A bio-based non-isocyanate polyurethane binder having a cluster light emitting property and a method of preparing the same

Abstract

The application belongs to the technical field of high polymer materials, and discloses a bio-based non-isocyanate polyurethane binder with cluster light-emitting properties and a preparation method thereof. The preparation method comprises the following steps: S1, CO2 is inserted into epoxy linseed oil, a catalyst is added for reaction, and ring carbonated linseed oil is obtained; S2, the ring carbonated linseed oil is mixed and dissolved in a solvent, a catalyst is added for reaction, and heating and curing are performed to obtain the bio-based non-isocyanate polyurethane binder. The curing agent is one of hyperbranched polyethylene imine, polyamide-amine, polypropylene imine and polylysine, and is mixed with Priamine 1074. The hyperbranched polyamine in the curing agent can construct a bio-based NIPU with a supramolecular crosslinking structure, so that the obtained bio-based NIPU polymer material has excellent mechanical properties, thermal stability, chemical resistance and diverse light-emitting properties. The preparation process is simple, the problem of toxicity and environmental pollution commonly existing in isocyanate polyurethane is solved, the obtained bio-based NIPU has excellent performance, can be applied to coatings, inks and the like, and the application field is widened.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high polymer materials, and particularly relates to a bio-based non-isocyanate polyurethane binder with cluster luminescence properties and a preparation method thereof. BACKGROUND

[0002] Ink is a viscous colloidal fluid formed by uniformly mixing binders (resins), pigments, fillers, additives and solvents and repeatedly rolling. As an important material for printing, it is used in books, packaging decoration, building decoration and electronic circuit board materials, etc. This material presents patterns, characters on the printing material through printing or drawing. With the increase of social demand, the variety and output of ink have also expanded and increased. Among them, fluorescent ink is an important type of ink. Fluorescent ink is usually prepared by grinding fluorescent pigments with high molecular resin binders, solvents and additives. Fluorescent pigments can absorb energy and excite photons under ultraviolet light, and release energy in the form of low visible light, thereby producing different color fluorescent phenomena. However, these fluorescent pigments are mainly inorganic materials and have relatively coarse particles, and have poor compatibility with binders. The preparation of fluorescent pigments from inorganic pigments requires strict requirements in printing, which requires that the fluorescent ink has sufficient concentration when used, and thick coating on the printed matter, so as to ensure satisfactory fluorescent effect. This undoubtedly increases the cost and use range of ink.

[0003] In order to solve the use dilemma of fluorescent pigments in ink, many researchers have taken a different approach to design new fluorescent ink binders to reduce the dependence of ink on fluorescent pigments. Polyurethane has excellent stability, chemical resistance, adhesion and resilience, and is widely used as an ink binder. However, traditional polyurethane materials not only depend on petrochemical resources, causing a growing resource crisis, but also have the problems of low mechanical strength, low fluorescent intensity and single fluorescent color, which are difficult to meet the actual needs in the application of ink. SUMMARY

[0004] In view of the above problems existing in the prior art, the inventors propose to develop a bio-based non-isocyanate polyurethane ink binder with cluster luminescence properties using renewable plant oil. By converting epoxy vegetable oil into cyclic carbonate vegetable oil and using bio-based diamine Priamine 1074 and hyperbranched structure polyamine as a curing agent, a bio-based non-isocyanate polyurethane is synthesized through a simple preparation process. The hyperbranched structure polyamine is beneficial to the formation of a dense supramolecular network of polyurethane, which can absorb energy and excite photons under light stimulation and generate fluorescence by releasing energy. The ratio of hyperbranched structure polyamine to Priamine 1074 can regulate the supramolecular network structure of polyurethane and thus regulate the color of fluorescence. In addition, the polyhydroxy structure and flexible Priamine 1074 inside the polyurethane can provide cohesive energy for the polyurethane, thereby endowing the polyurethane binder with excellent mechanical properties and thermal stability, so as to meet the requirements of ink on the mechanical properties, thermal stability and fluorescence diversity of the binder in actual use.

[0005] The primary object of the present application is to provide a preparation method of a bio-based non-isocyanate polyurethane binder with cluster luminescence properties. Epoxy linseed oil (ELSO) is used as a raw material to prepare cyclic carbonate linseed oil (CLSO) with high conversion rate by coupling reaction with CO2. Then, NIPU is obtained by addition polymerization reaction of CLSO with a curing agent monomer. The prepared NIPU polymer material exhibits excellent chemical resistance, thermal stability and mechanical properties, and also has diverse luminescence properties, which makes it promising to be applied in the fields of coatings and inks.

[0006] To achieve the above object, the present application provides the following technical scheme:

[0007] A preparation method of a bio-based non-isocyanate polyurethane binder with cluster luminescence properties, comprising the following steps:

[0008] S1 inserting CO2 into epoxy linseed oil (ELSO) and reacting under the condition of adding a catalyst to obtain cyclic carbonate linseed oil;

[0009] S2 mixing and dissolving the cyclic carbonate linseed oil prepared in step S1 with a curing agent in a solvent, then adding a catalyst, stirring and heating to cure;

[0010] The curing agent is one of hyperbranched polyethyleneimine (PEI) (Formula 1), polyamide-amine (PAMAM) (Formula 2), polypropyleneimine (PPI) (Formula 3) and polylysine (PLL) (Formula 4) mixed with Priamine 1074.

[0011]

[0012]

[0013] Preferably, the catalyst in step S1 is tetrabutylammonium bromide (TBAB) or tetrabutylammonium iodide, and the amount is 2wt.%-8wt.% of epoxidized linseed oil.

[0014] Preferably, the amount of CO2 introduced in step S1 makes the pressure of the reaction system reach 2MPa-7MPa.

[0015] Preferably, the reaction temperature in step S1 is 100℃-150℃, and the reaction time is 6h-24h.

[0016] Preferably, the catalyst in step S2 is one of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,8-diazabicycloundec-7-ene (DBU), and 4-dimethylaminopyridine (DMAP), and the amount is 1wt.%-6wt.% of cyclic carbonate linseed oil.

[0017] Preferably, the molar ratio of cyclic carbonate linseed oil to curing agent in step S2 is 1:1, and the molar ratio of one of hyperbranched polyethyleneimine (PEI), polyamidoamine (PAMAM), polypropyleneimine (PPI), and polylysine (PLL) to Priamine 1074 in the curing agent is 0.25:0.75-0.75:0.25.

[0018] The present application can obtain a bio-based non-isocyanate polyurethane adhesive with excellent mechanical properties, thermal stability, chemical resistance, and diverse luminescent properties by controlling the molar ratio of the two amines in the curing agent.

[0019] Preferably, the dissolving solvent in step S2 is butanone or tetrahydrofuran, the reaction temperature is 60℃-100℃, and the reaction time is 1h-10h.

[0020] Preferably, the heating and curing conditions in step S2 are a temperature of 100℃-140℃ and a curing time of 6h-24h.

[0021] Another object of the present application is to provide a bio-based non-isocyanate polyurethane adhesive with luminescent properties obtained by the above preparation method.

[0022] Compared with the prior art, the present application has the following advantages:

[0023] (1) The present application replaces the synthesis of polyurethane with highly toxic isocyanate by the addition reaction of cyclic carbonate and curing agent to generate non-isocyanate polyurethane.

[0024] (2) The present application uses vegetable oil as raw material, replaces petroleum-based cyclic carbonates by cyclizing the epoxy groups on the branched chain, and then uses one of hyperbranched polyethyleneimine (PEI), polyamide-amine (PAMAM), polypropyleneimine (PPI) and polylysine (PLL) and Priamine 1074 mixed with a curing agent to synthesize bio-based non-isocyanate polyurethane through a simple preparation process, which improves the environmental pollution of petroleum-based materials, and the material has excellent mechanical properties, chemical resistance and thermal stability, which can meet the application requirements of coatings and inks.

[0025] (3) The present application prepares bio-based non-isocyanate polyurethane with cluster light-emitting performance by controlling the molar ratio of the two amines in the curing agent, and according to the different contents of the two amines in the curing agent, non-isocyanate polyurethane emitting blue light, green light, yellow light and red light can be obtained, which expands the application in the fields of coatings and inks. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The present application is a schematic diagram of the synthesis route (taking Example 1 as an example).

[0027] Figure 2 The present application is a CLSO prepared in the examples and comparative examples of the present application. 1 HNMR spectrum (a), GPC (b), FTIR spectrum (c).

[0028] Figure 3 The present application is an FTIR spectrum prepared in the examples and comparative examples of the present application.

[0029] Figure 4 The present application is a TGA of the bio-based NIPU film prepared in the examples and comparative examples of the present application.

[0030] Figure 5 The present application is a solvent resistance statistical chart and specific data of the bio-based NIPU polymer network prepared in the examples and comparative examples of the present application.

[0031] Figure 6 The present application is a cluster light-emitting intuitive diagram and fluorescence excitation emission spectrum of the bio-based NIPU film of the examples and comparative examples of the present application. DETAILED DESCRIPTION

[0032] The technical solutions of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0033] The experimental methods used in the following examples are conventional methods unless otherwise specified; the materials, reagents, etc. used are commercially available reagents and materials unless otherwise specified.

[0034] Example 1

[0035] A bio-based non-isocyanate polyurethane binder with cluster light emitting properties is prepared by the following method:

[0036] S1. ELSO (50 g) and catalyst TBAB (2.5 g, 5 wt.% ELSO) were charged into an autoclave equipped with a mechanical stirrer, and carbon dioxide was introduced to reach a pressure of 5 MPa. The reaction was carried out at 120 °C and the reaction time was controlled for 12 h to obtain a functionalized linseed oil with cyclic carbonate functionality;

[0037] S2. The cyclic carbonate linseed oil (CLSO) prepared in step S1 was mixed with a curing agent in a molar ratio of 1:1 in butanone with the addition of a DBU catalyst (3 wt.% CLSO) and the molar ratio of hyperbranched polyethyleneimine (PEI) and Priamine 1074 in the curing agent was 0.25:0.75, then the mixture was stirred at 78 °C for 2 h and poured into a glass dish, followed by placing it in an oven at 105 °C for 20 h, and the sample was recorded as NIPU-PEI 0.25 .

[0038] Example 2

[0039] A bio-based non-isocyanate polyurethane binder with cluster light emitting properties is prepared by the following method:

[0040] S1. ELSO (50 g) and catalyst TBAB (2.5 g, 5 wt.% ELSO) were charged into an autoclave equipped with a mechanical stirrer, and carbon dioxide was introduced to reach a pressure of 5 MPa. The reaction was carried out at 120 °C and the reaction time was controlled for 12 h to obtain a functionalized linseed oil with cyclic carbonate functionality;

[0041] S2. The cyclic carbonate linseed oil (CLSO) prepared in step S1 was mixed with a curing agent in a molar ratio of 1:1 in butanone with the addition of a DBU catalyst (3 wt.% CLSO) and the molar ratio of hyperbranched polyethyleneimine (PEI) and Priamine 1074 in the curing agent was 0.25:0.75, then the mixture was stirred at 78 °C for 2 h and poured into a glass dish, followed by placing it in an oven at 105 °C for 20 h, and the sample was recorded as NIPU-PEI 0.5 .

[0042] Example 3

[0043] A bio-based non-isocyanate polyurethane binder with cluster light emitting properties is obtained by the following method:

[0044] S1. ELSO (50 g) and catalyst TBAB (2.5 g, 5 wt.% ELSO) were charged into an autoclave equipped with a mechanical stirrer, carbon dioxide was introduced to reach a pressure of 5 MPa. The reaction was carried out at 120 °C and the reaction time was controlled for 12 h to obtain a functionalized linseed oil with cyclic carbonate functionality;

[0045] S2. The cyclic carbonate linseed oil (CLSO) prepared in step S1 was mixed with a curing agent in a molar ratio of 1 : 1 in butanone with the addition of a DBU catalyst (used in an amount of 3 wt.% CLSO), the molar ratio of hyperbranched polyethyleneimine (PEI) and Priamine 1074 in the curing agent was 0.75:0.25, then the mixture was stirred at 78 °C for 2 h and poured into a glass dish, followed by placing it in an oven at 105 °C for 20 h, the sample was recorded as NIPU-PEI 0.75 .

[0046] Example 4

[0047] A bio-based non-isocyanate polyurethane binder with cluster light emitting properties is obtained by the following method:

[0048] S1. ELSO (50 g) and catalyst TBAB (2.5 g, 5 wt.% ELSO) were charged into an autoclave equipped with a mechanical stirrer, carbon dioxide was introduced to reach a pressure of 5 MPa. The reaction was carried out at 120 °C and the reaction time was controlled for 12 h to obtain a functionalized linseed oil with cyclic carbonate functionality;

[0049] S2. The cyclic carbonate linseed oil (CLSO) prepared in step S1 was mixed with a curing agent in a molar ratio of 1 : 1 in butanone with the addition of a DBU catalyst (used in an amount of 3 wt.% CLSO), the molar ratio of hyperbranched polyethyleneimine (PEI) and Priamine 1074 in the curing agent was 0.75:0.25, then the mixture was stirred at 78 °C for 2 h and poured into a glass dish, followed by placing it in an oven at 105 °C for 20 h, the sample was recorded as NIPU-PEI 0.25 .

[0050] Example 5

[0051] A bio-based non-isocyanate polyurethane binder with cluster light emitting properties is obtained by the following method:

[0052] S1. ELSO (50 g) and catalyst TBAB (2.5 g, 5 wt.% ELSO) were charged into an autoclave equipped with a mechanical stirrer, carbon dioxide was introduced to reach a pressure of 5 MPa. The reaction was carried out at 120 °C and the reaction time was controlled for 12 h to obtain functionalized linseed oil with cyclic carbonate functionality;

[0053] S2. The cyclic carbonate linseed oil (CLSO) prepared in step S1 was mixed with a curing agent in a molar ratio of 1 : 1 in butanone with the addition of DBU catalyst (used in an amount of 3 wt.% CLSO), the molar ratio of polypropylene imine (PPI) and Priamine 1074 in the curing agent was 0.25:0.75, then the mixture was stirred at 78 °C for 2 h and poured into a glass dish, followed by placing in an oven at 105 °C for curing for 20 h, the sample was recorded as NIPU-PPI 0.25 .

[0054] Example 6

[0055] A bio-based non-isocyanate polyurethane binder with cluster light-emitting properties was prepared by the following method:

[0056] S1. ELSO (50 g) and catalyst TBAB (2.5 g, 5 wt.% ELSO) were charged into an autoclave equipped with a mechanical stirrer, carbon dioxide was introduced to reach a pressure of 5 MPa. The reaction was carried out at 120 °C and the reaction time was controlled for 12 h to obtain functionalized linseed oil with cyclic carbonate functionality;

[0057] S2. The cyclic carbonate linseed oil (CLSO) prepared in step S1 was mixed with a curing agent in a molar ratio of 1 : 1 in butanone with the addition of DBU catalyst (used in an amount of 3 wt.% CLSO), the molar ratio of polypropylene imine (PPI) and Priamine 1074 in the curing agent was 0.25:0.75, then the mixture was stirred at 78 °C for 2 h and poured into a glass dish, followed by placing in an oven at 105 °C for curing for 20 h, the sample was recorded as NIPU-PPI 0.25 .

[0058] Comparative Example 1

[0059] A bio-based non-isocyanate polyurethane binder with cluster light-emitting properties was prepared by the following method:

[0060] S1. ELSO (50 g) and catalyst TBAB (2.5 g, 5 wt.% ELSO) were charged into an autoclave equipped with a mechanical stirrer, carbon dioxide was introduced to reach a pressure of 5 MPa. The reaction was carried out at 120 °C and the reaction time was controlled for 12 h to obtain functionalized linseed oil with cyclic carbonate functionality;

[0061] S2. With the addition of DBU catalyst (3 wt.% CLSO), the cyclic carbonate linseed oil (CLSO) prepared in step S1 was mixed with a curing agent at a molar ratio of 1:1 and dissolved in methyl ethyl ketone. The curing agent contained only Priamine 1074. The mixture was then stirred at 78°C for 2 hours and poured into a glass dish. Subsequently, it was placed in an oven and cured at 105°C for 20 hours. The sample was named NIPU-Priamine 10741.

[0062] Comparative Example 2

[0063] A bio-based non-isocyanate polyurethane binder with cluster luminescence properties is prepared by the following method:

[0064] S1.ELSO (50g) and catalyst TBAB (2.5g, 5wt.%ELSO) were loaded into a high-pressure reactor equipped with a mechanical stirrer, and carbon dioxide was introduced to bring the pressure to 5MPa. The reaction was carried out at 120°C and the reaction time was controlled at 12h to obtain functional linseed oil with cyclic carbonate functionality.

[0065] S2. With the addition of DBU catalyst (3 wt.% CLSO), the cyclic carbonate linseed oil (CLSO) prepared in step S1 was mixed with the curing agent in a molar ratio of 1:1 and dissolved in methyl ethyl ketone. The curing agent contained only hyperbranched polyethyleneimine (PEI). The mixture was stirred at 78°C for 2 hours and then poured into a glass dish. Subsequently, it was placed in an oven and cured at 105°C for 20 hours. The sample was named NIPU-PEI1.

[0066] To further illustrate the successful synthesis and excellent effects of the preparation method in this application, the obtained materials were characterized and tested.

[0067] The testing method is as follows:

[0068] (1) Chemical structure testing:

[0069] 1 H nuclear magnetic resonance (H nuclear magnetic resonance) 1 The 1H NMR analysis was performed on a Bruker AV 600M spectrometer (Germany) with deuterated chloroform as solvent and tetramethylsilane as internal standard. 1 HNMR was used to determine the structural characteristics of ELSO and CLSO, and to calculate the functionality of the synthesized CLSO.

[0070] The chemical structure of the NIPU thin films was characterized using a Nicolet IS10 FTIR spectrometer (Thermo Fisher, USA). Attenuated total reflectance analysis was performed using a Thermo Nicolet Nexus 670 to record the chemical structure of the NIPU thin films, with a scan range of 4000 to 400 cm⁻¹. -1 The number of scans was 32.

[0071] (2) Mechanical property testing:

[0072] The test was conducted at room temperature using an MTS universal testing machine at a tensile rate of 100 mm / min. Both the experimental and comparative samples were tested in parallel three times. After the experimental sample cured into a dry film at room temperature, the film was cut into strips 3 cm long and 1 cm wide.

[0073] (3) Test method for TGA curve:

[0074] Thermogravimetric analysis (TGA) was performed using a NETZSCH-STA 449C thermal analyzer. A 5 mg sample was placed in an aluminum crucible and heated at 10 °C for [time missing] min under a nitrogen atmosphere. -1 The heating rate was tested from 30℃ to 700℃.

[0075] (4) Chemical resistance test

[0076] The dried sample (approximately 50 mg, M1) was placed in a 100 ml amber glass bottle and soaked in acid, alkali, and ethanol solvents at room temperature for 6 days. After drying in a vacuum oven at 60°C for 48 hours, it was weighed (M2).

[0077]

[0078] (5) Fluorescence performance analysis

[0079] Fluorescence measurements were performed on an F-7000 spectrometer (Hitachi, Japan) with a built-in 150W xenon lamp. The scan rate was 1200 nm-min. -1 Fluorescence testing was used to characterize the cluster emission properties of NIPU films.

[0080] Results Analysis

[0081] 1. Chemical structure analysis

[0082] The characterization results of the CLSO prepared in the comparative examples and embodiments of the present invention are as follows: Figure 2 As shown. Under TBAB catalysis, the cycloaddition reaction of CO2 and ELSO yielded an orange-brown viscous liquid. The chemical structures of ELSO and CLSO were characterized by FTIR, GPC, and 1H NMR. Figure 2The 1H NMR results shown in a confirmed the conversion of ELSO to CLSO. Specifically, after conversion, the peak corresponding to the ELSO epoxide group at 2.85-3.28 ppm disappeared, while the signal corresponding to the CLSO cyclic carbonate group at 4.45-5.10 ppm appeared, indicating that the epoxide group of ELSO was completely consumed to form CLSO. Figure 2 The GPC in b measured the molecular weight distribution of ELSO and CLSO. First, the CLSO peak time was 18.22 min and was a single peak, and its corresponding peak value was lower than that of ELSO at 18.70 min, indicating that the molecular weight increased after conversion. As shown in Figure 2 The FTIR spectrum in c showed that the infrared peak representing the epoxide group (824 cm -1 ) weakened and disappeared, while the new carbonyl peak (1795 cm -1 ) and the new C-O peak (1047 cm -1 ) in the cyclic carbonate group gradually increased. The above results confirmed the successful conversion of ELSO to CLSO.

[0083] To further study the conversion efficiency of the epoxide group in ELSO to the cyclic carbonate group in CLSO, the normalized integral area of the epoxide group in ELSO and the cyclic carbonate group in CLSO was calculated with the 5.2-5.3 ppm signal corresponding to the -CH- in triglyceride (a) as a reference. Figure 2 According to formula (1), the number of epoxide groups (Em) was calculated from the b signal of the epoxide ring (2.85-3.28 ppm). Similarly, according to formula (2), the number of cyclic carbonate groups (Cm) was calculated from the relevant c signal (4.45-5.10 ppm). Emi represents the initial number of epoxide groups (i.e., the number of epoxide groups not involved in the reaction), and Emf represents the final number of epoxide groups (i.e., the number of epoxide groups remaining at the end of the reaction). Finally, according to formulas (3)-(5), the conversion rate (%C), carbonation rate or yield (%Y), and selectivity (%S) were calculated.

[0084]

[0085]

[0086]

[0087]

[0088]

[0089] Conversion results of ELSO to CLSO: conversion rate %C = 97.25%, selectivity %S = 77.38%, and yield %Y = 75.25%.

[0090] like Figure 3 As shown, in the infrared spectra of the comparative examples and NIPU of the present invention, the ester carbonyl group of CLSO cyclic carbonate is at 1795 cm⁻¹. -1 The absorption peak disappears at 3200-3500 cm⁻¹, and the NH stretching vibration of polyurethane bonds and the OH stretching vibration of derived hydroxyl groups in the polymer system are at 3200-3500 cm⁻¹. -1 A broad absorption peak appeared at 1700-1730 cm⁻¹, indicating that the C=O stretching vibration of the generated polyurethane bond occurred at 1700-1730 cm⁻¹. -1 Typical absorption peaks appeared at [location missing]. These indicate that the bio-based NIPU thin film has been successfully prepared.

[0091] 2. Mechanical properties

[0092] The mechanical properties of the bio-based NIPUs prepared in the comparative examples and embodiments of this invention are shown in Table 1. Because only Priamine 1074 was used as a curing agent in Comparative Example 1, the resulting Comparative Example 1 NIPU-Priamine 10741 had low structural density and weak mechanical properties, with a tensile strength of 1.2 MPa and an elongation at break of 153.49%. In contrast, the use of polyethyleneimine as a single curing agent in Comparative Example 2 resulted in an excessively rigid structure in Comparative Example 2 NIPU-PEI1, leading to brittleness (elongation at break of only 8.31%). Compared to Comparative Examples 1 and 2, Examples 1-6, which utilized a mixture of hyperbranched polyethyleneimine (PEI), polyamide-amine (PAMAM), polypropyleneimine (PPI), polylysine (PLL), and Priamine 1074 to regulate NIPU properties, exhibited not only excellent tensile strength but also excellent toughness. This is attributed to the hyperbranched rigid structure provided by the hyperbranched polyamines to achieve high strength in the polyurethane binder, and the flexibility of Priamine 1074 to impart flexibility to the material to achieve toughness in the polyurethane binder, wherein Example 3 NIPU-PEI 0.75 It has the highest tensile strength of 47.8 MPa and maintains an elongation at break of 49.55%.

[0093] Table 1. Test results of mechanical properties of bio-based NIPU films

[0094]

[0095]

[0096] 3. Thermal stability

[0097] The thermal stability of the fully bio-based NIPU films prepared in the comparative and example studies was evaluated by TGA under nitrogen atmosphere. All samples exhibited similar degradation behavior with increasing temperature. Figure 4The initial decomposition temperature of Comparative Example 1 NIPU-Priamine 1074, which was prepared from Priamine 1074, was 200 °C (corresponding to the temperature at which 5% weight loss occurred, T5%), which was attributed to the fact that the NIPU prepared from Priamine 1074, which has a low-density structure due to the flexible chain structure, was easily decomposed into small molecular fragments during heating. The initial decomposition temperature of Comparative Example 2 NIPU-PEI 1, which was prepared by using polyethyleneimine (PEI) alone as the curing agent, was 220 °C, which was attributed to the fact that the material had defects that were prone to pyrolysis before the molecular chain due to the stress concentration caused by the rigid structure of the hyperbranched structure. The initial decomposition temperatures of Examples 1-6, which were prepared by mixing hyperbranched polyethyleneimine (PEI), polyamide-amine (PAMAM), polypropyleneimine (PPI), and polylysine (PLL) with Priamine 1074, were all > 250 °C. This was attributed to the fact that the Examples prepared by mixing hyperbranched polyethyleneimine (PEI), polyamide-amine (PAMAM), polypropyleneimine (PPI), and polylysine (PLL) with Priamine 1074 had a defect-free hyperbranched structure due to the synergistic effect of the hyperbranched structure of the polyamine and the flexible Priamine 1074, which ensured the density of the material and reduced the internal defects of the material, thereby improving the thermal stability.

[0098] 4. Chemical resistance

[0099] The chemical resistance of the comparative examples and the examples of the present application was evaluated in an aqueous hydrochloric acid solution, an aqueous sodium hydroxide solution, and an ethanol solvent, as shown in Table 2. Figure 5 Compared to Comparative Example 1, which had a loose structure, and Comparative Example 2, which had internal defects, the biobased NIPU of Examples 1-6 had good acid resistance, alkali resistance, and solvent resistance, and the mass percentage of the samples of Examples 1-6 after testing was still about 90%, while the mass percentage of the samples of Comparative Examples 1 and 2 after testing was only 70%. In addition, the chemical resistance was enhanced as the content and degree of branching of the hyperbranched curing agent increased and the internal defects of the material decreased (the mass percentage of the samples of Examples 2-6 after testing was > 95%). This was attributed to the fact that the defect-free hyperbranched dense structure of the NIPU prepared by mixing hyperbranched polyethyleneimine (PEI), polyamide-amine (PAMAM), polypropyleneimine (PPI), and polylysine (PLL) with Priamine 1074 made it difficult for the material to be eroded by chemicals.

[0100] 5. Photoluminescence performance

[0101] As shown in Table 3, the photoluminescence performance of the comparative examples and the examples of the present application was evaluated in an aqueous hydrochloric acid solution, an aqueous sodium hydroxide solution, and an ethanol solvent. Figure 6As shown, the bio-based NIPU films prepared in the embodiments of the present application exhibit significant luminescence behavior under different excitation wavelengths. In addition, Examples 1-3 can emit green light, yellow light and red light under excitation wavelengths due to different contents of hyperbranched PEI, which is because the higher the content of PEI, the more compact the structure of the prepared NIPU, which increases the degree of light-emitting cluster aggregation, limits the molecular rotation, reduces the energy consumed by the excited state molecules due to molecular rotation, thereby facilitating the excited state molecules to release energy in the form of luminescence and emit light of different wavelengths (see Figure 6 fluorescence emission spectrum). Examples 4-6 can emit deep blue to light blue light due to the addition of polyamide-amine (PAMAM), polypropylene imine (PPI) and polylysine (PLL) with different degrees of branching, which is because the different branching structures result in different degrees of spatial interaction and spatial delocalization overlap of electron clouds in the material, and then n→π* transition occurs under ultraviolet excitation to exhibit blue fluorescence. Comparative Example 1 does not exhibit fluorescence under ultraviolet light, which is because the low density of the NIPU structure constructed by Priamine 1074 makes it difficult to achieve spatial interaction and spatial delocalization overlap of electron clouds in the material, so that the excited electron transition cannot occur to exhibit luminescence behavior. Comparative Example 2 also does not exhibit fluorescence under ultraviolet light, which is because the spatial interaction and spatial delocalization overlap of electron clouds in the material are too strong due to the presence of defective hyperbranched polymers, resulting in fluorescence quenching and thus no luminescence.

[0102] The above embodiments of the present application are merely examples for clearly illustrating the technical solutions of the present application, and are not all the specific implementations of the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a bio-based non-isocyanate polyurethane binder with cluster luminescence properties, characterized in that, Includes the following steps: S1 inserts CO2 into epoxidized linseed oil, adds a catalyst to react, and obtains cyclic carbonate linseed oil; S2 involves mixing and dissolving the cyclic carbonate linseed oil prepared in step S1 with the curing agent in a solvent, then adding the catalyst, stirring the reaction, and heating to cure the mixture. The curing agent is one of hyperbranched polyethyleneimine, polyamide-amine, polypropyleneimine, and polylysine, mixed with Priamine 1074. In step S2, the molar ratio of cyclic carbonate linseed oil to curing agent is 1:1, and the molar ratio of one of the hyperbranched polyethyleneimine, polyamide-amine, polypropyleneimine, and polylysine in the curing agent to Priamine 1074 is 0.25:0.75~0.75:0.

25.

2. The preparation method according to claim 1, characterized in that, The catalyst in step S1 is tetrabutylammonium bromide or tetrabutylammonium iodide, and the amount used is 2 wt.% ~ 8 wt.% epoxidized linseed oil.

3. The preparation method according to claim 1, characterized in that, The amount of CO2 introduced in step S1 is such that the pressure of the reaction system reaches 2 MPa ~ 7 MPa.

4. The preparation method according to claim 1, characterized in that, The reaction temperature in step S1 is 100℃~150℃, and the reaction time is 6 h~24 h.

5. The preparation method according to claim 1, characterized in that, The catalyst in step S2 is one of 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1,8-diazabicycloundec-7-ene, and 4-dimethylaminopyridine, and is used in an amount of 1 wt.% to 6 wt.% cyclic carbonate linseed oil.

6. The preparation method according to claim 1, characterized in that, The solvent in step S2 is methyl ethyl ketone or tetrahydrofuran, the reaction temperature is 60℃ ~ 100℃, and the reaction time is 1 h ~ 10 h.

7. The preparation method according to claim 1, characterized in that, The heating and curing conditions described in step S2 are a temperature of 100℃ ~ 140℃ and a curing time of 6 h ~ 24 h.

8. A bio-based non-isocyanate polyurethane binder with cluster luminescence properties prepared by the method according to any one of claims 1-7.

9. The application of the bio-based non-isocyanate polyurethane binder with cluster luminescence properties as described in claim 8 in the preparation of coatings and ink materials.

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