Preparation method of lactide and caprolactone random copolymer

Abstract

The invention discloses a preparation method of a lactide and caprolactone random copolymer. The preparation method is characterized in that a nitrogen and oxygen two-tooth coordination aluminum compound with different substituted groups is used as a catalyst, and structurally contains a salicylaldiminato ligand and two alkyls X; the nitrogen and oxygen two-tooth coordination aluminum compound has the advantages of simple and convenient preparation method, low cost, stable property, higher catalyzing activity and excellent random co-polymerizing property, and is especially suitable for catalyzing the random co-polymerizing of lactide and caprolactone; by introducing large substituted groups into the ligand, and adjusting the reactivity ratio in the co-polymerizing of the lactide and the caprolactone, the random co-polymerizing of the lactide and the caprolactone is realized. The nitrogen and oxygen two-tooth coordination aluminum compound has the characteristics that the cost is low, the activity is high, and the controllability is good. The prepared random copolymer has the characteristics that the microstructure can be controlled and degraded, and the biocompatibility is good; the requirements of industrial departments are met.

Description

technical field

[0001] The invention belongs to the technical field of polymer material synthesis, and in particular relates to a preparation method of a random copolymer of lactide and caprolactone. Background technique

[0002] Aliphatic polyesters, including polylactide (PLA) and polyε-caprolactone (PCL), have excellent biodegradability and biocompatibility, and are widely used in medical and health care, environmental protection, and food packaging. It is a kind of new polymer material with great potential, environment-friendly and sustainable development.

[0003] Homopolymers of PLA and PCL are used as polymer materials and have their own advantages. However, the disadvantages of these homopolymers are also obvious, such as PLA is hard and brittle, has poor processability, poor impact resistance, and poor drug permeability; PCL has poor mechanical strength and slow degradation rate. These disadvantages severely limit the range of applications of homopolymers. Copoly...

Examples

Embodiment 1

[0044] Bidentate nitroxide ligand 2-Ph 2 CH-4- t Bu-6-(2,6-Ph 2 CH-4- i Pr-C 6 h 2 -N=CH)C 6 h 2 Preparation of OH.

[0045] 2,6-diphenylmethyl-4-isopropylaniline (4.67g, 10.0mmol) and 3-diphenylmethyl-5-tert-butyl salicylaldehyde (3.44g, 10.0mmol) 1:1 After the molar ratio is mixed, add 20mg p-toluenesulfonic acid, react in toluene for 10-18 hours, the reaction temperature is 120°C, then remove the solvent under reduced pressure, add 50mL petroleum ether, and filter to obtain the salicylaldimine ligand (6.75g, 8.5 mmol, 85%). 1 H NMR (CDCl 3 ):δ12.60(s,1H,OH),7.23(t,J=7.5Hz,4H),7.14(t,J=7.5Hz,2H),7.13-7.05(m,16H),6.90(d, J=6.8Hz,8H),6.86(s,1H),6.70(s,1H),6.60(s,2H),6.05(s,1H),5.91(s,1H),5.32(s,2H), 2.60(sept,J=6.7Hz,1H,CH(CH 3 ) 2 ),1.01(s,9H, t Bu),0.96(d,J=6.7Hz,6H,CH(CH 3 ) 2 ). 13 C NMR (CDCl 3 ):δ169.67,156.16,146.30,144.24,143.75,143.56,140.18,134.72,131.05,130.63,129.66,129.37,128.13,128.09,127.20,126.20,126.13,126.05,117.15,52.40,49.39,33.76,33.54,31...

Embodiment 2

[0047] Bidentate Nitrogen-Oxygen Coordination Aluminum Compound 2-Ph 2 CH-4- t Bu-6-(2,6-Ph 2 CH-4- i Pr-C 6 h 2 -N=CH)C 6 h 2 OAlMe 2 preparation.

[0048] The ligand 2-Ph in Example 1 2 CH-4- t Bu-6-(2,6-Ph 2 CH-4- i Pr-C 6 h 2 -N=CH)C 6 h 2 OH (0.794g, 1.00mmol) was dissolved in 30mL of toluene, 1.0 equivalent of trimethylaluminum was added, stirred at room temperature under nitrogen protection for 12 hours, the solvent was removed under reduced pressure, and washed three times with n-hexane to obtain the corresponding nitrogen-oxygen bidentate complex Aluminum compound (0.807 g, 0.95 mmol, 95%). 1 H NMR (CDCl 3 ):δ7.35-7.33(m,5H),7.28(d,J=7.5Hz,4H),7.15-7.10(m,8H),7.06-7.01(m,6H),6.96-6.91(m,4H ),6.88-6.81(m,6H),6.33(s,1H),6.14(s,2H),6.06(s,1H),5.56(s,1H),2.40(sept,J=6.9Hz,1H) ,1.11(s,9H),0.91(d,J=6.9Hz,6H),-0.03(s,6H,Al-Me). 13 C NMR (CDCl 3 ):δ176.73,160.09,147.13,144.15,143.11,142.78,142.18,138.88,138.21,135.32,134.95,129.95,129.82,129.55,128.41,128...

Embodiment 3

[0050] Compound Al1 and benzyl alcohol catalyze the copolymerization of lactide and caprolactone.

[0051] In the Schlenk bottle, under anhydrous and oxygen-free conditions, add 0.288g lactide and 0.228gε-caprolactone, and add 3mL toluene. 20 μmol of compound Al1 (7.3 mg), 2.1 μL of benzyl alcohol (20 μmol) dissolved in 2 mL of toluene, were added into a Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 110°C for 1 h, add 5 mL of 5% acetic acid methanol solution, pour into methanol to precipitate the polymer, filter and vacuum dry for 24 hours to obtain a copolymer. Conversion: lactide 51% and caprolactone 35%. The number average molecular weight M of the copolymer n :1.09×10 4 g / mol, molecular weight distribution PDI=1.14; average chain length L of lactide and caprolactone monomers LA and L CL 3.1 and 1.4 respectively.

technical field

[0001] The invention belongs to the technical field of polymer material synthesis, and in particular relates to a preparation method of a random copolymer of lactide and caprolactone. Background technique

[0002] Aliphatic polyesters, including polylactide (PLA) and polyε-caprolactone (PCL), have excellent biodegradability and biocompatibility, and are widely used in medical and health care, environmental protection, and food packaging. It is a kind of new polymer material with great potential, environment-friendly and sustainable development.

[0003] Homopolymers of PLA and PCL are used as polymer materials and have their own advantages. However, the disadvantages of these homopolymers are also obvious, such as PLA is hard and brittle, has poor processability, poor impact resistance, and poor drug permeability; PCL has poor mechanical strength and slow degradation rate. These disadvantages severely limit the range of applications of homopolymers. Copoly...

Examples

Embodiment 1

[0044] Bidentate nitroxide ligand 2-Ph 2 CH-4- t Bu-6-(2,6-Ph 2 CH-4- i Pr-C 6 h 2 -N=CH)C 6 h 2 Preparation of OH.

[0045] 2,6-diphenylmethyl-4-isopropylaniline (4.67g, 10.0mmol) and 3-diphenylmethyl-5-tert-butyl salicylaldehyde (3.44g, 10.0mmol) 1:1 After the molar ratio is mixed, add 20mg p-toluenesulfonic acid, react in toluene for 10-18 hours, the reaction temperature is 120°C, then remove the solvent under reduced pressure, add 50mL petroleum ether, and filter to obtain the salicylaldimine ligand (6.75g, 8.5 mmol, 85%). 1 H NMR (CDCl 3 ):δ12.60(s,1H,OH),7.23(t,J=7.5Hz,4H),7.14(t,J=7.5Hz,2H),7.13-7.05(m,16H),6.90(d, J=6.8Hz,8H),6.86(s,1H),6.70(s,1H),6.60(s,2H),6.05(s,1H),5.91(s,1H),5.32(s,2H), 2.60(sept,J=6.7Hz,1H,CH(CH 3 ) 2 ),1.01(s,9H, t Bu),0.96(d,J=6.7Hz,6H,CH(CH 3 ) 2 ). 13 C NMR (CDCl 3 ):δ169.67,156.16,146.30,144.24,143.75,143.56,140.18,134.72,131.05,130.63,129.66,129.37,128.13,128.09,127.20,126.20,126.13,126.05,117.15,52.40,49.39,33.76,33.54,31...

Embodiment 2

[0047] Bidentate Nitrogen-Oxygen Coordination Aluminum Compound 2-Ph 2 CH-4- t Bu-6-(2,6-Ph 2 CH-4- i Pr-C 6 h 2 -N=CH)C 6 h 2 OAlMe 2 preparation.

[0048] The ligand 2-Ph in Example 1 2 CH-4- t Bu-6-(2,6-Ph 2 CH-4- i Pr-C 6 h 2 -N=CH)C 6 h 2 OH (0.794g, 1.00mmol) was dissolved in 30mL of toluene, 1.0 equivalent of trimethylaluminum was added, stirred at room temperature under nitrogen protection for 12 hours, the solvent was removed under reduced pressure, and washed three times with n-hexane to obtain the corresponding nitrogen-oxygen bidentate complex Aluminum compound (0.807 g, 0.95 mmol, 95%). 1 H NMR (CDCl 3 ):δ7.35-7.33(m,5H),7.28(d,J=7.5Hz,4H),7.15-7.10(m,8H),7.06-7.01(m,6H),6.96-6.91(m,4H ),6.88-6.81(m,6H),6.33(s,1H),6.14(s,2H),6.06(s,1H),5.56(s,1H),2.40(sept,J=6.9Hz,1H) ,1.11(s,9H),0.91(d,J=6.9Hz,6H),-0.03(s,6H,Al-Me). 13 C NMR (CDCl 3 ):δ176.73,160.09,147.13,144.15,143.11,142.78,142.18,138.88,138.21,135.32,134.95,129.95,129.82,129.55,128.41,128...

Embodiment 3

[0050] Compound Al1 and benzyl alcohol catalyze the copolymerization of lactide and caprolactone.

[0051] In the Schlenk bottle, under anhydrous and oxygen-free conditions, add 0.288g lactide and 0.228gε-caprolactone, and add 3mL toluene. 20 μmol of compound Al1 (7.3 mg), 2.1 μL of benzyl alcohol (20 μmol) dissolved in 2 mL of toluene, were added into a Schlenk bottle with a syringe to initiate polymerization. Control the reaction temperature at 110°C for 1 h, add 5 mL of 5% acetic acid methanol solution, pour into methanol to precipitate the polymer, filter and vacuum dry for 24 hours to obtain a copolymer. Conversion: lactide 51% and caprolactone 35%. The number average molecular weight M of the copolymer n :1.09×10 4 g / mol, molecular weight distribution PDI=1.14; average chain length L of lactide and caprolactone monomers LA and L CL 3.1 and 1.4 respectively.

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