A method for preparing an aerogel type papermaking aid based on composite fiber material

Abstract

The application relates to the technical field of papermaking processing, in particular to a preparation method of an aerogel type papermaking additive based on composite fiber materials, which comprises the following steps: S1, diluting an additive intermediate with water, adjusting the pH value to 9.0-9.5, stirring and mixing for 12-18 minutes, and controlling the temperature at 32-36 DEG C to obtain an additive intermediate solution; S2, adding glyoxal to the additive intermediate solution under stirring, adjusting the pH value to 9.0-9.3, reacting until the viscosity of the material reaches 20-50 cps, stopping the reaction when the pH value is adjusted to 2.5-4.0, and adding an aerogel type composite fiber material after the reaction is completed, fully stirring and dispersing to obtain a papermaking additive. The papermaking additive prepared in the application can effectively improve the tensile strength and ring pressure strength of paper when introduced into a papermaking process, so that the paper has excellent strength and toughness, and can better meet the needs of special industries.

Description

Technical Field

[0001] This invention relates to the field of papermaking processing technology, specifically to a method for preparing an aerogel-type papermaking additive based on composite fiber materials. Background Technology

[0002] The dry strength of paper is one of its structural properties. It is primarily obtained through the formation of the fiber network and the bonding between fibers after drying. In fact, the strength of paper depends mainly on the strength of individual fibers and the degree, number, and distribution of bonding between them. The strength of the fiber network can be improved through mechanical beating and refining because increasing the degree of beating increases the number of microfibers, thereby increasing the formation of bonds between fibers. While covalent bonds, ionic bonds, and van der Waals forces exist among the bonding forces between fibers, hydrogen bonds play a crucial role. Unlike other bonds, hydrogen bonds can only form over extremely short distances and require close molecular contact to interact.

[0003] For example, Chinese patent CN103866629A discloses a papermaking processing aid and its preparation method, which is composed of the following components in the following weight ratio: 13-15 parts of toluene diisocyanate, 2-4 parts of C9 petroleum resin, 9-12 parts of potassium octadecylbenzenesulfonate, 1-2 parts of potassium oxalate, 4-5 parts of propylene glycol, 4-6 parts of ethyl acetate, and 120-124 parts of deionized water. This papermaking aid improves paper strength by increasing the bonding between paper fibers. However, the formation of bonds between paper fibers is affected by various factors such as reaction dimensions and pH. Not only is the bonding rate low, but the chemical bonds formed can only interact when the molecules are in close contact. Therefore, the improvement in paper strength is poor, and the paper strength can only meet the needs of daily use. It cannot meet the needs of some special industries with high paper strength requirements. Summary of the Invention

[0004] To address the problems existing in the prior art, the purpose of this invention is to provide a method for preparing aerogel-type papermaking additives based on composite fiber materials.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for preparing an aerogel-type papermaking additive based on composite fiber materials, the method comprising the following steps:

[0007] S1. Dilute the auxiliary intermediate with water, adjust the pH value to 9.0-9.5, stir and mix for 12-18 minutes, and control the temperature at 32-36℃ to obtain the auxiliary intermediate solution;

[0008] S2. Under stirring, add glyoxal to the intermediate solution of the auxiliary agent using a circulating pump, and control the oven-dry mass ratio of the intermediate agent to glyoxal to be (3.2-7.6):1. Adjust the pH value to 9.0-9.3 and react until the material viscosity reaches 20-50 cps. When the pH value is adjusted to 2.5-4.0, stop the reaction. After the reaction is completed, add the aerogel-type composite fiber material and stir and disperse it thoroughly to obtain the papermaking auxiliary agent.

[0009] The preparation method of the aerogel-type composite fiber material includes the following steps:

[0010] 1) Using a mixture of sodium alginate / carrageenan / chitosan as a precursor, a precursor was prepared by wet spinning technology. A composite aerogel was prepared by co-precipitation with aspartic acid as an organic ligand and copper as a metal center.

[0011] 2) Porous nanosheets are synthesized by hydrothermal method, and nanowires are deposited on the surface of the porous nanosheets as substrate to obtain nanomaterials. The nanomaterials are then combined with carbon fibers through physical bonding to obtain composite fiber materials.

[0012] 3) After the composite fiber material and composite aerogel are fully mixed by vacuum treatment under ultrasonic and mechanical stirring, they are placed in a reaction solution composed of sulfur source and antimony source for hydrothermal reaction to obtain aerogel composite fiber material.

[0013] As a further preferred embodiment of the present invention, the method for preparing the auxiliary intermediate includes the following steps:

[0014] According to the weight percentage, 30-42 parts of acrylamide monomer, 4-7 parts of anionic monomer, 28-42 parts of cationic monomer, 1-3 parts of chain transfer agent, and 0.02-0.05 parts of complexing agent are added to a reaction vessel. Soft water is added to prepare an aqueous solution with a mass percentage concentration of 20-28%. Nitrogen gas is introduced for 25-50 minutes. 2-6 parts of pH adjuster are added to adjust the pH value to 4.0-5.5. 3-5 parts of catalyst and 1-3 parts of initiator are added dropwise at a uniform rate at 68-72℃. The reaction is stirred for 120-170 minutes. After holding at this temperature for 50-100 minutes, the reaction is stopped. The temperature is lowered to room temperature, and 0.1-0.5 parts of antibacterial agent are added to obtain the auxiliary intermediate.

[0015] As a further preferred embodiment of the present invention, the cationic monomer is composed of equal mass of dimethyl diallyl ammonium chloride monomer and acryloyloxyethyl trimethyl ammonium chloride monomer;

[0016] The anionic monomer is selected from one or more of itaconic acid, 2-acrylamido-2-methylpropanesulfonic acid, and their salts;

[0017] The initiator is selected from one or more of ammonium persulfate, sodium persulfate, potassium persulfate, azobisisobutyramidine hydrochloride, and azobisisopropylimidazoline hydrochloride.

[0018] The pH adjuster comprises a base and an acid, wherein the base is selected from one or more of sodium hydroxide and ammonia; and the acid is selected from one or more of hydrochloric acid, phosphoric acid, formic acid, and citric acid.

[0019] The chain transfer agent is sodium formate, the catalyst is phosphoric acid, the complexing agent is disodium ethylenediaminetetraacetate, and the antibacterial agent is isothiazolinone.

[0020] As a further preferred embodiment of the present invention, the composite aerogel is prepared by the following method:

[0021] Sodium alginate, κ-carrageenan, and chitosan were mixed in a mass ratio of (3-4):1:(2-3) to obtain a precursor. An aqueous solution of the precursor was then prepared, and the precursor was precipitated by wet spinning with ethanol as the coagulation bath. The precipitated gel was solidified in a 5-8% copper nitrate solution, dried, and then placed in a muffle furnace at 800-830℃ for 2-3 hours. The obtained product was soaked in acetic acid, repeatedly washed with deionized water, and dried to obtain carbon aerogel.

[0022] 2) Dissolve L-aspartic acid in a sodium hydroxide solution with a concentration of 6.0-6.8 mol / L, then add carbon aerogel, sonicate for 30-50 min, disperse evenly, then add copper nitrate solution with a concentration of 0.5-0.8 mol / L, stir and react for 3-5 h, centrifuge the obtained product, wash it repeatedly with deionized water, acetic acid solution and ethanol solution in sequence, and dry it to obtain composite aerogel.

[0023] Furthermore, the precursor aqueous solution has a mass fraction of 3-5%;

[0024] The ratio of L-aspartic acid, sodium hydroxide solution, carbon aerogel, and copper nitrate solution is (0.04-0.07) mol: (10-20) mL: (0.3-0.5) g: (100-130) mL.

[0025] As a further preferred embodiment of the present invention, the composite fiber material is prepared by the following method:

[0026] 1) Place 0.2-0.5g of nano-magnesium oxide into 100-160mL of methanol solution and ultrasonically disperse for 30-50min. Then add 1.2-1.8g of zinc nitrate and stir for 1-2h to obtain solution A. Disperse 1.4-2.0g of 2-methylimidazole evenly into 300-500mL of methanol solution to obtain solution B. Mix solution A and solution B and stir the reaction at room temperature for 24-30h. Centrifuge the obtained product, wash it repeatedly with methanol, and dry it to obtain the framework template material.

[0027] 2) The pre-crushed asphalt, potassium bicarbonate and skeleton template material are placed in a mortar and mixed evenly. Then, the mixture is placed in a tube furnace and heated to 300-320℃. The temperature is kept constant for 30-50 minutes. Then, the temperature is increased to 900-950℃ at the same rate and kept constant for 1-2 hours. After cooling to room temperature, the product is stirred and soaked in hydrochloric acid solution for 24-30 hours. After filtration, washing, drying and grinding, porous carbon nanosheets are obtained.

[0028] 3) Add copper nitrate, potassium permanganate, and manganese sulfate to deionized water and stir magnetically for 30-50 min to form a homogeneous solution. Then add porous carbon nanosheets and disperse them evenly. Seal the reactor and react at a constant temperature of 160-165℃ for 12-15 h under ultrasonic treatment. After the reaction is completed, allow it to cool naturally to room temperature. Wash the product obtained after centrifugation repeatedly with water and ethanol, and dry it to obtain the composite nanomaterial.

[0029] 4) Add carbon fiber and composite nanomaterials to a container, add deionized water, stir mechanically for 1-2 hours, then sonicate for 1-2 hours. After the treatment is completed, filter the product and dry it to obtain composite fiber material.

[0030] Furthermore, the stirring reaction is carried out at a speed of 500-600 r / min;

[0031] The mass ratio of the asphalt, potassium bicarbonate, and skeleton template material is (1.0-1.8):(3.0-5.4):(1.0-1.8).

[0032] The heating rate is 5-8℃ / min;

[0033] The hydrochloric acid solution has a concentration of 0.1-0.3 mol / L.

[0034] Furthermore, the ratio of copper nitrate, potassium permanganate, manganese sulfate, deionized water, and porous carbon nanosheets is (0.025-0.030) mol: (0.14-0.18) mol: (0.045-0.052) mol: (70-100) mL: (5-8) g;

[0035] The ultrasonic action has a power of 100-150W;

[0036] The ratio of carbon fiber, composite nanomaterials, and deionized water is (10-20)g:(3-7)g:(200-300)mL;

[0037] The mechanical stirring is performed at a speed of 800-1200 r / min;

[0038] The ultrasonic treatment has a power of 500-600W.

[0039] As a further preferred embodiment of the present invention, the aerogel-type composite fiber material is prepared by the following method:

[0040] 1) Disperse the composite fiber material in deionized water to obtain a dispersion, then add the composite aerogel to the dispersion, evacuate to 50-100 Pa, and maintain for 30-50 min under the action of 200-300 r / min and 200-300 W ultrasound. After the treatment is completed, centrifuge the product to obtain the pretreated composite fiber material.

[0041] 2) Dissolve potassium antimony tartrate in deionized water, stir magnetically for 15-30 min, add polyvinylpyrrolidone, continue stirring for 15-30 min, then add thioacetamide to the mixture and stir thoroughly to obtain the reaction solution.

[0042] 3) Clean the pretreated composite fiber material with acetone, distilled water and ethanol in sequence for 10-20 min, dry it and add it to the reaction solution. After ultrasonic treatment for 10-20 min, transfer it to the reaction vessel, seal it and place it in an oven. Heat it at 180-186℃ for 24-26 h. After the reaction is completed, cool it to room temperature, centrifuge the product, wash it repeatedly with deionized water and dry it.

[0043] Furthermore, the dispersion has a solid content of 5-8 wt%.

[0044] The composite aerogel and dispersion have a solid-liquid ratio of 1:(150-260)g / mL;

[0045] The ratio of potassium antimony tartrate, deionized water, polyvinylpyrrolidone, and thioacetamide is (0.6-1.4) mol : (60-130) mL : (0.3-0.6) g : (1.3-2.1) mol;

[0046] The ratio of the pretreated composite fiber material to the reaction solution is (5-12)g:(160-280)mL.

[0047] Compared with the prior art, the beneficial effects of the present invention are:

[0048] In this invention, a mixture of sodium alginate / carrageenan / chitosan is used as a precursor to prepare a precursor by wet spinning technology. Then, in the precursor, aspartic acid is used as an organic ligand and copper is used as a metal center to prepare a composite aerogel by co-precipitation. The introduced metallic copper is deposited on the pore walls of the porous aerogel to form nano-copper particles, thereby increasing the roughness of the pore walls and which is beneficial to increasing the frictional resistance between the pore walls and the nanowires.

[0049] Then, using pitch as a carbon source, a framework template material synthesized from magnesium oxide, zinc nitrate, and 2-methylimidazole as raw materials was used as a dual template and auxiliary carbon source. Potassium bicarbonate was used as an activator, and porous carbon nanosheets were prepared by template-induced coupling chemical method. The porous carbon nanosheets have a large number of pores on their surface, which is conducive to the embedding of nanowires into the pores after deposition, thereby enhancing the bonding strength between the two.

[0050] Then, using a hydrothermal method, nanowires are deposited on the surface of porous carbon nanosheets to obtain nanomaterials. Taking advantage of the fact that a large number of non-carbon elements escape in gaseous form during the carbonization process of carbon fibers, resulting in defects such as pores and protrusions on the carbon fiber surface, mechanical stirring and ultrasonic dispersion are used to achieve a physical bonding method. This allows the nanomaterials to be embedded into the defects on the carbon fiber surface through nanosheets, thus realizing the physical structure of the nanomaterials and carbon fibers. Moreover, since the nanosheets have a porous structure, they can easily adapt to the protrusions and defects on the carbon fiber surface, resulting in good bonding strength between the two and a stable composite fiber material structure.

[0051] Finally, the composite fiber material and composite aerogel are thoroughly mixed through vacuum treatment under ultrasonic and mechanical stirring to obtain a pretreated composite fiber material. The nanowires in the composite fiber material are embedded into the pores of the composite aerogel under the capillary action of the porous structure. Vacuum treatment helps increase the embedding depth of the nanowires into the pores, making it easier for them to contact each other. During ultrasonic and mechanical stirring, the embedded nanowires become intertwined and connected, allowing the composite fiber material to be bonded together through the entanglement of the nanowires, thus constructing independent network structures. Since the connection nodes between the composite fibers are located within the composite aerogel, the porous framework structure of the composite aerogel can effectively disperse and transfer stress, exhibiting excellent resistance to external forces. Therefore, it provides excellent protection for the connection nodes, preventing them from breaking under stress and improving the stability of the network structure.

[0052] Meanwhile, potassium antimony tartrate and thioacetamide were used as antimony and sulfur sources, respectively, to form the reaction solution. The pretreated composite fiber material was cleaned and added to the reaction solution. After hydrothermal reaction, the generated antimony sulfide nanoparticles were deposited and attached to the surface of the pretreated composite fiber material. As the hydrothermal reaction proceeded, the antimony sulfide nanoparticles agglomerated and grew a network structure from the surface, thus embedding the surface of the pretreated composite fiber material. On the one hand, embedding the composite aerogel can further prevent the nanowires from detaching from the pores of the composite aerogel, which helps to improve the stability of the connection nodes and makes the network structure formed between the composite fibers less prone to collapse. At the same time, the formed network structure increases the surface roughness of the aerogel composite fiber material, resulting in high frictional resistance between the aerogel composite fibers and making separation difficult after they come into contact.

[0053] By incorporating synthetic aerogel-type composite fiber materials into the papermaking process, individual small network structures can be formed in the paper. These small network structures are randomly dispersed in the paper, which can continuously change the stress transmission path, thereby increasing the paper's resistance. At the same time, the small network structures have a large contact area, resulting in high frictional resistance during paper tearing and making them difficult to separate, thus making the paper less prone to breakage.

[0054] The papermaking additives prepared in this invention, when introduced into the papermaking process, can effectively improve the tensile strength and ring crush strength of paper, giving the paper excellent strength and toughness, and better meeting the needs of special industries. Detailed Implementation

[0055] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] In this embodiment of the invention, chitosan with a degree of deacetylation greater than 80% was purchased from Sinopharm Chemical Reagent Co., Ltd.; κ-type carrageenan and sodium alginate, food grade, were purchased from Qingdao Bairen Biotechnology Co., Ltd.

[0057] The cationic monomer is composed of equal mass of dimethyl diallyl ammonium chloride monomer and acryloyloxyethyl trimethyl ammonium chloride monomer;

[0058] The anionic monomer is selected from itaconic acid; the initiator is selected from ammonium persulfate; the pH adjuster includes a base and an acid, the base being selected from sodium hydroxide and the acid from hydrochloric acid; the chain transfer agent is sodium formate; the catalyst is phosphoric acid; the complexing agent is disodium ethylenediaminetetraacetate; and the antibacterial agent is isothiazolinone.

[0059] Example 1

[0060] A method for preparing an aerogel-type papermaking additive based on composite fiber materials, specifically including the following steps:

[0061] S1. Dilute the auxiliary intermediate with water, adjust the pH value to 9.0, stir and mix for 12 minutes, and control the temperature at 32℃ to obtain the auxiliary intermediate solution;

[0062] S2. Under stirring, glyoxal is added to the intermediate solution of the auxiliary agent using a circulating pump. The dry mass ratio of the intermediate agent to glyoxal is controlled at 3.2:1. The pH value is adjusted to 9.0. The reaction continues until the viscosity of the material reaches 20 cps. The reaction is stopped when the pH value is adjusted to 2.5. After the reaction is completed, aerogel-type composite fiber material is added and stirred and dispersed to obtain the papermaking auxiliary agent.

[0063] The preparation method of aerogel-type composite fiber material includes the following steps:

[0064] 1) Sodium alginate, κ-carrageenan and chitosan were mixed in a mass ratio of 3:1:2 to obtain a precursor. Then, a 3% (w / w) aqueous solution of the precursor was prepared. The precursor was then precipitated by wet spinning with ethanol as the coagulation bath. The precipitated gel was solidified in a 5% (w / w) copper nitrate solution, dried and placed in a muffle furnace at 800°C for 2 hours. The obtained product was soaked in acetic acid, washed repeatedly with deionized water and dried to obtain carbon aerogel.

[0065] 2) Dissolve 0.04 mol L-aspartic acid in 10 mL of 6.0 mol / L sodium hydroxide solution, then add 0.3 g carbon aerogel, sonicate at 300 W for 30 min, disperse evenly, add 100 mL of 0.5 mol / L copper nitrate solution, stir at 200 r / min for 3 h, centrifuge the obtained product, wash repeatedly with deionized water, acetic acid solution and ethanol solution, and dry to obtain composite aerogel;

[0066] 3) 0.2g of nano-magnesium oxide was placed in 100mL of methanol solution and dispersed by ultrasonication at 200W for 30min. Then, 1.2g of zinc nitrate was added and stirred at 150r / min for 1h to obtain solution A. 1.4g of 2-methylimidazole was uniformly dispersed in 300mL of methanol solution to obtain solution B. Solution A and solution B were mixed and reacted at 500r / min at room temperature for 24h. The obtained product was centrifuged, washed repeatedly with methanol, and dried to obtain the framework template material.

[0067] 4) Place 1.0g of pre-crushed asphalt, 3.0g of potassium bicarbonate and 1.0g of skeleton template material in a mortar and mix evenly. Then place it in a tube furnace and heat it to 300℃ at 5℃ / min. Keep it at the temperature for 30min. Then heat it to 900℃ at the same rate and keep it at the temperature for 1h. Then cool it naturally to room temperature. Stir and soak the obtained product in 0.1mol / L hydrochloric acid solution for 24h. After filtration, washing, drying and grinding, porous carbon nanosheets are obtained.

[0068] 5) Add 0.025 mol copper nitrate, 0.14 mol potassium permanganate and 0.045 mol manganese sulfate to 70 mL of deionized water and stir magnetically for 30 min to form a homogeneous solution. Then add 5 g of porous carbon nanosheets, disperse them evenly and seal them in a reactor. Under the action of 100 W ultrasound, react at 160 °C for 12 h. After the reaction is completed, let it cool naturally to room temperature. Wash the product obtained after centrifugation repeatedly with water and ethanol, and dry it to obtain composite nanomaterials.

[0069] 6) Add 10g of carbon fiber and 3g of composite nanomaterial to a container, add 200mL of deionized water, first stir mechanically at 800r / min for 1h, then sonicate at 500W for 1h. After the treatment is completed, filter the product and dry it to obtain the composite fiber material.

[0070] 7) The composite fiber material was dispersed in deionized water to obtain a dispersion with a solid content of 5 wt%. Then, the composite aerogel was added to the dispersion at a solid-liquid ratio of 1:150 g / mL. The vacuum was drawn to 50 Pa and maintained at 200 r / min and 200 W ultrasound for 30 min. After the treatment was completed, the product was centrifuged to obtain the pretreated composite fiber material.

[0071] 8) Dissolve 0.6 mol of potassium antimony tartrate in 60 mL of deionized water, stir magnetically for 15 min, add 0.3 g of polyvinylpyrrolidone, continue stirring for 15 min, then add 1.3 mol of thioacetamide to the mixture and stir thoroughly to obtain the reaction solution.

[0072] 9) Clean 5g of pretreated composite fiber material with acetone, distilled water and ethanol in sequence for 10min each. After drying, add it to 160mL of reaction solution and sonicate at 200W for 10min. Then transfer it to the reaction vessel, seal it and place it in an oven. Heat it at 180℃ for 24h. After the reaction is completed, cool it to room temperature, centrifuge the product, wash it repeatedly with deionized water and dry it.

[0073] Example 2

[0074] A method for preparing an aerogel-type papermaking additive based on composite fiber materials, specifically including the following steps:

[0075] S1. Dilute the auxiliary intermediate with water, adjust the pH value to 9.5, stir and mix for 15 minutes, and control the temperature at 35℃ to obtain the auxiliary intermediate solution.

[0076] S2. Under stirring, glyoxal is added to the intermediate solution of the auxiliary agent using a circulating pump. The dry mass ratio of the intermediate agent to glyoxal is controlled at 5.3:1. The pH value is adjusted to 9.3. The reaction continues until the viscosity of the material reaches 35 cps. The reaction is stopped when the pH value is adjusted to 3.5. After the reaction is completed, aerogel-type composite fiber material is added and stirred and dispersed to obtain the papermaking auxiliary agent.

[0077] The preparation method of aerogel-type composite fiber material includes the following steps:

[0078] 1) Sodium alginate, κ-carrageenan and chitosan were mixed in a mass ratio of 3.5:1:2.5 to obtain a precursor. Then, a 4% (w / w) aqueous solution of the precursor was prepared. The precursor was then precipitated by wet spinning with ethanol as the coagulation bath. The precipitated gel was solidified in a 7% (w / w) copper nitrate solution, dried and placed in a muffle furnace at 820°C for 2.5 h. The obtained product was soaked in acetic acid, washed repeatedly with deionized water and dried to obtain carbon aerogel.

[0079] 2) Dissolve 0.05 mol L-aspartic acid in 15 mL of 6.5 mol / L sodium hydroxide solution, then add 0.4 g carbon aerogel, sonicate at 400 W for 40 min, disperse evenly, add 120 mL of 0.7 mol / L copper nitrate solution, stir at 260 r / min for 4 h, centrifuge the obtained product, wash repeatedly with deionized water, acetic acid solution and ethanol solution, and dry to obtain composite aerogel;

[0080] 3) 0.3 g of nano-magnesium oxide was placed in 130 mL of methanol solution and dispersed by ultrasonication at 260 W for 40 min. Then, 1.6 g of zinc nitrate was added and stirred at 200 r / min for 1.5 h to obtain solution A. 1.8 g of 2-methylimidazole was uniformly dispersed in 400 mL of methanol solution to obtain solution B. Solution A and solution B were mixed and reacted at 550 r / min at room temperature for 27 h. The obtained product was centrifuged, washed repeatedly with methanol, and dried to obtain the framework template material.

[0081] 4) 1.5g of pre-crushed asphalt, 4.5g of potassium bicarbonate and 1.5g of skeleton template material were placed in a mortar and mixed evenly. Then the mixture was placed in a tube furnace and heated to 310℃ at 6℃ / min and kept at that temperature for 40min. Then the temperature was increased to 920℃ at the same rate and kept at that temperature for 1.5h. After cooling to room temperature, the product was stirred and soaked in 0.2mol / L hydrochloric acid solution for 27h. After filtration, washing, drying and grinding, porous carbon nanosheets were obtained.

[0082] 5) Add 0.028 mol copper nitrate, 0.16 mol potassium permanganate and 0.050 mol manganese sulfate to 85 mL of deionized water and stir magnetically for 40 min to form a homogeneous solution. Then add 7 g of porous carbon nanosheets, disperse them evenly and seal them in a reactor. Under the action of 130 W ultrasound, react at 162 °C for 13 h. After the reaction is completed, let it cool naturally to room temperature. Wash the product obtained after centrifugation repeatedly with water and ethanol, and dry it to obtain composite nanomaterials.

[0083] 6) Add 15g of carbon fiber and 5g of composite nanomaterial to a container, add 260mL of deionized water, first stir mechanically at 1000r / min for 1.5h, then sonicate at 550W for 1.5h. After the treatment is completed, filter the product and dry it to obtain the composite fiber material.

[0084] 7) The composite fiber material was dispersed in deionized water to obtain a dispersion with a solid content of 7wt%. Then, the composite aerogel was added to the dispersion at a solid-liquid ratio of 1:210g / mL. The vacuum was drawn to 80Pa and maintained at 250r / min and 250W ultrasound for 40min. After the treatment was completed, the product was centrifuged to obtain the pretreated composite fiber material.

[0085] 8) Dissolve 1.2 mol of potassium antimony tartrate in 100 mL of deionized water, stir magnetically for 25 min, add 0.5 g of polyvinylpyrrolidone, continue stirring for 25 min, then add 1.8 mol of thioacetamide to the mixture and stir thoroughly to obtain the reaction solution.

[0086] 9) Clean 8g of pretreated composite fiber material with acetone, distilled water and ethanol in sequence for 15min each. After drying, add it to 220mL of reaction solution and sonicate at 250W for 15min. Then transfer it to the reaction vessel, seal it and place it in an oven. Heat it at 182℃ for 25h. After the reaction is completed, cool it to room temperature, centrifuge the product, wash it repeatedly with deionized water and dry it.

[0087] Example 3

[0088] A method for preparing an aerogel-type papermaking additive based on composite fiber materials, specifically including the following steps:

[0089] S1. Dilute the auxiliary agent intermediate with water, adjust the pH value to 9.5, stir and mix for 18 minutes, and control the temperature at 36℃ to obtain the auxiliary agent intermediate solution.

[0090] S2. Under stirring, glyoxal is added to the intermediate solution of the auxiliary agent using a circulating pump. The dry mass ratio of the intermediate agent to glyoxal is controlled at 7.6:1. The pH value is adjusted to 9.3. The reaction continues until the viscosity of the material reaches 50 cps. The reaction is stopped when the pH value is adjusted to 4.0. After the reaction is completed, aerogel-type composite fiber material is added and stirred and dispersed thoroughly to obtain the papermaking auxiliary agent.

[0091] The preparation method of aerogel-type composite fiber material includes the following steps:

[0092] 1) Sodium alginate, κ-carrageenan and chitosan were mixed in a mass ratio of 4:1:3 to obtain a precursor. Then, a 5% (w / w) aqueous solution of the precursor was prepared. The precursor was then precipitated by wet spinning with ethanol as the coagulation bath. The precipitated gel was solidified in an 8% (w / w) copper nitrate solution, dried and placed in a muffle furnace at 830°C for 3 hours. The obtained product was soaked in acetic acid, washed repeatedly with deionized water and dried to obtain carbon aerogel.

[0093] 2) Dissolve 0.07 mol L-aspartic acid in 20 mL of 6.8 mol / L sodium hydroxide solution, then add 0.5 g carbon aerogel, sonicate at 500 W for 50 min, disperse evenly, add 130 mL of 0.8 mol / L copper nitrate solution, stir at 300 r / min for 5 h, centrifuge the obtained product, wash repeatedly with deionized water, acetic acid solution and ethanol solution, and dry to obtain composite aerogel;

[0094] 3) 0.5 g of nano-magnesium oxide was placed in 160 mL of methanol solution and dispersed by ultrasonication at 300 W for 50 min. Then, 1.8 g of zinc nitrate was added and stirred at 260 r / min for 2 h to obtain solution A. 2.0 g of 2-methylimidazole was uniformly dispersed in 500 mL of methanol solution to obtain solution B. Solution A and solution B were mixed and reacted at 600 r / min at room temperature for 30 h. The obtained product was centrifuged, washed repeatedly with methanol, and dried to obtain the framework template material.

[0095] 4) 1.8g of pre-crushed asphalt, 5.4g of potassium bicarbonate and 1.8g of skeleton template material were placed in a mortar and mixed evenly. Then the mixture was placed in a tube furnace and heated to 320℃ at 8℃ / min and kept at that temperature for 50min. Then the temperature was increased to 950℃ at the same rate and kept at that temperature for 2h. After cooling to room temperature, the product was stirred and soaked in 0.3mol / L hydrochloric acid solution for 30h. After filtration, washing, drying and grinding, porous carbon nanosheets were obtained.

[0096] 5) Add 0.030 mol copper nitrate, 0.18 mol potassium permanganate and 0.052 mol manganese sulfate to 100 mL deionized water and stir magnetically for 50 min to form a homogeneous solution. Then add 8 g of porous carbon nanosheets, disperse them evenly and seal them in a reactor. Under the action of 150 W ultrasound, react at 165 °C for 15 h. After the reaction is completed, let it cool naturally to room temperature. Wash the product obtained after centrifugation repeatedly with water and ethanol, and dry it to obtain composite nanomaterials.

[0097] 6) Add 20g of carbon fiber and 7g of composite nanomaterial to a container, add 300mL of deionized water, first stir mechanically at 1200r / min for 2h, then sonicate at 600W for 2h. After the treatment is completed, filter the product and dry it to obtain the composite fiber material.

[0098] 7) The composite fiber material was dispersed in deionized water to obtain a dispersion with a solid content of 8wt%. Then, the composite aerogel was added to the dispersion at a solid-liquid ratio of 1:260g / mL. The vacuum was drawn to 100Pa and maintained at 300r / min and 300W ultrasound for 50min. After the treatment was completed, the product was centrifuged to obtain the pretreated composite fiber material.

[0099] 8) Dissolve 1.4 mol of potassium antimony tartrate in 130 mL of deionized water, stir magnetically for 30 min, add 0.6 g of polyvinylpyrrolidone, continue stirring for 30 min, then add 2.1 mol of thioacetamide to the mixture and stir thoroughly to obtain the reaction solution.

[0100] 9) Clean 12g of pretreated composite fiber material by ultrasonication with acetone, distilled water and ethanol for 20min in sequence, dry it and add it to 280mL of reaction solution. After ultrasonic treatment at 300W for 20min, transfer it to the reaction vessel, seal it and place it in an oven. Heat it at 186℃ for 26h. After the reaction is completed, cool it to room temperature, centrifuge the product, wash it repeatedly with deionized water and dry it.

[0101] Comparative Example 1: This comparative example is basically the same as Example 1, except that steps 1)-2) are omitted in the preparation of the aerogel composite fiber material.

[0102] Comparative Example 2: This comparative example is basically the same as Example 1, except that steps 3)-5) are omitted in the preparation of the aerogel composite fiber material.

[0103] Comparative Example 3: This comparative example is basically the same as Example 1, except that steps 6)-7) are omitted in the preparation of the aerogel composite fiber material.

[0104] Comparative Example 4: This comparative example is basically the same as Example 1, except that steps 8)-9) are omitted in the preparation of the aerogel composite fiber material.

[0105] Comparative Example 5: This comparative example is basically the same as Example 1, except that it does not contain aerogel-type composite fiber material.

[0106] Test experiment:

[0107] The papermaking additives prepared in Examples 1-3 and Comparative Examples 1-5 were applied to papermaking, ensuring that other conditions were the same during the papermaking process. After papermaking was completed, the tensile strength and ring crush strength of the paper made using the papermaking additives prepared in Examples 1-3 and Comparative Examples 1-5 were tested.

[0108] The paper obtained from the papermaking process in Examples 1-3 and Comparative Examples 1-5 was cut into 10cm×10cm pieces. The two sides of the paper pieces were pulled until the paper pieces broke. The tensile strength value was obtained by dividing the tensile force value when the paper pieces broke by the area of ​​the paper pieces.

[0109] The paper obtained from the papermaking process in Examples 1-3 and Comparative Examples 1-5 was cut into paper pieces with a diameter of 10 cm. The paper pieces were inserted into the sample holder to form a ring. Pressure was applied between the upper and lower pressure plates. The maximum force that the paper piece could withstand before being crushed was the ring crush strength.

[0110] After summarizing and statistically analyzing the test data, the test data of Comparative Example 5 was used as the control group, and the test data of Examples 1-3 and Comparative Examples 1-4 were used as the experimental group. The data of the experimental group were compared with those of the control group, and the changes in the data of the experimental group were recorded. The results are shown in Table 1.

[0111] Table 1

[0112] Example 1 Example 2 Example 3 Comparative Example 1 Tensile strength improvement rate % 38.6 39.3 39.0 32.9 Ring crush strength improvement rate % 35.1 36.2 35.7 30.3 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Tensile strength improvement rate % 30.7 28.4 34.5 - Ring crush strength improvement rate % 28.6 25.3 31.7 -

[0113] As shown in Table 1, the papermaking additives of this invention, when introduced into the papermaking process, can effectively improve the tensile strength and ring crush strength of the paper, giving the paper excellent strength and toughness, and better meeting the needs of special industries.

[0114] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing an aerogel-type papermaking additive based on composite fiber materials, characterized in that, The preparation method includes the following steps: S1. Dilute the auxiliary intermediate with water, adjust the pH value to 9.0-9.5, stir and mix for 12-18 minutes, and control the temperature at 32-36℃ to obtain the auxiliary intermediate solution; S2. Under stirring and with the aid of a circulating pump, add glyoxal to the intermediate solution of the auxiliary agent, and control the oven-dry mass ratio of the intermediate agent to glyoxal to be (3.2-7.6):

1. Adjust the pH value to 9.0-9.3 and react until the viscosity of the material reaches 20-50 cps. When the pH value is adjusted to 2.5-4.0, stop the reaction. After the reaction is completed, add the aerogel-type composite fiber material and stir and disperse it thoroughly to obtain the papermaking auxiliary agent. The preparation method of the aerogel-type composite fiber material is as follows: 1) Disperse the composite fiber material in deionized water to obtain a dispersion, then add the composite aerogel to the dispersion, evacuate to 50-100 Pa, and maintain for 30-50 min under the action of 200-300 r / min and 200-300 W ultrasound. After the treatment is completed, centrifuge the product to obtain the pretreated composite fiber material. 2) Dissolve potassium antimony tartrate in deionized water, stir magnetically for 15-30 minutes, add polyvinylpyrrolidone, continue stirring for 15-30 minutes, then add thioacetamide to the mixture and stir thoroughly to obtain the reaction solution. 3) Clean the pretreated composite fiber material with acetone, distilled water and ethanol in sequence for 10-20 min, dry it and add it to the reaction solution. After ultrasonic treatment for 10-20 min, transfer it to the reaction vessel, seal it and place it in an oven. Heat it at 180-186℃ for 24-26 h. After the reaction is completed, cool it to room temperature, centrifuge the product, wash it repeatedly with deionized water and dry it. The preparation method of the auxiliary intermediate includes the following steps: According to the weight percentage, 30-42 parts of acrylamide monomer, 4-7 parts of anionic monomer, 28-42 parts of cationic monomer, 1-3 parts of chain transfer agent, and 0.02-0.05 parts of complexing agent are added to a reaction vessel. Soft water is added to prepare an aqueous solution with a mass percentage concentration of 20-28%. Nitrogen gas is introduced for 25-50 minutes. 2-6 parts of pH adjuster are added to adjust the pH value to 4.0-5.

5. 3-5 parts of catalyst and 1-3 parts of initiator are added dropwise at a uniform rate at 68-72℃. The reaction is stirred for 120-170 minutes. After holding at this temperature for 50-100 minutes, the reaction is stopped. The temperature is lowered to room temperature, and 0.1-0.5 parts of antibacterial agent are added to obtain the auxiliary intermediate. The preparation method of the composite aerogel is as follows: 1) Sodium alginate, κ-carrageenan and chitosan in a mass ratio of (3-4):1:(2-3) were mixed to obtain a precursor. Then an aqueous solution of the precursor was prepared. The precursor was precipitated by wet spinning with ethanol as the coagulation bath. The precipitated gel was solidified in a copper nitrate solution with a mass fraction of 5-8%. After drying, it was placed in a muffle furnace and carbonized at 800-830℃ for 2-3 hours. The obtained product was soaked in acetic acid, washed repeatedly with deionized water and dried to obtain carbon aerogel. 2) Dissolve L-aspartic acid in a sodium hydroxide solution with a concentration of 6.0-6.8 mol / L, then add carbon aerogel, sonicate for 30-50 min, disperse evenly, add copper nitrate solution with a concentration of 0.5-0.8 mol / L, stir and react for 3-5 h, centrifuge the obtained product, wash it repeatedly with deionized water, acetic acid solution and ethanol solution in sequence, and dry it to obtain composite aerogel; The preparation method of the composite fiber material is as follows: 1) Place 0.2-0.5g of nano-magnesium oxide into 100-160mL of methanol solution and ultrasonically disperse for 30-50min. Then add 1.2-1.8g of zinc nitrate and stir for 1-2h to obtain solution A. Disperse 1.4-2.0g of 2-methylimidazole evenly into 300-500mL of methanol solution to obtain solution B. Mix solution A and solution B and stir the reaction at room temperature for 24-30h. Centrifuge the obtained product, wash it repeatedly with methanol, and dry it to obtain the framework template material. 2) The pre-crushed asphalt, potassium bicarbonate and skeleton template material are placed in a mortar and mixed evenly. Then, the mixture is placed in a tube furnace and heated to 300-320℃ and kept at that temperature for 30-50 minutes. Then, the temperature is increased to 900-950℃ at the same rate and kept at that temperature for 1-2 hours. After cooling to room temperature, the product is stirred and soaked in hydrochloric acid solution for 24-30 hours. After filtration, washing, drying and grinding, porous carbon nanosheets are obtained. 3) Add copper nitrate, potassium permanganate, and manganese sulfate to deionized water and stir magnetically for 30-50 min to form a homogeneous solution. Then add porous carbon nanosheets, disperse them evenly, and seal them in a reactor. Under ultrasonic action, react at a constant temperature of 160-165℃ for 12-15 h. After the reaction is completed, cool naturally to room temperature. Wash the product obtained after centrifugation repeatedly with water and ethanol, and dry it to obtain composite nanomaterials. 4) Add carbon fiber and composite nanomaterials to a container, add deionized water, stir mechanically for 1-2 hours, then sonicate for 1-2 hours. After the treatment is completed, filter the product and dry it to obtain composite fiber material.

2. The method for preparing an aerogel-type papermaking additive based on composite fiber materials according to claim 1, characterized in that, In the preparation method of the auxiliary intermediate, the cationic monomer is composed of dimethyl diallyl ammonium chloride monomer and acryloyloxyethyl trimethyl ammonium chloride monomer in equal mass. The anionic monomer is selected from one or more of itaconic acid, 2-acrylamido-2-methylpropanesulfonic acid, and their salts; The initiator is selected from one or more of ammonium persulfate, sodium persulfate, potassium persulfate, azobisisobutyramidine hydrochloride, and azobisisopropylimidazoline hydrochloride; The pH adjuster comprises a base and an acid, wherein the base is selected from one or more of sodium hydroxide and ammonia; and the acid is selected from one or more of hydrochloric acid, phosphoric acid, formic acid, and citric acid. The chain transfer agent is sodium formate, the catalyst is phosphoric acid, the complexing agent is disodium ethylenediaminetetraacetate, and the antibacterial agent is isothiazolinone.

3. The method for preparing an aerogel-type papermaking additive based on composite fiber materials according to claim 1, characterized in that, In the preparation method of composite aerogels, the mass fraction of the precursor aqueous solution is 3-5%; The ratio of L-aspartic acid, sodium hydroxide solution, carbon aerogel, and copper nitrate solution is (0.04-0.07) mol : (10-20) mL : (0.3-0.5) g : (100-130) mL.

4. The method for preparing an aerogel-type papermaking additive based on composite fiber materials according to claim 1, characterized in that, In the preparation method of composite fiber materials, the stirring speed is 500-600 r / min; The mass ratio of the asphalt, potassium bicarbonate, and skeleton template material is (1.0-1.8):(3.0-5.4):(1.0-1.8). The heating rate is 5-8℃ / min; The concentration of the hydrochloric acid solution is 0.1-0.3 mol / L.

5. The method for preparing an aerogel-type papermaking additive based on composite fiber materials according to claim 1, characterized in that, In the preparation method of composite fiber materials, the ratio of copper nitrate, potassium permanganate, manganese sulfate, deionized water, and porous carbon nanosheets is (0.025-0.030) mol: (0.14-0.18) mol: (0.045-0.052) mol: (70-100) mL: (5-8) g; The power of the ultrasound is 100-150W; The ratio of carbon fiber, composite nanomaterials, and deionized water is (10-20) g: (3-7) g: (200-300) mL; The mechanical stirring speed is 800-1200 r / min; The power of the ultrasonic treatment is 500-600W.

6. The method for preparing an aerogel-type papermaking additive based on composite fiber materials according to claim 1, characterized in that, In the preparation method of aerogel-type composite fiber materials, the solid content of the dispersion is 5-8 wt%; The solid-liquid ratio of the composite aerogel and dispersion is 1:(150-260)g / mL; The ratio of potassium antimony tartrate, deionized water, polyvinylpyrrolidone, and thioacetamide is (0.6-1.4) mol : (60-130) mL : (0.3-0.6) g : (1.3-2.1) mol; The ratio of the pretreated composite fiber material to the reaction solution is (5-12) g: (160-280) mL.