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

Abstract

The application discloses a kind of fire material evidence transportation violence sorting and high temperature early warning flexible material preparation method, belong to judicial material evidence circulation field and logistics transportation field, comprising: step 1: indium-gallium alloy liquid metal is added to container, pour into ethanol aqueous solution, fully stir, drop into dopamine hydrochloride solution, adjust pH value to 7.5~9.0, stir at room temperature;Dropping into acetone settlement to reaction liquid, centrifugal, filtration, filter cake is washed after stirring with acetone and natural drying, obtain polydopamine coated liquid metal;Step 2: take (4-vinylphenyl) dimethyl silane, acrylic acid ester group p-benzoic acid, 1-vinyl-3-butyl imidazole hexafluorophosphate, dissolved in dichloromethane to make solution, add photoinitiator Irgacure-2959, add polydopamine coated liquid metal, material is fully stirred after pouring into polytetrafluoroethylene mold, under 650W ultraviolet lamp, light initiation polymerization, solvent is dried to constant weight, obtain fire material evidence transportation violence sorting and high temperature early warning flexible material.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of judicial evidence circulation and the field of logistics transportation, and particularly relates to a preparation method of a reusable fire evidence transportation violence sorting and high-temperature early warning flexible material. BACKGROUND

[0002] Fire investigation is a basic work of fire supervision and management, and is a necessary means to clarify the causes of accidents, reduce subsequent related fire risks, and protect the legitimate rights and interests of the public. During the fire investigation process, evidence identification is usually required to assist in confirming the cause of the fire, clarifying the responsibilities of each party, and summarizing relevant experience and lessons. However, on the one hand, due to the small number of fire evidence identification laboratories in China and the uneven regional distribution, the randomness of fire accidents, and the superposition of the two, the submission of fire evidence is mainly through the form of express logistics transportation.

[0003] According to statistics from the State Post Bureau, in the first half of 2021, the cumulative business volume of express service enterprises nationwide reached 49.39 billion, up 45.8% year-on-year. However, the rapid development of the express industry has also brought some problems, with the phenomenon of violent sorting being particularly prominent. Due to the fact that fire evidence such as burned debris is easily broken and pulverized, metal wires and glass evidence have sharp fractures, and extracted evidence is usually large in quantity, volume, and weight, once violent sorting occurs, the overall time sequence of the fire evidence will be destroyed (such as burned lithium battery packs being damaged during mailing, scattering, and making it difficult to trace their positional relationship), and even causing the express packaging box to be damaged, resulting in the loss of key small evidence such as molten beads; at the same time, violent sorting also causes the possibility of secondary combustion accidents of fire evidence (such as battery debris that has not been fully discharged or causes leakage of liquid flammable evidence).

[0004] An important aspect of evidence examination and identification in practice is whether the evidence has been damaged or changed during collection, storage, transportation, and identification. However, the traceable information when transporting evidence through express logistics is limited to the location-time dimension, and it is impossible to know whether the evidence has been subjected to violent sorting or affected by high-temperature environments during transportation. Once the evidence is confused or lost during this process, it is difficult to clarify the responsibilities, and related disputes continue to arise, which has become a new growth point for judicial disputes.

[0005] The main monitoring means for violent sorting at present is video monitoring, and a large number of literature and patents have reported related algorithms. However, due to the limited angle and hardware monitoring capability, it is impossible to guarantee the coverage of evidence in the entire express circulation chain, and related monitoring is usually arranged by express companies, which makes it doubtful to save, extract, and verify the effectiveness of related evidence when disputes arise, and it is easy to cause more judicial disputes in a judicial dispute.

[0006] Using sensors is another technical path for monitoring violent sorting and high temperature effects, but the MEMS (Microelectromechanical Systems) sensors used in current public literature and patent reports are rigid structures themselves, which are arranged in the evidence packaging box. When violent sorting or impact and vibration during transportation occurs, the sensor itself will collide with the fire evidence, thereby affecting the integrity of the fire evidence. At the same time, due to the high humidity and fine particle size of the fire evidence, and the common sharp fracture of the lead or the heavy lithium battery residue, all of which will significantly affect the service life and signal stability of the above-mentioned sensor. Finally, the above-mentioned MEMS type sensor does not have flame retardant performance, which may introduce the risk of fire.

[0007] At present, a large number of fire evidence is transported and sorted to the identification center through express logistics. Due to the fragility of the fire evidence, once subjected to violent sorting or high temperature, it is easy to be damaged and lost, which destroys the spatiotemporal order between the internal parts of the evidence, making it difficult to trace the cause of the accident, and even causing a secondary accident. Therefore, it is necessary to monitor and record whether the evidence is subjected to violent sorting or high temperature during the logistics process, in order to clarify the relevant responsibilities and protect the legal rights and interests of the inspection party and the identification center. SUMMARY

[0008] In view of the deficiencies of the existing violent sorting monitoring and high temperature warning technology and the particularity of fire evidence, the present application proposes a preparation method of a reusable intrinsic flame-retardant flexible material for violent sorting and high temperature warning of fire evidence, which can realize stress / temperature detection exceeding the threshold value and automatic alarm, and has self-healing performance and self-adhesion, which is suitable for different properties of various fire evidence and achieves the universality of application.

[0009] To achieve the above object, the present application adopts the following technical scheme:

[0010] A preparation method of a flexible material for violent sorting and high temperature warning of fire evidence during transportation, comprising the following steps:

[0011] Step 1: Add indium-gallium alloy liquid metal (EGaIn) to the container, pour into ethanol aqueous solution, stir thoroughly, drop in dopamine hydrochloride solution, and adjust the pH value to 7.5~9.0 using ammonia water, and stir at room temperature for 8h~24h. Drop acetone into the reaction solution, centrifuge, filter, and then wash the filter cake with acetone and dry naturally to obtain polydopamine-coated liquid metal;

[0012] Step 2: take (4-vinylphenyl) dimethyl silane (cas:4556-72-3), acrylate p-toluic acid (cas:41514-45-8), 1-vinyl-3-butyl imidazole hexafluorophosphate (cas:915358-85-9), dissolved in dichloromethane to form a solution, the total mass of the above three materials accounts for 78%~90% of the total mass of the solution; add the photoinitiator Irgacure-2959 (cas:106797-53-9), add the polydopamine coated liquid metal, after the material is fully stirred, pour into a polytetrafluoroethylene mold, under a 650W ultraviolet lamp, light irradiation to initiate polymerization for 5min~10min, dry the solvent to constant weight, and obtain a fire evidence transportation violence sorting and high temperature early warning flexible material.

[0013] In step 1, the mass fraction of ethanol in the ethanol aqueous solution is 30%~60%.

[0014] In step 1, the density of the dopamine hydrochloride solution is 0.03g / mL~0.08g / mL.

[0015] In step 1, the centrifugal speed is 500r / min~1500r / min, and the centrifugal time is 5min~15min.

[0016] In step 1, the mass ratio of indium-gallium alloy liquid metal to dopamine hydrochloride is (50~90):(50~10).

[0017] In step 2, the molar ratio of (4-vinylphenyl) dimethyl silane, acrylate p-toluic acid, and 1-vinyl-3-butyl imidazole hexafluorophosphate is (5~80):(5~80):(10~90).

[0018] In step 2, the ratio of the total molar amount of (4-vinylphenyl) dimethyl silane, acrylate p-toluic acid and 1-vinyl-3-butyl imidazole hexafluorophosphate to the molar amount of the photoinitiator is (95~99):(1~5).

[0019] In step 2, the mass ratio of (4-vinylphenyl) dimethyl silane, acrylate p-toluic acid and 1-vinyl-3-butyl imidazole hexafluorophosphate to the polydopamine coated liquid metal is (80%~99%):(20%~1%).

[0020] A fire evidence transportation violence sorting and high temperature early warning flexible material is prepared by the above preparation method.

[0021] The prepared early warning material has a limiting oxygen index of 28.3% to 33.1%, a UL-94 vertical burning test reaching V-0 level, a 30-day weight gain rate of 0.21% to 3.3%, an elongation at break of 500% to 1026%, a breaking strength of 138kPa to 1810kPa, and a specification factor of 8.1kPa -1 ~67kPa -1 , a 90° peeling strength (iron) of 0.82N to 5.22N, a response time of 200ms to 300ms, a recovery time of 200ms to 500ms, a 12h self-healing efficiency at room temperature of 28% to 92%, and a temperature sensing early warning capability: when the temperature is raised to 100℃ at a rate of 10℃ / min, the time interval from when the temperature reaches 90℃ to when the alarm light is on is less than 10s.

[0022] The present application has the following beneficial effects:

[0023] The present application has the following beneficial effects: Figure 2 The present application has the following beneficial effects:

[0024] In summary, the early warning material has the functions of sensing sensitivity, self-healing and intrinsic flame retardation. Figure 3As shown, the material can change resistance by sensing external stress changes and temperature changes, thereby changing current, providing a warning signal indicating that the evidence has encountered violence sorting or high temperature threat; the material has excellent flame retardant effect, is difficult to burn, self-extinguishes from fire, and has no dripping, which can effectively prevent secondary accidents caused by fire evidence; at the same time, the material has good adhesion damping effect, which can not only greatly reduce the probability of moving impact damage of fire evidence during transportation, but also can play a role in adhering and preserving the debris of falling fire evidence such as molten beads, effectively preventing the loss of key small evidence; the warning material can automatically repair the broken part after being broken, has normal temperature self-healing ability, reduces the possibility of loss of fire evidence, greatly improves the recycling times of the material, and has low cost and good economic benefit. The above characteristics can greatly improve the safety and traceability of fire evidence during express delivery / logistics transportation, and significantly reduce related judicial disputes. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Schematic diagram of liquid metal reaction coated with polydopamine;

[0026] Figure 2 Schematic diagram for preparing fire evidence transportation violence sorting and high temperature warning material;

[0027] Figure 3 Schematic diagram of material temperature sensing warning;

[0028] Figure 4 Transmission electron microscope image of liquid metal coated with polydopamine in Example 1;

[0029] Figure 5 Fracture elongation and fracture strength curve of warning material in Example 1;

[0030] Figure 6 Response and recovery time curve of warning material in Example 1;

[0031] Figure 7 Scanning electron microscope image of polydopamine coated liquid metal doped in warning material in Example 2;

[0032] Figure 8 Response and recovery time curve of warning material in Example 3;

[0033] Figure 9 Fracture elongation and fracture strength curve of warning material in Example 4;

[0034] Figure 10 30-day weight gain rate curve of warning material in Example 5;

[0035] Figure 11 Fracture elongation and fracture strength curve of warning material in Example 5;

[0036] Figure 12 Response and recovery time curve of the early warning material in Example 5;

[0037] Figure 13 12h self-healing efficiency test curve of the early warning material in Example 5;

[0038] Figure 14 Response curve of the early warning material in Example 5 to the gravity of different weights;

[0039] Figure 15 Cycle stability curve of the early warning material in Example 5 under the continuous action of the same stress for a short time. DETAILED DESCRIPTION

[0040] The application will be further described in conjunction with the examples, which are further detailed description of the application, but not limit the protection scope of the application.

[0041] The limiting oxygen index test refers to the standard GB / T 2406.2-2009, the UL-94 vertical burning test refers to the standard GB / T 2408-2021, and the 90° peel strength test refers to the standard ASTM D429-14.

[0042] The 30-day weight gain rate test method in the example is as follows: the prepared early warning material is placed in an indoor environment, weighed daily, and the percentage of the increased weight to the original weight after 30 days is the 30-day weight gain rate. Stable 30-day weight gain rate indicates that the material is not hygroscopic and does not dry, which characterizes the stability of the product.

[0043] The elongation at break and the strength at break test is carried out at room temperature using an electronic universal testing machine. The sample is cut into a rectangle (size, 50mm*4mm*2mm), and the tensile test is carried out at a tensile rate of 50mm / min. The elongation at break is defined as the deformation length (measured by an extensometer) at break of the material divided by the original length of the sample, and the strength at break is the tensile strength experienced by the material at break.

[0044] When detecting the stress sensor, the material is cut into a rectangle (size, 20mm*10mm*2mm), and then electrode clamps are fixed at both ends of the material. The signal of the material after being subjected to stress is monitored by an electrochemical workstation. The change in resistance of the material is recorded by the above-mentioned electrochemical workstation. The relative resistance change rate is calculated by formula (1):

[0045] (1)

[0046] Wherein, R0 and R are the initial resistance and the resistance when the strain is applied, respectively.

[0047] The normalization factor GF in the embodiment is calculated by formula (2):

[0048] (2)

[0049] wherein, is the pressure applied on the material. GF has a unit of (kPa -1 ).

[0050] The test method of response time and recovery time in the embodiment is that electrode clamps are fixed at both ends of a rectangular (size, 20mm*10mm*2mm) material, 1N stress is applied to it and then removed immediately, and the response time and recovery time of the material after being subjected to stress are monitored by an electrochemical workstation.

[0051] The test method of 12h self-healing efficiency in the embodiment is as follows: two identical samples are taken from the prepared early warning material, one of which is directly tested for fracture stress as an original sample, and the other is cut with a scalpel to form a 1cm long and 1cm deep incision on its surface, and then is realigned. After being placed at room temperature for 12h without applying any external force, the fracture strength is measured under the same conditions, and the percentage of the fracture strength of the original sample is the 12h self-healing efficiency.

[0052] The test method of temperature sensing early warning capability in the embodiment is as follows: the early warning material is placed on the surface of a hot stage, and the temperature is raised to 100℃ at a rate of 10℃ / min. When the temperature reaches 90℃, the alarm light turns on within 10s, which is considered as passing the early warning, otherwise it is considered as failing. The time interval from when the temperature is raised to 90℃ to when the alarm light turns on is recorded as the early warning time.

[0053] Example 1

[0054] A preparation method of a fire evidence transportation violence sorting and high temperature early warning flexible material, the specific operation steps are as follows:

[0055] Step 1: 10g of indium-gallium alloy liquid metal is added to a flask, poured into a 30% ethanol aqueous solution, stirred thoroughly, 125ml of 0.08g / mL dopamine hydrochloride solution (liquid metal:dopamine hydrochloride mass ratio 50:50) is added dropwise, and ammonia water is used to adjust the pH value to 7.5, and the reaction is stirred at room temperature for 24h. 10min of acetone is added dropwise to the reaction solution, centrifuged (500r / min) for 15min, filtered, the filter cake is washed with acetone for 3 times and naturally dried, and polydopamine coated liquid metal is obtained, as shown in Figure 1 . Figure 4 It is a transmission electron microscope image of polydopamine coated liquid metal.

[0056] Step 2: Take (4-vinylphenyl)dimethylsilane 1.62 g (0.01 mol), acrylate p-toluic acid 1.92 g (0.01 mol), 1-vinyl-3-butylimidazole hexafluorophosphate 53.30 g (0.18 mol), the molar ratio of the three materials is 5:5:90, dissolved in 14.21 g of dichloromethane to form a solution, the total mass of the three materials accounts for 80% of the total mass of the solution. Add 2.24 g (0.01 mol) of photoinitiator Irgacure-2959, the molar ratio of the total amount of the three materials to the molar amount of the initiator is 95:5. Add 14.21 g of polydopamine-coated liquid metal, the mass ratio of the total mass of the three materials to the mass of the polydopamine-coated liquid metal is 80%:20%. After stirring the above materials well, pour them into a polytetrafluoroethylene mold, and irradiate under a 650W ultraviolet lamp for 5min to initiate polymerization. Dry the solvent in an oven at 50°C to constant weight to obtain a flexible material for fire evidence transportation violence sorting and high temperature early warning.

[0057] After testing, the prepared early warning material has a limiting oxygen index of 32.6%, a UL-94 vertical burning test reaching V-0 level, a 30-day weight gain rate of 3.3%, an elongation at break of 500%, a breaking strength of 193kPa, and a specification factor of 52kPa -1 , a 90° peel strength (iron) of 3.53N, a response time of 200ms, a recovery time of 400ms, a 12h self-healing efficiency at room temperature of 53%, and a temperature sensing warning capability: pass, 820ms. Figure 5 The elongation at break and breaking strength curve of the early warning material is shown in Figure 6 The response and recovery time curve of the early warning material is shown in

[0058] Example 2

[0059] A method for preparing a flexible material for fire evidence transportation violence sorting and high temperature early warning, the specific operation steps are as follows:

[0060] Step 1: Add 27 g of indium-gallium alloy liquid metal to a flask, pour into a 60% ethanol aqueous solution, stir well, and drop 100 ml of 0.03 g / mL dopamine hydrochloride solution (liquid metal:dopamine hydrochloride mass ratio 90:10) into the solution. Adjust the pH value to 9.0 using ammonia water, and stir at room temperature for 8h. Add acetone to the reaction solution and settle for 10min, centrifuge (1500r / min) for 5min, filter, wash the filter cake with acetone for 3 times and dry naturally to obtain polydopamine-coated liquid metal.

[0061] Step 2: Take (4-vinylphenyl)dimethylsilane 64.84 g (0.4 mol), acrylate p-toluic acid 9.62 g (0.05 mol), 1-vinyl-3-butylimidazole hexafluorophosphate 14.80 g (0.05 mol), the molar ratio of the three materials is 80:10:10, dissolved in 9.92 g of dichloromethane to form a solution, and the total mass of the three materials accounts for 90% of the total mass of the solution. Add 1.12 g (0.005 mol) of photoinitiator Irgacure-2959, the molar ratio of the total amount of the three materials to the molar amount of the initiator is 99:1. Add 0.90 g 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 the above materials are stirred well, pour them into a polytetrafluoroethylene mold, and irradiate under a 650W ultraviolet lamp to initiate polymerization for 10 min. Dry the solvent in an oven at 50°C to a constant weight, and obtain a flexible material for fire evidence transportation violence sorting and high temperature early warning.

[0062] After testing, the prepared early warning material has a limiting oxygen index of 29.1%, a UL-94 vertical burning test reaching V-1 level, a 30-day weight gain rate of 2.81%, an elongation at break of 621%, a breaking strength of 138 kPa, and a specification factor of 8.1 kPa -1 , 90° peel strength (iron) 0.82N, response time 300ms, recovery time 500ms, self-healing efficiency at room temperature 12h 37%, temperature sensing warning capability: pass, 1390ms. Figure 7 Scanning electron microscope image of the polydopamine-coated liquid metal doped in the early warning material prepared in Example 2.

[0063] Example 3

[0064] A method for preparing a flexible material for fire evidence transportation violence sorting and high temperature early warning, the specific operation steps are as follows:

[0065] Step 1: Add 12 g of indium-gallium alloy liquid metal to a flask, pour into a 60% ethanol aqueous solution, stir well, and drop 200 ml of 0.04 g / mL dopamine hydrochloride solution (liquid metal:dopamine hydrochloride mass ratio 60:40). Adjust the pH value to 8.0 using ammonia water, and stir at room temperature for 12 h. Add acetone to the reaction solution and settle for 10 min, centrifuge (750 r / min) for 6 min, filter, wash the filter cake with acetone for 3 times and dry naturally, and obtain polydopamine-coated liquid metal.

[0066] Step 2: Take (4-vinylphenyl)dimethylsilane 8.10 g (0.05 mol), acrylate p-toluic acid 76.82 g (0.4 mol), 1-vinyl-3-butylimidazole hexafluorophosphate 14.80 g (0.05 mol), the molar ratio of the three materials is 10:80:10, dissolved in 17.60 g 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 4.71 g (0.021 mol) of photoinitiator Irgacure-2959, the molar ratio of the total amount of the three materials to the molar amount of the initiator is 96:4. Add 5.25 g of polydopamine-coated liquid metal, the mass ratio of the total mass of the three materials to the mass of the polydopamine-coated liquid metal is 95%:5%. After stirring the above materials well, pour them into a polytetrafluoroethylene mold, and irradiate under a 650W ultraviolet lamp to initiate polymerization for 9min. Dry the solvent in an oven at 50°C to constant weight to obtain a flexible material for fire evidence transportation violence sorting and high temperature early warning.

[0067] After testing, the prepared early warning material has a limiting oxygen index of 28.3%, a UL-94 vertical burning test reaching V-1 level, a 30-day weight gain rate of 1.78%, an elongation at break of 705%, a breaking strength of 262kPa, and a specification factor of 23kPa -1 , 90° peel strength (iron) 1.15N, response time 300ms, recovery time 300ms, self-healing efficiency at room temperature 12h 28%, temperature sensing warning capability: pass, 1160ms. Figure 8 Response and recovery time curve of the early warning material prepared in Example 3.

[0068] Example 4

[0069] A method for preparing a flexible material for fire evidence transportation violence sorting and high temperature early warning, the specific operation steps are as follows:

[0070] Step 1: Add 21 g of indium-gallium alloy liquid metal to a flask, pour into a 40% ethanol aqueous solution, stir well, and drop 150 ml of 0.06 g / mL dopamine hydrochloride solution (liquid metal:dopamine hydrochloride mass ratio 70:30). Adjust the pH value to 8.5 using ammonia water, and stir at room temperature for 16 h. Add acetone to the reaction solution and settle for 10 min, centrifuge (1250 r / min) for 10 min, filter, wash the filter cake with acetone for 3 times and dry naturally to obtain polydopamine-coated liquid metal.

[0071] Step 2: Take (4-vinylphenyl)dimethylsilane 1.62 g (0.01 mol), acrylate p-toluic acid 7.68 g (0.04 mol), 1-vinyl-3-butylimidazole hexafluorophosphate 14.80 g (0.05 mol), the molar ratio of the three materials is 10:40:50, dissolved in 6.73 g of dichloromethane to form a solution, the total mass of the three materials accounts for 78% of the total mass of the solution. Add 0.67 g (0.003 mol) of photoinitiator Irgacure-2959, the molar ratio of the total amount of the three materials to the molar amount of the initiator is 97:3. Add 2.68 g of polydopamine-coated liquid metal, the mass ratio of the total mass of the three materials to the mass of the polydopamine-coated liquid metal is 90%:10%. After stirring the above materials well, pour them into a polytetrafluoroethylene mold, and irradiate under a 650W ultraviolet lamp to initiate polymerization for 8min. Dry the solvent in an oven at 50°C to constant weight to obtain a flexible material for fire evidence transportation violence sorting and high temperature early warning.

[0072] After testing, the prepared flexible material has an limiting oxygen index of 30.7%, a UL-94 vertical burning test reaching V-0 level, a 30-day weight gain rate of 0.53%, an elongation at break of 1026%, a breaking strength of 1308kPa, and a specification factor of 31kPa -1 , a 90° peel strength (iron) of 3.91N, a response time of 270ms, a recovery time of 320ms, a 12h self-healing efficiency at room temperature of 77%, and a temperature sensing warning capability: pass, 210ms. Figure 9 The elongation at break and breaking strength curves of the early warning material prepared in Example 4.

[0073] Example 5

[0074] A method for preparing a flexible material for fire evidence transportation violence sorting and high temperature early warning, the specific operation steps are as follows:

[0075] Step 1: Add 10 g of indium-gallium alloy liquid metal to a flask, pour into a 40% ethanol aqueous solution, stir well, and drop 50 ml of 0.05 g / mL dopamine hydrochloride solution (liquid metal:dopamine hydrochloride mass ratio 80:20), and adjust the pH value to 7.5 using ammonia water. Stir at room temperature for 12 h. Add acetone to the reaction solution and settle for 10 min, centrifuge (1000 r / min) for 8 min, filter, wash the filter cake with acetone for 3 times and dry naturally to obtain polydopamine-coated liquid metal.

[0076] Step 2: Take (4-vinylphenyl)dimethylsilane 4.86 g (0.03 mol), acrylate p-toluic acid 3.84 g (0.02 mol), 1-vinyl-3-butylimidazole hexafluorophosphate 14.80 g (0.05 mol), the molar ratio of the three materials is 30:20:50, dissolved in 2.61 g of dichloromethane to make a solution, and the total mass of the three materials accounts for 90% of the total mass of the solution. Add 0.45 g (0.002 mol) of photoinitiator Irgacure-2959, the molar ratio of the total amount of the three materials to the molar amount of the initiator is 98:2. Add 4.15 g of polydopamine coated liquid metal, the mass ratio of the total mass of the three materials to the mass of the polydopamine coated liquid metal is 85%:15%. After stirring the above materials well, pour them into a polytetrafluoroethylene mold, and irradiate under a 650 W ultraviolet lamp to initiate polymerization for 6 min. Dry the solvent in an oven at 50°C to constant weight, and obtain a fire evidence transportation violence sorting and high temperature warning flexible material.

[0077] Tested, the prepared warning material has a limiting oxygen index of 33.1%, a UL-94 vertical burning test reaching V-0 level, a 30-day weight gain rate of 0.21%, an elongation at break of 902%, a breaking strength of 1810 kPa, and a specification factor of 67 kPa -1 , 90° peel strength (iron) 5.22N, response time 200ms, recovery time 200ms, 12h self-healing efficiency at room temperature 92%, temperature warning capability: pass, 100ms. Figure 10 The 30-day weight gain rate curve of the warning material prepared in Example 5; Figure 11 The elongation at break and breaking strength curve of the warning material; Figure 12 The response and recovery time curve of the warning material; Figure 13 The 12h self-healing efficiency test curve of the warning material; Figure 14 The response curve of the warning material to the gravity of different weights; Figure 15 The cycle stability curve of the warning material under the continuous action of the same stress for a short time.

[0078] Comparative Example 1

[0079] A preparation method of a fire evidence transportation violence sorting and high temperature warning material, the specific operation steps are as follows:

[0080] Step 1: 10g of indium-gallium alloy liquid metal was added to a flask, poured into a 40% ethanol aqueous solution, stirred thoroughly, and 50ml of 0.05g / mL dopamine hydrochloride solution (liquid metal:dopamine hydrochloride mass ratio 80:20) was added dropwise, and the pH value was adjusted to 7.5 using ammonia water, and the reaction was stirred at room temperature for 12h. Acetone was added dropwise to the reaction solution and settled for 10min, centrifuged (1000r / min) for 8min, filtered, and the filter cake was washed with acetone for 3 times and naturally dried to obtain polydopamine-coated liquid metal.

[0081] Step 2: 3.12g of styrene (0.03mol), 3.84g of acrylic ester-based p-toluic acid (0.02mol), and 14.80g of 1-vinyl-3-butylimidazole hexafluorophosphate (0.05mol) were dissolved in 2.42g of dichloromethane to form a solution, and the total mass of the above three materials accounted for 90% of the total mass of the solution. 0.45g (0.002mol) of photoinitiator Irgacure-2959 was added, and the total molar amount of the three materials to the molar amount of the initiator was 98:2. 3.84g of polydopamine-coated liquid metal was added, and the mass ratio of the total mass of the three materials to the polydopamine-coated liquid metal was 85%:15%. After the above materials were stirred thoroughly, they were poured into a polytetrafluoroethylene mold, and polymerization was initiated under a 650W ultraviolet lamp for 6min, and the solvent was dried to constant weight in a 50℃ oven to obtain a fire evidence transportation violence sorting and high temperature warning material.

[0082] After testing, the prepared warning material had a limiting oxygen index of 26.1%, a UL-94 vertical burning test reached V-1 level, a 30-day weight gain rate of 3.88%, an elongation at break of 83%, a breaking strength of 117kPa, a specification factor of 3.7kPa, a 90° peel strength (iron) of 0.55N, a response time of 830ms, a recovery time of 950ms, a self-healing efficiency of 7.5% at room temperature for 12h, and a temperature warning capability: failed at 15s. -1

[0083] Comparative Example 2

[0084] A preparation method of a fire evidence transportation violence sorting and high temperature warning material, the specific operation steps are as follows:

[0085] ​Step 1: Add 10g of indium gallium alloy liquid metal to a flask, pour in a 40% (w / w) ethanol aqueous solution, stir thoroughly, add 50ml of 0.05g / mL dopamine hydrochloride solution (liquid metal: dopamine hydrochloride mass ratio 80:20), and adjust the pH to 7.5 with ammonia water. Stir the reaction at room temperature for 12h. Add acetone dropwise to the reaction solution for 10min to allow precipitation, centrifuge (1000r / min) for 8min, filter, wash the filter cake three times with acetone and let it air dry to obtain polydopamine-coated liquid metal.

[0086] Step 2: Take 4.86 g (0.03 mol) of (4-vinylphenyl)dimethylsilane, 3.28 g (0.02 mol) of 4-hydroxyphenyl acrylate (CAS: 3233-36-1), and 14.80 g (0.05 mol) of 1-vinyl-3-butylimidazolium hexafluorophosphate, with a molar ratio of 30:20:50, and dissolve them in 2.61 g of dichloromethane to prepare a solution. The total mass of the three materials accounts for 90% of the total mass of the solution. Add 0.45 g (0.002 mol) of photoinitiator Irgacure-2959, with a molar ratio of the total molar mass of the three materials to the molar mass of the initiator of 98:2. Add 4.15 g of polydopamine-coated liquid metal, with a mass ratio of the total mass of the three materials to the mass of the polydopamine-coated liquid metal of 85%:15%. After the above materials are thoroughly mixed, they are poured into a polytetrafluoroethylene mold and polymerized under a 650W ultraviolet lamp for 6 minutes. The solvent is then dried in a 50°C oven to constant weight to obtain materials for transporting fire evidence, handling violent sorting, and high-temperature warning.

[0087] Testing revealed that the prepared warning material had a limiting oxygen index of 28.6%, achieved a V-1 rating in the UL-94 vertical burning test, a 30-day weight gain of 5.23%, an elongation at break of 357%, a tensile strength of 89 kPa, and a specification factor of 1.2 kPa. -1 90° peel strength (iron) 1.67N, response time 500ms, recovery time 770ms, self-healing efficiency at room temperature for 12h 12s , temperature warning capability: failed, 12s.

[0088] Comparative Example 3

[0089] A method for preparing a material for violent sorting during the transportation of fire evidence and for high-temperature early warning, the specific operation steps are as follows:

[0090] Step 1: 10 g of indium-gallium alloy liquid metal was added to a flask, poured into a 40% ethanol aqueous solution, stirred thoroughly, and 50 ml of 0.05 g / mL dopamine hydrochloride solution (liquid metal:dopamine hydrochloride mass ratio 80:20) was added dropwise, and the pH value was adjusted to 7.5 using ammonia water, and the reaction was stirred at room temperature for 12 h. Acetone was added dropwise to the reaction solution and settled for 10 min, centrifuged (1000 r / min) for 8 min, filtered, and the filter cake was washed with acetone for 3 times and naturally dried to obtain polydopamine-coated liquid metal.

[0091] Step 2: (4-vinylphenyl)dimethylsilane 4.86 g (0.03 mol), acrylic acid ester group p-toluic acid 3.84 g (0.02 mol), 1-butyl-3-ethylimidazole hexafluorophosphate (cas:256647-89-9) 14.91 g (0.05 mol), the molar ratio of the three materials is 30:20:50, dissolved in 2.62 g of dichloromethane to make a solution, the total mass of the above three materials accounts for 90% of the total mass of the solution. Add 0.45 g (0.002 mol) of photoinitiator Irgacure-2959, the total molar amount of the three materials to the molar amount of the initiator is 98:2. Add 4.17 g of polydopamine-coated liquid metal, the mass ratio of the total mass of the three materials to the polydopamine-coated liquid metal is 85%:15%. After the above materials are stirred thoroughly, pour into a polytetrafluoroethylene mold, and irradiate under a 650 W ultraviolet lamp for 6 min to initiate polymerization, and dry the solvent in a 50°C oven to constant weight to obtain a fire evidence transportation violence sorting and high temperature early warning material.

[0092] After testing, the prepared early warning material has a limiting oxygen index of 27.5%, a UL-94 vertical burning test reaching V-1 level, a 30-day weight gain rate of 18.30%, an elongation at break of 27%, a breaking strength of 33 kPa, a specification factor of 5.5 kPa, a 90° peel strength (iron) of 0.13 N, a response time of 1060 ms, a recovery time of 1250 ms, a 12 h self-healing efficiency at room temperature of 3.9%, and a temperature sensing warning capability of 18 s. -1 , 90° peel strength (iron) 0.13 N, response time 1060 ms, recovery time 1250 ms, room temperature 12 h self-healing efficiency 3.9%, temperature sensing warning capability: not passed, 18 s.

Claims

1. A method for preparing a fire evidence transport violence sorting and high temperature early warning flexible material, characterized in that, Comprising the following steps: Step 1: adding indium-gallium alloy liquid metal into a container, pouring into an ethanol aqueous solution, stirring thoroughly, dropping in a dopamine hydrochloride solution, and adjusting the pH value to 7.5-9.0 using ammonia water, stirring at room temperature for 8-24 hours; dropping acetone into the reaction solution to precipitate, centrifuging, filtering, washing the filter cake with acetone by stirring, and naturally drying to obtain polydopamine-coated liquid metal; Step 2: taking (4-vinylphenyl)dimethylsilane, acrylate p-toluic acid, and 1-vinyl-3-butylimidazole hexafluorophosphate, dissolving them in dichloromethane to form a solution, the total mass of the three materials accounting for 78-90% of the total mass of the solution, the molar ratio of (4-vinylphenyl)dimethylsilane, acrylate p-toluic acid, and 1-vinyl-3-butylimidazole hexafluorophosphate being (5-80):(5-80):(10-90); adding a photoinitiator Irgacure-2959 and polydopamine-coated liquid metal, stirring the materials thoroughly, pouring into a polytetrafluoroethylene mold, and irradiating under a 650W ultraviolet lamp to initiate polymerization for 5-10 minutes, and drying the solvent to constant weight to obtain a fire evidence transportation violence sorting and high-temperature early warning flexible material; wherein the mass ratio of the total mass of (4-vinylphenyl)dimethylsilane, acrylate p-toluic acid, and 1-vinyl-3-butylimidazole hexafluorophosphate to polydopamine-coated liquid metal is (80-99):(20-1).

2. The preparation method of the fire evidence transportation violence sorting and high temperature early warning flexible material according to claim 1, characterized in that, In step 1, the mass fraction of ethanol in the ethanol aqueous solution is 30-60%.

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

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

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

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

7. A fire evidence transport violence sorting and high temperature early warning flexible material, characterized in that, The fire evidence transportation violence sorting and high-temperature early warning flexible material is prepared by the method of any one of claims 1-6.

8. The fire evidence transport violence sorting and high temperature early warning flexible material according to claim 7, characterized in that, The warning material has a limiting oxygen index of 28.3%~33.1%, achieves a V-0 rating in the UL-94 vertical burning test, a 30-day weight gain of 0.21%~3.3%, an elongation at break of 500%~1026%, a tensile strength of 138kPa~1810kPa, and a specification factor of 8.1kPa. -1 ~67kPa -1 Peel strength at 90°C is 0.82N~5.22N, response time is 200ms~300ms, recovery time is 200ms~500ms, self-healing efficiency at room temperature for 12 hours is 28%~92%, and temperature warning capability: when the temperature is raised to 100°C at a rate of 10°C / min, the time interval between when the temperature reaches 90°C and when the alarm light is on is less than 10s.

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