CN115651125A - Preparation method and application of graft copolymerization cationic hemicellulose - Google Patents

Abstract

The invention discloses a preparation method of a graft copolymerization cationic hemicellulose solution, which is characterized in that the preparation raw materials comprise the following components in parts by mass: 100 parts of hemicellulose, 1.3-1.5 parts of initiator, 2.5-2.7 parts of acrylamide, 2-3 parts of cross-linking agent, 22-25 parts of cationic etherifying agent, 1.8-2 parts of bactericide and 400-700 parts of water. The invention also provides a specific preparation step of the graft copolymerization cationic hemicellulose solution and application of the graft copolymerization cationic hemicellulose solution in a papermaking wet end additive. The invention has high grafting efficiency and good stability, can effectively improve the retention rate of the filler and the drainage performance of the pulp when being used as an additive for a wet end of papermaking, and can effectively improve the strength of paper.

Description

A kind of preparation method and application of graft copolymerization cationic hemicellulose

technical field

The invention relates to the technical field of preparation of hemicellulose solution, in particular to a preparation method and application of graft copolymerized cationic hemicellulose.

Background technique

Although hemicelluloses are widely distributed in plants, their structural complexity limits their industrial applications. Hemicellulose has two notable characteristics: (1) There are significant differences in the solubility of hemicellulose. Natural hemicellulose containing one or two free hydroxyl groups is hydrophilic, while synthetic hemicellulose polymers usually are hydrophobic; (2) the chemical and molecular structures of hemicelluloses vary, such as branched, amorphous, composed of different monosaccharides (heterosaccharides) and different functional groups (for example, hydroxyl, Acetoxy, Methoxy) and so on. These two features cause hemicellulose to behave chemically differently from cellulose and starch, thereby limiting its industrial applications. However, these disadvantages can be overcome by modification methods such as hydroxyl oxidation, hydrolysis, reduction, etherification, esterification, and crosslinking.

Hemicellulose is similar to low-molecular alcohols. The hydroxyl groups on hemicellulose can react with acids to form hemicellulose esters, and the hydroxyl groups on hemicellulose can react with different types of etherification agents to form hemicellulose ethers. Common hemicellulose etherification reactions include carboxymethylation, quaternization, benzylation and methoxylation reactions. It can increase the water solubility, electrophoreticity, hydrophobicity, surface activity and other characteristics of hemicellulose through the etherification reaction of hemicellulose hydroxyl, so that hemicellulose can be used in pharmaceuticals, sewage treatment, papermaking additives, thermoplastic materials, food, etc. Additives have great application potential.

Retaining or adding hemicellulose in pulp is beneficial to pulp beating, because hemicellulose is easier to hydrate and swell than cellulose, and fiber swelling is very beneficial to fiber fibrillation. Hemicellulose is adsorbed on cellulose, which increases the swelling and elasticity of the fiber, thus reducing the energy consumption of beating and obtaining the ideal pulp strength. In addition, beating for a short time, the addition of hemicellulose can improve the properties of the pulp (better formation and faster drainage). In short, paper with better strength can be obtained on low-cost, high-speed paper machines.

Hemicellulose has a certain hydrophilic property, which will cause swelling of the cell wall, which can endow the fiber with elasticity. It is beneficial to the structure of fibers and the bonding between fibers during the sheet forming process. Therefore, the addition of hemicellulose affects the adsorption of surface fibers and has a greater impact on paper strength. In addition, there are a large number of hydroxyl groups on the molecular chain of hemicellulose, which can form hydrogen bonds with cellulose, enhance the bonding force between fibers, and effectively improve the strength of paper.

In addition, the quaternization reaction of hemicellulose can increase the water solubility, yield and cationic or zwitterionic properties of hemicellulose. The present invention is prepared into a hemicellulose solution with good stability, and the hemicellulose solution prepared by the traditional quaternization reaction has a low viscosity, and when used as an additive in the wet end of papermaking, the adsorption capacity becomes weak during the papermaking process. Reduced bonding force between fibers, thus reducing paper strength. In addition, the present invention utilizes ammonium persulfate initiator graft copolymerization and then carries out etherification reaction, adopts the method of graft copolymerization, increases the viscosity of hemicellulose solution, thereby increases the binding force between fibers, obtains high grafting efficiency, stable Good, cationic hemicellulose solution with high viscosity, high degree of substitution, and good storage stability, as an additive in the wet end of papermaking can effectively improve the retention rate of fillers and improve the drainage performance of pulp.

Contents of the invention

To achieve the above object, the present invention provides the following technical solutions.

A preparation method of graft copolymerized cationic hemicellulose, the raw material of which comprises the following components by mass: 100 parts of hemicellulose, 1.3-1.5 parts of initiator, 2.5-2.7 parts of acrylamide, and 2-3 parts of crosslinking agent parts, cationic etherification agent 22-25 parts, fungicide 1.8-2 parts, water 400-700 parts.

Preferably, the initiator includes one or more of ammonium persulfate, potassium persulfate, potassium persulfate-sodium bisulfite.

Preferably, the crosslinking agent includes one or more of epichlorohydrin and sodium trimetaphosphate.

Preferably, the cationic etherifying agent includes one or more of 3-chloro-2-hydrocarbylpropyltrimethylammonium chloride and 2,3-epoxypropyltrimethylammonium chloride.

Preferably, the bactericide includes one or more of tributyltin chloride and benzisothiazolinone.

Preferably, the liquid caustic soda is NaOH solution; the acid includes one or more of citric acid, hydrochloric acid, sulfuric acid or acetic acid.

A preparation method of graft copolymerized cationic hemicellulose, specifically comprising the following steps:

(1) dissolving the hemicellulose powder in a certain amount of deionized water, stirring evenly to obtain a hemicellulose solution;

(2) Add the hemicellulose solution to the lye to adjust the pH to 9-10.0, raise the temperature to 85-90°C, react for 0.5-2h, add the initiator and acrylamide monomer to it, and make it continue to react in an alkaline environment 0.5-2h, denoted as E1;

(3) Add an appropriate amount of cross-linking agent to E1, and continue to react at 85-90°C for 2-3 hours, denoted as E2;

(4) Cool down to 50-60°C, add an appropriate amount of cationic etherification agent to E2, and continue the reaction for 5-6 hours, denoted as E3;

(5) After the etherification reaction, add an appropriate amount of acid to E3 to adjust the pH to 6.5-7.5, and then lower the temperature to 30-45°C;

(6) After cooling down, add an appropriate amount of bactericide, and then sieve to obtain a grafted cationic hemicellulose solution.

The present invention also provides a graft copolymerized cationic hemicellulose solution, which is prepared by the above-mentioned graft copolymerized cationic hemicellulose solution preparation method.

The present invention also provides the application of the above-mentioned graft copolymerized cationic hemicellulose solution in papermaking wet end additives.

The present invention utilizes ammonium persulfate initiator to carry out graft copolymerization and then carries out etherification reaction, the grafting efficiency is high, the stability is good, and the cationic hemicellulose solution with high viscosity, high degree of substitution and good storage stability is obtained, which is used as an additive in the wet end of papermaking It can effectively improve the retention rate of fillers, improve the drainage performance of pulp, and effectively increase the strength of paper.

Detailed ways

The present invention is further described in conjunction with the following examples, but the protection scope of the present invention is not limited thereto.

Instruments or raw materials in the present invention that do not indicate the manufacturer are all conventional commercial instruments or raw materials.

If the detection indicators involved in the examples of the present invention are not mentioned, they are all detected by conventional detection methods in the art.

Example 1

A preparation method of graft copolymerized cationic hemicellulose, comprising the following steps:

(1) Add 100g of hemicellulose powder and 500g of deionized water in a four-port fired glass reactor and keep stirring to obtain a hemicellulose solution;

(2) Add NaOH lye to adjust the pH to 9-10.0, raise the temperature to 85°C, and react for 1h, add 1.3g potassium persulfate and 2.5g acrylamide monomer to it, and make it react in an alkaline environment for 1h, recorded as E1;

(3) Add 2g of epichlorohydrin to E1, and continue to react at 90°C for 2h, denoted as E2;

(4) Cool down to 50°C, add 20g of 3-chloro-2-hydrocarbyltrimethylammonium chloride to E2, and continue the reaction at 50°C for 6h, denoted as E3;

(5) After the etherification reaction is finished, add sulfuric acid to E3 to adjust the pH to 6.5, and then lower the temperature to 40°C;

(6) After cooling down, add 1.8 g of benzisothiazolinone into it, and pass through a 325 mesh sieve to obtain a graft copolymerized cationic hemicellulose solution.

Example 2

A preparation method of graft copolymerized cationic hemicellulose, comprising the following steps:

(1) Add 120g of hemicellulose powder and 500g of deionized water in a four-port fired glass reactor and keep stirring to obtain a hemicellulose solution;

(2) Add NaOH lye to adjust the pH to 9-10.0, raise the temperature to 90°C, react for 1 hour, add 1.5g of ammonium persulfate and 2.6g of acrylamide monomer to it, and make it react for 1 hour in an alkaline environment, denoted as E1;

(3) Add 2.1g of epichlorohydrin to E1, and continue to react at 90°C for 2h, denoted as E2;

(4) Cool down to 50°C, add 22g of 3-chloro-2-hydrocarbyltrimethylammonium chloride to E2, and continue the reaction at 50°C for 6h, denoted as E3;

(5) After the etherification reaction is completed, add an appropriate amount of hydrochloric acid to E3 to adjust the pH to 6.5, and then lower the temperature to 40°C;

(6) After cooling down, add 2g of benzisothiazolinone, and pass through a 325-mesh sieve to obtain a graft copolymerized cationic hemicellulose solution.

Example 3

A preparation method of graft copolymerized cationic hemicellulose, comprising the following steps:

(1) Add 130g of hemicellulose powder and 500g of deionized water in a four-port fired glass reactor and keep stirring to obtain a hemicellulose solution;

(2) Add NaOH lye to adjust the pH to 9-10.0, raise the temperature to 90°C, react for 1 hour, add 1.5g of potassium persulfate-sodium bisulfite and 2.7g of acrylamide monomer to make it in an alkaline environment Reaction 1h, denoted as E1;

(3) Add 3g of epichlorohydrin to E1, and continue to react at 90°C for 2h, denoted as E2;

(4) Cool down to 50°C, add 25g of 3-chloro-2-hydrocarbyltrimethylammonium chloride to E2, and continue the reaction at 50°C for 6h, denoted as E3;

(5) After the etherification reaction is completed, add an appropriate amount of glacial acetic acid to E3 to adjust the pH to neutral, and the pH to 6.5, and then cool down to 40°C;

(6) After cooling down, add 2g of triethyl chloride or tributyltin to the inside, and pass through a 325 mesh sieve to obtain a graft copolymerized cationic hemicellulose solution.

Comparative example 1

Commercially available cationic starch (the cationic starch produced by Shandong Xilai Starch Co., Ltd.).

Implementation Effect

The graft copolymerized cationic hemicellulose solution prepared in Examples 1-3 of the present invention and comparative sample 1 were subjected to an iso-dry retention aid application test, and the application test results are shown in Table 1.

Application steps:

Raw materials and feeding order: pulp (70%) + cationic starch (6kg/t paper, dry/dry) + ASA (11.5kg/t paper) + filler (30%, calcium mixed) + CPAM (0.1kg/t paper, dry/dry) + fine particles (0.2kg/t paper, dry/dry).

Design papermaking weight 80g/m ² , stir the weighed pulp for 1 minute, add cationic starch and stir for 1 minute, then add ASA, mixed calcium, CPAM, microparticles, etc. in turn, stir for 2 minutes, use LABTECH73-62 semi-automatic paper former Sheets are copied, pressed by a LABTECH 73-50 standard paper press, dried by a glazing machine, and indicators such as retention and internal bonding strength are tested.

Table 1.

Test items reserve% % difference from the control sample Internal bonding strength J/m2 % difference from the control sample blank 79.68 / 140.84 / Comparative example 1 83.96 / 160.77 / Embodiment one 94.98 +13.12 176.86 +10.00 Embodiment two 95.15 +13.33 178.74 +11.18 Embodiment three 95.67 +13.95 177.97 +10.69

The results of the above application experiments show that the retention effect of the graft copolymerized cationic hemicellulose solution prepared by the present invention is better than that of the comparative sample.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (9)

1. The preparation method of the graft copolymerization cationic hemicellulose is characterized in that the preparation raw materials comprise the following components in parts by mass: 100 parts of hemicellulose, 1.3-1.5 parts of initiator, 2.5-2.7 parts of acrylamide, 2-3 parts of cross-linking agent, 22-25 parts of cationic etherifying agent, 1.8-2 parts of bactericide and 400-700 parts of water.

2. The method of claim 1, wherein the initiator comprises one or more of ammonium persulfate, potassium persulfate, and potassium persulfate-sodium bisulfite.

3. The method of claim 1, wherein the cross-linking agent comprises one or more of epichlorohydrin or sodium trimetaphosphate.

4. The method of claim 1, wherein the cationic etherifying agent comprises one or more of 3-chloro-2-hydrocyclopropyltrimethylammonium chloride or 2, 3-epoxypropyltrimethylammonium chloride.

5. The method of claim 1, wherein the antimicrobial agent comprises one or more of tributyltin chloride, benzisothiazolinone.

6. The method for preparing graft copolymerization cationic hemicellulose according to claim 1, wherein the alkali solution is NaOH solution; the acid comprises one or more of citric acid, hydrochloric acid, sulfuric acid and acetic acid.

7. The method for preparing the graft copolymerization cationic hemicellulose according to claim 1, which comprises the following steps:

(1) Dissolving hemicellulose powder in a certain amount of deionized water, and uniformly stirring to obtain a hemicellulose solution;

(2) Adding an alkali liquor into a hemicellulose solution to adjust the pH value to 9-10.0, heating to 85-90 ℃, reacting for 0.5-2h, adding an initiator and an acrylamide monomer into the mixture, and continuously reacting for 0.5-2h in an alkaline environment, wherein the mark is E1;

(3) Adding a proper amount of cross-linking agent into the E1, and continuously reacting for 2-3h at the temperature of 85-90 ℃ to be recorded as E2;

(4) Cooling to 50-60 deg.C, adding appropriate amount of cationic etherifying agent into E2, and reacting for 5-6h, and recording as E3;

(5) After the etherification reaction is finished, adding a proper amount of acid into E3 to adjust the pH value to 6.5-7.5, and then cooling to 30-45 ℃;

(6) And after the temperature reduction is finished, adding a proper amount of bactericide, and then sieving to obtain the grafted cationic hemicellulose solution.

8. A graft copolymerized cationic hemicellulose solution, which is produced according to the production method of any one of claims 1 to 7.

9. Use of the graft copolymerized cationic hemicellulose solution according to claim 8 in a papermaking wet end additive.