Cardanol-based room-temperature phosphorescent shape memory polymer as well as preparation method and application thereof

Abstract

The invention relates to a cardanol-based room-temperature phosphorescent shape memory polymer and a preparation method and application thereof, and the preparation method comprises the following steps: (1) taking cardanol as a raw material, and synthesizing a multifunctional cardanol epoxy compound through Friedel-Crafts alkylation, epoxidation and other chemical modifications; (2) synthesizing nitrogen-containing boric acid ester polyamine; and (3) adding the nitrogen-containing borate polyamine obtained in the step (2) into the polyfunctional cardanol epoxy compound obtained in the step (1), heating to 140-160 DEG C, and carrying out polymerization reaction for 5-10 hours to finally obtain the cardanol-based room-temperature phosphorescent shape memory polymer. The obtained polymer has double anti-counterfeiting effects of phosphorescence anti-counterfeiting and shape memory anti-counterfeiting, and the application field of biomass room-temperature phosphorescence materials is expanded.

Description

Technical Field

[0001] The present invention belongs to the field of functional polymer materials, and particularly relates to a bio-based room temperature phosphorescent shape memory polymer and a preparation method and application thereof. Background Art

[0002] With the development of modern science and technology and economy, room temperature phosphorescent materials (RTP) have attracted increasing attention in the fields of anti-counterfeiting, bioimaging, information encryption, etc. Among them, organic RTP polymer materials with unique flexibility and easy modification are increasingly favored due to their wide availability in multiple fields such as intelligent sensing, wearable devices, optoelectronic devices, etc., as well as their general synthesis methods and economic, environmental protection and good adaptability. However, due to the inherent spin-forbidden intersystem crossing (ISC) of organic RTP polymers and the sensitivity of triplet excitons to environmental conditions, it is challenging to achieve efficient and persistent RTP emission.

[0003] In recent years, epoxy resins with high thermal and chemical stabilities have shown considerable room temperature phosphorescence (RTP) potential. This is because the highly crosslinked three-dimensional polymer network formed after curing of epoxy resins can effectively inhibit intramolecular motion, contribute to promoting intersystem crossing (ISC) transitions, and stabilize the triplet excited state by preventing non-radiative transitions. Currently reported room temperature phosphorescent epoxy resin materials are mainly achieved through host-guest doping strategies (B. Wu, N. Guo, X. Xu, Y. Xing, K. Shi, W. Fang, G. Wang, Ultralong and high-efficiency room temperature phosphorescence of organic-phosphors-doped polymer films enhanced by 3D Network, Advanced Optical Materials 8(22) (2020); J. A. Li, L. Zhang, C. Wu, Z. Huang, S. Li, H. Zhang, Q. Yang, Z. Mao, S. Luo, C. Liu, G. Shi, B. Xu, Switchable and highly robust ultralong room-temperature phosphorescence from polymer-based transparent films with three-dimensional covalent networks for erasable light printing, Angew. Chem. Int. Ed. Engl. 62(7) (2023) e202217284.). However, due to the irreversible three-dimensional permanent network structure of epoxy resins after curing, their reprocessing performance is lost, resulting in waste of resources. Gradually replacing petroleum-based resources with bio-based resources, introducing reversible dynamic covalent bonds, and preparing bio-based resins with the reprocessing properties of thermoplastic materials and the excellent properties of thermosetting materials can largely solve the above problems. Cardanol, a natural phenolic compound derived from the low-value agricultural and forestry residue cashew nut shell, is one of the most commonly used renewable resources, with advantages such as low price and rich resources. The unique benzene ring and multiple active functional groups such as the olefinic unsaturated long carbon chain of cardanol endow cardanol not only with the reaction characteristics of phenolic compounds but also with the chemical properties of unsaturated olefins. Preparing epoxy resins from cardanol not only forms a rigid microenvironment to achieve efficient RTP; at the same time, the long alkyl chain and the introduced dynamic units provide an ideal platform for realizing the repeated plasticity and reusability of polymers. Summary of the Invention

[0004] Technical problems to be solved: The present invention provides a cardanol-based room temperature phosphorescent shape memory polymer, its preparation method and application. Compared with other phosphorescent epoxy resins, this polymer exhibits excellent multi-stimulus responsive shape memory performance due to the dynamic characteristics of N-coordinated borate bonds; after the cardanol epoxide is cured, a highly cross-linked three-dimensional polymer network is formed, effectively restricting intramolecular rotation and vibration, significantly suppressing the occurrence of non-radiative transitions, realizing long-life phosphorescence of this material, and still maintaining good phosphorescent performance in harsh environments such as water, acid, and alkali. At the same time, the cardanol polymer obtained in the present invention has a dual anti-counterfeiting function of phosphorescent anti-counterfeiting and shape memory anti-counterfeiting, expanding the application fields of biomass room temperature phosphorescent materials.

[0005] Technical solution: A preparation method of a cardanol-based room temperature phosphorescent shape memory polymer, comprising the following steps: (1) Using cardanol, phenol and epichlorohydrin as raw materials, a multi-functional cardanol epoxide is synthesized through Friedel-Crafts alkylation and epoxidation reactions, wherein the molar ratio of cardanol to phenol is 1:(3-10), and the molar ratio of polyphenol of cardanol to epichlorohydrin is 1:(6-15); (2) Using hydroxylamine-containing and aminophenylboric acid or its derivatives as raw materials, reacting at 30°C to 60°C to obtain a nitrogen-containing borate polyamine; (3) Mixing the nitrogen-containing borate polyamine obtained in step (2) with the multi-functional cardanol epoxide obtained in step (1) according to the molar ratio of epoxy group to amino group of 1:(0.8-2), and carrying out a polymerization reaction at 140°C to 160°C for 5 to 10 hours to obtain a cardanol-based room temperature phosphorescent shape memory polymer.

[0006] In step (1), the Friedel-Crafts alkylation reaction is carried out in the presence of an acid catalyst, and the acid catalyst is tetrafluoroboric acid; the epoxidation reaction is carried out in the presence of a base and a phase transfer catalyst, the base is selected from sodium hydroxide, potassium hydroxide or their solutions, and the phase transfer catalyst is selected from polyethylene glycol, benzyltriethylammonium chloride or their combinations.

[0007] In step (2), the hydroxylamine-containing is selected from tetra-hydroxyethyl ethylenediamine, N,N-bis(2-hydroxyethyl)ethylenediamine, diethanolamine or their combinations; the aminophenylboric acid or its derivatives are selected from 3-aminophenylboric acid, 4-aminophenylboric acid, 1,4-benzenediboronic acid or their combinations.

[0008] In step (3), the shape fixing rate of the cardanol-based room temperature phosphorescent shape memory polymer is ≥95%, the shape recovery rate is ≥95%, and the afterglow time is 7 to 11 seconds under 365 nm ultraviolet light excitation.

[0009] The cardanol-based room temperature phosphorescent shape memory polymer prepared by the above method has a three-dimensional network structure cross-linked by dynamic N-coordinated borate bonds, and still maintains an afterglow time ≥7 seconds after being soaked in an acid, alkali or water environment for 4 weeks.

[0010] Application of cardanol-based room temperature phosphorescent shape memory polymer in preparing room temperature phosphorescent materials, wherein the materials show long-lived phosphorescence under ultraviolet excitation, and the phosphorescence lifetime can be regulated by adjusting the structure of nitrogen-containing borate polyamine and the molar ratio with epoxide.

[0011] Application of cardanol-based room temperature phosphorescent shape memory polymer in anti-counterfeiting materials, wherein the anti-counterfeiting materials show dynamic coding patterns under ultraviolet excitation, and the visibility of the patterns changes dynamically with the difference in phosphorescence lifetime.

[0012] The above anti-counterfeiting materials realize the shape memory function in response to external stimuli, and the external stimuli include a temperature of 40-100 °C, ultraviolet light or infrared light, and the shape recovery time is 5 seconds to 2.5 minutes.

[0013] The above anti-counterfeiting materials are folded and unfolded through thermal response or light response, and form a dual anti-counterfeiting mechanism in combination with phosphorescent characteristics. Among them, the pattern is unrecognizable in the folded state and can be clearly recognized in the unfolded state.

[0014] An anti-counterfeiting material, which realizes the dynamic encryption function by blending cardanol-based room temperature phosphorescent shape memory polymers with different phosphorescence lifetimes, and shows encrypted information that changes with time after the ultraviolet light is turned off.

[0015] Beneficial effects: 1. The present invention uses the forest product characteristic resource cardanol as a raw material to synthesize a cardanol-based room temperature phosphorescent shape memory polymer. The raw material cardanol used is a green biomass raw material, which has the advantages of wide source, rich yield and low cost. 2. The cardanol-based room temperature phosphorescent shape memory polymer provided by the present invention has multi-stimulus response shape memory properties such as ultraviolet, infrared and temperature due to the dynamic characteristics of N-coordinated borate bonds, shows excellent shape memory properties, and the shape fixation rate and shape recovery rate reach more than 95%. 3. The cardanol-based room temperature phosphorescent shape memory polymer provided by the present invention can still maintain good phosphorescent properties in harsh environments such as water, acid and alkali. 4. The obtained cardanol polymer of the present invention has a dual anti-counterfeiting effect of phosphorescent anti-counterfeiting and shape memory anti-counterfeiting, realizes the high-value sustainable utilization of cardanol, and expands the application field of biomass room temperature phosphorescent materials. Description of the Drawings

[0016] Figure 1 It is the nuclear magnetic spectrum diagram of the cardanol-based polyphenol and multifunctional cardanol epoxide prepared in Example 1 of the present invention.

[0017] Figure 2 It is the shape memory electronic diagram of the cardanol-based room temperature phosphorescent shape memory polymer prepared in Example 3 of the present invention (a: thermal response shape memory performance; b: ultraviolet response shape memory performance; infrared response shape memory performance).

[0018] Figure 3 This is the phosphorescence time electron diagram of the cardanol-based room temperature phosphorescent shape memory polymer prepared in Example 3 of the present invention.

[0019] Figure 4 This is the phosphorescence time electron diagram of the cardanol-based room temperature phosphorescent shape memory polymer prepared in Example 3 of the present invention after being soaked in hydrochloric acid for 4 weeks.

[0020] Figure 5 This is the dynamic encryption process of the cardanol-based room temperature phosphorescent shape memory polymer prepared in Example 4 of the present invention.

[0021] Figure 6 This is the dual anti-counterfeiting process of the cardanol-based room temperature phosphorescent shape memory polymer prepared in Example 5 of the present invention. Detailed implementation manners

[0022] The following examples further illustrate the content of the present invention, but should not be construed as limiting the present invention. Without departing from the spirit and essence of the present invention, the modifications and substitutions made to the methods, steps or conditions of the present invention all fall within the scope of the present invention.

[0023] Example 1

[0024] Step (1): According to a molar ratio of 1:10, cardanol and phenol were successively added to a reaction flask in an oil bath at 90 °C, and reacted for 1 h in the presence of tetrafluoroboric acid to synthesize cardanol-based polyphenols; according to a molar ratio of 1:8, the obtained cardanol-based polyphenols were reacted with epichlorohydrin at 80 °C for 4 h in the presence of solid NaOH and benzyltriethylammonium chloride to prepare a multi-functional cardanol epoxide.

[0025] Step (2): According to a molar ratio of 1:1.2, N,N-bis(2-hydroxyethyl)ethylenediamine and 3-aminophenylboronic acid were added to a reaction flask and reacted at 40 °C for 1 h to prepare a nitrogen-containing borate polyamine.

[0026] Step (3): According to an epoxy to NH2 molar ratio of 1:1, the nitrogen-containing borate polyamine obtained in step (2) was added to the multi-functional cardanol epoxide obtained in step (1), and the temperature was raised to 160 °C, and the polymerization reaction was carried out for 9 h to finally obtain a cardanol-based room temperature phosphorescent shape memory polymer.

[0027] The cardanol-based room temperature phosphorescent shape memory polymer has a phosphorescence afterglow of up to 10 s under 365 nm ultraviolet light excitation. After being soaked in hydrochloric acid for 4 weeks, it still has an afterglow of 8 s. The shape fixation rate was determined to be 97% by dynamic thermomechanical (DMA) analysis, and the shape recovery rate was about 100%. It was fixed into a temporary shape and heated to 70 °C, and it could return to the original shape in 5 s.

[0028] Example 2

[0029] Step (1): Add cardanol and phenol into a reaction flask in a molar ratio of 1:6, and place it in an oil bath at 100 °C. In the presence of tetrafluoroboric acid, react for 1 h to synthesize cardanol-based polyphenols. Then, in a molar ratio of 1:6, add the obtained cardanol-based polyphenols and epichlorohydrin to react at 80 °C for 5 h in the presence of an aqueous NaOH solution and benzyltriethylammonium chloride to obtain a multi-functional cardanol epoxide.

[0030] Step (2): Add N,N-bis(2-hydroxyethyl)ethylenediamine and 4-aminophenylboronic acid into a reaction flask in a molar ratio of 1:1.1, and react at 50 °C for 1 h to obtain a nitrogen-containing borate polyamine.

[0031] Step (3): Add the nitrogen-containing borate polyamine obtained in step (2) to the multi-functional cardanol epoxide obtained in step (1) according to an epoxy-to-NH2 molar ratio of 1:1.2, heat up to 160 °C, and carry out a polymerization reaction for 8 h to finally obtain a cardanol-based room temperature phosphorescent shape memory polymer.

[0032] The cardanol-based room temperature phosphorescent shape memory polymer has a 7 s afterglow under 365 nm ultraviolet light excitation. After being immersed in water for 4 weeks, it still has a 7 s afterglow. The shape fixation rate and shape recovery rate are determined by DMA analysis to be approximately 96%. Fix it into a temporary shape and place it under 0.57 W / cm 2 infrared light irradiation, and it can completely return to its original shape in 2.5 min.

[0033] Example 3

[0034] Step (1): Add cardanol and phenol into a reaction flask in a molar ratio of 1:7, and place it in an oil bath at 100 °C. In the presence of tetrafluoroboric acid, react for 1 h to synthesize cardanol-based polyphenols. Then, in a molar ratio of 1:7, add the obtained cardanol-based polyphenols and epichlorohydrin to react at 70 °C for 5 h in the presence of solid NaOH and benzyltriethylammonium chloride to obtain a multi-functional cardanol epoxide.

[0035] Step (2): Add N,N,N',N'-tetrahydroxyethyl ethylenediamine and 3-aminophenylboronic acid into a reaction flask in a molar ratio of 1:1.8, and react at 40 °C for 1 h to obtain a nitrogen-containing borate polyamine.

[0036] Step (3): Add the nitrogen-containing borate polyamine obtained in step (2) to the multi-functional cardanol epoxide obtained in step (1) according to an epoxy-to-NH2 molar ratio of 1:1.8, heat up to 160 °C, and carry out a polymerization reaction for 8 h to finally obtain a cardanol-based room temperature phosphorescent shape memory polymer.

[0037] Under the excitation of 365 nm ultraviolet light, the cardanol-based room temperature phosphorescent shape memory polymer has an afterglow of 11 s. After being immersed in hydrochloric acid for 4 weeks, it still has an afterglow of 10 s. The shape fixation rate is determined to be 98% by DMA analysis, and the shape recovery rate is about 100%. Fix it into a temporary shape and place it under ultraviolet light, and it can completely return to the original shape in 20 s.

[0038] Example 4

[0039] From Examples 1-3, it can be seen that by adjusting the molar ratio of polyfunctional cardanol epoxide and nitrogen-containing borate polyamine, as well as the structure of nitrogen-containing borate polyamine, cardanol-based room temperature phosphorescent shape memory polymers with different phosphorescent times can be obtained. Based on the above characteristics, the present invention has fabricated a dynamic encryption process, such as Figure 5 shown. The number "8888" is made of the cardanol-based room temperature phosphorescent shape memory polymers of Examples 1 and 3. Under the irradiation of 365 nm ultraviolet light, "8888" appears; when the ultraviolet lamp is turned off, the number "1960" is visible. As time goes by, the RTP of the number composed of Example 1 with a shorter lifespan fades, while the RTP of the number composed of Example 3 (with a longer RTP lifespan) continues to exist. Therefore, the number becomes "1967", demonstrating the dynamic encryption process.

[0040] Example 5

[0041] When there is no ultraviolet light irradiation, the polymer with a QR code pattern fabricated in Example 3 is a yellow film. Under the irradiation of 365 nm ultraviolet light, the film turns blue, and the QR code pattern is still invisible. The film is folded into a temporary shape through thermal response. When the ultraviolet lamp is turned off, a folded QR code that cannot be recognized by a mobile phone can be seen. Then the film is restored to the original shape through thermal response. When the ultraviolet lamp is turned off, the QR code that can be recognized by a mobile phone is clearly visible (see the schematic diagram in Figure 6 ). Therefore, the polymer prepared by the present invention exhibits dual anti-counterfeiting properties of phosphorescence and shape memory.

Claims

1. A method for preparing a cardanol-based room temperature phosphorescent shape memory polymer, characterized in that: The following steps are involved: (1) Using cardanol, phenol and epichlorohydrin as raw materials, a multifunctional cardanol epoxy compound is synthesized by Friedel-Crafts alkylation and epoxidation reaction, wherein the molar ratio of cardanol to phenol is 1:(3-10), and the molar ratio of cardanol polyphenol to epichlorohydrin is 1:(6-15); (2) Using hydroxylamine and aminophenylboronic acid or its derivatives as raw materials, a nitrogen-containing borate polyamine is prepared by reaction at 30°C-60°C; (3) The nitrogen-containing borate polyamine obtained in step (2) and the multifunctional cardanol epoxy compound obtained in step (1) are mixed at a molar ratio of epoxy group to amino group of 1:(0.8-2), and the mixture is polymerized at 140°C-160°C for 5-10 hours to obtain a cardanol-based room temperature phosphorescent shape memory polymer.

2. The preparation method according to claim 1, characterized in that: In step (1), the Friedel-Crafts alkylation reaction is carried out in the presence of an acid catalyst, which is tetrafluoroboric acid; the epoxidation reaction is carried out in the presence of a base and a phase transfer catalyst, which is selected from sodium hydroxide, potassium hydroxide or a solution thereof, and the phase transfer catalyst is selected from polyethylene glycol, benzyltriethylammonium chloride or a combination thereof.

3. The preparation method according to claim 1, characterized in that: In step (2), the hydroxylamine is selected from tetrahydroxyethylethylenediamine, N,N-bis(2-hydroxyethyl)ethylenediamine, diethanolamine or a combination thereof; the aminophenylboronic acid or its derivative is selected from 3-aminophenylboronic acid, 4-aminophenylboronic acid, 1,4-phenylenediboronic acid or a combination thereof.

4. The preparation method according to claim 1, characterized in that: In step (3), the shape fixation rate of the cardanol-based room temperature phosphorescent shape memory polymer is ≥95%, the shape recovery rate is ≥95%, and the afterglow time under 365nm ultraviolet light excitation is 7 to 11 seconds.

5. A cardanol-based room temperature phosphorescent shape memory polymer prepared by the method according to any one of claims 1 to 4, characterized in that: The polymer has a three-dimensional network structure cross-linked by dynamic N-coordinated borate bonds, and after being immersed in an acid, alkali or water environment for 4 weeks, the afterglow time is still greater than or equal to 7 seconds.

6. Use of the cardanol-based room temperature phosphorescent shape memory polymer according to claim 5 in preparing room temperature phosphorescent materials, characterized in that: The material exhibits long-life phosphorescence under ultraviolet light excitation, and the phosphorescence lifetime can be regulated by adjusting the structure of the nitrogen-containing borate polyamine and the molar ratio to the epoxy compound.

7. The use of the cardanol-based room temperature phosphorescent shape memory polymer in anti-counterfeiting materials according to claim 5, characterized in that: The anti-counterfeiting material displays a dynamic coding pattern through ultraviolet light excitation, and the visibility of the pattern changes dynamically with the difference in phosphorescence lifetime.

8. The use according to claim 7, characterized in that: The anti-counterfeiting material realizes a shape memory function in response to external stimulation, wherein the external stimulation includes a temperature of 40 to 100° C., ultraviolet light or infrared light, and the shape recovery time is 5 seconds to 2.5 minutes.

9. The use according to claim 7, characterized in that: The anti-counterfeiting material achieves folding and unfolding through thermal response or light response, and forms a dual anti-counterfeiting mechanism in combination with phosphorescent properties, wherein the pattern is unrecognizable in the folded state and clearly recognizable in the unfolded state.

10. An anti-counterfeiting material according to any one of claims 7 to 9, characterized in that: The material realizes a dynamic encryption function by blending cardanol-based room temperature phosphorescent shape memory polymers with different phosphorescence lifetimes, and displays encrypted information that changes with time after the ultraviolet light is turned off.

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