WO2018119772A1 - Light/heat stage responsive shape-memory polymer, preparation method for same, and applications thereof - Google Patents

Abstract

The present invention is applicable in the field of smart polymer materials. Provided are a light/heat stage responsive shape-memory polymer, a preparation method for same, and applications thereof. The light/heat stage responsive shape-memory polymer is formed by polymerizing monomer A, monomer B, and monomer C, where the structural formula of monomer A is formula (I), monomer B is hexamethylene diisocyanate, and monomer C is N-methyl diethanolamine. The light/heat stage responsive shape-memory polymer provided in the present invention provides unique light/heat stage responsive shape-memory effects and provides discrete shape-change responses with respect respectively to an ultraviolet light and to a heat stimulus.

Description

Light/thermal grading response shape memory polymer and preparation method and application thereof Technical field

The invention belongs to the field of intelligent polymer materials, and in particular relates to a light/heat grading response shape memory polymer, a preparation method and application thereof.

Background technique

In the research of shape memory polymers (SMPs) in recent decades, the research and application of thermally induced shape memory polymer materials (TSMPs) have been greatly developed. However, TSMPs are not easy to achieve remote control, and it is necessary to directly induce the phase transformation of the material to achieve deformation. This makes the application of TSMPs in shielding systems and non-contact systems very limited. On the other hand, photo-induced SMPs are highly valued by researchers because of their environmentally friendly, remote controllability, and transient properties. Photo-induced SMPs have the unique advantages of non-contact regulation deformation, fixed-point regulation deformation and rapid, clean regulation and deformation, and can directly convert light energy into mechanical energy and improve light utilization efficiency. However, ordinary light-stimulated SMPs are highly dependent on light, deformed when illuminated, and deformed when there is no light, and the temporary shape cannot be fixed. In addition, in order to further expand the multi-functionality and practical application range of SMPs, the research on SMPs at home and abroad is more and more focused on achieving multiple responsiveness and multiple shape memory effects. However, the current multi-shape memory effect is achieved by temperature control of multiple reversible phases or by a wide range of glass transitions as a reversible equal manner to achieve triple or multiple shape memory, which is limited by temperature. There are also some studies that study the triple-shape memory performance by the heat generated by electricity or light. In the final analysis, it still belongs to a single heat-induced triple shape memory effect.

Therefore, the prior art has drawbacks and needs improvement.

Summary of the invention

In order to solve the above technical problems, the present invention provides a light/thermal grading response shape memory polymer and The preparation method and application thereof aim at improving the fixing effect of the temporary shape of the existing shape memory polymer, and developing the controllability of the shape fixing, thereby realizing the development and application of the multifunctional SMPs.

The present invention is achieved by a light/thermal grading response shape memory polymer, wherein the light/heat grading response shape memory polymer is polymerized from monomer A, monomer B, and monomer C;

单体B为六亚甲基二异氰酸酯，单体C为N-甲基二乙醇胺。Wherein, the structural formula of monomer A is

Monomer B is hexamethylene diisocyanate and monomer C is N-methyldiethanolamine.

The invention also provides a method for preparing the above light/heat grading response shape memory polymer, comprising the following steps:

Polymerizing monomer A and monomer B to obtain a shape memory polymer prepolymer containing azobenzene structural unit;

The high molecular weight shape memory polymer is obtained by adding monomer C and monomer B to the shape memory polymer prepolymer.

Compared with the prior art, the present invention has the beneficial effects that the light/thermal grading response shape memory polymer provided by the embodiment of the present invention constructs shape memory and shape change by utilizing the photostructural isomerization change of azobenzene molecules. Polymer polymer material. The resulting light/thermal grading response shape memory polymer has a unique light/thermal grading response shape memory effect with independent deformation response to ultraviolet light and thermal stimuli, respectively. Under the ultraviolet light, the shape memory polymer can be actively deformed; after the ultraviolet light is removed, the deformation remains unchanged under normal temperature and visible light environment, and a temporary shape is obtained; when the thermal stimulus is used, the temperature is raised to the shape memory polymer. Above the glass transition temperature, the shape memory polymer can actively recover deformation from the temporary shape to the original shape.

DRAWINGS

1 is a schematic view showing the shape change and recovery process of the light/heat grading response of the LHSMPU prepared in Example 2 of the present invention;

2 is a schematic view showing the structural change of the azobenzene structural unit of the LHSMPU prepared in Example 3 of the present invention under ultraviolet light stimulation at different times.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

A first embodiment of the present invention provides a light/thermal grading response shape memory polymer, wherein the light/thermal grading response shape memory polymer is polymerized from monomer A, monomer B, and monomer C;

单体B为六亚甲基二异氰酸酯，单体C为N-甲基二乙醇胺。Wherein, the structural formula of monomer A is

Monomer B is hexamethylene diisocyanate and monomer C is N-methyldiethanolamine.

The light/thermal grading response shape memory polymer provided by the first embodiment of the present invention is polymerized by azobenzene dicarboxylic acid, hexamethylene diisocyanate and N-methyldiethanolamine. The azobenzene soft segment chain was constructed by the addition polymerization of azobenzene dicarboxylic acid and some hexamethylene diisocyanate under the action of a catalyst; the N-methyldiethanolamine and the remaining hexamethylene diisocyanate were The addition polymerization reaction occurs under the action of a catalyst to construct a hard segment phase of N-methyldiethanolamine; subsequently, the soft segment of the azobenzene segment is bonded to the hard segment of the N-methyldiethanolamine by a chemical bond, and the photostructuring of the azobenzene molecule is utilized. The type of isomerization changes to construct a polymer polymer material with shape memory and shape change. The resulting light/thermal grading response shape memory polymer has a unique light/thermal grading response shape memory effect with independent deformation response to ultraviolet light and thermal stimuli, respectively.

Referring to FIG. 1, the shape memory polymer can be actively deformed under ultraviolet light irradiation; after the ultraviolet light is removed, the deformation remains unchanged under normal temperature and visible light conditions, and a temporary shape is obtained; when thermal stimulation is used, the temperature is raised to When the shape memory polymer has a glass transition temperature or higher, the shape memory polymer can actively recover deformation from the temporary shape to the original shape.

Specifically, the structural formula of the shape memory polymer is as follows:

Wherein n≥10 and m≥10. Light/thermal grading response shape memory aggregation provided by the first embodiment of the present invention The compound is introduced into the polyurethane main chain in the azobenzene structural unit and has a photoresponsive function. The rigid segment of polyurethane provides a physical cross-linking point for heat recovery. Under the action of thermal stimulation, the azobenzene structure undergoes structural changes, causing main chain motion, elastic recovery, and returning to the initial state.

Specifically, the mass ratio of the monomer A, the monomer B, and the monomer C is (10 to 20): (30 to 40): (40 to 60). By adjusting the amount of the monomer A, the monomer B and the monomer C, the mass percentage of the monomer A in the shape memory polymer is 10% by weight to 20% by weight, and the mass percentage of the monomer C is 30% by weight. ～40% by weight, the mass percentage of the monomer B is 40% by weight to 60% by weight. Thereby, the control of the amount of deformation of the photo-response of the shape memory polymer is achieved by regulating the content of the monomer A; the control of the temperature response range of the thermal response of the shape memory polymer is achieved by adjusting the B and C contents.

Specifically, the monomer B includes at least one of aliphatic diisocyanates. The monomer C includes at least one of N-methyldiethanolamine and N-methyldimethanolamine.

Specifically, the number of moles of carboxyl groups a in the monomer A, the number of moles of isocyanate groups in the monomer B, and the number of moles of hydroxyl groups in the monomer C satisfy the following relationship:

r=b/(a+c), r ranges from 0.95 to 1.05.

By limiting the number of moles of carboxyl groups a in the monomer A, the number of moles of isocyanate groups in the monomer B, and the number of moles of hydroxyl groups c in the monomer C, the number average molecular weight of the polymerized shape memory polymer is greater than 5000, thereby making the shape memory polymer have better moldability.

Specifically, the light/thermal grading response shape memory polymer has a glass transition temperature of 30 to 90 °C. The polyurethane glass transition temperature is maintained at 30 to 90 ° C by adjusting the content of the monomers A, B, and C in the shape memory polymer.

A second embodiment of the present invention provides a method for preparing the above light/heat grading response shape memory polymer, comprising the following steps:

Polymerizing monomer A and monomer B to obtain a shape memory polymer prepolymer containing azobenzene structural unit;

The high molecular weight shape memory polymer is obtained by adding monomer C and monomer B to the shape memory polymer prepolymer.

A method for preparing a photo/thermal grading response shape memory polymer according to a second embodiment of the present invention comprises azobenzene dicarboxylic acid, diisocyanate and N-methyldiethanolamine as raw materials for polymerization synthesis. First, the azobenzenedicarboxylic acid and a part of the diisocyanate are alternately copolymerized to construct a soft chain of azobenzene. The catalyst for reacting the azobenzenedicarboxylic acid with the diisocyanate is dibutyltin dilaurate; N-methyldiethanolamine and The remaining diisocyanate is alternately copolymerized to form an azobenzene hard segment phase, and the azobenzene soft segment chain and the azobenzene hard segment phase are linked by a chemical bond, and the photo-isomerization isomerization of the azobenzene molecule is used to construct the shape. A polymer polymer material with memory and shape changes.

Specifically, the chemical structure of the shape memory polymer prepolymer is as follows:

其中n≥10。

Where n≥10.

所述制备方法过程简单，适合大规模生产。A method for preparing a light/heat grading response shape memory polymer according to a second embodiment of the present invention, wherein the chemical structure of the light/heat grading response shape memory polymer obtained is:

The preparation method is simple in process and suitable for large-scale production.

A third embodiment of the present invention provides the use of the above light/thermal grading response shape memory polymer for the preparation of the smart nanodevice, intelligent drug controlled release using the light/thermal grading response shape memory polymer Agent or smart sensor.

In the third embodiment of the present invention, an azobenzene compound is used as a photoresponsive group in a device or a formulation for light energy conversion mechanical movement, and has broad application prospects.

The technical solutions of the present invention are further described below in conjunction with specific embodiments.

Example 1

0.37 g of 4,4'-azobenzenedicarboxylic acid was added to a three-necked flask, and 10.0 g of N,N'-dimethylformamide was dissolved; then 1.5 g of hexamethylene diisocyanate and 0.6 mL of dilauric acid were added dropwise. Dibutyltin, reacted at 80 ° C for 30 min; then added 1.96 g of N-methyldiethanolamine, 1.5 g of hexamethylene diisocyanate, and further reacted at 80 ° C for 30 min; after the reaction was over, the solution was poured into a Teflon mold. The light/heat grading response shape memory polyurethane (LHSMPU) was obtained by baking in an air drying oven at 80 ° C for 24 hours. The azobenzene structural unit is introduced into the polyurethane main chain and has a photoresponsive function. Polyurethane hard segment provides physical cross-linking for heat recovery Point, the structure of azobenzene can also undergo structural changes under thermal stimulation, causing the main chain to move, elastic recovery, and return to the initial state.

Example 2

0.54 g of 4,4'-azobenzenedicarboxylic acid and 12.0 g of N,N'-dimethylformamide were added to a three-necked flask; then 1.5 g of hexamethylene diisocyanate and 0.6 mL of dilauric acid were added dropwise. Dibutyltin, reacted at 80 ° C for 30 min; then add 1.89 g of N-methyldiethanolamine, 1.5 g of hexamethylene diisocyanate, and react at 80 ° C for another 30 min; after the reaction is over, pour the solution into a Teflon mold. The light/heat grading response shape memory polyurethane (LHSMPU) was obtained by baking in an air drying oven at 80 ° C for 24 hours. Fig. 1 is a schematic view showing the shape change and recovery process of the light/heat classification response of the prepared LHSMPU. It can be seen from Fig. 1 that under the ultraviolet light irradiation, the polyurethane main chain is curled and has a photo-induced shape deformation; after the ultraviolet light stops, the curl shape remains stable at room temperature, and has a good shape fixing function. During the heating process, without the light stimulation, the curled shape gradually returns to the initial flat state, and the heat-induced shape recovery is realized.

Example 3

0.96 g of 4,4'-azobenzenedicarboxylic acid and 15.0 g of N,N'-dimethylformamide were added to the three-necked flask; then 1.5 g of hexamethylene diisocyanate and 0.6 mL of dilauric acid were added dropwise. Dibutyltin, reacted at 80 ° C for 30 min; then add 1.69 g of N-methyldiethanolamine, 1.5 g of hexamethylene diisocyanate, and react at 80 ° C for another 30 min; after the reaction is over, the solution is poured into a Teflon mold. The light/heat grading response shape memory polyurethane (LHSMPU) was obtained by baking in an air drying oven at 80 ° C for 24 hours. Figure 2 is a graph showing the changes in the structure of azobenzene structural units in LHSMPU prepared by ultraviolet absorption spectroscopy at different times. As shown in Fig. 2, under the action of ultraviolet light stimulation, with the increase of the time of ultraviolet light stimulation, the π-π* electronic transition of the nitrogen-nitrogen double bond (-N=N-) in the azobenzene group at 362 nm (reverse) The isomers gradually decrease in the intensity of the absorption peak, indicating that the azobenzene group gradually changes from the trans isomer to the cis isomer; that is, the molecular structure changes by ultraviolet light stimulation, and the material is macroscopically Curled deformation.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the present invention. Within the scope of protection.

Claims (10)

A light/thermal grading response shape memory polymer characterized in that the light/heat grading response shape memory polymer is polymerized from monomer A, monomer B and monomer C; Wherein, the structural formula of monomer A is

Monomer B is hexamethylene diisocyanate and monomer C is N-methyldiethanolamine. The light/thermal graded response shape memory polymer of claim 1 wherein said shape memory polymer has the structural formula:

Wherein n≥10 and m≥10. The light/heat grading response shape memory polymer according to claim 1, wherein the mass ratio of the monomer A, the monomer B, and the monomer C is (10 to 20): (30 to 40): (40 ~ 60). The light/heat grading response shape memory polymer according to claim 1, wherein the monomer B comprises at least one of aliphatic diisocyanates. The light/thermal graded response shape memory polymer according to claim 1, wherein the monomer C comprises at least one of N-methyldiethanolamine and N-methyldimethanolamine. The photo/thermal graded response shape memory polymer according to claim 1, wherein the number of moles of carboxyl groups in the monomer A, the number of moles of isocyanate groups in the monomer B, and the hydroxyl groups in the monomer C The number of moles c satisfies the following relationship: r=b/(a+c), r ranges from 0.95 to 1.05. The light/thermal graded response shape memory polymer of claim 1 wherein said light/thermal graded response shape memory polymer has a glass transition temperature of from 30 to 90 °C. The method for preparing a light/heat grading response shape memory polymer according to any one of claims 1 to 7, comprising the steps of: Polymerization of monomer A and monomer B to obtain shape memory polymerization of azobenzene-containing structural units Prepolymer The high molecular weight shape memory polymer is obtained by adding monomer C and monomer B to the shape memory polymer prepolymer. The method of producing a photo/thermal classification response shape memory polymer according to claim 8, wherein the catalyst for polymerizing the monomer A and the monomer B is dibutyltin dilaurate. The use of the light/thermal grading response shape memory polymer according to any one of claims 1 to 7, wherein the application is to use the light/thermal grading response shape memory polymer for preparing an intelligent nano device , smart drug controlled release or smart sensor.

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