Preparation method of anticoagulant super absorbent resin

Abstract

The invention relates to the technical field of resin preparation, in particular to a preparation method of anticoagulant super absorbent resin.The preparation method comprises the steps that hydrolyzed tannic acid and nanocellulose are combined through an oxidative coupling reaction, citric acid is loaded, and an anticoagulant compound is obtained; the preparation method comprises the following steps: dissolving acrylic acid, lignin sulfonate, an anticoagulant compound, polylactic acid diacrylate, azodicarbonamide, nano silicon dioxide and a photoinitiator in water, and uniformly mixing to obtain a mixed solution; injecting the mixed solution into a micro-channel reactor, and carrying out polymerization reaction under the irradiation of pulsed ultraviolet light to obtain super absorbent resin gel; the super absorbent resin gel is immersed in a polylactic acid diacrylate solution, surface crosslinking is conducted through ultraviolet irradiation, drying and grinding are conducted, and the anticoagulant super absorbent resin particles are obtained.The anticoagulant super absorbent resin particles can inhibit platelet aggregation, delay starting of a blood coagulation cascade reaction and block activation of blood coagulation factors, the blood coagulation time is effectively prolonged, and the anticoagulant super absorbent resin particles are prepared. And a more sufficient liquid absorption window is provided for the super absorbent resin.

Description

Technical Field

[0001] The present invention relates to the technical field of resin preparation, and more specifically, it relates to a preparation method of an anticoagulant superabsorbent resin. Background Art

[0002] Hygienic absorbent products, such as diapers and sanitary napkins, play an important role in the fields of infant care, female menstrual care, and incontinence care. Superabsorbent Polymer (SAP), as the core liquid-absorbing material in such products, is widely used because it can absorb and lock a large amount of liquid. By significantly improving the dryness and comfort of hygienic products, SAP effectively reduces the risk of skin irritation and infection. However, when dealing with complex liquids such as blood, existing SAPs face various technical challenges. Especially in products such as female sanitary napkins, higher requirements are put forward for the efficient absorption and anticoagulant properties of blood.

[0003] Blood is rich in coagulation factors and platelets. Once it comes into contact with air or the surface of foreign objects, it will quickly trigger the coagulation cascade reaction, resulting in rapid blood coagulation. This rapid coagulation phenomenon poses a significant obstacle to the liquid-absorbing performance of SAP. The coagulated blood will form clots on the surface of the resin, blocking the liquid-absorbing channels, making it difficult for the internal resin to contact and absorb deep-layer liquids, thereby reducing the overall liquid-absorbing efficiency and surface dryness. Users may feel uncomfortable due to surface dampness during use, and the risk of skin irritation is increased. In addition, the high viscosity and complex composition of blood (including plasma proteins, red blood cells, etc.) are quite different from water or urine, further exacerbating the deficiencies of existing SAPs in blood absorption.

[0004] To solve the above problems, some improvement schemes have been proposed in the prior art. For example, the patent with the publication number CN118459649A discloses an anticoagulant superabsorbent resin and its preparation method. This method prepares the acrylene-1,2,3-tricarboxylic acid functional monomer by dehydrating citric acid and uses it in the synthesis of the superabsorbent resin. The carboxylate ions combine with calcium ions in the blood to form soluble complexes, blocking the activation process of coagulation factors. However, in this technology, the stability constant of calcium acrylene-1,2,3-tricarboxylate is relatively low, making it difficult to meet the requirements of long-term anticoagulation. Especially in a dynamic blood environment, the stability of the anticoagulant performance is insufficient. It uses a single surface cross-linking agent for secondary cross-linking, unable to form a gradient cross-linking network, resulting in less than ideal dynamic coagulation index and compressive performance of the resin, and limited liquid-absorbing efficiency and dryness. This method does not optimize other coagulation mechanisms such as platelet aggregation and only relies on the single path of calcium ion chelation, limiting the comprehensiveness of the anticoagulant effect.

[0005] Therefore, the development of a preparation method of superabsorbent resin that can effectively inhibit platelet aggregation, delay the coagulation cascade reaction, block the activation of coagulation factors, and at the same time has high liquid absorption performance has become a technical need to be solved urgently. Summary of the Invention

[0006] For this reason, the purpose of the present invention is to provide a preparation method of an anti-coagulant superabsorbent resin, which can inhibit platelet aggregation, delay the initiation of the coagulation cascade reaction, block the activation of coagulation factors, effectively prolong the blood coagulation time, and provide a more sufficient liquid absorption window for the superabsorbent resin.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A preparation method of an anti-coagulant superabsorbent resin, comprising the following steps:

[0009] S1. Prepare an anticoagulant complex: Combine hydrolyzed tannic acid and nanocellulose through an oxidative coupling reaction, and then load citric acid to obtain an anticoagulant complex;

[0010] S2. Prepare a mixed solution: Dissolve acrylic acid, sulfonated lignin, anticoagulant complex, polylactic acid diacrylate, azodicarbonamide, nano-silica and photoinitiator in water, and mix well to obtain a mixed solution;

[0011] S3. UV micro-reaction polymerization: Inject the mixed solution into a microchannel reactor, and carry out a polymerization reaction under pulsed ultraviolet light irradiation to obtain a superabsorbent resin gel;

[0012] S4. Surface strengthening: Immerse the superabsorbent resin gel in a polylactic acid diacrylate solution, carry out surface cross-linking under ultraviolet light irradiation, dry and grind to obtain anti-coagulant superabsorbent resin particles.

[0013] The present invention is further provided as: The S1 includes the following steps:

[0014] S11. Mix hydrolyzed tannic acid and nanocellulose in a mass ratio of (2–3):(1–2), add FeCl 3 ·6H 2 O and H 2 O 2 solution, stir and react at pH 3–4 and temperature 50–55°C for 2–3 hours to carry out oxidative coupling to form a graft product;

[0015] S12. Add citric acid with a mass ratio of (1–2):3 to the graft product, adsorb at a temperature of 50°C for 2 hours under ultrasonic assistance, centrifuge and dry at 60°C for 3h to obtain an anticoagulant complex.

[0016] The present invention is further provided as: In the step S11:

[0017] The mass ratio of the FeCl 3 ·6H 2 O to hydrolyzed tannic acid is 1:(10–15); the concentration of the H 2 O 2 is 10–20 wt%, nitrogen is introduced during the reaction process,

[0018] The Zeta potential of the complex after citric acid loading is –35~–25 mV, and the specific surface area is 50–80 m² / g.

[0019] The present invention is further configured as: the step S2 includes:

[0020] Neutralize acrylic acid with sodium hydroxide to a neutralization degree of 60-80%, first stir at a rotation speed of 200-300 rpm for 10-15 minutes, and then stir at a rotation speed of 400-500 rpm for 5-10 minutes;

[0021] Add sulfonated lignin, anticoagulant complex, polylactic acid diacrylate, azodicarbonamide, nano-silica and photoinitiator to the neutralized acrylic acid solution, first treat it at an ultrasonic dispersion power of 200-300W for 10-15 minutes, and then treat it at an ultrasonic dispersion power of 350-500W for 5-10 minutes.

[0022] The present invention is further configured as: in the step S2, the mass parts of each raw material are:

[0023] 200-300 parts of acrylic acid, 5-15 parts of sulfonated lignin, 5-15 parts of anticoagulant complex, 3-7 parts of polylactic acid diacrylate, 3-7 parts of azodicarbonamide, 1-3 parts of nano-silica, 0.3-1 part of photoinitiator, 400-600 parts of water.

[0024] The present invention is further configured as: the step S3 includes:

[0025] Inject the mixed solution into a microchannel reactor with a channel width of 100-300μm, first inject it at a flow rate of 0.5-1 mL / min, and then inject it at a flow rate of 1-2 mL / min;

[0026] Carry out a polymerization reaction under pulsed ultraviolet light irradiation. First, irradiate at a temperature of 10-15°C, a power of 50-100W, and a pulse frequency of 3-5 Hz for 20-25 seconds;

[0027] Then irradiate at a temperature of 15-20°C, a power of 100-150W, and a pulse frequency of 5-10 Hz for 10-15 seconds.

[0028] The present invention is further configured such that: the azodicarbonamide decomposes under ultraviolet light irradiation to generate nitrogen gas, forming a porous structure, and the porosity after decomposition is 70–90%, and the pore size distribution is 10–200 μm.

[0029] The present invention is further configured such that: the step S4 includes:

[0030] Immerse the superabsorbent resin gel in the polylactic acid diacrylate solution, first soak it at 20-25 °C for 5-10 minutes, and then soak it at 25-30 °C for 3-5 minutes;

[0031] Perform surface crosslinking using ultraviolet light, first irradiate it at a power of 30-50 W for 10-15 seconds, and then irradiate it at a power of 50-70 W for 5-10 seconds;

[0032] When drying, first treat it at 60-70 °C for 1-1.5 hours, and then treat it at 70-80 °C for 0.5-1 hour.

[0033] The present invention is further configured such that: in the step S4:

[0034] The concentration of the polylactic acid diacrylate solution is 5-15 wt%, and the mass ratio of the superabsorbent resin gel to the polylactic acid diacrylate is 100:(3-7); the particle size of the particles after grinding is 200-400 μm.

[0035] The present invention is further configured such that: in the step S2, it further includes:

[0036] Add S-nitrosothiol to the mixed solution, first stir it at an addition amount of 0.1-0.5 parts at a rotation speed of 300-400 rpm for 5-10 minutes, and then stir it at an addition amount of 0.1-0.5 parts at a rotation speed of 500-600 rpm for 3-5 minutes.

[0037] Comparing with the deficiencies of the prior art, the beneficial effects of the present invention are as follows:

[0038] By using the oxidative coupling reaction induced by Fe 3+ / H 2 O 2 between hydrolyzed tannic acid and nanocellulose to form a stable graft structure and load citric acid, a dual anticoagulant function is achieved. Hydrolyzed tannic acid is rich in polyphenol structures, which can effectively inhibit platelet aggregation and delay the initiation of the blood coagulation cascade reaction; citric acid chelates calcium ions in the blood to block the activation process of blood coagulation factors.

[0039] Using azodicarbonamide as a foaming agent, it decomposes under pulsed ultraviolet light irradiation to generate nitrogen gas, and in-situ forms a porous structure. It effectively increases the penetration channels of blood and avoids the problem of the coagulated blood blocking the liquid absorption channels on the surface.

[0040] The superabsorbent resin prepared by the present invention not only improves in anticoagulant performance, but also performs excellently in liquid absorption speed, capacity, and product stability, fully meeting the requirements of complex scenarios such as feminine hygiene products. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is the process flow chart of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0042] Refer to Figure 1 The embodiments of the preparation method of an anticoagulant superabsorbent resin of the present invention are further described, including the following steps:

[0043] Example 1:

[0044] The first step is to prepare an anticoagulant complex:

[0045] Hydrolyzed tannic acid and nanocellulose are mixed at a mass ratio of 2:1, and FeCl 3 ·6H 2 O and H 2 O 2 solution (Fe 3+ :H 2 O 2 molar ratio 1:5) are added, where the mass ratio of FeCl 3 ·6H 2 O to hydrolyzed tannic acid is 1:10, the concentration of H 2 O 2 is 10–20 wt%, and the reaction is stirred at pH 3 and a temperature of 50°C for 2 hours. Nitrogen is introduced to maintain an anaerobic environment, and Fe 3+ catalyzes the oxidation of tannic acid to form quinone intermediates, which undergo a condensation reaction with the hydroxyl groups of nanocellulose to form a grafted product. Subsequently, citric acid (the mass ratio of citric acid to the grafted product is 1:2) is added to the grafted product, and under ultrasonic assistance (power 200), it is stirred and adsorbed at 50°C for 2 hours to achieve the loading of citric acid through hydrogen bonding and electrostatic interactions. After the reaction is completed, centrifugal separation (8000 rpm, 10 minutes) is carried out, and it is dried at 60°C for 3 hours to obtain an anticoagulant complex with a Zeta potential of -3 mV and a specific surface area of 50 m² / g.

[0046] The second step is to prepare a mixed solution:

[0047] Before preparing the mixed solution, 200 parts of acrylic acid are first neutralized with sodium hydroxide to a neutralization degree of 60%, and stirred step by step to ensure uniformity: first stir at a rotation speed of 200 rpm for 10 minutes, and then stir at a rotation speed of 400 rpm for 5 minutes. Subsequently, other components are added to the neutralized acrylic acid solution. The specific mixed solution contains the following components:

[0048] 5 parts of sulfonated lignin, 5 parts of anticoagulant complex, 3 parts of polylactic acid diacrylate, 3 parts of azodicarbonamide, 1 part of nano-silica, 0.3 part of photoinitiator (2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone), and 400 parts of water. The mixed solution is first treated at an ultrasonic dispersion power of 200 W for 10 minutes, and then treated at an ultrasonic dispersion power of 350 W for 5 minutes to ensure uniform dispersion of the components. Microencapsulated S-nitrosothiol is added to the mixed solution. First, it is stirred at a rotational speed of 300 rpm for 5 minutes with an addition amount of 0.1 part, and then stirred at a rotational speed of 500 rpm for 3 minutes with an addition amount of 0.1 part. The microencapsulation technology wraps S-nitrosothiol with a polyurea shell to prevent the release of NO during the UV polymerization process from interfering with the free radical reaction.

[0049] The third step, UV micro-reaction polymerization:

[0050] The mixed solution is injected into a microchannel reactor with a channel width of 100 μm. Segmented flow rate control is adopted: first, it is injected at 0.5 mL / min into the initial segment (accounting for 50% of the total length), and then injected at 1 mL / min into the subsequent segment (accounting for 50% of the total length). The polymerization reaction is carried out under pulsed ultraviolet light irradiation, and 0.1 part of benzophenone is added as a photosensitizer to cooperate with the decomposition of azodicarbonamide. The specific conditions are: first, irradiated at a temperature of 10 °C, a power of 50 W, and a pulse frequency of 3 Hz for 20 seconds, and then irradiated at a temperature of 15 °C, a power of 100 W, and a pulse frequency of 5 Hz for 10 seconds.

[0051] The fourth step, surface strengthening:

[0052] The superabsorbent resin gel is immersed in a polylactic acid diacrylate solution (concentration 5 wt%, solvent is a water / ethanol mixture with a volume ratio of 1:1). The mass ratio of the superabsorbent resin gel to polylactic acid diacrylate is 100:3. Soaking is carried out step by step: first soak at 20 °C for 5 minutes, and then soak at 25 °C for 3 minutes. Subsequently, surface cross-linking is carried out using ultraviolet light: first irradiate at a power of 30 W for 10 seconds, and then irradiate at a power of 50 W for 5 seconds. The drying process is carried out step by step: first treat at 60 °C for 1 hour, and then treat at 70 °C for 0.5 hour. After drying, it is ground using a ball mill (rotational speed 500 rpm, grinding time 10 minutes) to obtain anti-coagulant superabsorbent resin particles with a particle size of 200 μm.

[0053] Example 2:

[0054] The first step, preparation of anticoagulant complex: Hydrolyzed tannic acid and nanocellulose are mixed at a mass ratio of 3:2, and FeCl 3 ·6H2 O and H 2 O 2 solution (Fe3 + :H 2 O 2 molar ratio 1:5), where the mass ratio of FeCl 3 ·6H 2 O to hydrolyzed tannic acid is 1:15, and the concentration of H 2 O 2 is 20 wt%. Stir and react at pH 4 and a temperature of 55 °C for 3 hours. Pass nitrogen to maintain an anaerobic environment. Catalyze the oxidation of tannic acid by Fe3+ to generate quinone intermediates, which undergo a condensation reaction with the hydroxyl groups of nanocellulose to form a grafted product. Subsequently, add citric acid (mass ratio of citric acid to grafted product is 1:3) to the grafted product. Under ultrasonic assistance (power 300 W), stir and adsorb at 50 °C for 2 hours to achieve the loading of citric acid through hydrogen bonding and electrostatic interactions. After the reaction is completed, centrifuge (8000 rpm, 10 minutes) and dry at 60 °C for 3 hours to obtain an anticoagulant complex with a Zeta potential of -25 mV and a specific surface area of 80 m² / g.

[0055] Second step, prepare a mixed solution: Before preparing the mixed solution, first neutralize 300 parts of acrylic acid with sodium hydroxide to a neutralization degree of 80%, and stir step by step to ensure uniformity: first stir at a rotation speed of 300 rpm for 15 minutes, and then stir at a rotation speed of 500 rpm for 10 minutes. Subsequently, add other components to the neutralized acrylic acid solution. The specific mixed solution contains the following components: 15 parts of sulfonated lignin, 15 parts of anticoagulant complex, 7 parts of polylactic acid diacrylate, 7 parts of azodicarbonamide, 3 parts of nano-silica, 1 part of photoinitiator (2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone), and 600 parts of water. The mixed solution is first treated at an ultrasonic dispersion power of 300 W for 15 minutes, and then treated at an ultrasonic dispersion power of 500 W for 10 minutes to ensure the uniform dispersion of the components. Add microencapsulated S-nitrosothiol to the mixed solution, first stir at an addition amount of 0.5 parts at a rotation speed of 400 rpm for 10 minutes, and then stir at an addition amount of 0.5 parts at a rotation speed of 600 rpm for 5 minutes.

[0056] Third step, UV micro-reaction polymerization: Inject the mixed solution into a microchannel reactor with a channel width of 300 μm. Use segmented flow rate control: First, inject the initial section (accounting for 60% of the total length) at 1 mL / min, and then inject the subsequent section (accounting for 40% of the total length) at 2 mL / min. Conduct the polymerization reaction under pulsed ultraviolet light irradiation. Add 0.3 parts of benzophenone as a photosensitizer to synergistically decompose azodicarbonamide. The specific conditions are: First, irradiate for 25 seconds at a temperature of 15°C, a power of 100W, and a pulse frequency of 5 Hz, and then irradiate for 15 seconds at a temperature of 20°C, a power of 150W, and a pulse frequency of 10 Hz.

[0057] Fourth step, surface strengthening: Immerse the superabsorbent resin gel in a polylactic acid diacrylate solution (concentration 15wt%, solvent is a water / ethanol mixture with a volume ratio of 1:1). The mass ratio of the superabsorbent resin gel to polylactic acid diacrylate is 100:7. Immerse in steps: First, immerse at 25°C for 10 minutes, and then immerse at 30°C for 5 minutes. Subsequently, conduct surface cross-linking using ultraviolet light. First, irradiate at a power of 50W for 15 seconds, and then irradiate at a power of 70W for 10 seconds. The drying process is carried out in steps: First, treat at 70°C for 1.5 hours, and then treat at 80°C for 1 hour. After drying, grind using a ball mill (rotation speed 500 rpm, grinding time 20 minutes) to obtain anti-coagulant superabsorbent resin particles with a particle size of 400 μm.

[0058] Example 3:

[0059] First step, preparation of anti-coagulant complex:

[0060] Mix hydrolyzed tannic acid and nanocellulose at a mass ratio of 2.5:1.5, and add FeCl 3 ·6H 2 O and H 2 O 2 solution (Fe3 + :H 2 O 2 molar ratio 1:5), where the mass ratio of FeCl 3 ·6H 2 O to hydrolyzed tannic acid is 1:12.5, the concentration of H 2 O 2 is 15wt%. Conduct the stirring reaction for 2.5 hours under nitrogen gas flow at pH 3.5 and a temperature of 52.5°C to form a grafted product; then add citric acid to the grafted product, adsorb at a temperature of 50°C for 2 hours under ultrasonic assistance, centrifuge, and dry at 60°C for 3 hours to obtain the anti-coagulant complex.

[0061] Second step, preparation of the mixed solution:

[0062] Neutralize acrylic acid with sodium hydroxide to a neutralization degree of 70%. First, stir at a speed of 250 rpm for 12.5 minutes, and then stir at a speed of 450 rpm for 7.5 minutes. Add the following components to the neutralized acrylic acid solution: 250 parts of acrylic acid, 10 parts of sulfonated lignin, 10 parts of anticoagulant complex, 5 parts of polylactic acid diacrylate, 5 parts of azodicarbonamide, 2 parts of nano-silica, 0.65 part of photoinitiator, and 500 parts of water. The mixed solution is first treated at an ultrasonic dispersion power of 250 W for 12.5 minutes, and then treated at 425 W for 7.5 minutes. Finally, add S-nitrosothiol. First, add it in an amount of 0.3 part and stir at a speed of 350 rpm for 7.5 minutes, and then add it in an amount of 0.3 part and stir at a speed of 550 rpm for 4 minutes.

[0063] The third step, UV micro-reaction polymerization:

[0064] Inject the mixed solution into a microchannel reactor with a channel width of 200 μm. First, inject it at a flow rate of 0.75 mL / min, and then inject it at a flow rate of 1.5 mL / min. Carry out the polymerization reaction under pulsed ultraviolet light irradiation. First, irradiate at a temperature of 12.5 °C, a power of 75 W, and a pulse frequency of 4 Hz for 22.5 seconds; then irradiate at a temperature of 17.5 °C, a power of 125 W, and a pulse frequency of 7.5 Hz for 12.5 seconds to obtain a superabsorbent resin gel.

[0065] The fourth step, surface strengthening:

[0066] Immerse the superabsorbent resin gel in a 10 wt% polylactic acid diacrylate solution. The mass ratio of the superabsorbent resin gel to polylactic acid diacrylate is 100:5. First, soak it at 22.5 °C for 7.5 minutes, and then soak it at 27.5 °C for 4 minutes; carry out surface cross-linking with ultraviolet light. First, irradiate at a power of 40 W for 12.5 seconds, and then irradiate at 60 W for 7.5 seconds; when drying, first treat it at 65 °C for 1.25 hours, and then treat it at 75 °C for 0.75 hours. After grinding, the particle size is 300 μm.

[0067] Comparative example 1: Anticoagulant complex without citric acid loading

[0068] The first step: Mix hydrolyzed tannic acid and nanocellulose in a mass ratio of 2:2, and add FeCl 3 ·6H 2 O and H 2 O 2 solution (Fe 3+ :H 2 O 2 molar ratio 1:5), where the mass ratio of FeCl 3 ·6H 2 O to hydrolyzed tannic acid is 1:10, H2 O 2 The concentration of O is 10–20 wt%, and the reaction is stirred for 2 hours at pH 3 and a temperature of 50 °C while purging with nitrogen to form a grafted product; the step of loading citric acid is omitted, and after directly centrifuging, it is dried at 60 °C for 3 hours to obtain a composite containing only tannic acid-nanocellulose.

[0069] Second step: The same as in Example 1 (200 parts of acrylic acid, 5 parts of sulfonated lignin, 5 parts of the composite, 3 parts of polylactic acid diacrylate, 3 parts of azodicarbonamide, 1 part of nano-silica, 0.3 part of photoinitiator, 400 parts of water, etc.).

[0070] Third step: The same as in Example 1.

[0071] Fourth step: The same as in Example 1.

[0072] Comparative Example 2: Sodium bicarbonate is used to replace azodicarbonamide

[0073] First step: The same as in Example 1.

[0074] Second step: The acrylic acid is neutralized with sodium hydroxide to a neutralization degree of 60%, first stirred at 200 rpm for 10 minutes, and then stirred at 400 rpm for 5 minutes; the following components are added: 5 parts of sulfonated lignin, 5 parts of anticoagulant composite, 3 parts of polylactic acid diacrylate, 3 parts of sodium bicarbonate (replacing azodicarbonamide), 1 part of nano-silica, 0.3 part of photoinitiator, and 400 parts of water, sonicated at a power of 200 W for 10 minutes, and then at 350 W for 5 minutes; 0.1 part of S-nitrosothiol is added, stirred at 300 rpm for 5 minutes, and then at 500 rpm for 3 minutes.

[0075] Third step: The same as in Example 1, and sodium bicarbonate decomposes in an acidic environment to generate CO 2 , forming a porous structure.

[0076] Fourth step: The same as in Example 2.

[0077] Comparative Example 3: A single traditional crosslinking agent replaces gradient crosslinking

[0078] First step: The same as in Example 1.

[0079] Second step: The same as in Example 1.

[0080] Third step: The same as in Example 1.

[0081] Fourth step: Immerse the superabsorbent resin gel in a 5 wt% N,N'-methylenebisacrylamide (MBAA) solution (replacing polylactic acid diacrylate) at a mass ratio of 100:3. First, soak it at 25°C for 5 minutes; perform ultraviolet cross-linking by irradiating for 10 seconds at a power of 30W (single cross-linking); dry it by treating at 60°C for 1 hour and then at 70°C for 0.5 hour, and grind it to a particle size of 200 μm.

[0082] Perform performance tests on the anticoagulant superabsorbent resins obtained in Examples 1 to 3 and Comparative Examples 1 to 3. The test methods are as follows:

[0083] Determination of blood absorption time: Take 2.0 g of resin sample and disperse it evenly in 25 mL of mixed blood at 37°C (fresh pig blood: artificial blood = 1:1, viscosity 3.5 mPa·s). Start timing in a magnetic stirrer (300 rpm) and observe until the resin completely absorbs the liquid and shows no lumps and no undissolved white particles. Record the total time taken (seconds). Refer to GB / T 22875-2020 "Determination of Blood Absorption Time of Absorbent Hygiene Products" and repeat 3 times to take the average value.

[0084] Blood absorption capacity (mL / g): Accurately weigh 1.00 g of dry resin sample and place it in a 50 mL beaker.

[0085] Add 25 mL of simulated blood preheated to 37°C (fresh pig blood: artificial blood = 1:1, viscosity 3.5 mPa·s), and gently stir evenly. Let it stand for 30 minutes to ensure that the resin fully absorbs the liquid.

[0086] Wrap the sample with filter paper, place it in a centrifuge, and centrifuge at 3000 rpm for 5 minutes to remove the unabsorbed liquid. Weigh the sample after centrifugation and calculate the blood absorption capacity:

[0087]

[0088] Whole blood clotting time: Take 10 mL of fresh pig blood (after anticoagulation treatment, keep it at 37°C), add 0.5 g of resin sample, and gently shake well. Immediately use a coagulation analyzer (such as TEG or coagulation time analyzer) to measure the coagulation curve.

[0089] Record the time from adding the resin to the start of blood coagulation, compare it with the blank control (without resin), and calculate the prolongation of coagulation time.

[0090] Specific surface area (m² / g): Take 0.5 g of dry sample and place it in a BET test tube. Degas it under vacuum at 100°C for 4 hours to remove moisture and impurities. Use a nitrogen adsorption analyzer (such as Micromeritics ASAP 2460) to measure the adsorption / desorption isotherm. Calculate the specific surface area according to the BET model.

[0091] Porosity (%): Weigh approximately 1 g of the dried sample and place it in the sample chamber of a mercury intrusion porosimeter (such as AutoPore IV 9500). Apply a pressure range of 0.5 - 60000 psi, record the volume of mercury intrusion, and calculate the porosity.

[0092] Centrifugal water retention rate (g / g): Weigh 1.00 g of the dried sample and immerse it in 0.9% NaCl physiological saline for 30 minutes.

[0093] Wrap the sample with filter paper, place it in a centrifuge, centrifuge at 3000 rpm for 5 minutes, weigh the mass after centrifugation, and calculate the water retention rate.

[0094] Pressurized absorption rate (g / g): Use a liquid absorption capacity tester (AUL) to apply a pressure of 0.7 psi. Weigh 0.16 g of the sample and evenly spread it on the bottom of the test cup. Add 0.9% NaCl physiological saline, record the mass of the absorbed liquid, and calculate the pressurized absorption rate.

[0095] Dryness (residual liquid mg / cm²): Weigh 1.00 g of the sample and immerse it in 0.9% NaCl physiological saline for 30 minutes.

[0096] Place the liquid-absorbed sample on filter paper, apply a pressure of 0.7 psi for 10 minutes. Weigh the weight gain of the filter paper and calculate the re-permeation amount per square centimeter.

[0097] The test results are shown in Table 1.

[0098] Table 1:

[0099]

[0100] As can be seen from Table 1, the examples show that: The blood-sucking times of Examples 1 - 3 are 8 seconds, 5 seconds, and 6 seconds respectively, which are significantly lower than those of the comparative examples. This is due to the anticoagulant complex (the synergistic effect of hydrolyzed tannic acid and citric acid) delaying blood coagulation, enabling the resin to quickly disperse and absorb blood. At the same time, the uniform porous structure (porosity 70 - 90%) generated by azodicarbonamide accelerates blood penetration. The blood-sucking time of Example 2 is the shortest (5 seconds), which is related to its highest specific surface area (80 m² / g) and porosity (90%).

[0101] Comparative Example 1 (without citric acid loading): The blood-sucking time is 25 seconds, much higher than that of the examples. The reason is the lack of the calcium ion chelating function of citric acid. Only relying on tannic acid to inhibit platelet aggregation is not sufficient to effectively delay blood coagulation (the whole blood coagulation time is only 6.5 minutes), resulting in the formation of blood clots before absorption and hindering penetration.

[0102] Comparative Example 2 (sodium bicarbonate replacing azodicarbonamide): The blood-sucking time was 18 seconds, slower than that of the example. Sodium bicarbonate decomposes in an acidic environment to generate CO 2 , with a lower porosity (55%) and specific surface area (30 m² / g), and the pore distribution is not uniform enough, which affects the rapid penetration of blood.

[0103] Comparative Example 3 (single MBAA crosslinking): The blood-sucking time was 15 seconds, slightly better than that of Comparative Examples 1 and 2, but still inferior to the example. Although single crosslinking maintained a certain liquid absorption capacity, the lack of a gradient structure led to a reduction in the utilization rate of internal pores and limited the blood penetration speed.

[0104] Through the synergistic effect of the anticoagulant complex and the porous structure of azodicarbonamide, the present invention significantly shortened the blood-sucking time (5 - 8 seconds), far superior to the comparative examples (15 - 25 seconds). This shows the key role of the dual anticoagulation mechanism and the efficient porous design in improving the blood absorption efficiency, providing an excellent performance basis for sanitary absorbent products.

[0105] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any ordinary changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an anticoagulant superabsorbent resin, characterized in that: The following steps are involved: S1. preparing an anticoagulant complex: combining hydrolyzed tannic acid with nanocellulose through an oxidative coupling reaction, and then loading citric acid to obtain an anticoagulant complex; S2, preparing a mixed solution: dissolving acrylic acid, sulfonated lignin, anticoagulant complex, polylactic acid diacrylate, azodicarbonamide, nano-silica and photoinitiator in water, and mixing to obtain a mixed solution; S3, UV micro-reaction polymerization: injecting the mixed solution into a microchannel reactor, and performing polymerization reaction under pulsed ultraviolet light irradiation to obtain a highly absorbent resin gel; S4, surface strengthening: immersing the super absorbent resin gel in a polylactic acid diacrylate solution, irradiating with ultraviolet light for surface cross-linking, drying and grinding to obtain anticoagulant super absorbent resin particles.

2. The method for preparing an anticoagulant superabsorbent resin according to claim 1, characterized in that: The S1 comprises the following steps: S11, mixing hydrolyzed tannic acid and nanocellulose in a mass ratio of (2–3):(1–2), adding FeCl3·6H2O and H2O2 solution, stirring and reacting at pH 3–4 and temperature 50–55°C for 2–3 hours, and performing oxidative coupling to form a grafted product; S12. Add citric acid in a mass ratio of (1–2):3 to the grafted product, adsorb at 50°C for 2 hours under ultrasound assistance, centrifuge and dry at 60°C for 3 hours to obtain an anticoagulant complex.

3. The method for preparing an anticoagulant superabsorbent resin according to claim 2, characterized in that: In the step S11: The mass ratio of FeCl3·6H2O to hydrolyzed tannic acid is 1:(10–15); the concentration of H2O2 is 10–20 wt%, and nitrogen is passed during the reaction; The zeta potential of the citric acid-loaded composite is -35~-25 mV, and the specific surface area is 50-80 m² / g.

4. The method for preparing an anticoagulant superabsorbent resin according to claim 1, characterized in that: The step S2 comprises: Neutralize acrylic acid with sodium hydroxide to a neutralization degree of 60-80%, first stir at a speed of 200-300 rpm for 10-15 minutes, and then stir at a speed of 400-500 rpm for 5-10 minutes; Add sulfonated lignin, anticoagulant complex, polylactic acid diacrylate, azodicarbonamide, nano-silica and photoinitiator to the neutralized acrylic acid solution, first treat at an ultrasonic dispersion power of 200-300W for 10-15 minutes, and then treat at an ultrasonic dispersion power of 350-500W for 5-10 minutes.

5. The method for preparing an anticoagulant superabsorbent resin according to claim 4, characterized in that: In step S2, the mass fractions of each raw material are: 200-300 parts of acrylic acid, 5-15 parts of sulfonated lignin, 5-15 parts of anticoagulant complex, 3-7 parts of polylactic acid diacrylate, 3-7 parts of azodicarbonamide, 1-3 parts of nano silicon dioxide, 0.3-1 parts of photoinitiator and 400-600 parts of water.

6. The method for preparing an anticoagulant superabsorbent resin according to claim 5, characterized in that: The step S3 comprises: The mixed solution was injected into a microchannel reactor with a channel width of 100-300 μm, first at a flow rate of 0.5-1 mL / min, and then at a flow rate of 1-2 mL / min; The polymerization reaction was carried out under pulsed UV irradiation, first at a temperature of 10-15°C, a power of 50-100W, and a pulse frequency of 3-5 Hz for 20-25 seconds; Then irradiate for 10-15 seconds at a temperature of 15-20°C, a power of 100-150W, and a pulse frequency of 5-10 Hz.

7. The method for preparing an anticoagulant superabsorbent resin according to claim 6, characterized in that: The azodicarbonamide decomposes to generate nitrogen under the triggering of ultraviolet light to form a porous structure. After decomposition, the porosity is 70-90% and the pore size distribution is 10-200 μm.

8. The method for preparing an anticoagulant superabsorbent resin according to claim 1, characterized in that: The step S4 comprises: Immerse the super absorbent resin gel in a polylactic acid diacrylate solution, first at 20-25°C for 5-10 minutes, then at 25-30°C for 3-5 minutes; Use ultraviolet light for surface cross-linking, first irradiate at a power of 30-50W for 10-15 seconds, then irradiate at a power of 50-70W for 5-10 seconds; When drying, first treat it at 60-70°C for 1-1.5 hours, and then treat it at 70-80°C for 0.5-1 hour.

9. The method for preparing an anticoagulant superabsorbent resin according to claim 8, characterized in that: In step S4: The concentration of the polylactic acid diacrylate solution is 5-15 wt %, the mass ratio of the super absorbent resin gel to the polylactic acid diacrylate is 100:(3-7); and the particle size of the particles after grinding is 200-400 μm.

10. The method for preparing an anticoagulant superabsorbent resin according to claim 1, characterized in that: The step S2 also includes: S-nitrosothiol was added to the mixed solution, firstly at 0.1-0.5 parts, stirred at 300-400 rpm for 5-10 minutes, and then at 0.1-0.5 parts, stirred at 500-600 rpm for 3-5 minutes.

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