CN112457420B - Preparation method of ultralow-smoke seaweed polysaccharide material - Google Patents

Abstract

The invention belongs to the technical field of seaweed polysaccharide materials, and particularly relates to a preparation method of an ultralow-smoke seaweed polysaccharide material.

Description

A kind of preparation method of ultra-low smoke seaweed polysaccharide material

technical field

The invention belongs to the technical field of seaweed polysaccharide materials, in particular to a preparation method of ultra-low smoke seaweed polysaccharide materials.

Background technique

In addition to the crowded places such as shopping malls, hotels, restaurants, entertainment venues, and transportation vehicles, which are prone to fires, urban and rural residences are also prone to fires. In these numerous fires, the smoke produced by combustible materials, including flame-retardant materials, is very harmful. The people who "burned to death" were actually poisoned by smoke, suffocated, and then burned to death. So smoke is the main cause of casualties. Therefore, in addition to having a good flame retardant effect, it is more important to achieve low smoke or no smoke for flame retardant materials.

In the prior art, halogen flame retardants are one of the good flame retardants, but halogen-containing flame retardants usually increase the amount of smoke, which is its major defect, so it has always been the research direction of scientific and technological workers to improve. Calcium alginate material is a bulk flame retardant material, which has attracted great interest of researchers because it is an environmentally friendly material, but it is a polysaccharide material with limited flame retardant properties and weak antibacterial properties, especially it can still produce more The smoke cannot meet the higher requirements for flame retardant textiles and their decorative materials. Zinc salts are usually used in the development of low-smoke materials, but the total smoke emission of zinc alginate is still as high as 274.28m ² /m ² .

Using silver to impart antibacterial properties to seaweed polysaccharides while improving flame retardancy and reducing smoke emission has also been a challenge. The methods of adding silver to alginate fibers mainly include silver plating on the surface of the fibers, adding silver compounds, complexes or metallic silver to the fiber spinning solution and soaking the fibers in a silver-containing solution, and in order to achieve effective antibacterial, The content of silver in the material accounts for 1% to 7% of the mass of alginate fibers. Since these methods have a low loading rate of silver, the actual amount is much larger than this range, which undoubtedly puts pressure on the rare resource of silver. .

SUMMARY OF THE INVENTION

The present invention is a solution proposed to overcome the above-mentioned defects of the prior art. Its technical solutions are:

A preparation method of ultra-low-smoke seaweed polysaccharide material, comprising the following steps:

(1) Preparation of solution A: firstly, deionized water is heated to 30-50°C, and under the action of ultrasonic waves, polyvinylpyrrolidone K90, chloride and sodium alginate are dissolved in it in turn, and the reaction is maintained for 30-60min. ;

(2) preparation solution B: take by weighing equimolar silver nitrate with chloride, at normal temperature, silver nitrate is dissolved in deionized water, then under stirring, ammonia water is added dropwise to the solution, and then the stirring reaction is maintained for 3-5min, that is obtained;

(3) Preparation of crystallized product C: solution B was added dropwise to solution A under the conditions of heating in a water bath and stirring, and then, the stirring was terminated when the reaction solution became milky white, and maintained at a constant temperature of 40-50° C. for 10- 20min, that is;

(4) After placing the crystallized product C in the molding equipment, add it to the soluble non-halide salt solution for cross-linking reaction for 10-15 minutes, rinse with deionized water for 3-5 times, then steam dry, and cool to At room temperature, the ultra-low smoke seaweed polysaccharide material is obtained.

The chloride is any one or a combination of sodium chloride, potassium chloride and ammonium chloride; more preferably sodium chloride.

The mass ratio of chloride, polyvinylpyrrolidone, sodium alginate and deionized water in the solution A is 1:(0.1-0.3):(15-25):(400-500).

The polyvinylpyrrolidone has an average molecular weight of ≥120,000.

The soluble non-halide salt is any one or a combination of calcium nitrate, calcium acetate, calcium lactate, zinc nitrate, zinc acetate, and zinc lactate; preferably calcium lactate or zinc lactate.

The mass ratio of silver nitrate, ammonia water and deionized water in the solution B is 1:(5-6):(5-7).

The ammonia water has a volume concentration of 25%.

The water bath is heated at a temperature of 35-45°C.

The temperature of the constant temperature curing is 40-50°C.

The crystallite C has a particle size of 5-50 nm.

The mass concentration of the soluble non-halide salt solution is 1-3%.

In the cross-linking reaction, the mass ratio of the crystalline substance C to the soluble non-halide salt solution is 1:3-10.

The ultra-low smoke seaweed polysaccharide material has a limiting oxygen index greater than 60% and an antibacterial rate greater than 99%.

The ultra-low smoke seaweed polysaccharide material has a total smoke release (TSR) of less than 3m ² /m ² .

The technical effect directly brought about by the above technical solution is to use the marine biological resource sodium alginate as the raw material, prepare the nano-silver chloride sol through the particle size controllable technology, and place it in the coagulation bath of divalent metal ions after being shaped by a forming equipment. The ion exchange reaction takes place to prepare ultra-low smoke seaweed polysaccharide materials with a limiting oxygen index greater than 60%, an antibacterial rate greater than 99%, and a total smoke release less than 3m ² /m ² , which can meet the needs of homes, nursing homes, kindergartens, entertainment, military The demand for ultra-low smoke flame retardant and antibacterial materials for home textile products and decorative materials in equipment, automobiles, motor vehicles, passenger ships and other occasions.

Beneficial effects:

1. Nano-silver chloride seaweed polysaccharide material subverts the existing technical cognition of halogen-containing material smoke, nano-silver chloride not only endows seaweed polysaccharide material with high flame retardant and strong antibacterial properties, but also achieves ultra-low smoke effect: total The amount of smoke is only 3.4% of calcium alginate, 0.98% of zinc alginate, and 0.93% of zinc alginate/nano cuprous oxide composite material.

2. The original process is that sodium alginate and silver ammonia ion sol enter the calcium chloride coagulation bath to directly generate silver chloride and calcium alginate composite material by one-step method; In the sol, the one-step generation process of silver chloride and calcium alginate is changed to a two-step process of generating silver chloride and calcium alginate successively, which overcomes the disadvantage that the original process cannot control the particle size of silver chloride.

3. The polyvinylpyrrolidone model agent with an average molecular weight of ≥120,000 is premixed in the sol, which plays a role in regulating silver chloride grains.

4. The selection of soluble non-halide calcium salts and zinc salts avoids the disadvantage that excessive chloride ions can promote the aggregation and increase of nano-silver chloride and lose nano-size.

5. The process is simple, operability is strong, pollution-free, and the material is environmentally friendly, suitable for large-scale industrial production.

Description of drawings

Fig. 1: the electron microscope picture of finished material in embodiment 1;

Fig. 2: Electron micrograph of finished material in embodiment 4;

Fig. 3: Electron micrograph of finished material in embodiment 2;

Figure 4: Electron microscope image of finished material in Example 5;

Figure 5: Electron microscope image of finished material in Example 3;

Figure 6: Electron micrograph of the finished material in Example 6.

Detailed ways

The specific embodiments of the present invention are described in further detail below, but the present invention is not limited to these embodiments, and any improvement or substitution in the basic spirit of the present embodiment still belongs to the scope of protection of the claims of the present invention.

Example 1

(1) Sodium chloride, polyvinylpyrrolidone K90 with an average molecular weight of ≥120,000, sodium alginate, and deionized water were prepared into solution A according to the mass ratio of 1:0.2:20:450; specifically: first deionized The water is heated to 40°C, and under the action of ultrasonic waves, polyvinylpyrrolidone K90, chloride and sodium alginate are dissolved in it in turn, and the reaction is maintained for 50min.

(2) take by weighing the silver nitrate equimolar with sodium chloride, then respectively make solution B with silver nitrate, 25% ammonia water, deionized water according to the mass ratio of 1:5.5:6; specifically: first under normal temperature conditions Dissolving silver nitrate in water, then adding 25% ammonia water dropwise to the silver nitrate solution under stirring conditions, and maintaining the stirring reaction for 4 min to obtain;

(3) under 40 ℃ of water bath heating and stirring, the solution B was added dropwise to the solution A, and the stirring was terminated when the reaction solution became milky white, and the crystalline product C was obtained by standing at a constant temperature for 15 min at 45 ℃;

(4) After placing the crystallized product C in the molding equipment, according to the mass ratio of the crystallized product C and the soluble non-halide salt solution of 1:7, the crystallized product C was added to the 2% calcium lactate solution for cross-linking reaction 12min, soaked with deionized water for 4 times, finally steam dried, cooled to room temperature is the finished product.

Example 2

(1) Potassium chloride, polyvinylpyrrolidone K90 with an average molecular weight of ≥120,000, sodium alginate, and deionized water were prepared into solution A according to the mass ratio of 1:0.1:15:400; specifically: first deionized The water is heated to 30°C, and under the action of ultrasonic wave, polyvinylpyrrolidone K90, chloride and sodium alginate are dissolved in it in turn, and the reaction is maintained for 60min.

(2) take by weighing the silver nitrate that is equimolar with potassium chloride, then respectively silver nitrate, 25% ammonia water, deionized water are made into solution B according to the mass ratio of 1:5:5; specifically: first under normal temperature conditions Dissolving silver nitrate in water, then adding 25% ammonia water dropwise to the silver nitrate solution under stirring conditions, and maintaining the stirring reaction for 3 min to obtain;

(3) under 40 ℃ of water bath heating and stirring, solution B is added dropwise to solution A, and the stirring is terminated when the reaction solution becomes milky white, and the crystalline product C is obtained by standing at a constant temperature at 40 ℃ for curing for 10 min;

(4) After placing the crystallized product C in the molding equipment to shape, then according to the mass ratio of the crystallized product C to the soluble non-halide salt solution of 1:10, the crystallized product C was added to the 1% zinc nitrate solution for cross-linking reaction 10min, soaked with deionized water for 5 times, finally dried with steam, and cooled to room temperature is the finished product

Example 3

(1) ammonium chloride, polyvinylpyrrolidone K90 with an average molecular weight of ≥120,000, sodium alginate, and deionized water were prepared into solution A according to the mass ratio of 1:0.3:25:500; specifically: first deionized The water is heated to 50°C, and under the action of ultrasonic waves, polyvinylpyrrolidone K90, chloride and sodium alginate are dissolved in it in turn, and the reaction is maintained for 30min.

(2) take by weighing equimolar silver nitrate with ammonium chloride, then respectively make solution B with silver nitrate, 25% ammonia water, deionized water according to the mass ratio of 1:6:7; specifically: first under normal temperature conditions Dissolving silver nitrate in water, adding 25% ammonia water dropwise to the silver nitrate solution under stirring conditions, and maintaining the stirring reaction for 5 min, to obtain;

(3) under 40 ℃ of water bath heating and stirring, solution B was added dropwise to solution A, and the stirring was terminated when the reaction solution became milky white, and the crystalline product C was obtained by standing at a constant temperature for 20 min at 40 ℃;

(4) After the crystallized product C is placed in the molding equipment and shaped, then according to the mass ratio of the crystallized product C and the soluble non-halide salt solution of 1:3, the crystallized product C is added to the mass such as 3% calcium acetate and zinc acetate. After the cross-linking reaction in the mixed solution for 15 minutes, the product is washed with deionized water for 5 times, and finally steam dried and cooled to room temperature to obtain the finished product.

Example 4

(1) The sodium alginate and deionized water are respectively prepared into solution A according to the mass ratio of 20:450; specifically, the deionized water is first heated to 40° C., and then slowly sodium alginate is added to the solution under the action of ultrasound to dissolve Complete, maintain for 50min;

(2) take by weighing the silver nitrate of sodium alginate mass 5%, then respectively make solution B with silver nitrate, 25% ammoniacal liquor, deionized water according to the mass ratio of 1:5.5:6; The silver nitrate is dissolved in deionized water, and then 25% ammonia water is added dropwise to the silver nitrate solution under stirring, and the stirring reaction is maintained for 4 minutes to obtain;

(3) Heating in a water bath at 40°C, under stirring, add solution B dropwise to solution A, and then react at a constant temperature of 45°C for 15 min to obtain crystallized product C;

(4) After placing the crystallized product C in the molding equipment, then according to the mass ratio of the crystallized product C and the soluble non-halide salt solution of 1:7, the crystallized product C was added to the 2% calcium chloride solution for cross-linking The reaction is carried out for 12 minutes, and calcium alginate and silver chloride will be simultaneously generated in the reaction, immersed in deionized water for 4 times, and finally steam-dried and cooled to room temperature to obtain the finished product.

Example 5

(1) Potassium chloride, sodium alginate, and deionized water are respectively made into solution A according to the mass ratio of 1:15:400; specifically, potassium chloride is first dissolved in deionized water, heated to 40 ° C, and ultrasonically Under the action, slowly add sodium alginate into it to dissolve completely, and keep it for 30min;

(2) take by weighing the silver nitrate that is equimolar with potassium chloride, then respectively silver nitrate, 25% ammoniacal liquor, deionized water are made into solution B according to the mass ratio of 1:5:5; specifically: under normal temperature conditions, The silver nitrate is dissolved in deionized water, and then 25% ammonia water is added dropwise to the silver nitrate solution under stirring, and the stirring reaction is maintained for 3 minutes to obtain;

(3) Heating in a water bath at 40°C, adding solution B dropwise to solution A under stirring, stopping stirring when the reaction solution becomes milky white, and maintaining at 40°C for 10 minutes to obtain crystallized product C;

(4) After the crystallized product C is placed in the molding equipment for shaping, the mass ratio of the crystallized product C to the soluble non-halide salt solution is 1:10, and the crystallized product C is added to a 1% calcium nitrate solution for cross-linking. The reaction was carried out for 10 min, washed with deionized water for 5 times, and finally steam dried and cooled to room temperature to obtain the finished product.

Example 6

(1) ammonium chloride, polyvinylpyrrolidone K90 with an average molecular weight of ≥120,000, sodium alginate, and deionized water were prepared into solution A according to the mass ratio of 1:0.3:25:500; specifically: first deionized The water is heated to 40°C, and under the action of ultrasonic waves, polyvinylpyrrolidone K90, chloride and sodium alginate are dissolved in it in turn, and the reaction is maintained for 60min.

(2) Weigh silver nitrate in an equimolar amount with ammonium chloride, and then respectively mix silver nitrate, 25% ammonia water and deionized water into solution B according to the mass ratio of 1:6:7. Specifically: first, the silver nitrate is dissolved in water under normal temperature conditions, and then 25% ammonia water is added dropwise to the silver nitrate solution under stirring conditions, and the stirring reaction is maintained for 5 minutes, to obtain;

(3) under 40 ℃ of water bath heating and stirring, solution B was added dropwise to solution A, and the stirring was terminated when the reaction solution became milky white, and the crystalline product C was obtained by standing at a constant temperature for 20 min at 40 ℃;

(4) After placing the crystallized product C in the molding equipment, the mass ratio of the crystallized product C to the soluble non-halide salt solution is 1:7, and the crystallized product C is added to a 3% calcium chloride solution. Combined reaction for 15min, rinsed with deionized water for 3 times, finally steam dried, cooled to room temperature to obtain the finished product.

Fig. 1: the electron microscope image of finished material in embodiment 1; Namely the electron microscope image that silver chloride and calcium alginate two-step method generate seaweed polysaccharide material;

Fig. 2: the electron micrograph of finished material in embodiment 4; Namely the electron micrograph of silver chloride and calcium alginate one-step method to generate seaweed polysaccharide material;

By comparing Fig. 1 and Fig. 2, it can be seen that: the silver chloride in the one-step generation process is micron-level, and the agglomeration phenomenon is obvious, and the silver chloride in the two-step generation process is nano-level, and the particle size is between 5-50 nanometers Thus illustrate: the two-step method overcomes the defect that one-step method technology is not easy to obtain nano silver chloride in the present invention.

Fig. 3: the electron microscope image of finished material in embodiment 2; Namely the electron microscope image of the seaweed polysaccharide material produced by the process within the protection scope of the invention;

Fig. 4: Electron micrograph of finished material in embodiment 5; That is, the process difference from the inventive protection scope of the present invention is the electron micrograph of the seaweed polysaccharide material produced under the condition of not adding PVP K90;

By comparing the graph and Fig. 4, it can be seen that: when no PVP is added, the silver chloride has micron-sized particles exceeding 1200 nanometers; while the silver chloride in the two-step process with the addition of high-molecular-weight polyvinylpyrrolidone K90 is nano-sized, with a particle size of 5 Between -20 nanometers; this shows that: PVP K90 plays an effective role in controlling the growth of silver chloride crystal nucleus, thereby overcoming the defect that it is difficult to obtain nano-silver chloride in one-step process;

Fig. 5: Electron microscope image of finished material in Example 3; Fig. 6: Electron microscope image of finished material in Example 6; It can be seen from Fig. 5 and Fig. 6: Fig. 5 adopts calcium acetate and zinc acetate mixed solution as cross-linking agent , the electron microscope image of the seaweed polysaccharide material produced by the coagulation bath two-step method, and Figure 6 is the electron microscope image of the seaweed polysaccharide material produced by the coagulation bath two-step method using calcium chloride as the cross-linking agent. The nanometer micron-sized silver chloride particles indicate that chloride ions play a role in promoting the growth of silver chloride agglomeration, and the use of non-chloride ion calcium salts and zinc salts can maintain silver chloride in nanometer size, with a particle size below 50 nanometers.

Table 1 Comparison of flame retardant data of calcium alginate material and material of Example 1

UL-94: vertical combustion test flame retardant material grade; LOI: limiting oxygen index; PHRR: heat release rate; THR: total heat release; TSR: total smoke release; Residue: thermal decomposition residue.

Test Conditions:

Limiting Oxygen Index (LOI) The LOI test was carried out on a digital limiting oxygen index tester model LFY-606B according to the ISO 4589-1:1996 standard method. The dimensions of all samples are 130mm x 10mm.

The vertical burning (UL-94) data is tested on the LFY-601A vertical burning rate tester using the ANST/UL-94-1985 standard method. The dimensions of all samples are 130 mm × 13 mm × 5 mm.

Combustion performance PHRR, THR, TSR, Residue etc. data were obtained by CONE test: using FTT-0242 Cone Calorimeter (UK), the combustion behavior was checked at an external heat flux of 50kW/m2 according to ISO 5660 standard. The dimensions of all samples are 100mm x 100mm x 2mm.

Table 1 is a comparison of the flame retardant data of calcium alginate and Example 1. Although both of them reached the V-0 flame retardant grade in the UL-94 standard, the limiting oxygen index of Example 1 exceeded 60%, and the fire resistance was greatly improved. And the heat release rate and total heat release amount of Example 1 are significantly lower than those of calcium alginate material.

In particular, the total smoke emission of the seaweed polysaccharide material of Example 1 in Table 1 is extremely low, only 3.4% of the calcium alginate material, which achieves the ultra-low smoke emission target of the seaweed polysaccharide material.

The antibacterial data comparison of table 2 calcium alginate and embodiment 1-3

E. coli: Escherichia coli (gram-negative bacteria); S. aureus: Staphylococcus aureus (gram-positive bacteria).

Antibacterial performance testing is based on standards and methods:

The antibacterial activities of pure CA and Example CA/AgCl composites were detected by disc diffusion method and colony formation counting method. E. coli (ATCC25922) was grown in lysogenic broth and Staphylococcus aureus (ATCC6538) was grown overnight in 37% sodium chloride broth.

In the disc diffusion method, the zone of inhibition test is based on AATCC-90 (halo test). Pour sterilized plate agar into petri dishes and cool. Spread 50 μL of the E. coli and S. aureus bacterial suspensions on the agar surface and spread evenly. The hydrogel was then placed on a plate agar surface and incubated at 37°C in the dark for 24h. The role of the inhibitory band can be judged by preliminary observation. Antibacterial activity of the samples was evaluated using the following methods: antibacterial effect was rated as "good" (zone of inhibition > 1 mm), "fairly good" (zone of inhibition < 1 mm), "adequate" (growth). Until (but not on the hydrogel), "limited" (limited growth on the hydrogel) or "poor" (> 50% bacterial overgrowth in the hydrogel). The area of inhibition is expressed as the diameter without bacterial growth minus the diameter of the hydrogel. The inhibition zone directly shows the antibacterial properties of the composite.

In the colony formation counting method, CA/AgCl particles were dissolved in phosphate buffered saline (PBS) to obtain a 10 mg/L solution. Dilute the bacterial suspension to 102-103 CFU mL-1, then pipette 50 μL of the solution mixed with the lysing solution. After incubation, pipette 50 μL and incubate overnight at 37°C. Finally, the number of colonies was calculated, and the percentage of inhibition was expressed as the following equation:

Antibacterial rate=(control group-experimental group)/(control group)×100%

All materials were sterilized in an autoclave before experiments. Each sample was repeated three times and the results were averaged.

Table 2 is a comparison of the antibacterial properties of the ultra-low smoke algae polysaccharide materials and calcium alginate materials prepared in Examples 1-3. It can be seen that the bacteriostatic rate of pure calcium alginate material is 0, and the bacteriostatic rate of the seaweed polysaccharide material prepared in Examples 1-3 to Escherichia coli and Staphylococcus aureus is greater than 99%.

Table 3 Flame retardant performance data of zinc alginate and zinc alginate/nano cuprous oxide composites

Data source: Polymers, 2019, 11(10): 1575.

Table 3 is the flame retardant performance data of zinc alginate and zinc alginate/nano cuprous oxide composites (derived from Polymers, 2019, 11(10): 1575.). It can be seen that the total smoke emission of zinc alginate is 274.28m ² /m ² , and the total smoke emission of zinc alginate/nano cuprous oxide composite material is 288.75m ² /m ² , compared with the examples of this patent application. 1 The 2.67m ² /m ² of the prepared nano-silver chloride seaweed polysaccharide material exceeds 100 times.

To sum up, Table 1, Table 2, and Table 3 all prove that the present invention achieves the unity of the three goals of high flame retardancy, strong antibacterial, and ultra-low smoke of seaweed polysaccharide material.

Table 4 Total smoke emission data of 6 embodiments

Table 4 is the total smoke emission data of the 6 examples. By comparison, it is found that in the seaweed polysaccharide material, the silver chloride is nano-sized in Example 1, Example 2 and Example 3, which show ultra-low smoke emission; and Example 4, Example 5 and Example 6 in which silver chloride is in micron size in the seaweed polysaccharide material show high smoke output; it proves the ultra-low smoke mechanism and chlorination of the ultra-low smoke seaweed polysaccharide material created by the present invention. The nanometer size of silver is closely related.

Claims (4)

1. a preparation method of ultra-low smoke seaweed polysaccharide material, is characterized in that, comprises the following steps: (1) Preparation of solution A: firstly, deionized water is heated to 30-50°C, and under the action of ultrasonic waves, polyvinylpyrrolidone K90, chloride and sodium alginate are dissolved in it in turn, and the reaction is maintained for 30-60min. ; (2) preparation solution B: take by weighing equimolar silver nitrate with chloride, at normal temperature, silver nitrate is dissolved in deionized water, then under stirring, ammonia water is added dropwise to the solution, and then the stirring reaction is maintained for 3-5min, that is obtained; (3) Preparation of crystallized product C: solution B was added dropwise to solution A under the conditions of heating in a water bath and stirring, and then, the stirring was terminated when the reaction solution became milky white, and maintained at a constant temperature of 40-50° C. for 10- 20min, that is; (4) After placing the crystallized product C in the molding equipment, add it to the soluble non-halide salt solution for cross-linking reaction for 10-15 minutes, rinse with deionized water for 3-5 times, then steam dry, and cool to At room temperature, the ultra-low smoke seaweed polysaccharide material can be obtained; The polyvinylpyrrolidone has an average molecular weight of ≥120,000; Described chloride is any one or more combinations in sodium chloride, potassium chloride, ammonium chloride; The mass ratio of chloride, polyvinylpyrrolidone, sodium alginate and deionized water in the solution A is 1:(0.1-0.3):(15-25):(400-500); In the solution B, the mass ratio of silver nitrate, ammonia water and deionized water is 1:(5-6):(5-7); Described ammoniacal liquor, its volume concentration is 25%; The soluble non-halide salt is any one or a combination of calcium nitrate, calcium acetate, calcium lactate, zinc nitrate, zinc acetate, and zinc lactate. 2 . The preparation method of an ultra-low smoke seaweed polysaccharide material according to claim 1 , wherein the crystallite C has a particle size of 5-50 nm. 3 . 3 . The method for preparing an ultra-low smoke seaweed polysaccharide material according to claim 1 , wherein the soluble non-halide salt solution has a mass concentration of 1-3%. 4 . 4. the preparation method of a kind of ultra-low smoke seaweed polysaccharide material as claimed in claim 1, is characterized in that, in described cross-linking reaction, the mass ratio of crystalline substance C and soluble non-halide salt solution is 1:3-10.

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