Preparation method of a modified cellulose composite material

Abstract

The present invention discloses a preparation method of a modified cellulose composite material, belonging to the technical field of modification of poly(butylene terephthalate-co-adipate). First, tannic acid is dissolved in acetone to obtain a tannic acid solution; polypropylene glycol diglycidyl ether is added dropwise to the tannic acid solution to obtain a mixed solution; the mixed solution is sprayed onto the surface of cellulose, and mixed and reacted under stirring conditions to obtain modified cellulose; poly(butylene terephthalate-co-adipate) and modified cellulose are mixed at high speed to obtain a mixed material; the mixed material is melt-compounded by a twin-screw extruder to obtain a modified cellulose composite material. The performance of the modified cellulose composite material of the present invention is significantly improved. The tensile strength increases from 15.67 Mpa to 29.22 Mpa, the elongation at break increases from 520% to 660%, the contact angle of cellulose increases from 29.7° to 133.6°, and it has good hydrophobicity. The compatibility of the modified cellulose composite material is increased, expanding the application field of the modified cellulose composite material.

Description

Technical Field

[0001] The present invention belongs to the technical field of terephthalic acid - adipic acid butanediol ester modification, and particularly relates to a preparation method of a modified cellulose composite material for poly(butylene adipate - co - terephthalate) (PBAT). Background Technique

[0002] The copolymer of poly(butylene adipate - co - terephthalate) (PBAT) is a promising biodegradable polymer, which conforms to the current concept of green development and has attracted great interest in the biodegradable material industry. It can be a good substitute for a series of non - biodegradable plastics such as high - density polyethylene (HDPE) and polypropylene (PP), and can be used in the biodegradable and environmentally friendly applications of plastic bags, mulch films and general food packaging. PBAT has excellent physical properties compared with other materials, such as easy processability, high toughness and safe contact with food. However, PBAT also has some disadvantages, such as poor strength and high processing cost, which make its material properties not meet the requirements of food packaging. Therefore, by adding widely used fillers in the market (such as calcium carbonate, cellulose, etc.) to enhance the strength and modify the compatibility of poly(butylene adipate - co - terephthalate) (PBAT) materials, the composite PBAT materials can achieve high mechanical properties and heat resistance.

[0003] According to the currently poor mechanical properties of poly(butylene adipate-co-terephthalate) (PBAT), other resins or fillers are added to change the properties of the overall PBAT, thereby improving the mechanical strength of PBAT. Due to its advantages such as good biocompatibility, renewability, and biodegradability, cellulose is an effective reinforcing material that can be added to PBAT. However, because the repeating units in the cellulose molecule are simple and uniform, and its glucose units contain a large number of alcoholic hydroxyl groups, a large number of hydrogen bonds exist within and between cellulose molecules, making it insoluble in water and not easily soluble in organic solvents, which greatly limits the development and application of cellulose functional materials. In Patent CN 116987339A, a silane coupling agent is added to the bamboo fiber raw material for surface treatment, which can bridge the bamboo fiber and poly(butylene adipate-co-terephthalate) (PBAT) and polyethylene (PE). However, the silane coupling agent has a strong alkalinity, high reactivity, and strict reaction conditions, and cannot effectively modify the bamboo fiber, which is somewhat limited. Patent CN 116874849 A mixes neutral filter residue with sodium carbonate (Na2CO3) solution, and obtains straw cellulose through water bath, filtration, and washing; the straw cellulose, poly(butylene adipate-co-terephthalate) (PBAT), polylactic acid (PLA), and epoxidized soybean oil are fully mixed evenly and sent into a parallel twin-screw extruder to obtain injection molding standard test specimens. However, the compatibility between straw cellulose and poly(butylene adipate-co-terephthalate) (PBAT) is poor, and the process is complex and does not meet industrial large-scale production, and the mechanical properties of the products are not significantly improved. Summary of the Invention

[0004] In order to overcome the problem of poor compatibility between the filler and poly(butylene adipate-co-terephthalate), and to improve the mechanical and heat-resistant properties of poly(butylene adipate-co-terephthalate), the present invention provides a preparation method for a modified cellulose composite material for poly(butylene adipate-co-terephthalate).

[0005] The preparation operation steps of a modified cellulose composite material are as follows:

[0006] (1) Preparation of tannic acid solution

[0007] Dissolve 2.06 g of tannic acid (TA) in 25.32 mL of acetone (AC), and mix evenly to obtain a tannic acid solution;

[0008] (2) Preparation of modified cellulose

[0009] Slowly drop polypropylene glycol diglycidyl ether (PPGDGE) into the tannic acid solution at a mass ratio of 9:13, stir evenly to obtain a mixed solution; spray the mixed solution onto the surface of cellulose (Cellulose), keep the cellulose rotating at a low speed during spraying, and continue to rotate the cellulose at a low speed for mixed reaction after spraying, and dry it to obtain modified cellulose (Cellulose-PPGDGE-TA);

[0010] (3) Preparation of the mixture

[0011] Mix polybutylene adipate terephthalate (PBAT) and the modified cellulose at a high speed at a mass ratio of 5:1 to obtain a mixture;

[0012] (4) Melt extrusion

[0013] In a twin-screw extruder, melt-extrude the mixture to obtain a modified cellulose composite material;

[0014] The modified cellulose composite material is light yellow particles;

[0015] The tensile strength is 20.00 Mpa to 29.22 Mpa, the elongation at break is 600% to 660%, the flexural strength is 3.10 to 3.65 Mpa, and the contact angle of cellulose is 100.7° to 133.6°.

[0016] The further defined technical solutions are as follows:

[0017] In step (2), in a blender, under the condition of a rotation speed of 40 - 50 rpm, the low-speed mixing reaction time is 0.5 h.

[0018] In step (2), the spraying conditions: the spraying rate is 3 - 5 mL / s, and the rotation speed of the blender during spraying is 40 - 50 rpm; continue to mix the treated modified cellulose at a rotation speed of 85 - 200 rpm, and the reaction mixing time is 2 - 5 h.

[0019] In step (2), the drying conditions: temperature 80°C, time 4 h.

[0020] In step (3), the high-speed mixing conditions: rotation speed 400 - 500 rpm, time 1 - 2 h.

[0021] In step (4), the twin-screw extrusion conditions: the screw rotation speed is 50 - 250 rpm, the feeding speed is 3 - 6 Hz, and the extrusion temperature zones are set at 170, 175, 180, 180, 175, 170, 170, 165°C.

[0022] The beneficial technical effects of the present invention are reflected in the following aspects:

[0023] (1) The present invention utilizes the chemical reaction between cellulose and polypropylene glycol diglycidyl ether (PPGDGE). As shown in (2) of Figure 3 , the hydroxyl groups on the surface of cellulose react with the epoxy groups of polypropylene glycol diglycidyl ether (PPGDGE), and the epoxy groups break to form ether bonds, thereby improving the hydrophilicity of cellulose. The hydroxyl groups on the surface of cellulose decrease, enhancing its application in non-polar or hydrophobic matrices. As shown in Table 2, the contact angle of Cellulose increases from 29.7° to 55.1° after treatment with PPGDGE, which changes the surface properties of the cellulose matrix, increases the contact angle on the surface of cellulose, and improves the compatibility.

[0024] (2) The present invention introduces tannic acid (TA) and reacts it with cellulose-polypropylene glycol diglycidyl ether (Cellulose-PPGDGE). As shown in (3) of Figure 3 and (4) of Figure 3 , the hydroxyl groups of tannic acid (TA) react with the alcoholic hydroxyl groups of cellulose to form ether bonds. The hydroxyl groups (-O or H of -OH) of tannic acid (TA) form hydrogen bonds with the hydroxyl groups (-H or O of -OH) of cellulose and polypropylene glycol diglycidyl ether (PPGDGE). At the same time, the hydroxyl groups of tannic acid (TA) can form ester bonds with the carboxyl groups of poly(butylene adipate-co-terephthalate) (PBAT). A series of group reactions further improve the interfacial compatibility between the modified cellulose and poly(butylene adipate-co-terephthalate) (PBAT), and improve the mechanical properties and heat resistance of poly(butylene adipate-co-terephthalate) (PBAT). As shown in Figure 2 , the contact angle of the cellulose increases from 29.7° to 133.6° after the modification treatment, which also improves the hydrophobicity of cellulose and the barrier between the filler. The modified cellulose greatly improves the mechanical properties compared with the unmodified cellulose. The tensile strength increases from 15.67 Mpa to 29.22 Mpa, effectively improving the mechanical properties of poly(butylene adipate-co-terephthalate). Description of the Drawings

[0025] Figure 1 is the IR comparison diagram of the cellulose (Cellulose) and cellulose-polypropylene glycol diglycidyl ether-tannic acid (Cellulose-PPGDGE-TA) samples proposed by the present invention;

[0026] Figure 2It is the water contact angle diagram of the cellulose and cellulose - polypropylene glycol diglycidyl ether - tannic acid (Cellulose - PPGDGE - TA) samples proposed by the present invention;

[0027] Figure 3 It is the reaction mechanism diagram proposed by the present invention. Detailed implementation manners

[0028] The above content of the present invention will be further described in detail through examples below, but it should not be understood that the scope of the above - mentioned subject matter of the present invention is limited to the following examples. All technologies implemented based on the above content of the present invention belong to the scope of the present invention.

[0029] The present invention discloses a modified cellulose composite material for poly(butylene adipate - co - terephthalate) (PBAT) and its preparation method. First, dissolve a certain mass of tannic acid (TA) in acetone (AC) and mix evenly; secondly, drop polypropylene glycol diglycidyl ether (PPGDGE) into the mixed solution, mix well, then spray this mixed solution onto the surface of cellulose, and then carry out a mixing reaction at a certain stirring speed to obtain modified cellulose; finally, add PBAT and modified cellulose in a certain proportion and mix them at high speed, and then melt - compound them with a twin - screw extruder to obtain a modified cellulose composite material, that is, poly(butylene adipate - co - terephthalate) - cellulose - polypropylene glycol diglycidyl ether - tannic acid (PBAT - Cellulose - PPGDGE - TA) composite material.

[0030] Example 1

[0031] The preparation operation steps of a modified cellulose composite material are as follows:

[0032] S1: Preparation of tannic acid (TA) solution

[0033] First, measure 25.32 mL of acetone (AC) and place it in a three - necked flask; secondly, weigh 2.06 g of tannic acid (TA) and dissolve it in acetone (AC). Under normal temperature conditions, use a magnetic stirrer to completely dissolve tannic acid (TA) at a stirring speed of 200 rpm to obtain a tannic acid solution.

[0034] The structural formula of tannic acid (TA) is shown in Figure 3 in (1).

[0035] S2: Preparation of modified cellulose

[0036] Refer to Figure 3 in (2) and Figure 3In (3), weigh 18.54 g of polypropylene glycol diglycidyl ether (PPGDGE) and slowly add it dropwise to the 25 mL of tannic acid solution prepared in S1. After stirring evenly, a mixed solution is obtained. Dry cellulose at 80 °C for 1 h, weigh 200 g of the dried cellulose, spray the mixed solution onto the surface of the cellulose, and at the same time mix it at a low speed of 50 rpm in a blender for 0.5 h. The spraying rate is 3 mL / s, and the rotation speed of the blender during spraying is 50 rpm. After complete spraying, stir and mix at a rotation speed of 200 rpm for 2 h, and dry it in an oven at 80 °C for 4 h to obtain modified cellulose, namely cellulose-polypropylene glycol diglycidyl ether-tannic acid (Cellulose-PPGDGE-TA).

[0037] S3: Preparation of the mixture

[0038] Weigh 1 kg of poly(butylene adipate-co-terephthalate) (PBAT) and 200 g of modified cellulose (mass ratio 5:1), and mix them at a high speed of 400 rpm for 1 h to obtain the mixture.

[0039] The structural formula of poly(butylene adipate-co-terephthalate) (PBAT) is shown in Figure 3 (1) in.

[0040] S4: Melt extrusion:

[0041] See Figure 3 (4) in. Melt-extrude the mixture through a twin-screw extruder to obtain the modified cellulose composite material. The screw rotation speed is 250 rpm, the feeding speed is 5 Hz, and the extrusion temperature zones are set at 170, 175, 180, 180, 175, 170, 170, 165 °C.

[0042] The modified cellulose composite material prepared in Example 1 has a particle size of 400 mesh; the tensile strength is 29.22 Mpa, the elongation at break is 660%, the flexural strength is 3.65 Mpa, and the contact angle is 133.6°.

[0043] Example 2

[0044] The preparation operation steps of a modified cellulose composite material are as follows:

[0045] S1: Preparation of tannic acid (TA) solution

[0046] First, measure 25.32 mL of acetone (AC) and place it in a three-necked flask; second, weigh 2.06 g of tannic acid (TA) and dissolve it in tannic acid (AC). Under normal temperature conditions, use a magnetic stirrer to completely dissolve tannic acid (AC) at a stirring speed of 200 rpm to obtain a tannic acid solution.

[0047] S2: Preparation of Modified Cellulose

[0048] Weigh 20.60 g of polypropylene glycol diglycidyl ether (PPGDGE) and slowly add it dropwise to 25 mL of tannic acid solution prepared in S1. After stirring evenly, a mixed solution is obtained. Dry cellulose at 80 °C for 1 h, weigh 200 g of dried cellulose, spray the mixed solution onto the surface of cellulose, and at the same time mix it at a low speed of 50 rpm in a blender for 0.5 h; the spraying rate is 4 mL / s, the rotation speed of the blender during spraying is 50 rpm. After complete spraying, stir and mix at 200 rpm for 2 h, and then dry it in an oven at 80 °C for 4 h to obtain modified cellulose, namely cellulose-polypropylene glycol diglycidyl ether-tannic acid (Cellulose-PPGDGE-TA).

[0049] S3: Preparation of Mixture

[0050] Weigh 1 kg of poly(butylene adipate-co-terephthalate) (PBAT) and 200 g of the above-mentioned modified cellulose (mass ratio 5:1), and mix them at a high speed of 400 rpm for 1 h to obtain a mixture.

[0051] S4: Melt Extrusion

[0052] Melt-extrude the above-mentioned mixture through a twin-screw extruder to obtain a modified cellulose composite material. The screw rotation speed is 250 rpm, the feeding speed is 5 Hz, and the extrusion temperature zones are set at 170, 175, 180, 180, 175, 170, 170, 165 °C.

[0053] The modified cellulose composite material prepared in Example 2 has a particle size of 400 mesh; the tensile strength is 25.76 Mpa, the elongation at break is 620%, the flexural strength is 3.11 Mpa, and the contact angle is 121.0°.

[0054] Example 3

[0055] The preparation operation steps of a modified cellulose composite material are as follows:

[0056] S1: Preparation of Tannic Acid (TA) Solution

[0057] First, measure 25.32 mL of acetone (AC) and place it in a three-necked flask; second, weigh 2.06 g of tannic acid (TA) and dissolve it in acetone (AC). Under normal temperature conditions, use a magnetic stirrer to completely dissolve tannic acid (AC) at a stirring speed of 200 rpm to obtain a tannic acid solution.

[0058] S2: Preparation of Modified Cellulose

[0059] Weigh 19.57 g of polypropylene glycol diglycidyl ether (PPGDGE) and slowly add it dropwise to 25 mL of the tannic acid solution prepared in S1. After stirring evenly, a mixed solution is obtained. Dry cellulose at 80 °C for 1 h. Weigh 200 g of the dried cellulose, spray the mixed solution onto the surface of the cellulose, and at the same time mix it at a low speed of 50 rpm in a blender for 0.5 h. The spraying rate is 5 mL / s, and the rotation speed of the blender during spraying is 50 rpm. After complete spraying, stir and mix at 200 rpm for 2 h, and then dry it in an oven at 80 °C for 4 h to obtain modified cellulose, namely cellulose-polypropylene glycol diglycidyl ether-tannic acid (Cellulose-PPGDGE-TA).

[0060] S3: Preparation of the mixture

[0061] Weigh 1 kg of poly(butylene adipate-co-terephthalate) (PBAT) and 200 g of the above-mentioned modified cellulose, and mix them at a high speed of 400 rpm for 1 h to obtain a mixture.

[0062] S4: Melt extrusion

[0063] Melt-extrude the mixture described in S3 through a twin-screw extruder to obtain a modified cellulose composite material. The screw rotation speed is 250 rpm, the feeding speed is 5 Hz, and the extrusion temperature zones are set at 170, 175, 180, 180, 175, 170, 170, 165 °C.

[0064] The modified cellulose composite material prepared in Example 3 has a particle size of 400 mesh; the tensile strength is 24.27 Mpa, the elongation at break is 600%, the flexural strength is 3.23 Mpa, and the contact angle is 124.2°.

[0065] Comparative Example 1

[0066] S1: Weigh 1 kg of poly(butylene adipate-co-terephthalate) (PBAT) and 200 g of cellulose dried at 80 °C for 4 h, and mix them at a high speed of 400 rpm for 1 h to obtain a mixture.

[0067] S2: Melt-extrude the mixture described in S1, with the screw rotation speed of 250 rpm, the feeding speed of 5 Hz, and the extrusion temperature zones set at 170, 175, 180, 180, 175, 170, 170, 165 °C.

[0068] Comparative Example 2

[0069] S1: First, measure 25.32 mL of acetone (AC) and place it in a three-necked flask. Secondly, weigh 2.06 g of tannic acid (TA) and dissolve it in acetone (AC). Use a magnetic stirrer to completely dissolve tannic acid (TA) at a stirring speed of 200 rpm.

[0070] S2: Weigh 200 g of cellulose dried at 80 °C. Spray the solution from S1 onto the surface of the cellulose, and at the same time, mix it at a low speed of 50 rpm in a blender for 0.5 h. After the solution spraying is complete, stir and mix at 200 rpm for 2 h, and then dry it in an oven at 80 °C for 4 h to obtain cellulose-tannic acid (Cellulose-TA).

[0071] S3: Weigh 1 kg of poly(butylene adipate-co-terephthalate) (PBAT) and 200 g of the cellulose modified in S2 above, and mix them at a high speed of 400 rpm for 1 h to obtain a mixture.

[0072] S4: Melt-extrude the mixture described in S3. The screw speed is 250 rpm, the feeding speed is 5 Hz, and the extrusion temperature zones are set at 170, 175, 180, 180, 175, 170, 170, 165 °C.

[0073] Comparative Example 3

[0074] S1: Weigh 18.54 g of polypropylene glycol diglycidyl ether (PPGDGE), and slowly add it dropwise to the cellulose dried at 80 °C. At the same time, mix it at a low speed of 50 rpm in a blender for 0.5 h. After the solution spraying is complete, stir and mix at 200 rpm for 2 h, and then dry it in an oven at 80 °C for 4 h to obtain cellulose-polypropylene glycol diglycidyl ether (Cellulose-PPGDGE).

[0075] S2: Weigh 1 kg of poly(butylene adipate-co-terephthalate) (PBAT) and 200 g of the cellulose modified in S2 above, and mix them at a high speed of 400 rpm for 1 h to obtain a mixture.

[0076] S3: Melt-extrude the mixture described in S2. The screw speed is 250 rpm, the feeding speed is 5 Hz, and the extrusion temperature zones are set at 170, 175, 180, 180, 175, 170, 170, 165 °C.

[0077] Mechanical property experiments were carried out on poly(butylene adipate terephthalate) samples, poly(butylene adipate terephthalate) / cellulose samples and the modified cellulose composite materials (poly(butylene adipate terephthalate) / modified cellulose samples) of the present invention. The results are shown in Table 1. Among them, the standards for testing the flexural strength and flexural modulus are GB / T9341-2008 Plastics - Determination of flexural properties; the standards for testing the tensile strength and elongation at break are GB / T1040.1-2006 Plastics - Determination of tensile properties.

[0078] As can be seen from Table 1, compared with the pure poly(butylene adipate terephthalate), for the tensile strength of the poly(butylene adipate terephthalate) / cellulose samples and the modified cellulose composite materials (poly(butylene adipate terephthalate) / modified cellulose samples) of the present invention, the tensile strength of the poly(butylene adipate terephthalate) / modified cellulose samples is the highest, reaching 29.22 Mpa, and the elongation at break is 660%. When directly adding cellulose fillers, it is found that the compatibility between the fillers and the resin is poor, and the tensile strength and elongation at break are low. When adding modified cellulose and melting it with poly(butylene adipate terephthalate) resin, it is found that the compatibility between the two is improved, and the tensile strength and elongation at break are increased. Comparing the flexural strength of the poly(butylene adipate terephthalate) / cellulose samples, poly(butylene adipate terephthalate) / modified cellulose samples with pure poly(butylene adipate terephthalate), the flexural strength of the modified cellulose composite materials (poly(butylene adipate terephthalate) / modified cellulose samples) of the present invention is 3.65 Mpa, indicating that the stiffness of the modified cellulose composite materials of the present invention is increased and the ability to resist deformation is enhanced, showing that the modified cellulose plays a reinforcing role in the poly(butylene adipate terephthalate) matrix.

[0079] Table 1 Mechanical properties of the samples

[0080]

[0081]

[0082] Infrared detection and analysis were respectively carried out on cellulose (Cellulose) and cellulose - polypropylene glycol diglycidyl ether - tannic acid (Cellulose - PPGDGE - TA) samples, and the results are as Figure 1 shown. As Figure 1 can be seen, the peaks appearing at 3453 cm -1 and 2901 cm -1 in the spectrum respectively correspond to the stretching vibration peaks of -OH and C-H, and the peaks at 1028 cm -1 and 898 cm -1Correspond to the C-O-C stretching vibration peak of the pyranose ring and the β-glycosidic bond between glucose rings respectively. These are several main characteristic absorption peaks of cellulose. The stretching peak of C=O at 1742 cm -1 confirms that the product contains PPGDGE. The absence of an absorption peak at 843 cm -1 can be attributed to the reaction between the epoxy group of polypropylene glycol diglycidyl ether (PPGDGE) and the hydroxyl group of cellulose, which means that the polypropylene glycol diglycidyl ether (PPGDGE) in the cellulose-polypropylene glycol diglycidyl ether-tannic acid (Cellulose-PPGDGE-TA) scaffold is not free but has a chemical bond with cellulose, forming an ether bond. The hydroxyl peak in the cellulose-polypropylene glycol diglycidyl ether-tannic acid (Cellulose-PPGDGE-TA) sample is redshifted from 3453 cm -1 to 3494 cm -1 , and their characteristic ether bond peak also redshifts from 1028 cm -1 to 1051 cm -1 , indicating the hydrogen bond interaction between cellulose-polypropylene glycol diglycidyl ether-tannic acid (Cellulose-PPGDGE-TA) from the infrared spectrum.

[0083] Table 2 Contact angle tests of cellulose and cellulose-polypropylene glycol diglycidyl ether (Cellulose-PPGDGE)

[0084] Sample Contact Angle / ° Cellulose 29.7 Cellulose-PPGDGE 55.1

[0085] Water contact angle tests were carried out on the cellulose sample and the modified cellulose sample, that is, the water contact angles of the cellulose and cellulose-polypropylene glycol diglycidyl ether-tannic acid (Cellulose-PPGDGE-TA) samples are shown in Figure 2 . As can be seen from Figure 2 , due to its inherent hydrophilicity, the initial cellulose has a water contact angle of 29.7° at 3 min. After modification, the hydrophilicity of cellulose is weakened and stronger hydrophobicity is imparted. The water contact angle of cellulose-polypropylene glycol diglycidyl ether-tannic acid (Cellulose-PPGDGE-TA) at 3 min is 133.6°. After surface modification of cellulose, the special cross-linked network structure of cellulose-polypropylene glycol diglycidyl ether-tannic acid (Cellulose-PPGDGE-TA) improves its hydrophobicity, making the water contact angle of the modified cellulose increase more and the hydrophobicity of the material more obvious.

[0086] Those skilled in the art can easily understand that the above Examples 1-3 are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a modified cellulose composite material, characterized in that, The preparation steps are as follows: (1) Preparation of tannic acid solution Dissolve 2.06 g of tannic acid in 25.32 mL of acetone and mix evenly to obtain a tannic acid solution; (2) Preparation of modified cellulose Slowly drop polypropylene glycol diglycidyl ether into the tannic acid solution at a mass ratio of 9:13, stir evenly to obtain a mixed solution; spray the mixed solution onto the surface of cellulose. When spraying, the cellulose keeps rotating at a low speed. After spraying, the cellulose continues to rotate at a low speed for mixing reaction, and then dry it to obtain modified cellulose; (3) Preparation of the mixture Mix polybutylene terephthalate - adipate and the modified cellulose at a mass ratio of 5:1 at high speed to obtain a mixture; (4) Melt extrusion In a twin - screw extruder, extrude the mixture by melting to obtain a modified cellulose composite material; The modified cellulose composite material is light yellow particles; The tensile strength is 20.00 Mpa - 29.22 Mpa, the elongation at break is 600% - 660%, the flexural strength is 3.10 - 3.65 Mpa, and the contact angle of cellulose is 100.7° - 133.6°.

2. The preparation method according to claim 1, characterized in that: In step (2), in a blender, under the condition of a rotation speed of 40 - 50 rpm, the low - speed mixing reaction time is 0.5 h.

3. The preparation method according to claim 1, wherein: In step (2), the spraying conditions: the spraying rate is 3 - 5 mL / s, and the rotation speed of the blender during spraying is 40 - 50 rpm; continue to mix the treated modified cellulose at a rotation speed of 85 - 200 rpm, and the reaction mixing time is 2 - 5 h.

4. The preparation method according to claim 1, characterized in that: In step (2), the drying conditions: temperature 80°C, time 4 h.

5. The preparation method according to claim 1, characterized in that: In step (3), the high - speed mixing conditions: rotation speed 400 - 500 rpm, time 1 - 2 h.

6. The preparation method according to claim 1, characterized in that: In step (4), the twin - screw extrusion conditions: the screw rotation speed is 50 - 250 rpm, the feeding speed is 3 - 6 Hz, and the extrusion temperature zones are set at 170, 175, 180, 180, 175, 170, 170, 165°C.

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