SiO 2 -g-PAA / Modified Starch Blend Sizing Agent, Preparation Method and Application

Abstract

The present invention discloses a SiO2-g-PAA / modified starch blend sizing agent, a preparation method and an application thereof. The preparation method of the blend sizing agent is as follows: S1: Dispersing corn starch in distilled water, adding dilute hydrochloric acid for reaction to obtain acid-hydrolyzed starch ATS; dispersing the acid-hydrolyzed starch in distilled water containing Na2SO4, and then successively adding an etherifying agent and CaO for reaction to obtain quaternary ammonium cationic starch QS; dispersing the quaternary ammonium cationic starch QS in distilled water, and then adding butyric anhydride for reaction to obtain modified starch QBS; S2: Preparing a dispersion of nano-SiO2 and distilled water, and then adding acrylic acid, ammonium ferrous sulfate and hydrogen peroxide for reaction under an inert gas atmosphere to obtain SiO2-g-PAA; S3: Preparing a dispersion of the SiO2-g-PAA in S2 and distilled water, and then adding the modified starch QBS in S1 and mixing evenly to obtain the blend sizing agent. The spun yarn treated with the blend sizing agent of the present invention has better abrasion resistance, breaking strength and hairiness reduction rate.

Description

Technical Field

[0001] The present invention relates to the field of textile technology, and particularly to SiO 2 -g-PAA / modified starch blend sizing agent, preparation method and application. Background Art

[0002] There are a large number of hairs on the surface of the original yarn, and the fiber cohesion is low. In addition, during the weaving production process, the warp yarns rub against each other, and at the same time, mechanical components will exert repeated mechanical actions such as friction, stretching and bending on the warp yarns, which will cause the warp yarns to break and form hair balls, resulting in a significant reduction in weaving efficiency and product quality.

[0003] In order to improve the mechanical properties and wear resistance of warp yarns, sizing is mainly used. During the sizing process of warp yarns, part of the sizing agent will penetrate into the interior of the warp yarns and form an adhesive bonding layer between the internal fibers, playing a role in bonding and cohesion to improve the strength of the warp yarns; another part of the sizing agent will form a uniform sizing film on the surface of the warp yarns after drying, making the surface hairs lie flat, the surface of the warp yarns smooth, and improving the wear resistance of the warp yarns.

[0004] Current textile sizing agents mainly include adding nano-SiO 2 as an additive to starch sizing agents to prepare nano-SiO 2 / starch blend sizing agents to make up for the defects of starch sizing agents, promote the adhesion of starch to fibers, improve the properties of starch sizing films, and improve sizing performance. For example, in 2006, Yang studied the influence of nano-SiO 2 modified epoxy emulsion sizing agent on the interfacial bonding properties of carbon fiber reinforced composites. The results showed that after sizing treatment, the number of hydroxyl groups on the surface of carbon fibers increased slightly; compared with the unsized CFRP, the interlaminar shear strength (ILSS) of the CFRP treated with the unmodified sizing agent increased by 9%, and the ILSS of the CFRP treated with the modified nano-SiO 2 sizing agent increased by 14%. No holes and carbon fiber pull-out phenomena were observed on the fracture surface, and the cross-section of the CFRP treated with the nano-SiO 2 modified sizing agent was denser, and fiber debonding was more difficult. In 2008, Wang Yuanyuan et al. added nano-SiO 2 as a filler to starch sizing agents and conducted sizing experiments on pure cotton fine yarns and polyester / cotton blended yarns with different linear densities, and studied the influence of the dosage of nano-SiO 2 on the sizing performance of starch. The results showed that after adding nano-SiO 2 , the wear resistance, breaking strength and hairiness reduction rate of the sized yarns all increased to a certain extent; the dosage of nano-SiO 2 in starch will have a certain impact on the actual sizing effect, and it is advisable to be 3% - 4%.

[0005] Nano - SiO 2 As an additive, it can effectively improve the performance of the sizing slurry and have a positive impact on the sizing effect. The purpose of the present invention is to modify nano - SiO 2 and starch on the basis of the existing scheme, and then prepare a blended sizing slurry to further improve the sizing performance. Summary of the Invention

[0006] Based on the technical problems existing in the background technology, the present invention proposes SiO 2 -g - PAA / modified starch blended sizing slurry, its preparation method and application. The spinning treated with this sizing slurry significantly improves the abrasion resistance, breaking strength and hairiness reduction rate.

[0007] The preparation method of the SiO 2 -g - PAA / modified starch blended sizing slurry proposed by the present invention is as follows:

[0008] S1: Preparation of modified starch QBS;

[0009] S2: Preparation of SiO 2 -g - PAA

[0010] Disperse nano - SiO 2 with distilled water to form a dispersion liquid, then add acrylic acid, ammonium ferrous sulfate aqueous solution and hydrogen peroxide aqueous solution to react under an inert gas atmosphere. After the reaction, it is washed, centrifuged and dried to obtain SiO 2 -g - PAA;

[0011] S3: Preparation of the blended sizing slurry

[0012] Disperse the SiO 2 -g - PAA in S2 with distilled water to form a dispersion liquid, and then add the modified starch QBS in S1 and mix evenly to obtain the blended sizing slurry.

[0013] Preferably, the preparation method of the modified starch QBS is as follows:

[0014] S11: Disperse corn starch in distilled water, add dilute hydrochloric acid to react. After the reaction, it is neutralized with alkali, filtered, washed, dried and pulverized to obtain acid - hydrolyzed starch ATS;

[0015] S12: Disperse the acid - hydrolyzed starch in S11 in distilled water containing Na 2 SO 4 , adjust the pH to 10 - 11, then successively add the mixed solution of cationic etherifying agent and NaOH and the aqueous solution of CaO to react. After the reaction, it is acid - neutralized, washed, dried and pulverized to obtain quaternary ammonium cationic starch QS;

[0016] S13: Disperse the quaternary ammonium cationic starch QS from S12 in distilled water, adjust the pH to 8 - 9, then add butyric anhydride for reaction. After the reaction, neutralize with acid, wash, dry and pulverize to obtain the modified starch QBS.

[0017] Preferably, the mass ratio of ATS, cationic etherifying agent and CaO in S12 is 324:5 - 50:0.5 - 2.5.

[0018] Preferably, the mass ratio of QS and butyric anhydride in S13 is 200:1 - 15.

[0019] Preferably, in S2, the mass - volume ratio of nano - SiO 2 , acrylic acid, ammonium ferrous sulfate and hydrogen peroxide is 4g:4 - 16g:5 - 45mL:4.6 - 42mL.

[0020] Preferably, in S2, the nano - SiO 2 is formulated with distilled water into a dispersion liquid with a concentration of 0.1 - 10%, and the pH of the dispersion liquid is adjusted to 3 - 4.

[0021] Preferably, the reaction temperature in S2 is 25 - 45°C and the time is 2 - 10h.

[0022] Preferably, in S3, the mass ratio of SiO 2 -g - PAA and the modified starch QBS is 0.25 - 1.5:100.

[0023] The SiO 2 -g - PAA / modified starch blend sizing agent prepared by the above - mentioned method proposed by the present invention.

[0024] The application of the above - mentioned SiO 2 -g - PAA / modified starch blend sizing agent in textile.

[0025] The beneficial technical effects of the present invention:

[0026] The conventional method is to directly blend nano - SiO 2 with unmodified starch to prepare nano - SiO 2 / starch blend sizing agent for use. The present invention first graft - modifies nano - SiO 2 and modifies starch, then prepares SiO 2 -g - PAA and the modified starch QBS, and mixes the two to obtain the SiO 2 -g - PAA / modified starch blend sizing agent. On the one hand, graft - modifying nano - SiO 2 enhances its water dispersibility and reduces the aggregate particle size, thus greatly improving the nano - SiO 2The degree of uniform dispersion in the blended sizing agent and its degree of combination with starch. On the other hand, the grafted side chains on SiO 2 -g-PAA and the substituents in the modified starch can produce good synergistic effects through molecular interactions, and can also produce good molecular interactions with the fibers, so that the adhesion performance of SiO 2 -g-PAA / modified starch blended sizing agent to the fibers has been greatly improved compared with the conventional nano-SiO 2 / modified starch blended sizing agent.

[0027] In addition, the introduction of hydrophilic grafted side chains on SiO 2 improves the affinity between the blended sizing agent and water, increases the degree of water dispersion of SiO 2 , hinders the hydrogen bond interaction between starch macromolecules, slows down the aging of the starch sizing, so that the SiO 2 -g-PAA / modified starch blended sizing agent has higher viscosity thermal stability compared with the nano-SiO 2 / modified starch blended sizing agent.

[0028] SiO 2 After modification, SiO 2 -g-PAA can be better dispersed uniformly in the positively charged modified starch QBS. Due to its small size effect and macroscopic quantum tunneling effect, it produces an infiltration effect, can penetrate into the macromolecular chains of QBS, and interact with the positively charged TMACHP substituents in QBS to form a spatial network structure. Therefore, compared with QBS (0% by mass of starch) and nano-SiO 2 / QBS, the sizing agent of SiO 2 -g-PAA / modified starch QBS has better film-forming property and the sizing film is more flexible.

[0029] Finally, the introduced grafted side chains have strong steric hindrance and hydrophilicity. The steric hindrance and the water absorbed in the sizing film can produce a strong plasticizing effect on the blended sizing film. Therefore, compared with the nano-SiO 2 / modified starch blended sizing agent, the sizing film of SiO 2 -g-PAA / modified starch blended sizing agent has a higher elongation at break and a lower breaking strength, further reducing the brittleness of the sizing film.

[0030] All of the above indicate that graft modification of nano-SiO 2 significantly improves the performance of it as a component of the blended sizing agent. The blended sizing agent of the present invention will endow the spinning with better abrasion resistance, breaking strength and hairiness reduction rate. Description of the Drawings

[0031] Figure 1For the nano-SiO proposed by the present invention 2 and SiO 2 -g-PAA infrared spectrogram;

[0032] Figure 2 For the nano-SiO proposed by the present invention 2 and SiO 2 -g-PAA TEM image; where a is nano-SiO 2 and b is SiO 2 -g-PAA;

[0033] Figure 3 For the nano-SiO proposed by the present invention 2 and SiO 2 -g-PAA particle size distribution diagram;

[0034] Figure 4 For the different nano-SiO proposed by the present invention 2 and SiO 2 -g-PAA apparent viscosity of the blended slurry at different addition amounts;

[0035] Figure 5 For the different nano-SiO proposed by the present invention 2 and SiO 2 -g-PAA viscosity thermal stability of the blended slurry at different addition amounts;

[0036] Figure 6 For the different nano-SiO proposed by the present invention 2 and SiO 2 -g-PAA adhesion of the blended slurry with different addition amounts to polyester fibers;

[0037] Figure 7 For the different nano-SiO proposed by the present invention 2 and SiO 2 -g-PAA adhesion of the blended slurry with different addition amounts to cotton fibers;

[0038] Figure 8 For the different nano-SiO proposed by the present invention 2 and SiO 2 -g-PAA breaking strength of the blended slurry film with different addition amounts;

[0039] Figure 9 For the different nano-SiO proposed by the present invention 2 and SiO 2 -g-PAA elongation at break of the blended slurry film with different addition amounts;

[0040] Figure 10 For the different nano-SiO proposed by the present invention 2 and SiO 2SEM images of the tensile fracture surfaces of blend sizing films with different amounts of -g-PAA added; where a is the QBS film, b is the nano-SiO 2 / QBS film, c is the SiO 2 -g-PAA / QBS film;

[0041] Figure 11 For different nano-SiO 2 and SiO 2 -g-PAA addition amounts in the blend sizing films of the present invention, the moisture regain. Specific Embodiments

[0042] The present invention will be further explained below in conjunction with specific embodiments.

[0043] Example 1

[0044] The preparation method of the SiO 2 -g-PAA / modified starch blend sizing agent proposed by the present invention is as follows:

[0045] S1: Preparation of modified starch QBS

[0046] Weigh 400 g of dry corn starch and disperse it in distilled water to prepare a 40% starch milk. Transfer it to a three-necked flask, set the water bath temperature to 50 °C, and control the stirring rod speed to 130 r / min. When the water bath temperature reaches 50 °C, slowly drip 37 mL of 2 mol / L dilute HCl solution with a separatory funnel. After the dripping is completed, start timing for 4 h. After the reaction is completed, drip 1 mol / L NaOH solution to neutralize the pH of the starch milk to 6 - 7. Filter, wash with distilled water, and vacuum filter. Repeat the operation 4 times, then place it in a blast dryer to dry, crush it with an ultra-fine grinder, seal it in a bag for later use, and obtain acid-hydrolyzed starch (ATS).

[0047] Weigh 324 g of dry ATS and disperse it in distilled water containing Na 2 SO 4 . Stir evenly and transfer it to a three-necked flask. Adjust the pH value to 10 - 11 with 3% NaOH solution, stir and heat to 40 °C, add a mixed solution containing equimolar cationic etherifying agent and NaOH (added within 1 min), add 30 mL of aqueous solution containing 1.8 g of CaO after 10 min, react for 8 h, then neutralize to pH value of 6 - 7 with 2 mol / L HCl solution, filter and wash 2 - 3 times, place it in a blast dryer to dry, crush it with an ultra-fine grinder, seal it in a bag for later use, and obtain quaternary ammonium cationic starch (QS);

[0048] Weigh 120 g of dry QS and mix it with distilled water, and form a 40% starch dispersion under stirring. Use 6% Na2 CO 3 After adjusting the pH value of the dispersion to 8 - 9 with the solution, heat it in a water bath to 30 °C and keep it warm under stirring conditions. Slowly add the butyric anhydride solution to the dispersion using a separatory funnel, and at the same time maintain the pH value at 8 - 9 with the above-mentioned alkaline solution. After the addition is completed, continue stirring and reacting for 0.5 h. Adjust the pH value of the reaction system to 6.5 - 7 with a 2 mol / L HCl solution, filter by suction and wash 3 times, then dry and pulverize to obtain the modified starch QBS;

[0049] S2: Preparation of SiO 2 -g-PAA

[0050] Add 4 g of dry nano-SiO 2 to a 250 mL beaker, prepare a 4% dispersion with distilled water, adjust the pH value of the solution to 3 - 4, transfer it to a four-necked flask equipped with a stirrer and a nitrogen gas inlet tube, and stir for a period of time. Control the temperature of the water bath to 30 °C, introduce nitrogen gas for 30 min, add dropwise 4 g of graft monomer AA, 30 mL of a 0.5% ammonium ferrous sulfate aqueous solution, and 28 mL of a 1% hydrogen peroxide aqueous solution. After the addition of the reagents is completed, react for 8 h. After the experiment is completed, wash it several times by centrifugation with absolute ethanol, then wash it by centrifugation with distilled water, and place it in an oven at 60 °C to dry for 24 h to obtain SiO 2 -g-PAA;

[0051] S3: Preparation of the blended slurry

[0052] Disperse 0.25 g of SiO 2 -g-PAA obtained in S2 with distilled water, and then add 100 g of the modified starch QBS obtained in S1 and mix evenly to obtain the blended slurry.

[0053] Example 2

[0054] The preparation method of the SiO 2 -g-PAA / modified starch blended slurry proposed by the present invention is as follows:

[0055] S1: Preparation of the modified starch QBS

[0056] Weigh 400 g of dry corn starch and disperse it in distilled water to prepare a 40% starch milk. Transfer it to a three-necked flask, set the temperature of the water bath to 50 °C, and control the rotation speed of the stirrer to 130 r / min. When the temperature of the water bath reaches 50 °C, slowly drip 37 mL of a 2 mol / L dilute HCl solution using a separatory funnel. After the dripping is completed, start timing for 4 h. After the reaction is completed, drip a 1 mol / L NaOH solution to neutralize the pH of the starch milk to 6 - 7. Filter, wash with distilled water, and perform vacuum filtration. Repeat the operation 4 times, then dry it in a blast dryer, crush it with an ultra-fine grinder, seal it in a bag for later use, and obtain acid hydrolyzed starch (ATS).

[0057] Weigh 324 g of dry ATS and disperse it in distilled water containing Na 2 SO 4 Stir well and transfer it to a three-necked flask. Adjust the pH value to 10 - 11 with 3% NaOH solution, stir and heat to 40 °C, add a mixed solution containing equimolar cationic etherifying agent and NaOH (added within 1 min). After 10 min, add 30 mL of an aqueous solution containing 1.8 g of CaO. After reacting for 8 h, neutralize it to a pH value of 6 - 7 with 2 mol / L HCl solution, filter and wash 2 - 3 times, dry it in a blast dryer, crush it with an ultra-fine grinder, seal it in a bag for later use, and prepare quaternary ammonium cationic starch (QS);

[0058] Weigh 120 g of dry QS and mix it with distilled water to form a 40% starch dispersion under stirring. Use a 6% Na 2 CO 3 solution to adjust the pH value of the dispersion to 8 - 9, then raise the temperature of the water bath to 30 °C and keep it warm under stirring conditions. Slowly drip the butyric anhydride solution into the dispersion using a separatory funnel, and at the same time maintain the pH value at 8 - 9 with the above-mentioned alkali solution. After the dripping is completed, continue to stir and react for 0.5 h. Adjust the pH value of the reaction system to 6.5 - 7 with a 2 mol / L HCl solution, filter and wash 3 times, dry and crush to obtain modified starch QBS;

[0059] S2: Preparation of SiO 2 -g-PAA

[0060] Add 4 g of dry nano-SiO 2, make it into a 4% dispersion with distilled water, adjust the pH value of the solution to 3 - 4, transfer it into a four-necked flask equipped with a stirrer and a nitrogen gas inlet tube, and stir for a period of time. Control the temperature of the water bath at 30 °C, introduce nitrogen for 30 min, add dropwise 4 g of graft monomer AA, 30 mL of an aqueous solution of ammonium ferrous sulfate with a concentration of 0.5%, and 28 mL of an aqueous solution of hydrogen peroxide with a concentration of 1%. After the addition of the drugs is completed, react for 8 h. After the experiment is completed, centrifuge and wash several times with absolute ethanol, then centrifuge and wash with distilled water, and place it in an oven at 60 °C to dry for 24 h to obtain SiO 2 -g-PAA;

[0061] S3: Preparation of the blended slurry

[0062] Disperse 0.5 g of SiO 2 -g-PAA obtained in S2 in distilled water to form a dispersion, and then add 100 g of modified starch QBS obtained in S1 and mix evenly to obtain the blended slurry.

[0063] Example 3

[0064] The preparation method of the SiO 2 -g-PAA / modified starch blended slurry proposed by the present invention is as follows:

[0065] S1: Preparation of modified starch QBS

[0066] Weigh 400 g of dry corn starch and disperse it in distilled water to prepare a 40% starch milk. Transfer it to a three-necked flask, set the temperature of the water bath at 50 °C, and control the rotation speed of the stirrer at 130 r / min. When the temperature of the water bath reaches 50 °C, slowly add 37 mL of a dilute HCl solution with a concentration of 2 mol / L using a separatory funnel. After the addition is completed, time for 4 h. After the reaction is completed, add a NaOH solution with a concentration of 1 mol / L to neutralize the pH of the starch milk to 6 - 7, filter, wash with distilled water, and perform vacuum filtration. After repeating the operation 4 times, place it in a blast dryer to dry, crush it with an ultrafine grinder, and seal it in a bag for later use to obtain acid hydrolyzed starch (ATS).

[0067] Weigh 324 g of dry ATS and disperse it in distilled water containing Na 2 SO 4 , stir evenly and transfer it into a three-necked flask. Adjust the pH value to 10 - 11 with 3% NaOH solution, stir and heat to 40 °C, add a mixed solution containing equimolar cationic etherifying agent and NaOH (added within 1 min), add 30 mL of an aqueous solution containing 1.8 g of CaO after 10 min, react for 8 h, then neutralize to a pH value of 6 - 7 with 2 mol / L HCl solution, filter and wash 2 - 3 times, place it in a blast dryer to dry, crush it with an ultrafine grinder, and seal it in a bag for later use to obtain quaternary ammonium cationic starch (QS);

[0068] Weigh 120 g of dry weight QS and mix it with distilled water, and under stirring, form a starch dispersion with a mass fraction of 40%. After adjusting the pH value of the dispersion to 8 - 9 with a 6% mass fraction of Na 2 CO 3 solution, heat it up to 30 °C in a water bath under stirring conditions and keep it warm. Slowly add the butyric anhydride solution to the dispersion using a separatory funnel, and at the same time, maintain the pH value at 8 - 9 with the above-mentioned alkaline solution. After the addition is completed, continue to stir and react for 0.5 h. Adjust the pH value of the reaction system to 6.5 - 7 with a 2 mol / L HCl solution, filter by suction and wash 3 times, dry and pulverize to obtain the modified starch QBS;

[0069] S2: Preparation of SiO 2 -g-PAA

[0070] Add 4 g of dry nano-SiO 2 to a 250 mL beaker, and make a 4% dispersion with distilled water. Adjust the pH value of the solution to 3 - 4, transfer it to a four-necked flask equipped with a stirrer and a nitrogen gas inlet tube, and stir for a period of time. Control the temperature of the water bath to 30 °C, introduce nitrogen gas for 30 min, add 4 g of graft monomer AA, 30 mL of a 0.5% ammonium ferrous sulfate aqueous solution and 28 mL of a 1% hydrogen peroxide aqueous solution dropwise. After the addition of the drugs is completed, react for 8 h. After the experiment is completed, centrifuge and wash several times with absolute ethanol, then centrifuge and wash with distilled water, and place it in an oven at 60 °C to dry for 24 h to obtain SiO 2 -g-PAA;

[0071] S3: Preparation of the blended slurry

[0072] Make a dispersion of 1.0 g of SiO 2 -g-PAA from S2 with distilled water, and then add 100 g of the modified starch QBS from S1 and mix evenly to obtain the blended slurry.

[0073] Example 4

[0074] The preparation method of the SiO 2 -g-PAA / modified starch blended slurry proposed by the present invention is as follows:

[0075] S1: Preparation of the modified starch QBS

[0076] Weigh 400 g of dry corn starch and disperse it in distilled water to prepare a 40% starch milk. Transfer it to a three-necked flask, set the temperature of the water bath to 50 °C, and control the rotation speed of the stirring rod to 130 r / min. When the temperature of the water bath reaches 50 °C, slowly add 37 mL of 2 mol / L dilute HCl solution using a separatory funnel. After the addition, start timing for 4 h. After the reaction is completed, add 1 mol / L NaOH solution to neutralize the pH of the starch milk to 6 - 7. Filter, wash with distilled water, and perform vacuum filtration. Repeat the operation 4 times, then dry it in a blast dryer, crush it with an ultra-fine grinder, seal it in a bag for later use, and obtain acid hydrolyzed starch (ATS).

[0077] Weigh 324 g of dry ATS and disperse it in distilled water containing Na 2 SO 4 Stir evenly and transfer it to a three-necked flask. Adjust the pH value to 10 - 11 with 3% NaOH solution, stir and heat to 40 °C, add a mixed solution containing equimolar cationic etherifying agent and NaOH (added within 1 min). After 10 min, add 30 mL of an aqueous solution containing 1.8 g of CaO. After reacting for 8 h, neutralize it to pH 6 - 7 with 2 mol / L HCl solution, filter and wash 2 - 3 times, dry it in a blast dryer, crush it with an ultra-fine grinder, seal it in a bag for later use, and prepare quaternary ammonium cationic starch (QS);

[0078] Weigh 120 g of dry QS and mix it with distilled water to form a 40% starch dispersion under stirring. Use 6% Na 2 CO 3 solution to adjust the pH value of the dispersion to 8 - 9, then heat it to 30 °C and keep it warm under stirring. Slowly add butyric anhydride solution to the dispersion using a separatory funnel, and at the same time maintain the pH value at 8 - 9 with the above-mentioned alkali solution. After the addition is completed, continue to stir and react for 0.5 h. Adjust the pH value of the reaction system to 6.5 - 7 with 2 mol / L HCl solution, filter and wash 3 times, dry and crush to obtain modified starch QBS;

[0079] S2: Preparation of SiO 2 -g-PAA

[0080] Add 4 g of dry nano-SiO 2, prepare a 4% dispersion with distilled water, adjust the pH value of the solution to 3 - 4, transfer it into a four-necked flask equipped with a stir bar and a nitrogen gas inlet tube, and stir for a period of time. Control the temperature of the water bath at 30 °C, introduce nitrogen for 30 min, add dropwise 4 g of graft monomer AA, 30 mL of an aqueous solution of ammonium ferrous sulfate with a concentration of 0.5%, and 28 mL of an aqueous solution of hydrogen peroxide with a concentration of 1%. After the addition of the drugs is completed, react for 8 h. After the experiment is completed, centrifuge and wash several times with absolute ethanol, then centrifuge and wash with distilled water, and place in an oven at 60 °C for drying for 24 h to obtain SiO 2 -g-PAA;

[0081] S3: Preparation of the blended slurry

[0082] Disperse 1.5 g of SiO 2 -g-PAA obtained in S2 with distilled water, and then add 100 g of modified starch QBS obtained in S1 and mix evenly to obtain the blended slurry.

[0083] The infrared spectrum analysis of the sample was carried out by the KBr tablet pressing method. Before the test, the sample was fully mixed with a certain amount of KBr and then tableted, and then placed on an IRPrestige-21 Fourier transform infrared spectrometer for infrared spectrum scanning analysis, and the scanning range was set at 500 - 3750 cm -1 . The results are as Figure 1 shown. By comparing with the infrared spectrum curve of nano-SiO 2 , a characteristic peak of carboxylate appeared at 1557 cm 2 in the spectrum curve of SiO -1 -g-PAA, which confirmed that the AA structural unit was successfully introduced onto the surface of nano-SiO 2 , verifying the successful preparation of SiO 2 -g-PAA.

[0084] Use a Tecnai G2 F20 transmission electron microscope to observe the phase structure of the sample. Mix 1 mg of nano-SiO 2 , SiO 2 -g-PAA, respectively, with 10 mL of distilled water, ultrasonically disperse in an ice bath for 30 min, and prepare samples on a copper mesh by the drop-casting method. Then observe and analyze on a Tecnai G2 F20 transmission electron microscope, and the results are as Figure 2 shown. As can be seen from part a in Figure 2 , the primary particles of nano-SiO 2 are spherical, with a particle size of 15 - 20 nm, and the particles are interconnected to form a network structure. Before modification, the aggregation degree of nano-SiO 2 is high. As can be seen from part b in Figure 2 : After modification, SiO 2-g-PAA has significantly better dispersibility and the degree of agglomeration is reduced.

[0085] The Malvern ZEN3700 potentiometric particle size analyzer was used for testing. With water as the medium, the measurement range was 0 - 6000 nm, and the results are as Figure 3 shown. The particle size distribution of the nano-SiO 2 aggregates was relatively wide and unevenly distributed. The aggregate diameter was concentrated in the range of 300 - 400 nm, indicating that the nano-SiO 2 before modification agglomerated severely in aqueous solution and there were large agglomerated particles; the aggregate diameter of SiO 2 -g-PAA was concentrated in the range of 180 - 230 nm. The average particle size decreased and the particle size distribution was relatively uniform, indicating that the dispersion of the modified nano-SiO 2 in the blended slurry was greatly improved and the dispersion stability was enhanced.

[0086] The test methods for apparent viscosity and viscosity thermal stability refer to the literature "Research on the Test Method for the Viscosity of Modified Starch Slurry (Zhao Qiming et al.)". Among them:

[0087] Figure 4 For the apparent viscosity of nano-SiO 2 / QBS and SiO 2 -g-PAA / QBS blended slurries, with the increase in the dosage of the nano-additive SiO 2 / SiO 2 -g-PAA, the apparent viscosity of the nano-SiO 2 / QBS blended slurry changed little, increasing from 7 mPa·s to 9.5 mPa·s; the apparent viscosity of the SiO 2 -g-PAA / QBS blended slurry increased from 7 mPa·s to 13 mPa·s. The reason why the apparent viscosity of the SiO 2 -g-PAA / QBS blended slurry is higher than that of the nano-SiO 2 / QBS blended slurry is as follows: The modified nano-SiO 2 has better dispersibility in aqueous solution, can better exert its volume effect, increase the distance between starch macromolecules, thereby further swelling the starch granule fragments and stretching the molecular chains, promoting an increase in the kinetic volume of the starch macromolecular coils and enhancing the resistance to slurry flow. In addition, because the AA unit is a hydrophilic unit, it can further improve the dispersion stability of nano-SiO 2 in aqueous solution; at the same time, the introduction of the PAA side chain makes the surface of SiO 2 carry long carbon chains, which will entangle with the starch macromolecular chains and increase the internal friction of the slurry.

[0088] Figure 5 For nano-SiO 2 / QBS and SiO 2 -g-PAA / QBS blend slurry viscosity thermal stability. With the increase of the amount of nano-additive SiO 2 / SiO 2 -g-PAA, the viscosity thermal stability of nano-SiO 2 / QBS blend slurry shows a trend of increasing first and then decreasing. And when the amount of nano-SiO 2 is 1%, the viscosity thermal stability of nano-SiO 2 / QBS blend slurry reaches the maximum value of 91.1%. Along with the increase of the amount of SiO 2 -g-PAA to 1.5%, the viscosity thermal stability of SiO 2 -g-PAA / QBS blend slurry increases from 88.57% to 92.46%. The reason is that grafted PAA branches are introduced on the surface of nano-SiO 2 , which can further enhance its volume effect to play a steric hindrance role, hinder the hydrogen bond interaction between starch macromolecules, and is conducive to slowing down the aging of starch slurry. At the same time, the grafted PAA branches are hydrophilic. The addition of SiO 2 -g-PAA helps to improve the water affinity of the blend slurry and slow down the damage of the shear force to the starch molecular chains.

[0089] The adhesion force is tested by the light slurry roving method. The test steps are as follows:

[0090] SiO 2 -g-PAA is mixed with distilled water to form a dispersion, and then modified starch QBS is added and mixed evenly to prepare a 1% blend slurry by mass fraction, which is transferred to a three-necked flask. Set the temperature of the water bath to 95 °C, control the rotation speed of the stirring rod to 130 r / min. When the temperature reaches 95 °C, start timing. After 1 h of timing, transfer the slurry to a super thermostat with a water bath temperature of 95 °C. Immerse the rectangular aluminum alloy frame wound with roving in the slurry for 5 min. Take out the roving frame and make the roving strip present a vertical natural state, and dry it at room temperature. Place the dried roving strip in a constant temperature and humidity environment (humidity 65 °C, temperature 20 °C) to balance for 24 h. Cut off the roving strip, set the parameters of the electronic fabric strength tester as the number of measurements 35 times, the clamping distance 100 mm, the fixed-point elongation 200%, the speed 50 mm / min, and the return speed 500 mm / min, test the breaking strength, and eliminate the outliers to find the average value.

[0091] Figure 6 and Figure 7 are the determinations of the adhesion between nano-SiO 2 / QBS and SiO 2 -g-PAA / QBS blend slurry and polyester fiber and cotton fiber respectively. SiO 2The adhesion between polyester fibers and cotton fibers of the -g-PAA / QBS blend sizing agent is better than that of nano-SiO 2 / QBS.

[0092] For polyester fibers, the modified SiO 2 -g-PAA has better dispersibility and a larger contact area with the starch matrix. When the roving is stretched and fractured, it can timely terminate the microcracks that will be generated during stretching to prevent them from turning into destructive cracks. In addition, the grafted side chains on SiO 2 -g-PAA and the substituents in the modified starch can produce good synergistic effects through molecular interactions and have good molecular interactions with the fibers, so that the adhesion performance of the SiO 2 -g-PAA / modified starch blend sizing agent to the fibers has been greatly improved compared with the conventional nano-SiO 2 / modified starch blend sizing agent.

[0093] For cotton fibers, hydrophilic grafted side chains PAA are introduced on the surface of SiO 2 -g-PAA, which increases the hydrophilicity of the blend sizing agent and promotes the diffusion and spreading of the blend sizing solution between cotton fibers, facilitating the generation of strong mutual forces inside the roving; in addition, SiO 2 -g-PAA, the modified starch QBS, and cotton fibers all contain polar functional groups, and hydrogen bonds are formed between the polar groups and strong van der Waals forces are generated, thus improving the adhesiveness.

[0094] The present invention also tests the mechanical properties of the blend sizing film. The preparation method of the sizing film is as follows: Weigh nano-SiO 2 / QBS and SiO 2 -g-PAA / QBS respectively. Set the temperature of the water bath to 95°C and control the rotation speed of the stirring rod to 120 r / min. Start timing when the temperature reaches 95°C. After 1 hour of timing, transfer the sizing solution to a 500 mL beaker. Wipe the glass clean in advance, lay a polyester film of the same area flat on the glass, scrape it flat with a ruler to remove air bubbles, place a resin film frame on the film, and clamp and fix the resin film frame. Pour the sizing solution cooled to 75°C in the beaker onto the film, scrape the sizing solution along the film frame to make the sizing solution spread evenly, and let it dry naturally.

[0095] Thickness test: Place the aluminum alloy mold on the sizing film, cut the sizing film into strip specimens of 200 mm × 10 mm along the mold, place them in the above constant temperature and humidity environment to balance for 24 hours, place the specimens on a thickness gauge to test the thickness, test 30 data, and the thickness value is accurate to 0.001 mm. Eliminate the abnormal values and calculate the average value.

[0096] Mechanical property test: Place the balanced strip specimen of 200 mm×10 mm on an electronic fabric strength tester. The machine parameters are 35 measurement times, a grip distance of 100 mm, a fixed-point elongation of 200%, a speed of 50 mm / min, and a return speed of 500 mm / min. Press the start button to conduct the test. Each group of samples is tested 35 times, and the average value is taken after excluding outliers. Calculate the breaking strength of the sizing film according to the following formula:

[0097]

[0098] In the formula: Q—the breaking strength of the sizing film, MPa; P—the average breaking force of the sizing film, N; K—the width of the sizing film, mm; D—the average thickness of the sizing film, mm.

[0099] Moisture regain test of the blended sizing film: Place the blended sizing film in the above constant temperature and humidity environment to balance for 24 h. Accurately weigh the mass of the weighing dish and record it as A 1 , take a sample of the blended sizing film with the same area and already balanced and put it into the weighing dish. Accurately weigh the total mass of the weighing dish and the blended sizing film sample as A 2 , place it in a forced-air drying oven heated to 120 °C, dry it to a constant weight, put it into a desiccator and cool it to room temperature, and accurately weigh its mass as A 3 . Each group of samples is tested 4 times, and the average value is taken after excluding outliers. Calculate the moisture regain of the blended sizing film according to the following formula.

[0100]

[0101] In the formula: Y—the moisture regain of the sizing film, %; A 2 -A 3 —the moisture absorption weight of the sizing film, g; A 3 -A 1 —the dry weight of the sizing film, g.

[0102] Figure 8 and Figure 9 are the breaking strength and elongation at break of the nano-SiO 2 / QBS and SiO 2 -g-PAA / QBS blended sizing films under different dosages of nano additives, respectively. With the increase of the dosage of nano additives, the breaking strength of the nano-SiO 2 / QBS blended sizing film decreases from 32.7 MPa to 26.5 MPa (at 1%), and then increases slightly, while the elongation at break increases from 2.96% to 3.55% (at 1%), and then decreases slightly; the breaking strength of the SiO 2 -g-PAA / QBS blended sizing film decreases from 32.7 MPa to 21.3 MPa (at 1%), and then increases slightly, while the elongation at break increases from 2.96% to 3.75% (at 1%), and then decreases slightly. It shows that SiO2 The -g-PAA / QBS blend sizing film has better mechanical properties.

[0103] The nano-SiO with multiple hydroxyl groups 2 After binding with the polar groups in QBS, the introduced positively charged TMACHP substituents can ionize in an aqueous medium. After the modification treatment, SiO 2 -g-PAA can be better dispersed uniformly in the QBS sizing agent. Due to its small size effect and macroscopic quantum tunneling effect, it can produce a percolation effect, penetrate deep between the macromolecular chains of QBS, and interact with the positively charged TMACHP substituents to form a spatial network structure. Therefore, compared with QBS and nano-SiO 2 / QBS, the modified SiO 2 / QBS blend sizing agent has better film-forming properties, and the sizing film will be more regular, dense, flexible. In addition, one important reason why the mechanical properties of the SiO 2 -g-PAA / QBS blend sizing film are superior to those of the nano-SiO 2 / QBS blend sizing film is that the hydrophilic grafted side chain PAA has strong moisture absorption, can absorb water and store it in the film, and water has a good plasticizing effect on the starch film.

[0104] Figure 10 Parts a, b, and c of are the SEM images of the cross-sections of the QBS film, nano-SiO 2 / QBS film, and SiO 2 -g-PAA / QBS film, respectively. It can be seen from the figure that compared with the QBS sizing film, the blend sizing film shows brittle fracture, but with lower brittleness. The reason for the analysis is that: SiO 2 -g-PAA is the dispersed phase, while the starch matrix is the continuous phase. There will be a strong interfacial interaction between the two. When subjected to a tensile force, it prevents the sizing film from undergoing tensile fracture and plays a role in toughening the sizing film.

[0105] Figure 11 reflects the moisture regain of nano-SiO 2 / QBS and SiO 2 -g-PAA / QBS blend sizing films under different dosages of nano additives. The moisture regain of nano-SiO 2 / QBS gradually decreases with the increase of the dosage of nano-SiO 2 ; the moisture regain of the SiO 2 -g-PAA / QBS blend sizing film first gradually increases with the increase of the dosage of the nano additive SiO 2 -g-PAA. When the dosage is 1%, the moisture regain reaches the maximum value and then levels off.

Claims

1. SiO 2 -g-PAA / Modified starch blend sizing agent preparation method, It is characterized in that The method steps are as follows: S1: Preparation of modified starch QBS S11: Disperse corn starch in distilled water, add dilute hydrochloric acid for reaction, after the reaction, neutralize with alkali, filter, wash, dry and crush to obtain acid-hydrolyzed starch ATS; S12: Disperse the acid-hydrolyzed starch ATS in S11 in distilled water containing Na 2 SO 4 , adjust the pH to 10 - 11, then successively add a mixed solution of a cationic etherifying agent and NaOH and an aqueous solution of CaO for reaction. After the reaction, through acid neutralization, washing, drying, and pulverization, quaternary ammonium cationic starch QS is obtained; S13: Disperse the quaternary ammonium cationic starch QS in S12 in distilled water and adjust the pH to 8-9, then add butyric anhydride for reaction, after the reaction, neutralize with acid, wash, dry and crush to obtain modified starch QBS; S2: SiO 2 Preparation of -g-PAA Disperse nano-SiO 2 in distilled water to form a dispersion liquid, and then add acrylic acid, ammonium ferrous sulfate aqueous solution and hydrogen peroxide aqueous solution to react under an inert gas atmosphere. After the reaction, wash, centrifuge and dry to obtain SiO 2 -g-PAA; S3: Preparation of blended slurry Disperse SiO in S2 2 -g-PAA and distilled water to form a dispersion, and then add the modified starch QBS in S1 and mix evenly to obtain a blended slurry.

2. The SiO 2 -g-PAA / modified starch blend sizing agent preparation method according to claim 1, It is characterized in that In S12, the mass ratio of acid-hydrolyzed starch ATS, cationic etherifying agent and CaO is 324:5-50:0.5-2.

5.

3. The SiO according to claim 1 2 -g-PAA / modified starch blend sizing agent preparation method, It is characterized in that In S13, the mass ratio of quaternary ammonium cationic starch QS and butyric anhydride is 200:1-15.

4. The preparation method of SiO 2 -g-PAA / modified starch blend sizing agent according to claim 1, It is characterized in that Nano-SiO in S2 2 The mass-to-volume ratio of acrylic acid, ammonium ferrous sulfate aqueous solution, and hydrogen peroxide aqueous solution is 4 g: 4 - 16 g: 5 - 45 mL: 4.6 - 42 mL.

5. The SiO according to claim 1 2 -g-PAA / modified starch blend sizing agent preparation method It is characterized in that Nano-SiO in S2 2 It is formulated with distilled water into a dispersion liquid with a concentration of 0.1-10%, and the pH of the dispersion liquid is adjusted to 3-4.

6. The preparation method of SiO 2 -g-PAA / modified starch blend sizing agent according to claim 1, It is characterized in that In S2, the reaction temperature is 25-45°C and the time is 2-10h.

7. The preparation method of the SiO 2 -g-PAA / modified starch blend sizing agent according to claim 1 It is characterized in that SiO in S3 2 The mass ratio of -g-PAA to modified starch QBS is 0.25 - 1.5:

100.

8. SiO prepared by the method according to any one of claims 1-7 2 -g-PAA / modified starch blended sizing agent.

9. The application of the SiO 2 -g-PAA / modified starch blend size in polyester fibers or cotton fibers.

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