Preparation method of functional hydroxyl-terminated polybutadiene-based polyurethane elastomer with fluorescence response

Abstract

The invention discloses a preparation method of a functional hydroxyl-terminated polybutadiene polyurethane elastomer with fluorescence response, and relates to a preparation method of functional hydroxyl-terminated polybutadiene. In order to establish a visual graphical corresponding relation between a microscopic size and an atomic scale molecular position, a molecular material with fluorescence performance is designed and constructed by adopting a nondestructive and non-contact measurement mode of a fluorescence labeling method; the 1-naphthylamine modified hydroxyl-terminated polybutadiene is prepared by adding the 1-naphthylamine into the hydroxyl-terminated polybutadiene, and the branched chain modification of a branched chain 1, 4 butadiene molecular chain in the hydroxyl-terminated polybutadiene is realized, so that the hydroxyl-terminated polybutadiene has fluorescence performance; the fluorescent polyurethane elastomer is synthesized by taking the functional hydroxyl-terminated polybutadiene as a soft segment, so that the soft segment fluorescent modification of the polyurethane elastomer is realized; and a specific case is provided for exploring a microcrack generation mechanism of the polyurethane elastomer under the action of external stress. The functional hydroxyl-terminated polybutadiene-based polyurethane elastomer with fluorescence response can be obtained by the preparation method disclosed by the invention.

Description

Technical Field

[0001] The invention relates to a method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer. Background Art

[0002] The generation of microcracks is one of the important factors affecting the life of hydroxyl-terminated polybutadiene (HTPB)-based polyurethane elastomers, but the generation and evolution mechanism of microcracks has not yet been clarified. The service life of elastomers is usually evaluated by mechanical properties. Microcracks have a direct impact on its mechanical properties, but its impact is a nonlinear process, which manifests as the initial generation and accumulation of microcracks, and has no significant effect on its mechanical properties; based on a certain critical point, its mechanical properties suddenly change, which manifests as the fracture of the elastomer. Therefore, it is difficult to establish a direct correspondence between the generation and evolution of microcracks and the changes in its mechanical properties.

[0003] Hydroxyl-terminated polybutadiene (HTPB)-based polyurethane elastomer is a polymer composed of HTPB as a soft segment and isocyanate and small molecule diol as hard segment blocks. In the polyurethane system, since the oligomer polyol molecular chain is relatively long and flexible, it is called a flexible segment or soft segment; the molecular chain composed of isocyanate and small molecule diol is relatively short and relatively rigid, so it is called a rigid segment or hard segment. Therefore, it is believed that the molecular chain of polyurethane is composed of soft segments and hard segments. However, the division of soft and hard segments is a convention in the industry, and there is no clear and specific division boundary, so it is not clear whether the microcracks of the elastomer are generated in the hard segment or the soft segment. The existing test methods are difficult to distinguish the location of the defect microcracks in the elastomer, and establish a direct correspondence with the molecular formula of the chemical reagents used in the casting process of the elastomer. Therefore, it is necessary to establish a direct molecular position tracer through molecular labeling, so as to form a visual graphical correspondence between microscopic dimensions (such as defect cracks) and atomic-scale molecular positions. Fluorescence labeling is a commonly used experimental technique that can be applied to the study of microcrack derivation processes in the field of materials science. Therefore, exploring HTPB modification methods and giving it fluorescent properties will greatly enrich the application range of HTPB-based polyurethane elastomers. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the existing testing methods are difficult to distinguish the locations of defect microcracks in terminal hydroxyl polybutadiene-based polyurethane elastomers, and it is impossible to establish direct molecular position tracing through molecular labeling to form a visual graphical correspondence between microscopic sizes, such as defect cracks, and atomic-scale molecular positions, and to provide a method for preparing a functionalized terminal hydroxyl polybutadiene-based polyurethane elastomer with fluorescent response.

[0005] In order to establish a visual graphical correspondence between microscopic dimensions and atomic-scale molecular positions, the present invention adopts a non-destructive, non-contact measurement method such as fluorescence labeling to design and construct a molecular material with fluorescence properties; that is, 1-naphthylamine-modified terminal hydroxyl polybutadiene (N-HTPB) is prepared, and the branched modification of the branched-1,4-butadiene molecular chain in the terminal hydroxyl polybutadiene is achieved, so that it has fluorescence properties; and a fluorescent polyurethane elastomer is synthesized using N-HTPB as the soft segment, and the soft segment fluorescence modification of the polyurethane elastomer is achieved; a specific case is provided for exploring the mechanism of microcrack generation in polyurethane elastomers when subjected to external stress.

[0006] A method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response is specifically completed by the following steps:

[0007] 1. Preparation of functionalized hydroxyl-terminated polybutadiene:

[0008] ①, dissolving the hydroxy-terminated polybutadiene in tetrahydrofuran, then adding concentrated hydrochloric acid under stirring, stirring and reacting for a period of time, then adding sodium carbonate, stirring and reacting for a period of time, to obtain solution A;

[0009] ②, add 1-naphthylamine to solution A, stir and react for a period of time, then add anhydrous magnesium sulfate, let it stand for a period of time, then filter it using a Buchner funnel, discard the precipitate, and collect the clarified filtrate; use a rotary evaporator to remove the solvent from the clarified filtrate at 30°C to 50°C to obtain a precipitate; wash the precipitate, and then put it into a vacuum drying oven for vacuum drying for a period of time to obtain a functionalized hydroxy-terminated polybutadiene;

[0010] 2. Preparation of functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response:

[0011] ①, dissolving the functionalized hydroxy-terminated polybutadiene in tetrahydrofuran, then adding methyl toluene diisocyanate, stirring evenly, adding dibutyltin dilaurate, stirring at room temperature for a period of time, and obtaining a prepolymer;

[0012] ②. Add 1,4-butanediol to the prepolymer, react at room temperature for a period of time, then pour into a mold and place for a period of time to form a film and dry, to obtain a preliminarily dried polyurethane elastomer; place the preliminarily dried polyurethane elastomer in a vacuum oven for further drying to obtain a functionalized terminal hydroxyl polybutadiene-based polyurethane elastomer with fluorescent response.

[0013] Principle of the present invention:

[0014] The present invention synthesizes 1-naphthylamine-modified hydroxy-terminated polybutadiene (N-HTPB) by adopting classical organic substitution and addition reaction to prepare functionalized hydroxy-terminated polybutadiene with fluorescence performance, further uses it as a soft segment to synthesize a polyurethane elastomer with adjustable fluorescence intensity, and constructs a corresponding relationship between the tensile strain of the polyurethane elastomer and the change in fluorescence intensity.

[0015] The remarkable effect that the present invention has compared with the prior art is:

[0016] 1. The functionalized hydroxy-terminated polybutadiene prepared by the present invention can efficiently and accurately control the substitution position of 1-naphthylamine in the hydroxy-terminated polybutadiene; compared with other molecular chain grafting methods, this method has mild reaction conditions, simple process steps, easy reaction control, and the equipment used does not require high energy consumption, and has good economy;

[0017] Second, the functionalized hydroxy-terminated polybutadiene prepared by the present invention has fluorescent properties;

[0018] 3. The functionalized hydroxy-terminated polybutadiene prepared by the present invention endows its corresponding polyurethane elastomer with adjustable fluorescence intensity;

[0019] 4. The present invention explores the changes in fluorescence intensity of soft segment fluorescently modified polyurethane elastomers under different tensile strains. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the infrared spectrum of the functionalized hydroxy-terminated polybutadiene prepared in Example 1;

[0021] Figure 2 This is the fluorescence spectrum of the functionalized hydroxy-terminated polybutadiene prepared in Example 1;

[0022] Figure 3 This is an infrared spectrum of the functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1;

[0023] Figure 4 This is a fluorescence spectrum of the functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1;

[0024] Figure 5 The stress-strain curve of the functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1;

[0025] Figure 6 The relationship curve between the tensile strain and the fluorescence intensity of the functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1;

[0026] Figure 7Schematic diagram of fluorescence of the functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1 under different tensile strains;

[0027] Figure 8 This is a dumbbell-shaped specimen of the functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1. DETAILED DESCRIPTION

[0028] Specific implementation method 1: This implementation method is a method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response, which is specifically completed by the following steps:

[0029] 1. Preparation of functionalized hydroxyl-terminated polybutadiene:

[0030] ①, dissolving the hydroxy-terminated polybutadiene in tetrahydrofuran, then adding concentrated hydrochloric acid under stirring, stirring and reacting for a period of time, then adding sodium carbonate, stirring and reacting for a period of time, to obtain solution A;

[0031] ②, add 1-naphthylamine to solution A, stir and react for a period of time, then add anhydrous magnesium sulfate, let it stand for a period of time, then filter it using a Buchner funnel, discard the precipitate, and collect the clarified filtrate; use a rotary evaporator to remove the solvent from the clarified filtrate at 30°C to 50°C to obtain a precipitate; wash the precipitate, and then put it into a vacuum drying oven for vacuum drying for a period of time to obtain a functionalized hydroxy-terminated polybutadiene;

[0032] 2. Preparation of functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response:

[0033] ①, dissolving the functionalized hydroxy-terminated polybutadiene in tetrahydrofuran, then adding methyl toluene diisocyanate, stirring evenly, adding dibutyltin dilaurate, stirring at room temperature for a period of time, and obtaining a prepolymer;

[0034] ②. Add 1,4-butanediol to the prepolymer, react at room temperature for a period of time, then pour into a mold and place for a period of time to form a film and dry, to obtain a preliminarily dried polyurethane elastomer; place the preliminarily dried polyurethane elastomer in a vacuum oven for further drying to obtain a functionalized terminal hydroxyl polybutadiene-based polyurethane elastomer with fluorescent response.

[0035] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that: the volume ratio of the mass of the hydroxy-terminated polybutadiene described in step 1① to tetrahydrofuran is 10g:(15mL-25mL); the volume ratio of the mass of the hydroxy-terminated polybutadiene described in step 1① to concentrated hydrochloric acid is 10g:(0.21mL-0.24mL). The other steps are the same as those in specific embodiment 1.

[0036] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that: the mass fraction of concentrated hydrochloric acid in step 1① is 37%; the volume ratio of the mass of sodium carbonate to concentrated hydrochloric acid in step 1① is 0.160g:(0.21mL~0.24mL). The other steps are the same as specific implementation method 1 or 2.

[0037] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that: in step 1①, hydroxy-terminated polybutadiene is dissolved in tetrahydrofuran, and then concentrated hydrochloric acid is added under stirring, and stirred for 0.5h to 6h, and then sodium carbonate is added, and stirred for 0.5h to 3h to obtain solution A. The other steps are the same as those of specific embodiments 1 to 3.

[0038] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that: the mass ratio of the terminal hydroxyl polybutadiene described in step 1① to the 1-naphthylamine described in step 1② is 10g:(0.3g-0.4g); the mass ratio of the terminal hydroxyl polybutadiene described in step 1① to the anhydrous magnesium sulfate described in step 1② is 10g:(0.4g-0.6g). The other steps are the same as those of specific embodiments 1 to 4.

[0039] Specific implementation method 6: The difference between this implementation method and specific implementation methods 1 to 5 is that: the stirring reaction time in step 1 ② is 2h to 5h; the standing time in step 1 ② is 0.5h to 12h; the precipitate is washed 3 to 5 times with anhydrous ethanol in step 1 ②; the vacuum drying temperature in step 1 ② is 40℃ to 60℃, and the vacuum drying time is 8h to 12h. The other steps are the same as those in specific implementation methods 1 to 5.

[0040] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that: the methyl toluene diisocyanate described in step 2① is CAS26471-62-5, purchased from Aladdin; the mass ratio of the functionalized hydroxyl-terminated polybutadiene described in step 2① to tetrahydrofuran is 5g:10mL; the mass ratio of the functionalized hydroxyl-terminated polybutadiene described in step 2① to methyl toluene diisocyanate is 5:(1.5-1.6). The other steps are the same as those of specific embodiments 1 to 6.

[0041] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that the mass ratio of the functionalized hydroxy-terminated polybutadiene to dibutyltin dilaurate in step 2① is 1:(0.005-0.02); the stirring time at room temperature in step 2① is 1h-2h. The other steps are the same as those in specific embodiments 1 to 7.

[0042] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that the mass ratio of 1,4-butanediol described in step 2 ② to the functionalized hydroxy-terminated polybutadiene described in step 2 ① is (0.5 g to 0.6 g): 5 g; in step 2 ②, 1,4-butanediol is added to the prepolymer and reacted at room temperature for 0.5 h to 1 h. The other steps are the same as those of specific embodiments 1 to 8.

[0043] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that: in step 2②, the polyurethane elastomer is poured into a mold and placed for 45h to 50h to form a film and dry; in step 2②, the preliminarily dried polyurethane elastomer is placed in a vacuum oven at a temperature of 65℃ to 75℃ and dried for 20h to 25h. The other steps are the same as those of specific embodiments 1 to 9.

[0044] The following examples are used to verify the beneficial effects of the present invention:

[0045] Example 1: A method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response, which is specifically completed by the following steps:

[0046] 1. Preparation of functionalized hydroxyl-terminated polybutadiene:

[0047] ①, dissolve 10g of hydroxy-terminated polybutadiene in 20mL of tetrahydrofuran, then add 0.215mL of 37% hydrochloric acid under stirring, stir and react for 2h, then add 0.160g of sodium carbonate, stir and react for 1h to obtain solution A;

[0048] The hydroxyl value of the hydroxy-terminated polybutadiene described in step 1① is 0.47 to 0.53 mmol / g, and the number average molecular weight (×10 3 ) is 3.80-4.60, purchased from: Tianyuan Aerospace Materials (Yingkou) Technology Co., Ltd.;

[0049] ②, add 0.358g 1-naphthylamine to solution A, stir and react for 3h, then add 0.5g anhydrous magnesium sulfate, let stand for 5h, filter using a Buchner funnel, discard the precipitate, and obtain a clear filtrate; use a rotary evaporator to evaporate the clarified filtrate at 38°C to remove the solvent to obtain a precipitate; wash the precipitate, and then place it in a vacuum drying oven at a temperature of 45°C for vacuum drying for 10h to obtain functionalized hydroxy-terminated polybutadiene (N-HTPB);

[0050] In step 1②, the precipitate is washed 3 times with anhydrous ethanol;

[0051] 2. Preparation of functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response:

[0052] ① Dissolve 5 g of functionalized hydroxy-terminated polybutadiene in 10 mL of tetrahydrofuran, then add 1.573 g of toluene diisocyanate (TDI), stir evenly, then add 0.05 g of dibutyltin dilaurate, react and stir for 1.5 h in anhydrous and room temperature to obtain a prepolymer;

[0053] The methyl toluene diisocyanate described in step 2① is CAS26471-62-5, purchased from Aladdin;

[0054] ②. Add 0.570 g of 1,4-butanediol (BDO) to the prepolymer, react at room temperature for 40 minutes, then pour into a mold and place at room temperature for 48 hours to form a film and dry to obtain a preliminarily dried polyurethane elastomer; place the preliminarily dried polyurethane elastomer in a vacuum oven at 70°C and dry for 24 hours to obtain a functionalized terminal hydroxyl polybutadiene (N-PU) with fluorescent response.

[0055] Example 2: The difference between this example and Example 1 is as follows: Step 2 ①, 5g of functionalized hydroxy-terminated polybutadiene was dissolved in 10mL of tetrahydrofuran, and then 0.949g of toluene diisocyanate (TDI) was added, and after stirring, 0.05g of dibutyltin dilaurate was added, and the mixture was stirred for 1.5h in anhydrous and room temperature to obtain a prepolymer; ②, 0.301g of 1,4-butanediol (BDO) was added to the prepolymer, and the mixture was reacted for 40min at room temperature, and then poured into a mold and placed at room temperature for 48h to form a film and dry, to obtain a preliminarily dried polyurethane elastomer; the preliminarily dried polyurethane elastomer was placed in a vacuum oven at 70°C and dried for 24h to obtain a functionalized hydroxy-terminated polybutadiene (N-PU) with a fluorescent response. The other steps and parameters were the same as those in Example 1.

[0056] Example 3: The difference between this example and Example 1 is as follows: Step 2 ①, 5g of functionalized hydroxy-terminated polybutadiene was dissolved in 10mL of tetrahydrofuran, and then 1.241g of toluene diisocyanate (TDI) was added, and after stirring, 0.05g of dibutyltin dilaurate was added, and the mixture was stirred for 1.5h in anhydrous and room temperature to obtain a prepolymer; ②, 0.426g of 1,4-butanediol (BDO) was added to the prepolymer, and the mixture was reacted for 40min at room temperature, and then poured into a mold and placed at room temperature for 48h to form a film and dry, to obtain a preliminarily dried polyurethane elastomer; the preliminarily dried polyurethane elastomer was placed in a vacuum oven at 70°C and dried for 24h to obtain a functionalized hydroxy-terminated polybutadiene (N-PU) with a fluorescent response. The other steps and parameters were the same as those in Example 1.

[0057] Example 4: The difference between this example and Example 1 is as follows: Step 2 ①, 5g of functionalized hydroxy-terminated polybutadiene was dissolved in 10mL of tetrahydrofuran, and then 1.958g of toluene diisocyanate (TDI) was added, and after stirring evenly, 0.05g of dibutyltin dilaurate was added, and the mixture was stirred for 1.5h at room temperature in anhydrous state to obtain a prepolymer; ②, 0.735g of 1,4-butanediol (BDO) was added to the prepolymer, and the mixture was reacted for 40min at room temperature, and then poured into a mold and placed at room temperature for 48h to form a film and dry, to obtain a preliminarily dried polyurethane elastomer; the preliminarily dried polyurethane elastomer was placed in a vacuum oven at 70°C and dried for 24h to obtain a functionalized hydroxy-terminated polybutadiene (N-PU) with a fluorescent response. The other steps and parameters were the same as those in Example 1.

[0058] Example 5: The difference between this example and Example 1 is as follows: Step 2 ①, 5g of functionalized hydroxy-terminated polybutadiene was dissolved in 10mL of tetrahydrofuran, and then 2.405g of toluene diisocyanate (TDI) was added, and after stirring, 0.05g of dibutyltin dilaurate was added, and the mixture was stirred for 1.5h in anhydrous and room temperature to obtain a prepolymer; ②, 0.928g of 1,4-butanediol (BDO) was added to the prepolymer, and the mixture was reacted for 40min at room temperature, and then poured into a mold and placed at room temperature for 48h to form a film and dry, to obtain a preliminarily dried polyurethane elastomer; the preliminarily dried polyurethane elastomer was placed in a vacuum oven at 70°C and dried for 24h to obtain a functionalized hydroxy-terminated polybutadiene (N-PU) with a fluorescent response. The other steps and parameters were the same as those in Example 1.

[0059] Examples 1 to 5 prepared polyurethane elastomers with different soft segment contents. The amounts of N-HTPB, TDI, and BDO used in Examples 1 to 5 and the mechanical properties of the prepared polyurethane elastomers are listed in Table 1;

[0060] Table 1

[0061]

[0062]

[0063] The functionalized hydroxy-terminated polybutadiene prepared in Example 1 was tested by infrared spectroscopy. The test results are as follows: Figure 1 As shown;

[0064] Figure 1 This is the infrared spectrum of the functionalized hydroxy-terminated polybutadiene prepared in Example 1;

[0065] pass Figure 1 It can be seen that the functionalized hydroxy-terminated polybutadiene prepared in Example 1 has an aromatic ring and a hydroxyl structure: Figure 1 Medium 3300~3600cm-1 The peak at 1490 cm-1 is attributed to the symmetric stretching vibration of the -OH group in the functionalized hydroxyl-terminated polybutadiene. -1 and 2950cm -1 At 725cm -1 It is the characteristic absorption peak of cis-1,4 structure at 910cm -1 For 1,2-vinyl structure, for 968cm -1 It is the characteristic absorption peak of the trans-1,4 structure; in addition, at 1638cm -1 The bending vibration absorption peak of NH appears at 1600-1450cm -1 There are four peaks; CH out-of-plane bending vibration is at 900-690cm -1 There is a peak at , indicating the existence of aromatic rings and the successful grafting of 1-naphthylamine onto the HTPB main chain.

[0066] The functionalized hydroxy-terminated polybutadiene (N-HTPB) prepared in Example 1 was dissolved in tetrahydrofuran for fluorescence spectrum testing. The fluorescence spectrum test results are as follows: Figure 2 As shown;

[0067] Figure 2 This is the fluorescence spectrum of the functionalized hydroxy-terminated polybutadiene prepared in Example 1;

[0068] from Figure 2 In Figure A, we can see that the excitation spectrum has two higher peaks at 375nm and 420nm. By fixing the excitation wavelength at 420nm, we can study its emission spectrum. Figure 2 As shown in B, from Figure 2 It can be seen from Figure B that when the excitation wavelength is fixed at 420 nm, the functionalized hydroxy-terminated polybutadiene (N-HTPB) prepared in Example 1 reaches the maximum emission at 445 nm.

[0069] The functionalized hydroxy-terminated polybutadiene (N-HTPB) prepared in Example 1 was tested by infrared spectroscopy. The test results are as follows: Figure 3 As shown;

[0070] Figure 3 This is an infrared spectrum of the functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1;

[0071] pass Figure 3 It can be seen that N-HTPB-based polyurethane elastomer has a peak at 3300 cm -1 The NH stretching vibration peak of the association appeared at 1540 cm -1 The NH bending vibration peak appeared at 1710 cm -1The stretching vibration peak of carbonyl (C=O) appeared at 2260 cm -1 There is no characteristic peak of isocyanate group (-NCO) in the system, which means that there is carbamate group in the system, which means that the polyurethane elastomer is successfully synthesized.

[0072] The functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer (N-PU) with fluorescence response prepared in Example 1 was tested by fluorescence spectrum. The fluorescence emission spectrum test results are as follows: Figure 4 As shown;

[0073] Figure 4 This is a fluorescence spectrum of the functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1;

[0074] from Figure 4 As can be seen in Figure A, the excitation spectrum has a maximum peak at 440nm. By fixing the excitation wavelength at 440nm, we can study its emission spectrum. Figure 4 B is the fluorescence emission spectrum of the functionalized hydroxy-terminated polybutadiene with fluorescence response prepared in Example 1. Figure 4 In B, it can be seen that when the excitation wavelength is fixed at 440nm, the maximum emission peak appears at 500nm. Figure 2 N-HTPB reaches its maximum emission at 445nm, and the emission wavelength of N-PU shows a red shift; this is because when N-HTPB is used as a raw material to synthesize polyurethane, the degree of hydrogen bonding in the system increases, resulting in a red shift.

[0075] The functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1 was subjected to mechanical property tests to determine its tensile strength and elongation at break. Its stress-strain curve is shown in FIG. Figure 5 As shown;

[0076] Figure 5 The stress-strain curve of the functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1;

[0077] pass Figure 5 It can be seen that when the curing parameter is fixed at 1.2, as the soft segment content decreases, the overall mechanical properties of N-PU show a trend of first increasing and then decreasing. For the elongation at break, the reduction of the soft segment content in the system causes the physical crosslinking density to gradually increase, the tensile strength to gradually increase, and the strain to first increase and then decrease. This supports the theory of moderate crosslinking, that is, moderate crosslinking helps to improve properties such as elongation at break, while excessive crosslinking is not conducive to improving the mechanical properties of elastomers. In summary, for N-PU, when the soft segment content is 70%, the tensile strength is the largest, reaching 7.775MPa; the elongation at break is the largest, at 365%.

[0078] The functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1 was subjected to tensile strain test in a fluorescence imaging system, and the fluorescence intensity under different strains was recorded. The test results are as follows: Figure 6 As shown;

[0079] Figure 6 The relationship curve between the tensile strain and the fluorescence intensity of the functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1;

[0080] pass Figure 6 It can be seen that the fluorescence intensity of the functionalized terminal hydroxyl polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1 increases with the increase of tensile deformation; based on this method of labeling the polyurethane elastomer by the soft segment, it can be concluded that the tensile deformation is positively correlated with the fluorescence intensity.

[0081] The functionalized terminal hydroxyl polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1 was subjected to tensile strain test in a fluorescence imaging system, and the fluorescence schematic diagrams under different strains were recorded. The results are shown in FIG. Figure 7 As shown;

[0082] Figure 7 Schematic diagram of fluorescence of the functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1 under different tensile strains;

[0083] pass Figure 7 It can be seen that the fluorescence intensity of the functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response prepared in Example 1 increases with the increase of tensile deformation; Figure 7 A more visual fluorescence diagram.

Claims

1. A method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer having a fluorescent response, characterized in that The preparation method is specifically completed according to the following steps:

1. Preparation of functionalized hydroxyl-terminated polybutadiene: ①, dissolving the hydroxy-terminated polybutadiene in tetrahydrofuran, then adding concentrated hydrochloric acid under stirring, stirring and reacting for a period of time, then adding sodium carbonate, stirring and reacting for a period of time, to obtain solution A; ②, add 1-naphthylamine to solution A, stir and react for a period of time, then add anhydrous magnesium sulfate, let it stand for a period of time, then filter it using a Buchner funnel, discard the precipitate, and collect the clarified filtrate; use a rotary evaporator to remove the solvent from the clarified filtrate at 30°C to 50°C to obtain a precipitate; wash the precipitate, and then put it into a vacuum drying oven for vacuum drying for a period of time to obtain a functionalized hydroxy-terminated polybutadiene; 2. Preparation of functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer with fluorescence response: ①, dissolving the functionalized hydroxy-terminated polybutadiene in tetrahydrofuran, then adding methyl toluene diisocyanate, stirring evenly, adding dibutyltin dilaurate, stirring at room temperature for a period of time, and obtaining a prepolymer; ②. Add 1,4-butanediol to the prepolymer, react at room temperature for a period of time, then pour into a mold and place for a period of time to form a film and dry, to obtain a preliminarily dried polyurethane elastomer; place the preliminarily dried polyurethane elastomer in a vacuum oven for further drying to obtain a functionalized terminal hydroxyl polybutadiene-based polyurethane elastomer with fluorescent response.

2. The method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer having a fluorescent response according to claim 1, characterized in that The mass ratio of the hydroxy-terminated polybutadiene described in step 1① to tetrahydrofuran is 10g:(15mL~25mL); the mass ratio of the hydroxy-terminated polybutadiene described in step 1① to concentrated hydrochloric acid is 10g:(0.21mL~0.24mL).

3. The method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer having a fluorescent response according to claim 1, characterized in that The mass fraction of the concentrated hydrochloric acid described in step 1① is 37%; the volume ratio of the mass of the sodium carbonate described in step 1① to the concentrated hydrochloric acid is 0.160g:(0.21mL~0.24mL).

4. The method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer having a fluorescent response according to claim 1, characterized in that In step 1①, the terminal hydroxyl polybutadiene is dissolved in tetrahydrofuran, and then concentrated hydrochloric acid is added under stirring, and the reaction is stirred for 0.5h to 6h, and then sodium carbonate is added, and the reaction is stirred for 0.5h to 3h to obtain solution A.

5. The method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer having a fluorescent response according to claim 1, characterized in that The mass ratio of the hydroxy-terminated polybutadiene described in step 1① to the 1-naphthylamine described in step 1② is 10g:(0.3g~0.4g); the mass ratio of the hydroxy-terminated polybutadiene described in step 1① to the anhydrous magnesium sulfate described in step 1② is 10g:(0.4g~0.6g).

6. The method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer having a fluorescent response according to claim 1, characterized in that The stirring reaction time described in step 1② is 2h to 5h; the standing time described in step 1② is 0.5h to 12h; the precipitate is washed 3 to 5 times with anhydrous ethanol in step 1②; the vacuum drying temperature described in step 1② is 40℃ to 60℃, and the vacuum drying time is 8h to 12h.

7. The method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer having a fluorescent response according to claim 1, characterized in that The mass ratio of the functionalized hydroxy-terminated polybutadiene described in step 2① to tetrahydrofuran is 5g:10mL; the mass ratio of the functionalized hydroxy-terminated polybutadiene described in step 2① to toluene diisocyanate is 5:(1.5-1.6).

8. The method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer having a fluorescent response according to claim 1, characterized in that The mass ratio of the functionalized hydroxy-terminated polybutadiene to dibutyltin dilaurate described in step 2① is 1:(0.005-0.02); the stirring time at room temperature in step 2① is 1h-2h.

9. The method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer having a fluorescent response according to claim 1, characterized in that The mass ratio of 1,4-butanediol described in step 2② to the functionalized terminal hydroxyl polybutadiene described in step 2① is (0.5g~0.6g):5g; in step 2②, 1,4-butanediol is added to the prepolymer and reacted at room temperature for 0.5h~1h.

10. The method for preparing a functionalized hydroxy-terminated polybutadiene-based polyurethane elastomer having a fluorescent response according to claim 1, characterized in that In step 2②, pour into a mold and place for 45h to 50h to form a film and dry; in step 2②, place the preliminarily dried polyurethane elastomer in a vacuum oven at a temperature of 65℃ to 75℃ and dry for 20h to 25h.

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