Crystalline polythiocarbonate and preparation method therefor

Abstract

The present disclosure provides a crystalline polythiocarbonate and a preparation method thereof. The crystalline polythiocarbonate is a random copolymer and includes five structural units L1 to L5 as shown in the following formula. The method includes carrying out a polymerization reaction natively or in solution using carbon disulfide, ethylene oxide, selectively added third monomer, initiator, Lewis acid, selectively added chain transfer agent, and selectively added solvent as raw materials. This method provides a new way for high value-added application of carbon disulfide and ethylene oxide by using inexpensive carbon disulfide and ethylene oxide as monomers; the product is a random copolymerized crystalline polythiocarbonate with novel structure, which has various chain link structures and excellent mechanical properties, processing properties and degradability.

Claims

1. A crystalline polythiocarbonate, being a random copolymer and comprising five structural units L1 to L5 as shown in the following formula: ##STR00003## wherein the structural unit L1 has a molar content of 10-80%, the structural unit L2 has a molar content of 10-80%, the structural unit L3 has a molar content greater than 0% and less than 15%, the structural unit L4 has a molar content greater than 0% and less than 10%, and the structural unit L5 has a molar content greater than 0% and less than or equal to 10%; the crystalline polythiocarbonate has a crystallinity of 1-78% and a melting temperature of 117-245° C.

2. The crystalline polythiocarbonate according to claim 1, wherein the structural unit L1 has a molar content of 30-55%, and the structural unit L2 has a molar content of 30-55%.

3. The crystalline polythiocarbonate according to claim 1, wherein molecular chain segments of the crystallizable polythiocarbonate further comprises, a polyether or a polyester link derived from a copolymerization of a third monomer; the third monomer is selected from at least one of: an epoxy compound, a cyclic anhydride, and a cyclic lactone.

4. The crystalline polythiocarbonate according to claim 1, wherein the crystallizable polythiocarbonate has a number-average molecular weight of 1-100 kg/mol and a molecular weight distribution of 1.1-5.0.

5. A preparation method of a crystalline polythiocarbonate, comprising: co-mixing carbon disulfide, ethylene oxide, an initiator, and a Lewis acid in a reactor, and carrying out a native or solution copolymerization reaction at 0-150° C. under autogenous pressure; wherein the crystalline polythiocarbonate is a random copolymer and comprises five structural units L1 to L5 as shown in the following formula: ##STR00004## the structural unit L1 has a molar content of 10-80%, the structural unit L2 has a molar content of 10-80%, the structural unit L3 has a molar content greater than 0% and less than 15%, the structural unit L4 has a molar content greater than 0% and less than 10%, and the structural unit L5 has a molar content greater than 0% and less than or equal to 10%; the crystalline polythiocarbonate has a crystallinity of 1-78% and a melting temperature of 117-245° C.

6. The method according to claim 5, wherein in the co-mixing the carbon disulfide, the ethylene oxide, the initiator, and the Lewis acid in the reactor, a third monomer is further added to be co-mixed with the carbon disulfide, the ethylene oxide, the initiator, and the Lewis acid; the third monomer is selected from at least one of an epoxy compound, a cyclic anhydride, and a cyclic lactone; the epoxy compound is selected from at least one of propylene oxide, alpha-alkylene oxide from C5 to C20, allyl glycidyl ether, 1,2-epoxybutane, epichlorohydrin, epoxyisobutane, epoxycyclohexane, 4-vinylcyclohexane oxide, limonene oxide, cyclopentane oxide, styrene oxide, and alkyl substituted styrene oxide; the cyclic anhydride is selected from at least one of maleic anhydride, glutaric anhydride, succinic anhydride, diglycolic anhydride, and phthalic anhydride; the cyclic lactone is selected from at least one of ethyl cross-ester, propyl cross-ester, butyl lactone, amyl lactone, hexyl lactone, heptyl lactone, and dimethyl trimethylene ester.

7. The method according to claim 5, wherein in the co-mixing the carbon disulfide, the ethylene oxide, the initiator, and the Lewis acid in the reactor, a solvent is further added to be co-mixed with the carbon disulfide, the ethylene oxide, the initiator, and the Lewis acid; the initiator is selected from at least one of 1,8-diazabicycloundec-7-carbene, 1,5,7-diazabicyclo[5.4.0]undec-7-carbene, 4-dimethylaminopyridine, tetraalkylammonium halide, bis(triphenylphosphinyl)ammonium chloride, N,N,N′,N′-tetramethylmethylenediamine, N,N,N′,N′-tetraethylethylenediamine, and tetraalkylphosphine halide; the Lewis acid is selected from at least one of triethylboron, tripropylboron, tributylboron, triphenylboron, tris(pentafluorophenyl)boron, bis(trimethylphenyl)fluoride boron, trimethylaluminum, triethylaluminum, and 3,5-Di-tert-butylsalicylaldehyde imide Schiff base chromium complex; the solvent is selected from at least one of tetrahydrofuran, dimethyl sulfoxide, trichlorobenzene, and dimethylformamide.

8. The method according to claim 5, wherein in the co-mixing the carbon disulfide, the ethylene oxide, the initiator, and the Lewis acid in the reactor, a chain transfer agent is further added to be co-mixed with the carbon disulfide, the ethylene oxide, the initiator, and the Lewis acid; the chain transfer agent is selected from at least one of water, alcohol, organic carboxylic acid, and remote claw polymer.

9. The method according to claim 5, wherein in the co-mixing the carbon disulfide, the ethylene oxide, the initiator, and the Lewis acid in the reactor, a third monomer is further added to be co-mixed with the carbon disulfide, the ethylene oxide, the initiator, and the Lewis acid; a molar ratio of carbon disulfide to ethylene oxide is 0.5-5:1; a molar ratio of the third monomer to ethylene oxide is 0-100:100; a molar ratio of initiator to ethylene oxide is 1:100-4000, and the molar ratio of the initiator to the Lewis acid is 1:0.5-2.

10. The method according to claim 5, wherein the structural unit L1 has a molar content of 30-55%, and the structural unit L2 has a molar content of 30-55%.

11. The method according to claim 5, wherein molecular chain segments of the crystallizable polythiocarbonate further comprises, a polyether or a polyester link derived from a copolymerization of a third monomer; the third monomer is selected from at least one of: an epoxy compound, a cyclic anhydride, and a cyclic lactone.

12. The method according to claim 5, wherein the crystallizable polythiocarbonate has a number-average molecular weight of 1-100 kg/mol and a molecular weight distribution of 1.1-5.0.

13. A preparation method of a crystalline polythiocarbonate, comprising: co-mixing an initiator, a Lewis acid, and a third monomer in a reactor and carrying out a native or solution copolymerization reaction at 0-150° C. under autogenous pressure, to obtain a polyether intermediate or a polyester intermediate with a target molecular weight; and co-mixing the polyether intermediate or the polyester intermediate with the target molecular weight with carbon disulfide and ethylene oxide in the reactor, carrying out a second stage reaction in a native or solution at 0-150° C. under autogenous pressure, and obtaining a final product by post-processing; wherein the crystalline polythiocarbonate is a random copolymer and comprises five structural units L1 to L5 as shown in the following formula: ##STR00005## the structural unit L1 has a molar content of 10-80%, the structural unit L2 has a molar content of 10-80%, the structural unit L3 has a molar content greater than 0% and less than 15%, the structural unit L4 has a molar content greater than 0% and less than 10%, and the structural unit L5 has a molar content greater than 0% and less than or equal to 10%; the crystalline polythiocarbonate has a crystallinity of 1-78% and a melting temperature of 117-245° C.; the molecular chain segments of the crystallizable polythiocarbonate further comprises, a polyether or a polyester link derived from a copolymerization of the third monomer; the third monomer is selected from at least one of: an epoxy compound, a cyclic anhydride, and a cyclic lactone.

14. The method according to claim 13, wherein the third monomer is selected from at least one of an epoxy compound, a cyclic anhydride, and a cyclic lactone; the epoxy compound is selected from at least one of propylene oxide, alpha-alkylene oxide from C5 to C20, allyl glycidyl ether, 1,2-epoxybutane, epichlorohydrin, epoxyisobutane, epoxycyclohexane, 4-vinylcyclohexane oxide, limonene oxide, cyclopentane oxide, styrene oxide, and alkyl substituted styrene oxide; the cyclic anhydride is selected from at least one of maleic anhydride, glutaric anhydride, succinic anhydride, diglycolic anhydride, and phthalic anhydride; the cyclic lactone is selected from at least one of ethyl cross-ester, propyl cross-ester, butyl lactone, amyl lactone, hexyl lactone, heptyl lactone, and dimethyl trimethylene ester.

15. The method according to claim 13, wherein in the co-mixing the initiator, the Lewis acid, and the third monomer in the reactor, a first solvent is further added to be co-mixed with the initiator, the Lewis acid, and the third monomer; in the co-mixing the polyether intermediate or the polyester intermediate with the target molecular weight with carbon disulfide and ethylene oxide in the reactor, a second solvent is further added to be co-mixed with the polyether intermediate or the polyester intermediate, the carbon disulfide, and the ethylene oxide; the initiator is selected from at least one of 1,8-[5.4.0]undec-7-carbene, 1,5,7-diazabicycloundec-7-carbene, 4-dimethylaminopyridine, tetraalkylammonium halide, bis(triphenylphosphinyl)ammonium chloride, N,N,N′,N′-tetramethylmethylenediamine, N,N,N′,N′-tetraethylethylenediamine, and tetraalkylphosphine halide; the Lewis acid is selected from at least one of triethylboron, tripropylboron, tributylboron, triphenylboron, tris(pentafluorophenyl)boron, bis(trimethylphenyl)fluoride boron, trimethylaluminum, triethylaluminum, and 3,5-Di-tert-butylsalicylaldehyde imide Schiff base chromium complex; each of the first solvent and the second solvent is selected from at least one of tetrahydrofuran, dimethyl sulfoxide, trichlorobenzene, and dimethylformamide.

16. The method according to claim 13, wherein, a molar ratio of carbon disulfide to ethylene oxide is 0.5-5:1; a molar ratio of the third monomer to ethylene oxide is 0-100:100; a molar ratio of initiator to ethylene oxide is 1:100-4000, and the molar ratio of the initiator to the Lewis acid is 1:0.5-2.

17. The method according to claim 13, wherein the crystallizable polythiocarbonate has a number-average molecular weight of 1-100 kg/mol and a molecular weight distribution of 1.1-5.0.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a .sup.1H-.sup.13C HMBC spectrum of a CS.sub.2/EO copolymerization product prepared in Embodiment 1 of the present disclosure.

(2) FIG. 2 is an XRD pattern of a CS.sub.2/EO copolymerization product prepared in Embodiment 14 and Embodiment 18 of the present disclosure, respectively.

(3) FIG. 3 is a DSC curve of a CS.sub.2/EO copolymerization product prepared in Embodiment 17 of the present disclosure.

DETAILED DESCRIPTION

(4) In order to describe the present disclosure more specifically, the technical solutions of the present disclosure will be described in detail below with reference to the accompanying drawings and specific embodiments.

(5) For convenience of distinction, the Lewis acids used in the following embodiments are numbered separately as A1 for triethylboron, A2 for tripropylboron, A3 for tributylboron, A4 for triphenylboron, A5 for tris(pentafluorophenyl)boron, A6 for di(trimethylphenyl)fluoroboron, A7 for trimethylaluminum, A8 for triethylaluminum, and A9 for 3,5-di-tert-butylsalicylimine Schiff base chromium complex.

Embodiment 1: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(6) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. The Lewis acid A1 and an initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in dimethyl sulfoxide (DMSO) to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by differential scanning calorimetry (DSC). The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 2: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(7) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A2 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/100. 3.4 mL of CS.sub.2 and 0.6 mL of EO (molar ratio of CS.sub.2 to EO being 5:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 0.5 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 3: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(8) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A3 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/1000. 1.3 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 48 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 4: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(9) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A4 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 0.6 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 0.5:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 4 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 5: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(10) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A5 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/500. 4 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 3:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 24 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 6: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(11) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A6 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/4000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 48 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 7: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(12) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A7 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2.6 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 2:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 10 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 8: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(13) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A8 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/750. 1.7 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.3:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 10 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 9: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(14) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A9 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 1.3 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 8 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 10: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(15) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A1 and initiator 1,5,7-diazabicyclo[5.4.0]undec-7-carbene (TBD) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in a 120° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 11: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(16) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A1 and initiator 4-dimethylaminopyridine (DMAP) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in a 60° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 12: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(17) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A1 and initiator hexadecyltrimethylammonium bromide (CTAB) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in a 120° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 13: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(18) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A1 and initiator bis(triphenylphosphinyl)ammonium chloride ([PPN]Cl) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 14: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(19) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A1 and initiator N,N,N′,N′-Tetramethylmethanediamine (TMDM) are sequentially added to the autoclave with a molar ratio of 1:0.5 (1:1 for the number ratio of boron to nitrogen). The molar ratio of Lewis acid to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in a 40° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 15: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(20) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A1 and initiator N,N,N′,N′-Tetraethyl ethylenediamine (TEED) are sequentially added to the autoclave with a molar ratio of 1:0.5 (1:1 for the number ratio of boron to nitrogen). The molar ratio of Lewis acid to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 16: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(21) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A1 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 17: One-Pot Copolymerization of CS2/EO to Synthesize Polythiocarbonate

(22) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. 2.2 mL of tetrahydrofuran, several masses of Lewis acid A1 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave, wherein the Lewis acid Al and the DBU are in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

(23) FIG. 3 is a DSC curve of a CS.sub.2/EO copolymerization product prepared in this embodiment. The crystallization properties of the product are found to be stable and reproducible after three warming-cooling cycles.

Embodiment 18: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(24) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A1 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in a 150° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 19: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(25) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A1 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in a 100° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 20: One-Pot Copolymerization of CS.SUB.2./EO to Synthesize Polythiocarbonate

(26) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A1 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in a 0° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 21: One-Pot Copolymerization of CS.SUB.2./EO/Propylene Oxide to Synthesize Polythiocarbonate

(27) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A1 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) and 100 μL of third monomer propylene oxide (molar ratio of propylene oxide to EO being 5:100) are added. The autoclave is then closed and placed in an 80° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 22: One-Pot Copolymerization of CS.SUB.2./EO Maleic Anhydride to Synthesize Polythiocarbonate

(28) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid Al and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) and 282 mg of third monomer maleic anhydride (molar ratio of maleic anhydride to EO being 10:100) are added. The autoclave is then closed and placed in an 80° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 23: One-Pot Two-step Copolymerization of CS.SUB.2./EO Lactide to Synthesize Polythiocarbonate

(29) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A1 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. 828 mg of a third monomer lactide is added. The autoclave is closed and placed in an 80° C. oil bath for 12 hours under autogenous pressure. The autoclave is cooled to room temperature and 1.1 mL of EO and 2 mL of CS.sub.2 (molar ratio of CS.sub.2 to EO being 1.5:1) are added. The autoclave is then closed and placed in an 80° C. oil bath for 12 hours under autogenous pressure to complete a second stage of polymerization. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

Embodiment 24: One-Pot Copolymerization of CS.SUB.2./EO/PEG2000 to synthesize Polythiocarbonate

(30) Before the polymerization, a 10 mL autoclave is placed at 110° C. for about 2 hours to remove water and cooled to room temperature in a desiccator. Several masses of Lewis acid A1 and initiator 1,8-diazabicyclo[5.4.0]undec-7-carbene (DBU) are sequentially added to the autoclave in equimolar quantities. The molar ratio of initiator to monomer EO is 1/2000. 2 mL of CS.sub.2 and 1.1 mL of EO (molar ratio of CS.sub.2 to EO being 1.5:1) and 2.87 g of chain transfer agent polyethylene glycol 2000 (PEG2000) (molar ratio of PEG2000 to EO being 5:100) are added. The autoclave is then closed and placed in an 80° C. oil bath for 12 hours under autogenous pressure. After the reaction is completed, it is cooled to room temperature, and a yellow product is taken out. The crude product is first dissolved in DMSO to 240° C. A polymer is precipitated in methanol, washed three times to obtain a pure product without catalyst, and dried under vacuum to constant weight. The conversion rate is calculated and obtained by the weighing method. The composition of each link in the polymer is detected by nuclear magnetic resonance spectroscopy. The molecular weight and molecular weight distribution of the polymer are determined by high temperature gel chromatography. The melting temperature of the polymer is determined by DSC. The crystallinity of the polymer is determined by X-ray diffraction. The test results are shown in Table 1.

(31) TABLE-US-00001 TABLE 1 T Lewis Initiator/ M.sub.n.sup.4 L.sub.1:L.sub.2:L.sub.3: T.sub.m.sup.7 Crystallinity No. (° C.) acid.sup.1 Initiator.sup.2 EO/CS.sub.2.sup.3 t(h) (kg/mol) PDI.sup.5 L.sub.4:L.sub.5.sup.6 (° C.) (%).sup.8 Embodiment 80 A1 DBU 1:2000:3000 12.0 46.1 1.4 43:37:7:8:5 168 67 1 Embodiment 80 A2 DBU 1:100:500 0.5 8.4 2.3 28:54:6:7:5 205 56 2 Embodiment 80 A3 DBU 1:1000:1000 48.0 3.0 2.8 62:21:5:4:8 130 43 3 Embodiment 80 A4 DBU 1:2000:1000 4.0 1.4 1.3 36:42:7:8:7 179 28 4 Embodiment 80 A5 DBU 1:500:1500 24.0 16.4 3.2 34:48:5:6:7 193 55 5 Embodiment 80 A6 DBU 1:4000:6000 48.0 98.0 4.4 68:15:5:4:8 124 50 6 Embodiment 80 A7 DBU 1:2000:4000 10.0 38.4 2.7 39:42:9:6:4 173 52 7 Embodiment 80 A8 DBU 1:750:975 10.0 29.8 3.3 25:61:4:3:7 224 46 8 Embodiment 80 A9 DBU 1:2000:2000 8.0 33.6 4.6 63:13:11:6:7 128 53 9 Embodiment 120 A1 TBD 1:2000:3000 12.0 25.3 2.0 43:45:4:2:6 184 72 10 Embodiment 60 A1 DMAP 1:2000:3000 12.0 70.2 1.6 52:35:5:4:4 148 31 11 Embodiment 120 A1 CTAB 1:2000:3000 12.0 27.9 1.4 40:41:6:6:7 147 41 12 Embodiment 80 A1 PPNCl 1:2000:3000 12.0 16.4 2.2 47:28:9:6:10 148 53 13 Embodiment 40 A1 TMDM 1:2000:3000 12.0 6.5 1.6 17:69:4:2:8 235 24 14 Embodiment 80 A1 TEED 1:2000:3000 12.0 32.7 1.8 49:29:12:5:5 153 19 15 Embodiment 80 A1 DBU 1:2000:3000 12.0 40.4 1.4 47:32:8:6:7 159 54 16 .sup.9 Embodiment 80 A1 DBU 1:2000:3000 12.0 32.3 1.3 57:25:6:4:8 138 58 17 .sup.10 Embodiment 150 A1 DBU 1:2000:3000 12.0 29.7 3.4 11:80:2:5:2 245 78 18 Embodiment 100 A1 DBU 1:2000:3000 12.0 35.6 2.0 37:46:7:5:5 185 63 19 Embodiment 0 A1 DBU 1:2000:3000 12.0 3.9 1.1 80:10:3:2:5 117 28 20 Embodiment 80 A1 DBU 1:2000:3000 12.0 84.2 2.8 71:15:4:7:3 120 34 21 .sup.11 Embodiment 80 A1 DBU 1:2000:3000 12.0 72.5 2.3 33:57:4:3:3 216 9 22 .sup.12 Embodiment 80 A1 DBU 1:2000:3000 24.0 55.8 2.2 39:41:7:8:5 160 57 23 .sup.13 Embodiment 80 A1 DBU 1:2000:3000 12.0 18.3 1.2 47:32:6:8:7 157 51 24 .sup.14

(32) where: .sup.1Speicies of Lewis acid. .sup.2Speicies of Lewis base initiator. The amount of substance of the added initiator is the same as that of the added Lewis acid. DBU=1,8-diazabicyclo[5.4.0]undec-7-carbene, TBD=1,5,7-diazabicyclo[5.4.0]undec-7-carbene, DMAP=4-dimethylaminopyridine, CTAB=hexadecyltrimethylammonium bromide, [PPN]Cl=bis(triphenylphosphinyl)ammonium chloride, TMDM=N,N,N′,N′-Tetramethylmethanediamine, TEED=N,N,N′,N′-Tetraethyl ethylenediamine. .sup.3Molar ratio of initiator, ethylene oxide to carbon disulfide. .sup.4M.sub.n: number-average molecular weight, determined by gel permeation chromatography. .sup.5PDI: molecular weight distribution, determined by gel permeation chromatography. .sup.6Composition ratio of polymeric thiocarbonate and carbonate links, determined by nuclear magnetic resonance spectroscopy. .sup.7T.sub.m: melting temperature, determined by differential scanning calorimetry method. .sup.8Crystallinity, estimated by XRD. .sup.9Tetrahydrofuran as a solvent, the ratio of tetrahydrofuran to ethylene oxide is 1:1. .sup.10Tetrahydrofuran as a solvent, the ratio of tetrahydrofuran to ethylene oxide is 2:1. .sup.11Propylene oxide as a third monomer, the ratio of propylene oxide to ethylene oxide is 5:100. .sup.12Maleic anhydride as a third monomer, the ratio of maleic anhydride to ethylene oxide is 10:100. .sup.13Lactide as a third monomer, the ratio of lactide to ethylene oxide is 20:100, and the polymerization is completed by one-pot two-step method. .sup.14Bishydroxyl polyethylene glycol having a molecular weight of 2000 as a chain transfer agent, the ratio of PEG2000 to ethylene oxide is 5:100.