Preparation method of fire evidence transportation violent sorting and high-temperature early warning flexible material

Abstract

The invention discloses a preparation method of a fire physical evidence transportation violent sorting and high-temperature early warning flexible material, and belongs to the field of judicial physical evidence circulation and logistics transportation, and the preparation method comprises the following steps: 1, adding indium gallium alloy liquid metal into a container, pouring an ethanol aqueous solution, fully stirring, dropwise adding a dopamine hydrochloride solution, adjusting the pH value to 7.5-9.0, and stirring at normal temperature; dropwise adding acetone into the reaction liquid for settling, centrifuging and filtering, stirring and washing a filter cake with acetone, and naturally drying to obtain polydopamine coated liquid metal; step 2, dissolving (4-vinyl phenyl) dimethylsilane, acrylate para-benzoic acid and 1-vinyl-3-butylimidazolium hexafluorophosphate in dichloromethane to prepare a solution, adding a photoinitiator Irgacure-2959, adding polydopamine coated liquid metal, fully stirring the materials, pouring the materials into a polytetrafluoroethylene mold, carrying out illumination under a 650W ultraviolet lamp to initiate polymerization, and carrying out vacuum drying, so as to obtain a coating; and drying the solvent to constant weight to obtain the fire evidence transportation violent sorting and high-temperature early warning flexible material.

Description

Technical Field

[0001] The present invention belongs to the field of judicial evidence circulation and logistics transportation, and specifically relates to a method for preparing a reusable fire evidence transportation violence sorting and high-temperature warning flexible material. Background Art

[0002] Fire investigation is the basic work of fire supervision and management. It is a necessary means to clarify the cause of the accident, reduce the subsequent related fire risks, and safeguard the legitimate rights and interests of the masses. During the fire investigation process, physical evidence identification is usually required to assist in confirming the cause of the fire, clarify the responsibilities of all parties, and summarize relevant lessons learned. However, on the one hand, due to the small number of fire physical evidence identification laboratories in my country, the uneven regional distribution, and the high randomness of fire accidents, the combination of the two has led to the inspection of fire physical evidence mainly being carried out through express logistics transportation.

[0003] Statistics from the State Post Bureau show that in the first half of 2021, the total business volume of express delivery service companies nationwide reached 49.39 billion pieces, a year-on-year increase of 45.8%. However, the rapid development of the express delivery industry has also brought some problems, among which violent sorting is particularly prominent. Because fire evidence, such as burning debris, is fragile and easy to pulverize; metal wires, glass and other evidence have sharp fractures; the extracted evidence is usually large in number, large in volume, and heavy in weight; once violent sorting occurs, the overall temporal sequence of fire evidence will be destroyed (such as burning lithium battery packs destroyed and scattered during the mailing process, making it difficult to trace their positional relationship), and even cause the express packaging box to be damaged, resulting in the loss of key tiny evidence such as molten beads; at the same time, violent sorting also creates the possibility of secondary combustion accidents of fire evidence (such as insufficiently discharged battery debris or leakage of liquid combustible evidence).

[0004] In the practice of law and politics, an important aspect of the examination and identification of physical evidence is whether the physical evidence has been damaged or altered during the collection, storage, transportation and identification process. However, when physical evidence is transported through express logistics, the traceable information is limited to the location-time dimension. It is impossible to know whether the physical evidence has been violently sorted or affected by high temperatures during transportation. Once the physical evidence is confused or lost during this process, it is difficult to clarify the responsibility. Related disputes continue, and it has become a new growth point for judicial contradictions.

[0005] At present, the main means of monitoring against violent sorting is video monitoring, and a large number of literature and patents have reported related algorithms. However, due to the limited video monitoring angles and hardware with monitoring capabilities, it is impossible to guarantee the coverage of physical evidence in the entire express delivery chain. At the same time, related monitoring is often arranged by express delivery companies. When disputes occur, the preservation, extraction and validity of related evidence are questionable, which can easily lead to more judicial disputes on one judicial dispute.

[0006] The use of sensors is another technical approach to monitor violent sorting and exposure to high temperatures, but currently, MEMS (Microelectromechanical Systems) sensors are used in public literature and patent reports. These sensors themselves are rigid structures and are arranged in evidence packaging boxes. When violent sorting or shock and vibration occur during transportation, they will collide with the fire evidence, thereby affecting the integrity of the fire evidence. At the same time, the high humidity and highly refined particle size of the fire evidence and the common sharp-broken wires or heavy lithium battery pack debris will significantly affect the service life and signal stability of the above sensors. Finally, the above MEMS sensors do not have flame retardant properties and may introduce fire risks.

[0007] Currently, a large number of fire evidences are sent to the identification center through express logistics. Due to the fragility of fire evidences, once they are subjected to violent sorting or high temperature, they are easily damaged and lost, which destroys the temporal and spatial order between the internal parts of the evidences, making it difficult to trace the cause of the accident, and even causing secondary accidents. Therefore, it is necessary to monitor and record whether the evidences are subjected to violent sorting or high temperature during the logistics process, so as to clarify the relevant responsibilities and protect the legitimate rights and interests of the inspection party and the identification center. Summary of the invention

[0008] In view of the shortcomings of existing violent sorting monitoring and high-temperature warning technologies and the particularity of fire evidence, the present invention proposes a method for preparing a reusable intrinsically flame-retardant fire evidence violent sorting and high-temperature warning flexible material, which can realize stress / temperature detection exceeding the threshold and automatic alarm, and at the same time has self-healing properties and self-adhesion, adapts to the different properties of various fire evidence, and achieves universal application.

[0009] To achieve the above object, the present invention adopts the following technical solutions: A method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning, comprising the following steps: Step 1: Add indium gallium alloy liquid metal (EGaIn) into a container, pour in ethanol aqueous solution, stir thoroughly, drop in dopamine hydrochloride solution, and use ammonia water to adjust the pH value to 7.5~9.0, stir and react at room temperature for 8h~24h, drop acetone into the reaction solution for sedimentation, centrifuge, filter, stir and wash the filter cake with acetone and dry it naturally to obtain polydopamine-coated liquid metal; Step 2: Take (4-vinylphenyl)dimethylsilane (cas: 4556-72-3), acrylate-based benzoic acid (cas: 41514-45-8), and 1-vinyl-3-butylimidazole hexafluorophosphate (cas: 915358-85-9), dissolve them in dichloromethane to prepare a solution, and the total mass of the above three materials accounts for 78% to 90% of the total mass of the solution; add photoinitiator Irgacure-2959 (cas: 106797-53-9), add polydopamine to coat the liquid metal, stir the materials thoroughly and pour them into a polytetrafluoroethylene mold, induce polymerization under a 650W ultraviolet lamp for 5 minutes to 10 minutes, dry the solvent to constant weight, and obtain a flexible material for fire evidence transportation, violent sorting, and high temperature warning.

[0010] In the step 1, the mass fraction of ethanol in the ethanol aqueous solution is 30% to 60%.

[0011] In the step 1, the density of the dopamine hydrochloride solution is 0.03 g / mL to 0.08 g / mL.

[0012] In step 1, the centrifugal speed is 500 r / min to 1500 r / min, and the centrifugal time is 5 min to 15 min.

[0013] In step 1, the mass ratio of the indium gallium alloy liquid metal to dopamine hydrochloride is (50-90): (50-10).

[0014] In the step 2, the molar ratio of (4-vinylphenyl)dimethylsilane, acrylated benzoic acid, and 1-vinyl-3-butylimidazole hexafluorophosphate is (5-80): (5-80): (10-90).

[0015] In the step 2, the ratio of the total molar amount of (4-vinylphenyl)dimethylsilane, acrylate-based benzoic acid and 1-vinyl-3-butylimidazole hexafluorophosphate to the molar amount of the photoinitiator is (95-99): (1-5).

[0016] In the step 2, the mass ratio of the total mass of (4-vinylphenyl)dimethylsilane, acrylate-based benzoic acid and 1-vinyl-3-butylimidazole hexafluorophosphate to the polydopamine-coated liquid metal is (80%~99%): (20%~1%).

[0017] A flexible material for fire evidence transportation, violent sorting and high temperature warning is prepared by adopting the preparation method.

[0018] After testing, the prepared warning material has a limiting oxygen index of 28.3%~33.1%, a UL-94 vertical combustion test that reaches V-0 level, a 30-day weight gain rate of 0.21%~3.3%, a breaking elongation of 500%~1026%, a breaking strength of 138kPa~1810kPa, and a specification factor of 8.1kPa. -1 ~67kPa -1 , 90° peel strength (iron) 0.82N~5.22N, response time 200ms~300ms, recovery time 200ms~500ms, 12h self-healing efficiency at room temperature 28%~92%, temperature sensing warning capability: rise to 100℃ at a heating rate of 10℃ / min, when the temperature reaches 90℃, the time interval from when the alarm light turns on is less than 10s.

[0019] The present invention has the following beneficial effects: The present invention uses room temperature reaction to prepare polydopamine in-situ coated modified liquid metal, thereby improving the compatibility of liquid metal and polymer materials. Liquid metal is doped with polydopamine and coated with (4-vinylphenyl) dimethylsilane, acrylate-based benzoic acid and 1-vinyl-3-butylimidazole hexafluorophosphate, and light initiation is used to prepare a flexible material for fire evidence transportation, violent sorting and high temperature warning. The reaction has the advantages of mild conditions, no need for inert gas protection, and fast reaction speed. At the same time, Figure 2 As shown in the figure, the silane functional group of (4-vinylphenyl)dimethylsilane can form hydrogen bonds with the imidazole group of 1-vinyl-3-butylimidazole hexafluorophosphate and the carboxylic acid group of acrylate-based benzoic acid after polymerization, giving the material a three-dimensional network structure and achieving viscoelasticity and self-healing properties. The ionic liquid 1-vinyl-3-butylimidazole hexafluorophosphate gives the material conductivity, which can identify high temperatures and violent sorting during the transportation of evidence, while the fluorine and phosphorus elements in the ionic liquid make the material inherently flame retardant, reducing the risk of secondary combustion of fire evidence; the polydopamine doped and dispersed in the material coated liquid metal greatly improves the temperature and stress sensitivity of the material, and the surface hydroxyl groups of polydopamine can hydrogen bond with the silane functional group of (4-vinylphenyl)dimethylsilane and the carboxylic acid group of acrylate-based benzoic acid, improving the stability of the doping system.

[0020] In summary, the early warning material has the functions of sensitive sensing, self-healing and intrinsic flame retardancy. Figure 3As shown in the figure, the material can change resistance and generate current changes by sensing external stress changes and temperature changes, providing early warning signals to indicate that physical evidence has been violently sorted or threatened by high temperature; the material has excellent flame retardant effect, is difficult to burn, self-extinguishes when away from fire, and does not drip, which can effectively prevent fire evidence from causing secondary accidents; at the same time, the material has good adhesion damping effect, which can not only greatly reduce the probability of fire evidence being damaged by movement and collision during transportation, but also play a role in adhesion preservation of molten beads and other detached fire evidence debris, effectively preventing the loss of key small evidence; the early warning material can automatically repair the break after damage, has the ability to self-heal at room temperature, reduces the possibility of fire evidence being scattered and lost, and greatly increases the number of times the material is recycled, and is low-cost and easy to promote and use, with good economic benefits. The above characteristics can greatly improve the safety and traceability of fire evidence in the express / logistics transportation process, and significantly reduce related judicial disputes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the reaction of polydopamine coating liquid metal; Figure 2 Schematic diagram of violent sorting of fire evidence transportation and preparation of high temperature warning materials; Figure 3 Schematic diagram of material temperature sensing warning; Figure 4 Transmission electron microscopy image of polydopamine coated liquid metal in Example 1; Figure 5 Elongation at break and strength at break curve of the warning material in Example 1; Figure 6 Response and recovery time curves of the warning material in Example 1; Figure 7 Scanning electron microscopy image of polydopamine-coated liquid metal doped in the warning material in Example 2; Figure 8 Response and recovery time curves of the warning material in Example 3; Fig. 9 Elongation at break and breaking strength curve of the warning material in Example 4; Fig.10 The 30-day weight gain curve of the warning material in Example 5; Fig.11 Elongation at break and breaking strength curve of the warning material in Example 5; Fig.12 Response and recovery time curves of the warning material in Example 5; Fig.13 12h self-healing efficiency test curve of the warning material in Example 5; Fig.14Response curve of the warning material to the gravity of weights of different weights in Example 5; Fig.15 Cyclic stability curve of the warning material in Example 5 subjected to continuous action of the same stress in a short period of time. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below in conjunction with the embodiments. The specific embodiments are for further describing the present invention in detail but are not intended to limit the protection scope of the present invention.

[0023] The limiting oxygen index test of the present invention is measured with reference to the standard "GB / T 2406.2-2009", the UL-94 vertical burning test is measured with reference to the standard "GB / T 2408-2021", and the 90° peel strength test is measured with reference to the standard "ASTM D429-14".

[0024] The 30-day weight gain rate test method in the embodiment is as follows: the prepared warning material is placed in an indoor environment and weighed every day. The percentage of the weight increase after 30 days to the original weight is the 30-day weight gain rate. A stable 30-day weight gain rate indicates that the material does not absorb moisture or dry, which indicates the stability of the product.

[0025] The elongation at break and the breaking strength test were conducted at room temperature using an electronic universal testing machine. The specimens were cut into rectangles (size, 50 mm*4 mm*2 mm) and the tensile test was conducted at a tensile rate of 50 mm / min. The elongation at break is defined as the deformation length (measured by an extensometer) at break divided by the original length of the sample, and the breaking strength is the tensile strength to which the material is subjected at break.

[0026] When testing stress sensing, the material is cut into rectangles (size, 20mm*10mm*2mm), and then electrode clamps are fixed at both ends of the material. The signal after the material is subjected to stress is monitored by the electrochemical workstation. The resistance change of the material is recorded using the above electrochemical workstation. The relative resistance change rate is calculated by formula (1): (1) Where R0 and R are the initial resistance and the resistance when strain is applied, respectively.

[0027] In the embodiment, the normalization factor GF is calculated by formula (2): (2) in, It is the pressure applied to the material. GF is expressed in kPa. -1 ).

[0028] The test method for the response time and recovery time in the embodiment is to fix electrode clamps at both ends of a rectangular material (size: 20 mm*10 mm*2 mm), apply 1 N stress thereto and then immediately remove it, and monitor the response time and recovery time of the material after being subjected to stress by an electrochemical workstation.

[0029] The 12h self-healing efficiency test method in the embodiment is as follows: two identical samples are taken from the prepared early warning material, one of which is used as the original sample to directly test its fracture stress, and the other is cut with a scalpel on its surface with a length of 1 cm and a depth of 1 cm, which is realigned and left to stand at room temperature for 12 hours without applying any external force. Then, its fracture strength is measured under the same conditions, and its percentage of the fracture strength of the original sample is the 12h self-healing efficiency.

[0030] The temperature sensing warning ability test method in the embodiment is as follows: the warning material is placed on the surface of the hot table and the temperature is raised to 100°C at a heating rate of 10°C / min. When the temperature reaches 90°C, the alarm light comes on within 10s and it is considered as passed. Otherwise, it is considered as failed. The time interval from when the temperature rises to 90°C to when the alarm light comes on is recorded as the warning time.

[0031] Example 1 A method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning, the specific operation steps are as follows: Step 1: Add 10g of indium gallium alloy liquid metal to the flask, pour in 30% ethanol aqueous solution, stir thoroughly, drop in 125ml of 0.08g / mL dopamine hydrochloride solution (liquid metal: dopamine hydrochloride mass ratio 50:50), and use ammonia water to adjust the pH value to 7.5, stir and react at room temperature for 24h. Drop acetone into the reaction solution and let it settle for 10min, centrifuge (500r / min) for 15min, filter, wash the filter cake with acetone for 3 times and dry it naturally to obtain polydopamine-coated liquid metal, such as Figure 1 shown. Figure 4 This is a transmission electron microscopy image of polydopamine-coated liquid metal.

[0032] Step 2: Take 1.62g (0.01mol) of (4-vinylphenyl) dimethylsilane, 1.92g (0.01mol) of acrylated benzoic acid, and 53.30g (0.18mol) of 1-vinyl-3-butyl imidazole hexafluorophosphate, the molar ratio of the three materials is 5:5:90, and dissolve them in 14.21g of dichloromethane to form a solution. The total mass of the above three materials accounts for 80% of the total mass of the solution. Add 2.24g (0.01mol) of photoinitiator Irgacure-2959, and the ratio of the total molar amount of the three materials to the molar amount of the initiator is 95:5. Add 14.21g of polydopamine-coated liquid metal, and the mass ratio of the total mass of the three materials to the mass of the polydopamine-coated liquid metal is 80%:20%. After being fully stirred, the above materials were poured into a polytetrafluoroethylene mold, and polymerization was initiated under a 650W ultraviolet lamp for 5 minutes. The solvent was dried in an oven at 50°C to constant weight to obtain a flexible material for fire evidence transportation, violent sorting, and high temperature warning.

[0033] After testing, the prepared warning material has a limiting oxygen index of 32.6%, a UL-94 vertical combustion test that reaches V-0 level, a 30-day weight gain rate of 3.3%, a breaking elongation of 500%, a breaking strength of 193kPa, and a specification factor of 52kPa. -1 , 90° peel strength (iron) 3.53N, response time 200ms, recovery time 400ms, 12h self-healing efficiency at room temperature 53%, temperature sensing warning capability: passed, 820ms. Figure 5 To provide the elongation at break and strength at break curves of early warning materials, Figure 6 Response and recovery time curves for early warning materials.

[0034] Example 2 A method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning, the specific operation steps are as follows: Step 1: Add 27g of indium gallium alloy liquid metal to the flask, pour in 60% ethanol aqueous solution, stir thoroughly, drop in 100ml of 0.03g / mL dopamine hydrochloride solution (liquid metal: dopamine hydrochloride mass ratio 90:10), and use ammonia water to adjust the pH value to 9.0, stir and react at room temperature for 8h. Drop acetone into the reaction solution and let it settle for 10min, centrifuge (1500r / min) for 5min, filter, wash the filter cake with acetone for 3 times and dry it naturally to obtain polydopamine-coated liquid metal.

[0035] Step 2: Take 64.84g (0.4mol) of (4-vinylphenyl) dimethylsilane, 9.62g (0.05mol) of acrylated benzoic acid, and 14.80g (0.05mol) of 1-vinyl-3-butyl imidazole hexafluorophosphate, the molar ratio of the three materials is 80:10:10, and dissolve them in 9.92g of dichloromethane to form a solution. The total mass of the above three materials accounts for 90% of the total mass of the solution. Add 1.12g (0.005mol) of photoinitiator Irgacure-2959, and the ratio of the total molar amount of the three materials to the molar amount of the initiator is 99:1. Add 0.90g of polydopamine-coated liquid metal, and the mass ratio of the total mass of the three materials to the mass of the polydopamine-coated liquid metal is 99%:1%. After being fully stirred, the above materials were poured into a polytetrafluoroethylene mold, and polymerization was initiated under a 650W ultraviolet lamp for 10 minutes. The solvent was dried in an oven at 50°C to constant weight to obtain a flexible material for fire evidence transportation, violent sorting, and high temperature warning.

[0036] After testing, the prepared warning material has a limiting oxygen index of 29.1%, a UL-94 vertical combustion test that reaches V-1 level, a 30-day weight gain rate of 2.81%, a break elongation of 621%, a break strength of 138kPa, and a specification factor of 8.1kPa. -1 , 90° peel strength (iron) 0.82N, response time 300ms, recovery time 500ms, 12h self-healing efficiency 37% at room temperature, temperature sensing warning capability: passed, 1390ms. Figure 7 This is a scanning electron microscope image of the polydopamine-coated liquid metal doped in the early warning material prepared in Example 2.

[0037] Example 3 A method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning, the specific operation steps are as follows: Step 1: Add 12g of indium gallium alloy liquid metal to the flask, pour in 60% ethanol aqueous solution, stir thoroughly, drop in 200ml of 0.04g / mL dopamine hydrochloride solution (liquid metal: dopamine hydrochloride mass ratio 60:40), and use ammonia water to adjust the pH value to 8.0, stir and react at room temperature for 12h. Drop acetone into the reaction solution and let it settle for 10min, centrifuge (750r / min) for 6min, filter, wash the filter cake with acetone for 3 times and dry it naturally to obtain polydopamine-coated liquid metal.

[0038] Step 2: Take 8.10g (0.05mol) of (4-vinylphenyl) dimethylsilane, 76.82g (0.4mol) of acrylated benzoic acid, and 14.80g (0.05mol) of 1-vinyl-3-butyl imidazole hexafluorophosphate, the molar ratio of the three materials is 10:80:10, and dissolve them in 17.60g of dichloromethane to form a solution. The total mass of the above three materials accounts for 85% of the total mass of the solution. Add 4.71g (0.021mol) of photoinitiator Irgacure-2959, and the ratio of the total molar amount of the three materials to the molar amount of the initiator is 96:4. Add 5.25g of polydopamine-coated liquid metal, and the mass ratio of the total mass of the three materials to the mass of the polydopamine-coated liquid metal is 95%:5%. After being fully stirred, the above materials were poured into a polytetrafluoroethylene mold, and polymerization was initiated under a 650W ultraviolet lamp for 9 minutes. The solvent was dried in an oven at 50°C to constant weight to obtain a flexible material for fire evidence transportation, violent sorting, and high temperature warning.

[0039] After testing, the prepared warning material has a limiting oxygen index of 28.3%, a UL-94 vertical combustion test that reaches V-1 level, a 30-day weight gain rate of 1.78%, a break elongation of 705%, a break strength of 262kPa, and a specification factor of 23kPa. -1 , 90° peel strength (iron) 1.15N, response time 300ms, recovery time 300ms, 12h self-healing efficiency at room temperature 28%, temperature sensing warning capability: passed, 1160ms. Figure 8 This is the response and recovery time curve of the early warning material prepared in Example 3.

[0040] Example 4 A method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning, the specific operation steps are as follows: Step 1: Add 21g of indium gallium alloy liquid metal to the flask, pour in 40% ethanol aqueous solution, stir thoroughly, drop in 150ml of 0.06g / mL dopamine hydrochloride solution (liquid metal: dopamine hydrochloride mass ratio 70:30), and use ammonia water to adjust the pH value to 8.5, stir at room temperature for 16h. Drop acetone into the reaction solution to settle for 10min, centrifuge (1250r / min) for 10min, filter, wash the filter cake with acetone for 3 times and dry naturally to obtain polydopamine-coated liquid metal.

[0041] Step 2: Take 1.62g (0.01mol) of (4-vinylphenyl) dimethylsilane, 7.68g (0.04mol) of acrylated benzoic acid, and 14.80g (0.05mol) of 1-vinyl-3-butyl imidazole hexafluorophosphate, the molar ratio of the three materials is 10:40:50, and dissolve them in 6.73g of dichloromethane to form a solution. The total mass of the above three materials accounts for 78% of the total mass of the solution. Add 0.67g (0.003mol) of photoinitiator Irgacure-2959, and the ratio of the total molar amount of the three materials to the molar amount of the initiator is 97:3. Add 2.68g of polydopamine-coated liquid metal, and the mass ratio of the total mass of the three materials to the mass of the polydopamine-coated liquid metal is 90%:10%. After being fully stirred, the above materials were poured into a polytetrafluoroethylene mold, and polymerization was initiated under a 650W ultraviolet lamp for 8 minutes. The solvent was dried in an oven at 50°C to constant weight to obtain a flexible material for fire evidence transportation, violent sorting, and high temperature warning.

[0042] After testing, the prepared flexible material has a limiting oxygen index of 30.7%, a UL-94 vertical combustion test that reaches V-0, a 30-day weight gain of 0.53%, a break elongation of 1026%, a break strength of 1308 kPa, and a specification factor of 31 kPa. -1 , 90° peel strength (iron) 3.91N, response time 270ms, recovery time 320ms, 12h self-healing efficiency at room temperature 77%, temperature sensing warning capability: passed, 210ms. Fig. 9 This is the elongation at break and strength at break curve of the warning material prepared in Example 4.

[0043] Example 5 A method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning, the specific operation steps are as follows: Step 1: Add 10g of indium gallium alloy liquid metal to the flask, pour in 40% ethanol aqueous solution, stir thoroughly, drop in 50ml of 0.05g / mL dopamine hydrochloride solution (liquid metal: dopamine hydrochloride mass ratio 80:20), and use ammonia water to adjust the pH value to 7.5, stir and react at room temperature for 12h. Drop acetone into the reaction solution and let it settle for 10min, centrifuge (1000r / min) for 8min, filter, wash the filter cake with acetone for 3 times and dry it naturally to obtain polydopamine-coated liquid metal.

[0044] Step 2: Take 4.86g (0.03mol) of (4-vinylphenyl) dimethylsilane, 3.84g (0.02mol) of acrylated benzoic acid, and 14.80g (0.05mol) of 1-vinyl-3-butyl imidazole hexafluorophosphate, the molar ratio of the three materials is 30:20:50, and dissolve them in 2.61g of dichloromethane to form a solution. The total mass of the above three materials accounts for 90% of the total mass of the solution. Add 0.45g (0.002mol) of photoinitiator Irgacure-2959, and the ratio of the total molar amount of the three materials to the molar amount of the initiator is 98:2. Add 4.15g of polydopamine-coated liquid metal, and the mass ratio of the total mass of the three materials to the mass of the polydopamine-coated liquid metal is 85%:15%. After being fully stirred, the above materials were poured into a polytetrafluoroethylene mold, and polymerization was initiated under a 650W ultraviolet lamp for 6 minutes. The solvent was dried in an oven at 50°C to constant weight to obtain a flexible material for fire evidence transportation, violent sorting, and high temperature warning.

[0045] After testing, the prepared warning material has a limiting oxygen index of 33.1%, a UL-94 vertical combustion test that reaches V-0 level, a 30-day weight gain rate of 0.21%, a break elongation of 902%, a break strength of 1810kPa, and a specification factor of 67kPa. -1 , 90° peel strength (iron) 5.22N, response time 200ms, recovery time 200ms, 12h self-healing efficiency at room temperature 92%, temperature sensing warning capability: passed, 100ms. Fig.10 The 30-day weight gain curve of the early warning material prepared in Example 5; Fig.11 Elongation at break and strength at break curve of the warning material; Fig.12 The response and recovery time curve of the warning material; Fig.13 This is the 12h self-healing efficiency test curve of the warning material; Fig.14 is the response curve of the warning material to the gravity of weights of different weights; Fig.15 This is the cyclic stability curve of the warning material subjected to continuous action of the same stress in a short period of time.

[0046] Comparative Example 1 A method for preparing fire evidence transportation violent sorting and high temperature warning materials, the specific operation steps are as follows: Step 1: Add 10g of indium gallium alloy liquid metal to the flask, pour in 40% ethanol aqueous solution, stir thoroughly, drop in 50ml of 0.05g / mL dopamine hydrochloride solution (liquid metal: dopamine hydrochloride mass ratio 80:20), and use ammonia water to adjust the pH value to 7.5, stir and react at room temperature for 12h. Drop acetone into the reaction solution and let it settle for 10min, centrifuge (1000r / min) for 8min, filter, wash the filter cake with acetone for 3 times and dry it naturally to obtain polydopamine-coated liquid metal.

[0047] Step 2: Take 3.12g (0.03mol) of styrene, 3.84g (0.02mol) of acrylated benzoic acid, and 14.80g (0.05mol) of 1-vinyl-3-butyl imidazole hexafluorophosphate, the molar ratio of the three materials is 30:20:50, and dissolve them in 2.42g of dichloromethane to form a solution. The total mass of the above three materials accounts for 90% of the total mass of the solution. Add 0.45g (0.002mol) of photoinitiator Irgacure-2959, and the ratio of the total molar amount of the three materials to the molar amount of the initiator is 98:2. Add 3.84g of polydopamine-coated liquid metal, and the mass ratio of the total mass of the three materials to the mass of the polydopamine-coated liquid metal is 85%:15%. After being fully stirred, the above materials were poured into a polytetrafluoroethylene mold and polymerized under a 650W ultraviolet lamp for 6 minutes. The solvent was dried in an oven at 50°C to constant weight to obtain fire evidence transportation, violent sorting and high temperature warning materials.

[0048] After testing, the prepared warning material has a limiting oxygen index of 26.1%, a UL-94 vertical combustion test that reaches V-1 level, a 30-day weight gain rate of 3.88%, an elongation at break of 83%, a breaking strength of 117kPa, and a specification factor of 3.7kPa. -1 , 90° peel strength (iron) 0.55N, response time 830ms, recovery time 950ms, 12h self-healing efficiency at room temperature 7.5%, temperature sensing warning capability: failed, 15s.

[0049] Comparative Example 2 A method for preparing fire evidence transportation violent sorting and high temperature warning materials, the specific operation steps are as follows: Step 1: Add 10g of indium gallium alloy liquid metal to the flask, pour in 40% ethanol aqueous solution, stir thoroughly, drop in 50ml of 0.05g / mL dopamine hydrochloride solution (liquid metal: dopamine hydrochloride mass ratio 80:20), and use ammonia water to adjust the pH value to 7.5, stir and react at room temperature for 12h. Drop acetone into the reaction solution and let it settle for 10min, centrifuge (1000r / min) for 8min, filter, wash the filter cake with acetone for 3 times and dry it naturally to obtain polydopamine-coated liquid metal.

[0050] Step 2: Take 4.86g (0.03mol) of (4-vinylphenyl) dimethylsilane, 3.28g (0.02mol) of 4-hydroxyphenyl acrylate (cas: 3233-36-1), and 14.80g (0.05mol) of 1-vinyl-3-butyl imidazole hexafluorophosphate, the molar ratio of the three materials is 30:20:50, and dissolve them in 2.61g of dichloromethane to form a solution. The total mass of the above three materials accounts for 90% of the total mass of the solution. Add 0.45g (0.002mol) of photoinitiator Irgacure-2959, and the ratio of the total molar amount of the three materials to the molar amount of the initiator is 98:2. Add 4.15g of polydopamine-coated liquid metal, and the mass ratio of the total mass of the three materials to the mass of the polydopamine-coated liquid metal is 85%:15%. After being fully stirred, the above materials were poured into a polytetrafluoroethylene mold and polymerized under a 650W ultraviolet lamp for 6 minutes. The solvent was dried in an oven at 50°C to constant weight to obtain fire evidence transportation, violent sorting and high temperature warning materials.

[0051] After testing, the prepared warning material has a limiting oxygen index of 28.6%, a UL-94 vertical combustion test that reaches V-1 level, a 30-day weight gain rate of 5.23%, a break elongation of 357%, a break strength of 89kPa, and a specification factor of 1.2kPa. -1 , 90° peel strength (iron) 1.67N, response time 500ms, recovery time 770ms, 12h self-healing efficiency at room temperature 12%, temperature sensing warning capability: failed, 12s.

[0052] Comparative Example 3 A method for preparing fire evidence transportation violent sorting and high temperature warning materials, the specific operation steps are as follows: Step 1: Add 10g of indium gallium alloy liquid metal to the flask, pour in 40% ethanol aqueous solution, stir thoroughly, drop in 50ml of 0.05g / mL dopamine hydrochloride solution (liquid metal: dopamine hydrochloride mass ratio 80:20), and use ammonia water to adjust the pH value to 7.5, stir and react at room temperature for 12h. Drop acetone into the reaction solution and let it settle for 10min, centrifuge (1000r / min) for 8min, filter, wash the filter cake with acetone for 3 times and dry it naturally to obtain polydopamine-coated liquid metal.

[0053] Step 2: Take 4.86g (0.03mol) of (4-vinylphenyl) dimethylsilane, 3.84g (0.02mol) of acrylated benzoic acid, and 14.91g (0.05mol) of 1-butyl-3-ethyl imidazolide hexafluorophosphate (cas: 256647-89-9), the molar ratio of the three materials is 30:20:50, and dissolve them in 2.62g of dichloromethane to form a solution. The total mass of the above three materials accounts for 90% of the total mass of the solution. Add 0.45g (0.002mol) of photoinitiator Irgacure-2959, and the ratio of the total molar amount of the three materials to the molar amount of the initiator is 98:2. Add 4.17g of polydopamine-coated liquid metal, and the mass ratio of the total mass of the three materials to the mass of the polydopamine-coated liquid metal is 85%:15%. After being fully stirred, the above materials were poured into a polytetrafluoroethylene mold and polymerized under a 650W ultraviolet lamp for 6 minutes. The solvent was dried in an oven at 50°C to constant weight to obtain fire evidence transportation, violent sorting and high temperature warning materials.

[0054] After testing, the prepared warning material has a limiting oxygen index of 27.5%, a UL-94 vertical combustion test that reaches V-1 level, a 30-day weight gain rate of 18.30%, a break elongation of 27%, a break strength of 33kPa, and a specification factor of 5.5kPa. -1 , 90° peel strength (iron) 0.13N, response time 1060ms, recovery time 1250ms, 12h self-healing efficiency at room temperature 3.9%, temperature sensing warning capability: failed, 18s.

Claims

1. A method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning, characterized in that: The following steps are involved: Step 1: Add indium gallium alloy liquid metal to a container, pour in ethanol aqueous solution, stir thoroughly, drop in dopamine hydrochloride solution, and use ammonia water to adjust the pH value to 7.5-9.0, and stir at room temperature for 8h-24h; drop acetone into the reaction solution for sedimentation, centrifuge, filter, stir and wash the filter cake with acetone and dry it naturally to obtain polydopamine-coated liquid metal; Step 2: Take (4-vinylphenyl)dimethylsilane, acrylate-based terephthalic acid, and 1-vinyl-3-butylimidazole hexafluorophosphate, dissolve them in dichloromethane to prepare a solution, and the total mass of the three materials accounts for 78% to 90% of the total mass of the solution; add photoinitiator Irgacure-2959, add polydopamine to coat the liquid metal, and pour the materials into a polytetrafluoroethylene mold after fully stirring. Initiate polymerization under a 650W ultraviolet lamp for 5 minutes to 10 minutes, dry the solvent to constant weight, and obtain a flexible material for fire evidence transportation, violent sorting, and high temperature warning.

2. The method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning according to claim 1, characterized in that: In the step 1, the mass fraction of ethanol in the ethanol aqueous solution is 30% to 60%.

3. The method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning according to claim 1, characterized in that: In the step 1, the density of the dopamine hydrochloride solution is 0.03 g / mL to 0.08 g / mL.

4. The method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning according to claim 1, characterized in that: In step 1, the centrifugal speed is 500 r / min to 1500 r / min, and the centrifugal time is 5 min to 15 min.

5. The method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning according to claim 1, characterized in that: In step 1, the mass ratio of the indium gallium alloy liquid metal to dopamine hydrochloride is (50-90): (50-10).

6. The method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning according to claim 1, characterized in that: In the step 2, the molar ratio of (4-vinylphenyl)dimethylsilane, acrylated benzoic acid, and 1-vinyl-3-butylimidazole hexafluorophosphate is (5-80): (5-80): (10-90).

7. The method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning according to claim 1, characterized in that: In the step 2, the ratio of the total molar amount of (4-vinylphenyl)dimethylsilane, acrylate-based benzoic acid and 1-vinyl-3-butylimidazole hexafluorophosphate to the molar amount of the photoinitiator is (95-99): (1-5).

8. The method for preparing a flexible material for fire evidence transportation, violent sorting and high temperature warning according to claim 1, characterized in that: In the step 2, the mass ratio of the total mass of (4-vinylphenyl)dimethylsilane, acrylate-based benzoic acid and 1-vinyl-3-butylimidazole hexafluorophosphate to the polydopamine-coated liquid metal is (80%~99%): (20%~1%).

9. A flexible material for fire evidence transportation, violent sorting and high temperature warning, characterized in that: The method for preparing the flexible material for fire evidence transportation, violent sorting and high temperature warning as described in any one of claims 1 to 8 is adopted.

10. The flexible material for fire evidence transportation, violent sorting and high temperature warning according to claim 9, characterized in that: The warning material has a limiting oxygen index of 28.3%~33.1%, a UL-94 vertical combustion test that reaches V-0 level, a 30-day weight gain rate of 0.21%~3.3%, a break elongation of 500%~1026%, a break strength of 138kPa~1810kPa, and a specification factor of 8.1kPa -1 ~67kPa -1 , 90° peel strength 0.82N~5.22N, response time 200ms~300ms, recovery time 200ms~500ms, 12h self-healing efficiency 28%~92% at room temperature, temperature sensing warning capability: rise to 100℃ at a heating rate of 10℃ / min, when the temperature reaches 90℃, the time interval from when the alarm light turns on is less than 10s.

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