Preparation method of pH responsive material

Abstract

The invention discloses a preparation method of a pH responsive material. The method comprises the following steps: adding a certain mass of starch and TEMPO (Tetramethylpiperidinooxy), NaClO2 and NaClO solutions into a sodium phosphate buffer solution, stirring and reacting for 24 hours under certain conditions, adding anhydrous ethanol to terminate the reaction, pouring the solution into a conical flask to stand and layer, pouring away supernatant liquid, replacing with ethanol with a volume concentration of 50 percent and water, obtaining a clean and thick gelatinous carboxyl modified starch solution, drying and finally obtaining a product. The preparation method has the benefits that 1, the starch is taken as a raw material in the preparation method, is wide in source and low in cost, still returns to the nature in a form of carbon dioxide and water after degradation and is a natural renewable material which is zero-pollution; 2, the preparation process is simple, the product biocompatibility is optimal, the degradation is complete or a degradation product has no harm to bodies, and the preparation method can be widely applied to the fields of material science, biology and medicine.

Description

technical field

[0001] The invention relates to the field of preparation of polymer materials, in particular to a preparation method of a pH responsive material. Background technique

[0002] Starch is a carbohydrate formed by plants through photosynthesis. It has a wide range of sources, is cheap, and returns to nature in the form of carbon dioxide and water after degradation. It is considered to be a natural and renewable material that is completely pollution-free. In the non-edible field Has been extensively researched and developed. pH-responsive materials refer to the change of pH value, the material molecules can interact with the H in the solution + Binding and dissociation, in which changes in its microscopic molecular structure lead to changes in its volume or morphology, which are based on stimulus responsiveness at the molecular level and at the macromolecular level. Due to this special property, it has attracted the attention of scholars at home and abroad, and...

Examples

Embodiment 1

[0013] A method for preparing a pH-responsive material, according to the following steps:

[0014] Weigh 1g starch, 0.024g TEMPO, 1.06g NaClO 2 Add 4ml of NaClO solution with a mass concentration of 15% into 40ml of pH5.7 sodium phosphate buffer solution, stir and react at 35°C for 24 hours, add absolute ethanol to terminate the reaction, and pour the solution into the Erlenmeyer flask Stand in the middle and stratify, pour off the supernatant, keep the lower layer, replace the lower layer with ethanol and water with a volume concentration of 50% in turn, to obtain a clean, thick gel-like carboxylated modified starch solution, which is obtained after drying. The product is the pH responsive material - carboxylated modified starch.

Embodiment 2

[0016] A method for preparing a pH-responsive material, according to the following steps:

[0017] Weigh 1g starch, 0.12g TEMPO, 1.56g NaClO 2 Add 10ml of NaClO solution with a mass concentration of 15% into a sodium phosphate buffer solution with a volume of 200ml of pH6.8, stir and react at 40°C for 24 hours, add absolute ethanol to terminate the reaction, and pour the solution into a conical flask Stand in the middle and stratify, pour off the supernatant, keep the lower layer, replace the lower layer with ethanol and water with a volume concentration of 50% in turn, to obtain a clean, thick gel-like carboxylated modified starch solution, which is obtained after drying. The product is the pH responsive material - carboxylated modified starch.

Embodiment 3

[0019] A method for preparing a pH-responsive material, according to the following steps:

[0020] Weigh 1g starch, 0.24g TEMPO, 2.52g NaClO 2 Add 16ml of NaClO solution with a mass concentration of 15% into 500ml of pH 8.0 sodium phosphate buffer solution, stir and react at 60°C for 24 hours, add absolute ethanol to terminate the reaction, and pour the solution into the Erlenmeyer flask Stand in the middle and stratify, pour off the supernatant, keep the lower layer, replace the lower layer with ethanol and water with a volume concentration of 50% in turn, to obtain a clean, thick gel-like carboxylated modified starch solution, which is obtained after drying. The product is the pH responsive material - carboxylated modified starch.

technical field

[0001] The invention relates to the field of preparation of polymer materials, in particular to a preparation method of a pH responsive material. Background technique

[0002] Starch is a carbohydrate formed by plants through photosynthesis. It has a wide range of sources, is cheap, and returns to nature in the form of carbon dioxide and water after degradation. It is considered to be a natural and renewable material that is completely pollution-free. In the non-edible field Has been extensively researched and developed. pH-responsive materials refer to the change of pH value, the material molecules can interact with the H in the solution + Binding and dissociation, in which changes in its microscopic molecular structure lead to changes in its volume or morphology, which are based on stimulus responsiveness at the molecular level and at the macromolecular level. Due to this special property, it has attracted the attention of scholars at home and abroad, and...

Examples

Embodiment 1

[0013] A method for preparing a pH-responsive material, according to the following steps:

[0014] Weigh 1g starch, 0.024g TEMPO, 1.06g NaClO 2 Add 4ml of NaClO solution with a mass concentration of 15% into 40ml of pH5.7 sodium phosphate buffer solution, stir and react at 35°C for 24 hours, add absolute ethanol to terminate the reaction, and pour the solution into the Erlenmeyer flask Stand in the middle and stratify, pour off the supernatant, keep the lower layer, replace the lower layer with ethanol and water with a volume concentration of 50% in turn, to obtain a clean, thick gel-like carboxylated modified starch solution, which is obtained after drying. The product is the pH responsive material - carboxylated modified starch.

Embodiment 2

[0016] A method for preparing a pH-responsive material, according to the following steps:

[0017] Weigh 1g starch, 0.12g TEMPO, 1.56g NaClO 2 Add 10ml of NaClO solution with a mass concentration of 15% into a sodium phosphate buffer solution with a volume of 200ml of pH6.8, stir and react at 40°C for 24 hours, add absolute ethanol to terminate the reaction, and pour the solution into a conical flask Stand in the middle and stratify, pour off the supernatant, keep the lower layer, replace the lower layer with ethanol and water with a volume concentration of 50% in turn, to obtain a clean, thick gel-like carboxylated modified starch solution, which is obtained after drying. The product is the pH responsive material - carboxylated modified starch.

Embodiment 3

[0019] A method for preparing a pH-responsive material, according to the following steps:

[0020] Weigh 1g starch, 0.24g TEMPO, 2.52g NaClO 2 Add 16ml of NaClO solution with a mass concentration of 15% into 500ml of pH 8.0 sodium phosphate buffer solution, stir and react at 60°C for 24 hours, add absolute ethanol to terminate the reaction, and pour the solution into the Erlenmeyer flask Stand in the middle and stratify, pour off the supernatant, keep the lower layer, replace the lower layer with ethanol and water with a volume concentration of 50% in turn, to obtain a clean, thick gel-like carboxylated modified starch solution, which is obtained after drying. The product is the pH responsive material - carboxylated modified starch.