide, including mono-substituted, di-substituted, tri-substituted, or tetra-substituted epoxides or episulfides. Di-substituted epoxides and episulfides can include 1,2-disubstituted alkyl epoxides and episulfides, 1,1-disubstituted epoxides and episulfides, and polycyclic epoxides and episulfides.

[0070] The first reactant can have the structure of formula (III):

[0071]

[0072] wherein X is S or O, and each occurrence of R1 and R2 is independently hydrogen or a hydrocarbon group selected from the group consisting of substituted or unsubstituted monovalent alkyl, alkenyl, alkaryl, aryl, and aralkyl groups, and divalent alkylene, alkenylene, alkarylene, arylene, and aralkylene groups, wherein one carbon atom of R1 is covalently bonded to the carbon of R2 to form a cyclic aliphatic structure. For example, the first reactant can be an epoxide such as ethylene oxide (EO), propylene oxide (PO), 1-butene oxide (BO), 1-hexene oxide (HO), 1-octene oxide (OO), glycidyl ether, glycidyl ester, butyl glycidyl ether (BGE), 2-ethylhexyl glycidyl ether (EHGE), phenyl glycidyl ether (PGE), benzyl glycidyl ether (BzGE), glycidyl azide (GA), allyl glycidyl ether (AGE), styrene oxide (SO), epichlorohydrin (ECH), cyclopentene oxide (CPO), cyclohexene oxide (CHO), 4-vinyl-1-cyclohexene 1,2-epoxide (VCHO), or limonene oxide (LO), which have the exemplary structures shown below:

[0073]

[0074] Sometimes, the first reactant is a cyclic sulfide, such as ethylene sulfide (EES), propylene sulfide (PES), styrene sulfide (SES), 2-(chloromethyl) ethylene sulfide (ETCH), 1-butene sulfide (BES), 1-hexene sulfide (HES), 1-octene sulfide (OES), 2-(butoxymethyl) thiirane (BOMT), 2-(allyloxymethyl) thiirane (AOMT), cyclohexene sulfide (CHES), 2-(benzyloxymethyl) thiirane (BzOMT) or 2-(phenoxymethyl) thiirane (PhOMT), which have the exemplary structures shown below:

[0075]

[0076] The reactant containing an isocyanate or isothiocyanate can have the structure of formula (IV) (i.e., the first allene):

[0077] R3-N=C=X (IV)

[0078] Wherein R3 is an electron-deficient group, and X is an oxygen atom or a sulfur atom. The electron-deficient group reduces side reactions such as the trimerization of isocyanates and promotes copolymerization under mild reaction conditions. Suitable electron-deficient groups include phenyl, benzoyl, acetyl, trichloroacetyl, allyl, benzenesulfonyl, p-toluenesulfonyl, 4-chlorobenzenesulfonyl, 4-fluorobenzenesulfonyl, chlorosulfonyl; fluorinated phenyl groups having one to five fluorine atoms in the ortho, meta or para positions; phenyl groups having one or more nitro groups in the ortho, meta or para positions; phenyl groups having one or more trifluoromethyl groups in the ortho, meta or para positions, and phenyl groups having two or more different substituents selected from the group consisting of: halogen atoms, fluorine atoms, nitro groups, trifluoromethyl groups, aromatic groups, cyclic alkyl groups and heteroatom-containing alkyl groups.

[0079] For example, the first allene can be an isocyanate selected from the group consisting of: trichloroacetyl isocyanate (TCAI), chlorosulfonyl isocyanate (CSI), benzenesulfonyl isocyanate (BSI), p-toluenesulfonyl isocyanate (TSI), 4-chlorobenzenesulfonyl isocyanate (CBSI), 4-nitrophenyl isocyanate (NPI), 4-trifluoromethylphenyl isocyanate (TFMPI), 4-fluorophenyl isocyanate (FPI), pentafluorophenyl isocyanate (PFPI) and 3,5-bis(trifluoromethyl)-phenyl isocyanate (BTFMPI), which have the exemplary structures shown below:

[0080]

[0081] Sometimes, the first allene can be an isothiocyanate selected from the group consisting of phenyl isothiocyanate (PIT), benzoyl isothiocyanate (BzIT), 4-fluorophenyl isothiocyanate (FPIT), 4-nitrophenyl isothiocyanate (NPIT), 4-trifluoromethylphenyl isothiocyanate (TFMPIT), allyl isothiocyanate (AIT), acetyl isothiocyanate (AcIT), ethoxycarbonyl isothiocyanate (EOCIT), pentafluorophenyl isothiocyanate (PFPIT), and 3,5-bis(trifluoromethyl)phenyl isothiocyanate (BTFMPIT), which have the exemplary structures shown below:

[0082]

[0083] The contacting step 101 can include combining the first reactant and the first allene in a predetermined molar ratio. For example, the molar ratio of the first reactant to the isocyanate or isothiocyanate reactant can be in the range of about 1:20 to about 20:1, such as about 1:1, about 2:1, about 2:3, about 4:1, and about 10:11. This molar ratio can be substantially maintained in the resulting copolymer (e.g., see Tables 1-3).

[0084] The Lewis acid can be selected from the group consisting of Lewis acids based on boranes, aluminum, magnesium, and zinc, such as alkyl boranes, trialkyl boranes, alkyl aluminums, trialkyl aluminums, dialkyl zincs, and dialkyl magnesiums. For example, the Lewis acid can be triethyl borane (TEB), triphenyl borane (TPB), triisobutyl borane (TsBB), tris(pentafluorophenyl) borane (BCF), trimethyl aluminum (TMA), triethyl aluminum (TEA), triisobutyl aluminum (TiBA), triphenyl aluminum (TPA), trioctyl aluminum (TOA), dimethyl zinc (DMZ), diethyl zinc (DEZ), diphenyl zinc (DPZ), or di-n-butyl magnesium (DBM). In certain embodiments, the Lewis acid is a metal-free Lewis acid, such as the above-mentioned borane-based Lewis acids. Exemplary structures of the Lewis acids are shown below:

[0085]

[0086] The contacting step 101 can include adding an initiator to a combination of a reactant and a Lewis acid. The initiator can be selected to provide an anion and a cation for forming an acid root type complex with the Lewis acid. In some cases, the initiator is selected from the group consisting of salts having a halogen root, a carboxylate root or an alkoxide anion and a tetraalkylammonium, a tetraalkylphosphonium or a phosphazenium cation. For example, the initiator can be tetrabutylammonium chloride (TBACl), bis(triphenylphosphine imide)-ammonium chloride (PPNCl), tetraoctylammonium chloride (TOACl), bis(triphenylphosphine imide)-ammonium acetate (PPNAc), 1,4-dihydroxymethylbenzene / P4-t-Bu (DHMB / P4-t-Bu), tetrabutylammonium butanolate (TBABO), hydroxymethylbenzene / P4-t-Bu (HMB / P4-t-Bu) or tetrabutylammonium succinate (TBAS). The initiator can be added to the Lewis acid in a predetermined molar ratio. In some cases, the Lewis acid can be present in a molar excess relative to the initiator so that an acid root type complex can be formed and the first reactant can be activated (see Scheme 1). The molar ratio of the Lewis acid to the initiator can be in the range of about 0.5:1 to 4:1.

[0087] In some cases, the method 100 is a method for preparing a terpolymer. Thus, the contacting step 101 can include using an additional heterallene selected from carbon dioxide, carbon disulfide and carbonyl sulfide. The contacting step 101 can include combining the first reactant, the first heterallene and the second heterallene in a predetermined molar ratio. For example, the molar ratio of the first reactant to the first heterallene to the second heterallene can be in the range of about 1-20:1-20:1-20, about 1-10:1-10:1-10 or about 1-5:1-5:1-5. In some cases, the ratio of the first reactant to the first heterallene to the second heterallene can be selected from the group consisting of about 2:1:1, about 4:3:1, about 5:4:1, about 5:3:2 and about 10:9:1. This ratio can be substantially maintained in the resulting terpolymer. For example, the addition order of the reactants can be controlled to provide a block or gradient terpolymer. For example, the first reactant can be added to the reaction vessel in a first addition step, and then the first heterallene can be added in a second addition step. The first heterallene can be added to the reaction vessel simultaneously with the additional heterallene(s), or the first heterallene and the additional heterallene can be added successively.

[0088] In some cases, the reactants and the Lewis acid are contacted in the presence of a solvent. A suitable solvent can be selected based on the solubility of the reactants, the Lewis acid, or the initiator. Generally, the solvent is selected from the group of organic solvents including the following: heterocyclic compounds, hydrocarbons, aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, ethers, esters, ketones. For example, the solvent can be hexane, tetrahydrofuran, toluene, dichloromethane, chloroform, 1,2-dichloroethane, propylene carbonate, acetonitrile, dimethylformamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, 1,4-dioxane, and 1,3-dioxane. In certain embodiments, the solvent is tetrahydrofuran.

[0089] Step 102 includes stirring (e.g., agitating) the reactants at a predetermined temperature. The methods of the present disclosure can employ mild reaction conditions. The predetermined temperature can be in the range of about 0 °C to about 80 °C, optionally about 20 °C to about 60 °C. In some cases, the reactants are stirred at ambient temperature or room temperature. The duration of stirring and temperature control (if required) can be in the range of about 4 hours to about 20 hours. For example, the reactants can be stirred at the predetermined temperature for about 4, 6, 8, 10, 12, 15, 18, or 20 hours.

[0090] Step 103 includes terminating the reaction by stopping the formation of the reactive intermediate. Termination can be achieved by consuming the reactants or by quenching the reaction. The reaction can be quenched by adding hydrochloric acid. After quenching with hydrochloric acid (HCl), the copolymer product can have hydrogen end groups (see Schemes 1 and 2).

[0091] In some cases, method 100 includes step 104 to separate the copolymer product from the crude product. The separation can include precipitating the copolymer by adding a precipitant. The selection of a suitable precipitant can be based on the copolymer structure. Sometimes, methanol can be used. The purified copolymer can be characterized by one or more methods within the capabilities of those skilled in the art. The resulting copolymer can be classified based on the comonomer distribution and can be a statistical (e.g., random), gradient, alternating, or block copolymer.

[0092] Embodiments of method 100 can be used to expand the structural diversity of polyurethane copolymers. The methods described in the present disclosure can be used to prepare polyurethane copolymers having arrangements that cannot be obtained using previously described synthetic strategies.

[0093] Embodiments of the present disclosure feature a polyurethane copolymer represented by formula (I):

[0094]

[0095] Wherein An is a halogen atom or a carboxylate or an alkoxy moiety; R1 and R2 are each independently selected from a hydrogen atom or an alkyl group, including straight-chain, branched-chain, saturated, unsaturated, aromatic, cyclic alkyl groups and heteroatom-containing alkyl groups; R3 is an electron-deficient group; and m and o are each independently selected from integers ≥1, and n is 0 or an integer ≥1. The An carboxylate and alkoxy groups can be selected from the group consisting of: monofunctional or polyfunctional carboxylates and monofunctional or polyfunctional alkoxy groups. Within the same repeating unit or within all repeating units, X and X' can be the same (i.e., both X and X' are oxygen, or both X and X' are sulfur), or different (i.e., X is oxygen and X' is sulfur, or X' is oxygen and X is sulfur). In some cases, in all cases of the m repeating units, n repeating units or all repeating units, X = X'. In each case in the polymer, each X can be the same. In some cases, the copolymer is completely alternating.

[0096] The value of n can be an integer ≥1, for example, when the copolymer is a terpolymer. The terpolymer can be a random, block or gradient copolymer. R1 and R2 can each independently be selected from the group consisting of: a hydrogen atom, straight-chain or branched-chain, saturated or unsaturated C1-C 20 alkyl group, a C1-C 20 alkyl group having one or more aromatic rings, and a straight-chain or branched-chain heteroatom-containing C1-C 20 alkyl group, wherein the heteroatom includes one or more atoms selected from O, N, S, Si, P and halogen atoms. R3 can be selected from the group consisting of: phenyl, benzoyl, acetyl, trichloroacetyl, allyl, benzenesulfonyl, p-toluenesulfonyl, 4-chlorobenzenesulfonyl, 4-fluorobenzenesulfonyl, chlorosulfonyl; a fluorinated phenyl having one to five fluorine atoms located at the ortho, meta or para positions; a phenyl having one or more nitro groups located at the ortho, meta or para positions; a phenyl having one or more trifluoromethyl groups located at the ortho, meta or para positions, and a phenyl having two or more different substituents selected from the group consisting of: halogen atoms, fluorine atoms, nitro groups, trifluoromethyl groups, aromatic groups, cyclic alkyl groups and heteroatom-containing alkyl groups.

[0097] The copolymer can have a number-average molecular weight (Mn) in the range of about 1,000 to about 300,000 kg / mol. The number-average molecular weight can be determined by gel permeation chromatography.

[0098] The copolymer can be substantially homogeneous. Thus, the width of the molar mass distribution of the copolymer can be relatively narrow. For example, the copolymer can have a dispersity less than 2, such as in the range of 1 to about 1.6, or about 1.1, 1.2, 1.3, 1.4, 1.5 or 1.6.

[0099] In certain embodiments, the copolymer has the structure of formula (II):

[0100]

[0101] wherein An, X, X', R1, R2, and R3 are as defined for formula (I); and m and n are independently selected from integers ≥ 1.

[0102] The following examples are intended to illustrate the above invention and should not be construed as limiting its scope.

[0103] Examples

[0104] Copolymerization of Epoxides or Episulfides with Isocyanates and Other Allene Monomers via Acid-Root Complexes for Use in Polyurethanes and Their Copolymers

[0105] The following examples describe a new method for synthesizing polyurethanes or polyureas by copolymerization of epoxides with isocyanates, as shown in Scheme 1.

[0106] Scheme 1

[0107]

[0108] An - represents an anion selected from halide, carboxylate, and alkoxide, wherein the carboxylate and alkoxide can be selected from the group consisting of monofunctional or polyfunctional carboxylates and alkoxides;

[0109] Ct + represents a cation selected from tetraalkylammonium, tetraalkylphosphonium, and phosphazenium;

[0110] Each X and X' represents an oxygen or sulfur atom, and in the scheme each X and X' can represent atoms of the same kind (i.e., both X and X' are oxygen or both X and X' are sulfur), or different kinds of atoms (i.e., X is oxygen and X' is sulfur, or X' is oxygen and X is sulfur);

[0111] R1 and R2 independently represent a hydrogen atom, a saturated or unsaturated straight-chain or branched C1-C 20 alkyl; a straight-chain or branched C1-C 20 alkyl containing one or more atoms selected from oxygen, nitrogen, sulfur, silicon, phosphorus, and halogen atoms; a C1-C 20 alkyl having one or more aromatic rings; R1 and R2 can be the same or different;

[0112] R3 represents an electron-deficient group, which can be one of the following: phenyl; benzoyl; acetyl; trichloroacetyl; allyl; benzenesulfonyl; p-toluenesulfonyl; 4-chlorobenzenesulfonyl; 4-fluorobenzenesulfonyl; chlorosulfonyl; fluorinated phenyl having one to five fluorine atoms at the ortho, meta or para positions; phenyl containing one or more nitro groups at the ortho, meta or para positions; phenyl bearing one or more trifluoromethyl groups at the ortho, meta or para positions; phenyl substituted with two or more different groups selected from halogen atoms, fluorine atoms, nitro groups, trifluoromethyl.

[0113] The Lewis acid (LA) based on borane, aluminum, magnesium, zinc can be any one of the following: triethylborane, triphenylborane, triisobutylborane, tris(pentafluorophenyl)borane, trimethylaluminum, triethylaluminum, triisobutylaluminum, triphenylaluminum, trioctylaluminum, dimethylzinc, diethylzinc, diphenylzinc and dibutylmagnesium.

[0114] In the presence of trialkylborane or trialkylaluminum or other Lewis acids, the copolymerization of epoxides with isocyanates gives fully alternating polyurethanes: when using electron-deficient isocyanates, the trimerization of isocyanates can be neglected, and polyurethanes are obtained as the main product under mild conditions. Such polymerization conditions are also applicable to isothiocyanates, as well as heterocyclic monomers such as episulfides.

[0115] 1. General procedure for the copolymerization of epoxides or episulfides with allene.

[0116] In a glove box, the initiator, epoxide (episulfide), allene, Lewis acid and solvent are added together to a Schlenk reactor. The specific compounds are shown in Table 1 ( Figure 2 ). For gaseous allene, the reaction is carried out in a Parr pressure vessel and the gas is charged outside the glove box. The reactor is sealed before being taken out of the glove box. The reaction medium is stirred at the specified temperature for the specified period of time. The residual pressure (if any) is released from the reactor. Then the reaction is quenched with a hydrochloric acid solution in tetrahydrofuran. The polymer is purified from the crude product by repeated precipitation from methanol. The reaction conditions and data for entries 1 - 18 are described in Figure 2-8 .

[0117] 2. Trialkylborane-mediated copolymerization of epoxides with p-toluenesulfonyl isocyanate.

[0118] Using the above general procedure, the initiator, epoxide (episulfide), p-toluenesulfonyl isocyanate and Lewis acid are added together with the solvent to a Schlenk reactor in a glove box. The specific compounds and reaction conditions are shown in Table 2 ( Figure 9 ). The data for entries 1 - 12 are shown in Figures 10-28in the middle.

[0119] 3. Lewis acid-assisted terpolymerization of epoxides or episulfides with two allenes.

[0120] The preparation of copolymers (statistical, gradient or block copolymers) by terpolymerization with allene monomers such as carbon dioxide, carbon disulfide or carbonyl sulfide is shown in Scheme 2 (variables are defined as in Scheme 1).

[0121]

[0122] Using the general procedure described above, the initiator, epoxide (episulfide), allene and Lewis acid are added to a Schlenk reactor in a glove box together with the solvent. Specific compounds and reaction conditions for Entries 1-12 are given in Table 3 ( Figure 29 ).

[0123] Other embodiments of the present disclosure are possible. Although the above description contains many specificities, the specific examples should not be construed as limiting the scope of the present disclosure. Various combinations or sub-combinations of specific features and aspects of the embodiments can be made, which fall within the scope of the present disclosure. The various features and aspects of the disclosed embodiments can be combined with or substituted for each other. Various examples have been described. These and other examples are within the scope of the following claims.

[0124] The scope of the present disclosure should be determined by the appended claims and their legal equivalents. The recitation of an element in the singular does not mean "one and only one" unless explicitly stated otherwise. All structural, chemical and functional equivalents of the elements of the above-described embodiments known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by these claims. No element, component or method step in the present disclosure is intended to be dedicated to the public, whether or not the element, component or method step is expressly recited in the claims.

Claims

1. A method for preparing a polyurethane copolymer, comprising: contacting a first reactant comprising an oxirane or thiirane moiety with one or more additional reactants selected from allenes in the presence of a Lewis acid, wherein the first allene is selected from the group consisting of isocyanates and isothiocyanates, wherein the first allene has a structure of formula (IV): R3-N=C=X (IV), wherein R3 is an electron-withdrawing group and X is an oxygen atom or a sulfur atom, and wherein the electron-withdrawing group is selected from the group consisting of: phenyl, benzoyl, acetyl, trichloroacetyl, allyl, benzenesulfonyl, p-toluenesulfonyl, 4-chlorobenzenesulfonyl, 4-fluorobenzenesulfonyl, chlorosulfonyl; fluorinated phenyl having one to five fluorine atoms at the ortho, meta or para positions; phenyl having one or more nitro groups at the ortho, meta or para positions; phenyl having one or more trifluoromethyl groups at the ortho, meta or para positions, and phenyl having two or more different substituents selected from the group consisting of: halogen atoms, nitro groups, trifluoromethyl groups, aromatic groups, cyclic alkyl groups and heteroatom-containing alkyl groups.

2. The method according to claim 1, wherein, The Lewis acid is selected from the group consisting of: Lewis acids based on boranes, aluminum, magnesium and zinc.

3. The method according to claim 1, wherein The Lewis acid is an alkylborane, triphenylborane, tris(pentafluorophenyl)borane, alkylaluminum, triphenylaluminum, dimethylzinc, diethylzinc, diphenylzinc or dibutylmagnesium.

4. The method according to claim 1, wherein The first reactant has a structure of formula (III): wherein X is S or O, and each occurrence of R1 and R2 is independently hydrogen or a hydrocarbyl group selected from the group consisting of: substituted or unsubstituted monovalent alkyl, alkenyl, alkaryl, aryl and aralkyl groups and divalent alkylene, alkenylene, alkarylene, arylene and aralkylene groups, wherein one carbon atom of R1 is covalently bonded to the carbon of R2 to form a cycloaliphatic structure.

5. The method according to claim 1, wherein The first reactant is an epoxide selected from the group consisting of: ethylene oxide (EO), propylene oxide (PO), 1-butene oxide (BO), 1-hexene oxide (HO), 1-octene oxide (OO), glycidyl ether, glycidyl ester, butyl glycidyl ether (BGE), 2-ethylhexyl glycidyl ether (EHGE), phenyl glycidyl ether (PGE), benzyl glycidyl ether (BzGE), glycidyl azide (GA), allyl glycidyl ether (AGE), styrene oxide (SO), epichlorohydrin (ECH), cyclopentene oxide (CPO), cyclohexene oxide (CHO), 4-vinyl-1-cyclohexene 1,2-epoxide (VCHO) and limonene oxide (LO).

6. The method according to claim 1, wherein, The first reactant is a episulfide selected from the group consisting of: ethylene sulfide (EES), propylene sulfide (PES), styrene episulfide (SES), 2-(chloromethyl)ethylene sulfide (ETCH), 1-butene episulfide (BES), 1-hexene episulfide (HES), 1-octene episulfide (OES), 2-(butoxymethyl)thiirane (BOMT), 2-(allyloxymethyl)thiirane (AOMT), cyclohexene episulfide (CHES), 2-(benzyloxymethyl)thiirane (BzOMT), and 2-(phenoxymethyl)thiirane (PhOMT).

7. The method according to claim 1, wherein The first allene is an isocyanate selected from the group consisting of: trichloroacetyl isocyanate (TCAI), chlorosulfonyl isocyanate (CSI), benzenesulfonyl isocyanate (BSI), p-toluenesulfonyl isocyanate (TSI), 4-chlorobenzenesulfonyl isocyanate (CBSI), 4-nitrophenyl isocyanate (NPI), 4-trifluoromethylphenyl isocyanate (TFMPI), 4-fluorophenyl isocyanate (FPI), pentafluorophenyl isocyanate (PFPI), and 3,5-bis(trifluoromethyl)phenyl isocyanate (BTFMPI).

8. The method according to claim 1, wherein The first allene is an isothiocyanate selected from the group consisting of: phenyl isothiocyanate (PIT), benzoyl isothiocyanate (BzIT), 4-fluorophenyl isothiocyanate (FPIT), 4-nitrophenyl isothiocyanate (NPIT), 4-trifluoromethylphenyl isothiocyanate (TFMPIT), allyl isothiocyanate (AIT), acetyl isothiocyanate (AcIT), ethoxycarbonyl isothiocyanate (EOCIT), pentafluorophenyl isothiocyanate (PFPIT), and 3,5-bis(trifluoromethyl)phenyl isothiocyanate (BTFMPIT).

9. The method according to claim 1, wherein The molar ratio of the first reactant to the additional reactant is in the range of 1:20 to 20:

1.

10. The method according to claim 1, further comprising contacting the reactants with an initiator optionally selected from the group consisting of: salts having a halogen root, carboxylate root or alkoxide anion and a tetraalkylammonium, tetraalkylphosphonium or phosphazene cation.

11. The method according to claim 10, wherein, The initiator is selected from the group consisting of: tetrabutylammonium chloride (TBACl), bis(triphenylphosphoranylidene)-ammonium chloride (PPNCl), tetraoctylammonium chloride (TOACl), bis(triphenylphosphoranylidene)-ammonium acetate (PPNAc), 1,4-dihydroxymethylbenzene / P4-t-Bu (DHMB / P4-t-Bu), tetrabutylammonium butoxide (TBABO), hydroxymethylbenzene / P4-t-Bu (HMB / P4-t-Bu), and tetrabutylammonium succinate (TBAS).

12. The method according to claim 10, wherein, The molar ratio of the Lewis acid to the initiator is in the range of 0.5:1 to 4:

1.

13. The method according to claim 1, further comprising a second allene selected from the group consisting of: carbon dioxide, carbon disulfide, and carbonyl sulfide.

14. The method according to claim 13, wherein, The molar ratio of the first reactant, the first allene oxide, and the second allene oxide is in the range of 1-10:1-10:1-10.

15. The method according to claim 1, wherein, Contacting includes adding the first reactant and the one or more additional reactants to the reaction vessel simultaneously or successively, optionally wherein contacting includes adding the first allene oxide and the second allene oxide to the reaction vessel simultaneously or successively.

16. The method according to claim 1, wherein, The contacting step is carried out at a temperature in the range of 0 °C to 80 °C.

17. The method according to claim 1, wherein The contacting step is carried out for a duration in the range of 4 hours to 20 hours.

18. A polyurethane copolymer obtained by the method according to any one of claims 1-17.

19. The polyurethane copolymer according to claim 18, wherein, The formula of the copolymer is wherein An is a halogen atom or a carboxylate or alkoxide moiety; X and X' are each independently an oxygen or sulfur atom upon each occurrence; R1 and R2 are each independently selected from a hydrogen atom or an alkyl group, including straight-chain, branched-chain, saturated, unsaturated, aromatic, cyclic alkyl groups, and alkyl groups containing heteroatoms; R3 is an electron-deficient group; and m and n are each independently selected from integers ≥ 1.

20. A composition for synthesizing polyurethane by chain-growth copolymerization, the composition comprising: A Lewis acid; A first reactant containing an oxirane or thiirane moiety; And One or more additional reactants selected from allene oxides, wherein the first allene oxide is selected from the group consisting of isocyanates and isothiocyanates, wherein the first allene oxide has the structure of formula (IV): R3-N=C=X (IV), wherein R3 is an electron-deficient group and X is an oxygen atom or a sulfur atom, and wherein the electron-deficient group is selected from the group consisting of: phenyl, benzoyl, acetyl, trichloroacetyl, allyl, benzenesulfonyl, p-toluenesulfonyl, 4-chlorobenzenesulfonyl, 4-fluorobenzenesulfonyl, chlorosulfonyl; fluorinated phenyls having one to five fluorine atoms in the ortho, meta, or para positions; phenyls having one or more nitro groups in the ortho, meta, or para positions; phenyls having one or more trifluoromethyl groups in the ortho, meta, or para positions, and phenyls having two or more different substituents selected from the group consisting of: halogen atoms, nitro groups, trifluoromethyl groups, aromatic groups, cyclic alkyl groups, and alkyl groups containing heteroatoms.

21. A method for preparing a polyurethane copolymer, comprising: In the presence of a Lewis acid, contacting a first reactant containing a thiirane moiety with one or more additional reactants selected from allene oxides, wherein the first allene oxide is selected from the group consisting of isocyanates and isothiocyanates, wherein the first allene oxide has the structure of formula (IV): R3-N=C=X (IV), wherein R3 is an electron-deficient group and X is an oxygen atom or a sulfur atom, and Among them, the electron-deficient group is selected from the group consisting of: phenyl, benzoyl, acetyl, trichloroacetyl, allyl, benzenesulfonyl, p-toluenesulfonyl, 4-chlorobenzenesulfonyl, 4-fluorobenzenesulfonyl, chlorosulfonyl; fluorinated phenyl having one to five fluorine atoms at the ortho, meta or para positions; phenyl having one or more nitro groups at the ortho, meta or para positions; phenyl having one or more trifluoromethyl groups at the ortho, meta or para positions, and phenyl having two or more different substituents selected from the group consisting of: halogen atom, nitro group, trifluoromethyl group, aromatic group, cyclic alkyl group and heteroatom-containing alkyl group.

22. The method according to claim 21, wherein, The first reactant is a cyclic sulfide selected from the group consisting of: ethylene sulfide (EES), propylene sulfide (PES), styrene sulfide (SES), 2-(chloromethyl) ethylene sulfide (ETCH), 1-butene sulfide (BES), 1-hexene sulfide (HES), 1-octene sulfide (OES), 2-(butoxymethyl) thiirane (BOMT), 2-(allyloxymethyl) thiirane (AOMT), cyclohexene sulfide (CHES), 2-(benzyloxymethyl) thiirane (BzOMT) and 2-(phenoxymethyl) thiirane (PhOMT).

23. The method according to claim 21, wherein The formula of the copolymer is wherein An is a halogen atom or a carboxylate or alkoxide moiety; X and X' are each independently an oxygen or sulfur atom upon each occurrence; R1 and R2 are each independently selected from a hydrogen atom or an alkyl group, including straight-chain, branched-chain, saturated, unsaturated, aromatic, cyclic alkyl group and heteroatom-containing alkyl group; R3 is an electron-deficient group; and m and n are independently selected from integers ≥ 1.

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