阅读说明：本技术 一种聚丙交酯己内酯的制备方法 (Preparation method of polylactide caprolactone ) 是由 袁文博 赵春华 王文静 于 2021-01-28 设计创作，主要内容包括：本发明属于高分子有机合成技术领域,具体涉及一种聚丙交酯己内酯的制备方法。本发明以丙交酯和己内酯为原料,采用不同功率的微波分段加热反应,反应完成后采用二氯甲烷溶解乙醇析浆的方式,得到最终产品。本发明采用微波加热,能使反应体系温度迅速升高,并使引发剂/封端剂以高于常规加热的速率产生自由基,缩短反应诱导期,加快了反应进行。本发明中催化剂的用量远远小于现有技术中催化剂的用量,有效避免了产品中催化剂的重金属含量超标。(The invention belongs to the technical field of high-molecular organic synthesis, and particularly relates to a preparation method of polylactide caprolactone. According to the invention, lactide and caprolactone are used as raw materials, microwave sectional heating reaction with different powers is adopted, and a mode of dissolving ethanol by dichloromethane and separating out slurry is adopted after the reaction is finished, so that a final product is obtained. The invention adopts microwave heating, can quickly raise the temperature of a reaction system, enables the initiator/end-capping reagent to generate free radicals at a rate higher than the conventional heating rate, shortens the reaction induction period and accelerates the reaction. The dosage of the catalyst in the invention is far less than that of the catalyst in the prior art, and the heavy metal content of the catalyst in the product is effectively prevented from exceeding the standard.)

1. A preparation method of polylactide caprolactone takes lactide and caprolactone as raw materials, and is characterized by comprising the following specific steps:

(1) heating lactide monomer to 80-90 ℃ for melting, adding caprolactone, catalyst and end-capping reagent into the lactide monomer in turn under the condition of stirring, and vacuumizing the system;

(2) heating the system at 800-1000W microwave for 10-15min, then heating at 400-500W microwave for 50-60min, stopping reaction, and cooling;

(3) adding dichloromethane into the reaction system for dissolving, then dropwise adding ethanol into the reaction system to separate out slurry, and separating out slurry I;

(4) and (3) adding dichloromethane into the slurry I to dissolve, dropwise adding ethanol to separate out slurry, repeating for 2-3 times to obtain a slurry II, and drying to obtain a finished product.

2. The method for preparing polylactide caprolactone according to claim 1, wherein the ratio of lactide: caprolactone ═ 2: 3.

3. The method for preparing polylactide caprolactone according to claim 1, wherein the catalyst is stannous octoate, and the amount of the catalyst is 0.006% to 0.01% of the total mass of the lactide and the caprolactone.

4. The method for preparing polylactide caprolactone according to claim 1, wherein the end-capping agent is glycerol or glycolic acid or n-dodecanol or ethylene glycol; molar amount of hydroxyl groups present in the blocking agent itself: the total molar weight of lactide and caprolactone is 2-10%.

5. The method for preparing polylactide caprolactone according to claim 1, wherein the vacuum degree of the system is-0.08 to-0.1 Mpa.

6. The method for preparing polylactide caprolactone according to claim 1, wherein the amount V of dichloromethane added₁The relation between the total mass m of lactide and caprolactone is V₁/m＝(5-10)ml/g。

7. The method of claim 1The preparation method of the polylactide caprolactone is characterized in that the adding amount of the ethanol is V₂The relation between the total mass m of lactide and caprolactone is V₂/m＝(5-10)ml/g。

Technical Field

The invention belongs to the technical field of high-molecular organic synthesis, and particularly relates to a preparation method of polylactide caprolactone.

Background

Copolymerization of two or more monomers may provide some improvement in their physical, chemical and biological properties over a single polymer. Compared with polylactic acid (PLA) and Polycaprolactone (PCL), the polylactide caprolactone (PLCL) has good biocompatibility in human bodies, excellent biodegradability, high strength and high elasticity, is an excellent tissue engineering scaffold material, can be used for preparing the scaffolds of urethra, heart, blood vessels, bones and the like, and has potential application prospects. At present, caprolactone and lactide are used as raw materials in the traditional preparation method, and the PLCL is synthesized at high temperature (above 130 ℃) under the catalysis of a heavy metal catalyst.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a preparation method of polylactide caprolactone. The invention effectively avoids high-temperature reaction, shortens reaction time, reduces catalyst consumption, has simple post-treatment and greatly reduces the heavy metal content of the catalyst in the product.

The invention relates to a preparation method of polylactide caprolactone, which takes lactide and caprolactone as raw materials and comprises the following steps:

(1) heating lactide monomer to 80-90 ℃ for melting, adding caprolactone, catalyst and end-capping reagent into the lactide monomer in turn under the condition of stirring, and vacuumizing the system;

(2) heating the system at 800-1000W microwave for 10-15min, then heating at 400-500W microwave for 50-60min, stopping reaction, and cooling;

(3) adding dichloromethane into the reaction system for dissolving, then dropwise adding ethanol into the reaction system to separate out slurry, and separating out slurry I;

(4) and (3) adding dichloromethane into the slurry I to dissolve, dropwise adding ethanol to separate out slurry, repeating for 2-3 times to obtain a slurry II, and drying to obtain a finished product.

Lactide: the ratio of caprolactone to caprolactone is 50: 50-75: 25.

The catalyst is stannous octoate, and the dosage of the catalyst is 0.006-0.01 percent of the total mass of the lactide and the caprolactone.

The end capping agent is glycerol or glycolic acid or n-dodecanol or ethylene glycol; molar amount of hydroxyl groups present in the blocking agent itself: the total molar weight of lactide and caprolactone is 2-10%.

The vacuum degree of the system is-0.08 to-0.1 Mpa.

The addition amount V of the dichloromethane₁With lactide andthe relation between the total mass m of caprolactone is V₁/m＝(5-10)ml/g。

The adding amount of the ethanol is V₂The relation between the total mass m of lactide and caprolactone is V₂/m＝(5-10)ml/g。

In the invention, the lactide monomer is firstly heated to 80-90 ℃ to be melted, and then caprolactone is added, so that the reaction raw materials can be fully mixed.

The invention carries out reaction under vacuum condition, and avoids side reaction caused by gases such as oxygen in the air.

The invention has the following beneficial effects:

the process reduces the molecular weight distribution (Mw/Mn is less than 1.5), and the microwave heating process can effectively avoid high-temperature reaction, shorten the reaction time and realize uniform heating. In the invention, the microwave energy can quickly raise the temperature of the reaction system, and the initiator/end-capping reagent can generate free radicals at a rate higher than the conventional heating rate, thereby shortening the reaction induction period and accelerating the reaction. Furthermore, the invention adopts microwave heating with different powers in a sectional manner, under the condition of microwave heating, the initial polymerization conversion rate is increased along with the increase of the power, and after the induction period is finished, the power is too large, the reactivity can not be further improved, but side reactions can be increased, so the invention stops the reaction after the microwave heating with 1000W of 800-.

The dosage of the catalyst in the invention is far less than that of the catalyst in the prior art, and the heavy metal content of the catalyst in the product is effectively prevented from exceeding the standard. In addition, the method of dissolving ethanol and separating slurry by using dichloromethane is adopted, and the content of tin in the product can be further reduced because the catalyst has certain solubility in dichloromethane.

Detailed Description

Example 1

60g of lactide monomer (LA) was weighed into a single-neck flask, melted at 80 ℃ and then 90g of Caprolactone (CL) was added, and 0.012g of stannous octoate and 3.0g of glycerin were added with stirring, and the system was evacuated.

Keeping the vacuum degree at-0.085 Mpa, heating with 800W microwave for 15min, heating with 500W microwave for 50min, stopping reaction, and cooling.

Adding 750ml of dichloromethane into the reaction system for dissolving, then dropwise adding 750ml of ethanol into the reaction system to separate out slurry I;

adding 750ml of dichloromethane into the slurry I to dissolve, dripping 750ml of ethanol to separate slurry, repeating for 2-3 times to obtain slurry II, and drying to obtain a finished product, wherein the yield is 82.14%, the Mw32574, the Mn26531, the molecular weight distribution is 1.23, and the viscosity is 33.25.

Example 2

60g of lactide monomer (LA) was weighed into a single-neck flask, and after melting at 90 ℃, 90g of Caprolactone (CL) was added, 0.015g of stannous octoate and 2.5g of glycolic acid were added with stirring, and the system was evacuated.

Keeping the vacuum degree at-0.085 Mpa, heating with 1000W microwave for 10min, heating with 400W microwave for 60min, stopping reaction, and cooling.

Adding 750ml of dichloromethane into the reaction system for dissolving, then dropwise adding 750ml of ethanol into the reaction system to separate out slurry I;

adding 750ml of dichloromethane into the slurry I to dissolve, dripping 750ml of ethanol to separate slurry, repeating for 2-3 times to obtain slurry II, and drying to obtain a finished product, wherein the yield is 76.84%, the Mw42861 is high, the Mn33214 is high, the molecular weight distribution is 1.29, and the viscosity is 42.36.

Example 3

Lactide monomer (LA) 40g was weighed into a single-neck flask, melted at 85 ℃ and then Caprolactone (CL)60g was added, stannous octoate 0.010g and glycolic acid 3.0g were added with stirring, and the system was evacuated.

Maintaining the vacuum degree at-0.085 Mpa, microwave heating at 900W for 10min, then microwave heating at 500W for 50min, stopping reaction, and cooling.

Adding 500ml of dichloromethane into the reaction system for dissolving, then dropwise adding 500ml of ethanol into the reaction system to separate out slurry I;

dissolving the slurry I with 500ml of dichloromethane, dropping 500ml of ethanol for precipitating slurry, repeating for 2-3 times to obtain slurry II, and drying to obtain the finished product with yield 79.11%, Mw13695, Mn11256, molecular weight distribution 1.22 and viscosity 15.39.

Comparative example 1

60g of lactide monomer (LA) was weighed into a single-neck flask, melted at 80 ℃ and then 90g of Caprolactone (CL) was added, 0.024g of stannous octoate and 3.0g of glycerin were added with stirring, and the system was evacuated. Keeping the vacuum degree below-0.080 Mpa, heating to 160 ℃, and keeping the temperature for reaction for 7 hours. After obtaining the crude product, the crude product is precipitated three times by using dichloromethane and ethanol, and the crude product is dried in vacuum to obtain the finished product, wherein the yield is 76.79%, the Mw30118 and Mn16342 have the molecular weight distribution of 1.84 and the viscosity of 28.56.

Comparative example 2

60g of lactide monomer (LA) was weighed into a single-neck flask, melted at 80 ℃ and then 90g of Caprolactone (CL) was added, and 0.012g of stannous octoate and 3.0g of glycerin were added with stirring, and the system was evacuated. Keeping the vacuum degree at-0.085 Mpa, and stopping the reaction after 800W microwave heating for 65 min. After obtaining the crude product, the crude product is precipitated three times by using dichloromethane and ethanol, and the crude product is dried in vacuum to obtain the finished product with the yield of 71.55%, Mw35574, Mn26531, molecular weight distribution of 1.34 and viscosity of 36.15.

Comparative example 3

60g of lactide monomer (LA) is weighed and added into a single-neck flask, after the lactide monomer (LA) is melted at 80 ℃, 90g of Caprolactone (CL) is added, 0.012g of stannous octoate and 3.0g of glycerol are added under stirring, the temperature is raised to 160 ℃, and black carbonized impurities are generated in the reaction process.

Comparative example 4

60g of lactide monomer (LA) was weighed into a single-neck flask, melted at 80 ℃ and then 90g of Caprolactone (CL) was added, and 0.012g of stannous octoate and 3.0g of glycerin were added with stirring, and the system was evacuated. Keeping the vacuum degree at-0.085 Mpa, heating with 800W microwave for 10min, and then heating with 400W microwave for 50min to stop the reaction. The crude product is detected to have Mw34587, Mn15539, molecular weight distribution of 2.22 and yield of 90.39%.