阅读说明：本技术 一种锂皂石增强的聚乳酸-聚乙二醇-聚乳酸三嵌段共聚物纳米立构复合水凝胶的制备方法 (Preparation method of hectorite-reinforced polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano-stereocomplex hydrogel ) 是由 何敏 龚勇吉 刘玉飞 于杰 秦舒浩 于 2019-08-31 设计创作，主要内容包括：本发明公开了一种锂皂石增强的聚乳酸-聚乙二醇-聚乳酸三嵌段共聚物纳米立构复合水凝胶,通过纳米锂皂石的增强作用和聚乳酸链段的立构络合作用对聚乳酸-聚乙二醇-聚乳酸三嵌段共聚物水凝胶进行了增强,复合水凝胶的物理机械性能得到了明显的改善。(The invention discloses a hectorite-reinforced polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano-stereocomplex hydrogel, which is reinforced through the reinforcing effect of nano-hectorite and the stereocomplex effect of a polylactic acid chain segment, and the physical and mechanical properties of the complex hydrogel are obviously improved.)

1. A hectorite-reinforced polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano-stereocomplex hydrogel is characterized in that: is prepared by mechanically blending hectorite, poly (lactic acid) -polyethylene glycol-poly (lactic acid) triblock copolymer with poly (lactic acid) with.

2. the method for preparing the hectorite-reinforced polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano-stereocomplex hydrogel according to claim 1, wherein the method comprises the following steps: (1) stirring at room temperature by taking a levorotatory polylactic acid-polyethylene glycol-polylactic acid triblock copolymer (PLLA-PEG-PLLA) and a dextrorotatory polylactic acid-polyethylene glycol-polylactic acid triblock copolymer (PDLA-PEG-PDLA) as matrixes and water as a solvent to obtain levorotatory and dextrorotatory polylactic acid-polyethylene glycol-polylactic acid triblock copolymer micelles; (2) mixing the two micelles to obtain a stereo micelle solution; (3) mechanically stirring to obtain a hectorite aqueous solution; (4) and (3) blending the stereoblock solution and the hectorite solution to obtain the polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano stereocomplex hydrogel.

3. The preparation method of the hectorite-reinforced polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano-stereocomplex hydrogel according to claim 2, wherein the preparation method comprises the following steps: the micelle concentration of PLLA-PEG-PLLA and PDLA-PEG-PDLA in the step (1) is 20%.

4. The preparation method of the hectorite-reinforced polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano-stereocomplex hydrogel according to claim 2, wherein the preparation method comprises the following steps: the mixing ratio of the two micelles in the step (2) is 1: 1.

5. The preparation method of the hectorite-reinforced polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano-stereocomplex hydrogel according to claim 2, wherein the preparation method comprises the following steps: in the step (3), the concentration of the hectorite aqueous solution is less than 14%.

6. The preparation method of the hectorite-reinforced polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano-stereocomplex hydrogel according to claim 2, wherein the preparation method comprises the following steps: in the step (4), the hydrogel is prepared by solution blending at 4 ℃ and gelling at 80 ℃.

Technical Field

The invention relates to a preparation method of hectorite-reinforced polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano-stereocomplex hydrogel, belonging to the field of preparation of polymer composite materials and biomedical materials.

Background

The hydrogel is a material with high water content and a three-dimensional network structure, and has wide application in the fields of intelligent materials and biomedicine. The polylactic acid-polyethylene glycol-polylactic acid triblock copolymer is a high molecular copolymer with good biocompatibility and degradability, has both hydrophilic and hydrophobic properties, and has wide application prospect in the field of biomedicine. Structurally, the polylactic acid chain segment in the polylactic acid-polyethylene glycol-polylactic acid triblock copolymer has levorotatory isomer and dextrorotatory isomer, so that the copolymer of the levorotatory isomer and the dextrorotatory isomer can generate stereocomplex action. The hectorite (LAP) is a layered silicate substance, has good antibacterial property and adsorbability biocompatibility, has good dispersibility in an aqueous solution, can form colorless and transparent hydrogel with a physical cross-linked network, and has wide application in the field of nano composite hydrogel. The physical and mechanical properties of the polylactic acid-polyethylene glycol-polylactic acid hydrogel can be enhanced by utilizing the characteristic of easy gelation in hectorite water and the stereocomplex effect of a polylactic acid chain segment, and the application range of the polylactic acid-polyethylene glycol-polylactic acid hydrogel material is expanded. .

related documents and patents mainly adopt a single polylactic acid-polyethylene glycol-polylactic acid triblock copolymer blending method, but the physical and mechanical properties are poor. The invention enhances the hydrogel by utilizing the complexation of the hectorite and the stereo structure, improves the physical and mechanical properties of the hydrogel and has innovation.

disclosure of Invention

The technical problem to be solved by the invention is as follows: provides a preparation method of hectorite reinforced polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano-stereocomplex hydrogel, which aims to solve the limitation of lower physical and mechanical properties of polylactic acid-polyethylene glycol-polylactic acid triblock hydrogel in the prior art.

The technical scheme of the invention is as follows: the laponite-reinforced polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano-stereocomplex hydrogel is obtained by mechanically blending laponite, levorotatory polylactic acid-polyethylene glycol-polylactic acid triblock copolymer and dextrorotatory polylactic acid-polyethylene glycol-polylactic acid triblock copolymer in distilled water according to a certain proportion.

The preparation method of the laponite-reinforced polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano stereocomplex hydrogel comprises the following steps of (1) stirring at room temperature by taking levorotatory polylactic acid-polyethylene glycol-polylactic acid triblock copolymer (PLLA-PEG-PLLA) and dextrorotatory polylactic acid-polyethylene glycol-polylactic acid triblock copolymer (PDLA-PEG-PDLA) as matrixes and water as a solvent to obtain levorotatory and dextrorotatory polylactic acid-polyethylene glycol-polylactic acid triblock copolymer micelles; (2) mixing the two micelles to obtain a stereo micelle solution; (3) mechanically stirring to obtain a hectorite aqueous solution; (4) and (3) blending the stereoblock solution and the hectorite solution to obtain the polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano stereocomplex hydrogel.

The micelle concentration of PLLA-PEG-PLLA and PDLA-PEG-PDLA in the step (1) is 20%.

the mixing ratio of the two micelles in the step (2) is 1: 1.

in the step (3), the concentration of the hectorite aqueous solution is less than 14%.

in the step (4), the hydrogel is prepared by solution blending at 4 ℃ and gelling at 80 ℃.

the invention has the beneficial effects that: in order to solve the problems, the invention prepares the hectorite-reinforced polylactic acid-polyethylene glycol-polylactic acid triblock copolymer nano-stereocomplex hydrogel, which can further improve the physical and mechanical properties of the polylactic acid-polyethylene glycol-polylactic acid triblock copolymer.

Drawings

FIG. 1 is a schematic diagram of the reaction of the present invention;

FIG. 2 is a rheological plot of storage modulus as a function of temperature for composite hydrogels of different hectorite concentrations thermostatically treated at 25 ℃;

FIG. 3 is a scanning electron micrograph of composite hydrogels treated at a constant temperature of 25 ℃ and varying hectorite concentrations;

FIG. 4 is (a) LLA₄₄ ^0.8EG₅₆ ²LLA₄₄ ^0.8And DLA₄₄ ^0.8EG₅₆ ²DLA₄₄ ^0.8The GPC curve of the copolymer; (b) LLA₄₄ ^0.8EG₅₆ ²LLA₄₄ ^0.8And DLA₄₄ ^0.8EG₅₆ ²DLA₄₄ ^0.8of copolymers¹H-NMR chart.

Detailed Description

The invention is further illustrated by the following specific examples, which do not limit the scope of the invention.

The preparation method of the polylactic acid-polyethylene glycol-polylactic acid comprises the following steps:

The PLLA-PEG-PLLA triblock copolymer is synthesized by a method of initiating lactide ring-opening polymerization by PEG macromolecules, and the synthetic reaction is shown as the following schematic formula.

Wherein x is 2000 and y is 800.

Firstly, adding a certain proportion of L (or D) -lactide, polyethylene glycol (PEG) and stannous octoate into a 100mL three-mouth round-bottom flask, and introducing N₂After several minutes, adding a certain amount of toluene solution, uniformly stirring by magnetic force, and reacting for 8 hours at 120 ℃;

Secondly, taking out a product obtained by the reaction, cooling to room temperature, and precipitating by using ethyl acetate to obtain a white solid product;

thirdly, dissolving the white solid by using dichloromethane, stirring, dripping into the ethyl acetate for precipitation, and carrying out suction filtration, wherein the process is repeated for three times;

And fourthly, putting the purified product into a vacuum drying oven for drying to obtain the pure PLLA-PEG-PLLA triblock copolymer.

TABLE 1 molecular weight and distribution of triblock copolymers