CN1974608A - Electronic beam radiopolymerization process of directly synthesizing temperature sensitive hydrogel - Google Patents

Abstract

The present invention is electronic beam radiopolymerization process of synthesizing temperature sensitive hydrogel directly, and belongs to the field of temperature sensitive hydrogel preparing technology. Material monomer, cross-linking agent and additive in the weight ratio of 75-98.5 to 0.1-1 to 1-10 are dissolved in deionized water and polymerized through electron radiation to form cross-linked polymer. The cross-linked polymer is then extracted in a Soxhlet extractor with boiled deionized water for 24 hr and dried in a vacuum oven to obtain the temperature sensitive hydrogel. The temperature sensitive hydrogel may be used in medicine controlled releasing system, memory element switch, artificial muscle, chemical separation and other field. The present invention has the features of simple technological process, high polymerization efficiency, less pollution, low cost, normal temperature operation, etc.

Description

A Method for Directly Synthesizing Thermosensitive Hydrogels by Electron Beam Radiation Polymerization

technical field

The invention relates to a method for directly synthesizing temperature-sensitive hydrogel by electron beam radiation polymerization, and belongs to the technical field of temperature-sensitive hydrogel preparation methods.

Background technique

Stimuli-responsive hydrogels are a type of hydrogels whose properties will change significantly in response to slight physical or chemical stimuli from the external environment. It is a water-insoluble, water-swellable, hydrophilic cross-linked polymer. Stimuli-responsive hydrogels can respond to changes in external environmental factors such as temperature, pH, light, electric and magnetic fields. Due to the potential application value of stimuli-responsive hydrogels in drug controlled release systems, memory element switches, artificial muscles, chemical separation and other fields, it has attracted extensive attention of many scholars at home and abroad.

Using the deformation properties of stimuli-responsive hydrogels under environmental stimuli, various chemical energy-mechanical energy conversion systems have been conceived, such as artificial muscle models, chemical valves, shape memory materials, controlled drug release, sewage treatment, etc. In recent years, stimuli-responsive hydrogels have been increasingly used in bioscience fields such as cell culture substrates, enzyme activity control, and targeted drug delivery. The basis for the research and development of stimuli-responsive polymer hydrogels is Flory PJ's gel swelling theory, which uses factors such as intermolecular force fields, ionic electric fields, and photochemical interactions to make the volume of hydrogels respond. From the perspective of the choice of hydrogel matrix, synthetic polymers are mostly used at home and abroad, consisting of homopolymers, graft or block copolymers, blends, interpenetrating polymer networks (IPN), polymer microspheres (PMS) ) etc. as the response system. In view of the great application value of stimuli-responsive hydrogels in the biological field, natural polymer materials with gel phase transition characteristics, especially chitosan (chitosan) with good biocompatibility The study of gels has received considerable attention. At present, many scholars are actively engaged in the research on the synthesis, structure, performance and response mechanism of hydrogels. I believe that in the near future we can experience the great convenience that stimuli-responsive hydrogels bring to our work and life.

Temperature-sensitive hydrogel: This type of hydrogel has a certain proportion of hydrophilic and hydrophobic groups in its structure. Changes in temperature can affect the hydrophobic interaction of these groups and the hydrogen bonding between macromolecular chains, thereby changing the hydrogel The network structure of the glue produces a volume phase transition. There are two types of thermosensitive hydrogels: high-temperature shrinkage and low-temperature shrinkage. Most of the hydrogels synthesized by traditional methods have the disadvantage of slow response speed, and the synthesis of fast-response hydrogels has always been an important topic in the research of smart hydrogels. Poly-N-isopropylacrylamide (PNIPA) is a typical high-temperature shrinkable hydrogel, and the general explanation for its response mechanism is that the interaction between hydrophobic phases increases when the temperature increases, causing the gel to shrink. Studies on the swelling and shrinking properties of isopropylacrylamide hydrogels in water at different temperatures showed that water molecules exist in three forms in hydrogels: (a) a hydration layer adsorbed near the hydrophobic chain of the polymer; ( b) Water molecules freely moving in a looser polymer network; (c) Water molecules attached to hydrophilic groups through hydrogen bonds. The polyvinyl alcohol/polyacrylic acid polymer interpenetrating network temperature-sensitive hydrogel can be prepared by using the sequential approximation method combining chemical cross-linking and cyclic freezing-thawing, and the size of the mutation volume can be controlled by adjusting the content of the cross-linking agent in the gel . Polyacrylic acid and poly N, N-dimethylacrylamide polymer interpenetrating network hydrogels are low-temperature shrinkable hydrogels. At low temperatures, hydrogen bonds are formed in the gel network to shrink the volume, while at high temperatures, hydrogen bonds dissociate. The gel swells. There are relatively few research reports on low-temperature shrinkable gels.

At present, the methods for preparing temperature-sensitive hydrogels at home and abroad are mainly traditional thermal polymerization and γ-ray radiation polymerization. The preparation of temperature-sensitive hydrogels by electron beam radiation polymerization is a new method. At present, there is no patent report in China. .

Contents of the invention

The object of the present invention is to provide a method for directly synthesizing thermosensitive hydrogel by electron beam radiation polymerization. It is a new technology to directly synthesize temperature-sensitive hydrogel by radiation polymerization using electron beam as radiation source. It has the characteristics of fast polymerization speed, high efficiency and reaction at room temperature, which greatly simplifies the polymerization process, avoids the disadvantages of multi-step, long-term and pollution in traditional preparation methods, and opens up new opportunities for industrial production of temperature-sensitive hydrogels. new way. The raw materials of the polymerization method include monomers, polymers, crosslinking agents, etc., and can form a stable homogeneous system in an aqueous solution. The polymerization process has no three waste pollution, and is an environmentally friendly method for preparing hydrogels.

A method for directly synthesizing thermosensitive hydrogel with electron beam radiation polymerization, the method comprises the following steps:

(1) Dissolve raw material monomers, crosslinking agents, and additives in deionized water according to the following mass percentages (excluding deionized water),

Monomer 75～98.5wt%,

Crosslinking agent 0.1～1wt%,

Additives 1～10wt%,

The mass percentages of the three raw materials are 100%;

The monomer is any one of N-isopropylacrylamide, acrylic acid or N-isopropylacrylamide, acrylic acid and N, N-dimethylacrylamide, N-isobutylacrylamide, methacrylic acid one or more components;

The crosslinking agent is N, N'-methylenebisacrylamide, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, hydroxyethyl acrylate, acrylic acid Any one of hydroxypropyl ester and methylol acrylamide;

The additive is one of polyvinyl alcohol, chitosan, polyacrylamide, and 2-methacryloyloxyethyltrimethylammonium chloride;

(2) The solution configured in step (1) is irradiated with an electron beam to polymerize a cross-linked polymer;

(3) Put the cross-linked polymer described in step (2) into a Soxhlet extractor and extract it with boiling deionized water for 24 hours; glue.

Its radiation polymerization reaction path is as follows:

A variety of hydrogels with different properties can be prepared by using the above-mentioned electron beam radiation polymerization method for directly synthesizing thermosensitive hydrogels. Its lower critical solution temperature LCST (the lower critical solution temperature) changes between 25°C and 90°C with the change of raw material formula. The equilibrium swelling ratio and mechanical strength of various synthetic hydrogels also vary with different raw materials. These hydrogels with different properties can be used in drug controlled release systems, memory element switches, artificial muscles, chemical separation and other fields. The preparation method has the characteristics of simple process, high polymerization efficiency, little pollution, low cost, normal temperature operation and the like.

Description of drawings

Fig. 1 is a schematic diagram of the radiation polymerization reaction path of the present invention.

Detailed ways

The present invention will be described below in conjunction with specific embodiments.

Embodiment The radiation device is an electron linear accelerator.

Example 1

Dissolve 3.5 g of monomer (N-isopropylacrylamide), 0.3 g of monomer (acrylic acid), 0.1 g of additive (chitosan), 0.25 g of cross-linking agent (tripolyethylene glycol diacrylate) in 21 mL deionized water. The prepared solution is placed in a beaker, and the cross-linked polymer is obtained by electron beam radiation. Put the cross-linked polymer into a Soxhlet extractor and extract it with boiling deionized water for 24 hours, take it out and put it into a vacuum oven to dry to obtain a temperature-sensitive hydrogel.

Example 2

Dissolve 3.5g monomer (N-isopropylacrylamide), 1.1g monomer (acrylic acid), 0.2g additive (polyvinyl alcohol), 0.15g crosslinking agent (diethylene glycol diacrylate) in 23mL to ionized water. The prepared solution is placed in a beaker, and the cross-linked polymer is obtained by electron beam radiation. Put the cross-linked polymer into a Soxhlet extractor and extract it with boiling deionized water for 24 hours, take it out and put it into a vacuum oven to dry to obtain a temperature-sensitive hydrogel.

Example 3

3.5g monomer (N-isopropylacrylamide), 0.5g monomer (acrylic acid), 0.25g monomer (N, N'-dimethylacrylamide), 0.1g additive (chitosan), 0.25 g Crosslinker (tetrapolyethylene glycol diacrylate) was dissolved in 20 mL of deionized water. The prepared solution is placed in a beaker, and the cross-linked polymer is obtained by electron beam radiation. Put the cross-linked polymer into a Soxhlet extractor and extract it with boiling deionized water for 24 hours, take it out and put it into a vacuum oven to dry to obtain a temperature-sensitive hydrogel.

Example 4

Dissolve 3.5 g of monomer (N-isopropylacrylamide), 0.36 g of monomer (acrylic acid), 0.15 g of additive (polyacrylamide), 0.25 g of crosslinker (tetrapolyethylene glycol diacrylate) in 21 mL deionized water. The prepared solution is placed in a beaker, and the cross-linked polymer is obtained by electron beam radiation. Put the cross-linked polymer into a Soxhlet extractor and extract it with boiling deionized water for 24 hours, take it out and put it into a vacuum oven to dry to obtain a temperature-sensitive hydrogel.

Example 5

3.5g monomer (N-isopropylacrylamide), 0.53g monomer (acrylic acid), 0.1g additive (chitosan), 0.01g crosslinking agent (N, N'-methylenebisacrylamide) Dissolve in 18mL deionized water. The prepared solution is placed in a beaker, and the cross-linked polymer is obtained by electron beam radiation. Put the cross-linked polymer into a Soxhlet extractor and extract it with boiling deionized water for 24 hours, take it out and put it into a vacuum oven to dry to obtain a temperature-sensitive hydrogel.

Example 6

3.5g monomer (N-isopropylacrylamide), 0.52g monomer (acrylic acid), 0.23g additive (2-methacryloyloxyethyltrimethylammonium chloride), 0.5g crosslinking agent ( hydroxyethyl acrylate) was dissolved in 20 mL of deionized water. The prepared solution is placed in a beaker, and the cross-linked polymer is obtained by electron beam radiation. Put the cross-linked polymer into a Soxhlet extractor and extract it with boiling deionized water for 24 hours, take it out and put it into a vacuum oven to dry to obtain a temperature-sensitive hydrogel.

Example 7

3.5g monomer (N-isopropylacrylamide), 0.33g monomer (acrylic acid), 0.15g monomer (methacrylic acid), 0.15g additive (polyvinyl alcohol), 0.1g crosslinking agent (N, N'-methylenebisacrylamide) was dissolved in 20 mL of deionized water. The prepared solution is placed in a beaker, and the cross-linked polymer is obtained by electron beam radiation. Put the cross-linked polymer into a Soxhlet extractor and extract it with boiling deionized water for 24 hours, take it out and put it into a vacuum oven to dry to obtain a temperature-sensitive hydrogel.

Example 8

3.5g monomer (N-isopropylacrylamide), 0.35g monomer (acrylic acid), 0.25g monomer (N-isobutylacrylamide), 0.1g additive (chitosan), 0.5g crosslinking The solvent (hydroxypropyl acrylate) was dissolved in 22 mL of deionized water. The prepared solution is placed in a beaker, and the cross-linked polymer is obtained by electron beam radiation. Put the cross-linked polymer into a Soxhlet extractor and extract it with boiling deionized water for 24 hours, take it out and put it into a vacuum oven to dry to obtain a temperature-sensitive hydrogel.

Example 9

3.5g monomer (N-isopropylacrylamide), 0.32g monomer (acrylic acid), 0.15g monomer (methacrylic acid), 0.1g additive (chitosan), 0.15g crosslinking agent (methylol base acrylamide) was dissolved in 22 mL of deionized water. The prepared solution is placed in a beaker, and the cross-linked polymer is obtained by electron beam radiation. Put the cross-linked polymer into a Soxhlet extractor and extract it with boiling deionized water for 24 hours, take it out and put it into a vacuum oven to dry to obtain a temperature-sensitive hydrogel.

Claims (1)

1, a kind of electronic beam radiopolymerization is directly synthesized the method for temperature-sensitive hydrogel, it is characterized in that this method may further comprise the steps:

(1) starting monomer, linking agent, additive are dissolved in the deionized water by following quality percentage composition (not comprising deionized water),

Monomer 75～98.5wt%,

Linking agent 0.1～1wt%,

Additive 1～10wt%,

The quality percentage composition 100% of three kinds of raw materials;

Described monomer is any or multiple composition in N-N-isopropylacrylamide, vinylformic acid or N-N-isopropylacrylamide, vinylformic acid and N,N-DMAA, N-isobutyl-acrylamide, the methacrylic acid;

Described linking agent is N, any in N '-methylene-bisacrylamide, diethylene glycol diacrylate, three polyethyleneglycol diacrylates, four polyethyleneglycol diacrylates, Hydroxyethyl acrylate, Propylene glycol monoacrylate, the n-methylolacrylamide;

Described additive is a kind of in polyvinyl alcohol, chitosan, polyacrylamide, the 2-methylacryoyloxyethyl trimethyl ammonium chloride;

(2) solution that step (1) is disposed aggregates into cross-linked polymer through electron beam irradiation;

(3) the described cross-linked polymer of step (2) is put into apparatus,Soxhlet's with the deionized water extracting 24 hours of boiling; After the taking-up, it is dry to put into vacuum drying oven, promptly obtains the described described temperature-sensitive hydrogel that promptly obtains.

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