CN102304238A - A kind of regenerated cellulose composite membrane and preparation method thereof - Google Patents

Abstract

The invention discloses a regenerated cellulose composite film, which is composed of 60% to 97.5% of cellulose and 2.5% to 40% of halogenated polymer in the following mass percentages, and has high toughness, biodegradability, good compatibility, etc. features. The invention also discloses a preparation method of a regenerated cellulose composite film, comprising: 1) adding cellulose to a pretreatment organic solvent, treating at 155-165°C for 0.5-1h, and then pressing; 2) pressing to obtain Add the pretreated cellulose into the co-dissolution organic solvent system, stir until a gel is produced, and then let it stand for 12-30 hours to obtain a transparent solution; 3) Add halogenated polymers to the transparent solution, stir and blend for 20-20 hours 40min to obtain the mixed solution; 4) The mixed solution is processed through film formation and film formation to obtain a regenerated cellulose composite film, which has the characteristics of simple preparation process, good controllability, and easy industrial production.

Description

A kind of regenerated cellulose composite membrane and preparation method thereof

technical field

The invention relates to the field of regenerated cellulose composite membrane and its preparation, in particular to a regenerated cellulose composite membrane and a preparation method thereof.

Background technique

my country is one of the top ten plastic products producing and consuming countries in the world. In 1995, the total national plastic consumption was about 11 million tons, of which 2.11 million tons were used for packaging. The major part of packaging plastics is discarded arbitrarily with the form of waste film, polybag and foamed plastics tableware. According to the survey, 3% of the domestic waste in Beijing is waste or old plastic packaging, with an annual output of about 140,000 tons; 7% of Shanghai's domestic waste is waste or used plastic packaging, with an annual output of about 190,000 tons. Waste packaging plastics discarded in the environment not only affect the appearance of the city and the natural landscape, causing "visual pollution", but also cause potential harm to the ecological environment because they are difficult to degrade. Our country spends about 18.5 million yuan on white pollution treatment each year. Therefore, in response to such problems, the development and use of biodegradable materials have received keen attention at home and abroad in recent years, and scientists from all over the world are vigorously conducting research on biodegradable polymer materials.

Cellulose is a cheap renewable resource. According to scientists' estimates, more than 100 billion tons of cellulose can be obtained through photosynthesis every year, exceeding the current oil reserves. The production of regenerated cellulose film mainly adopts viscose method and copper ammonia method. Compared with synthetic polymer film, its products have the following characteristics: 1. High mechanical strength, easy to make very thin film; 2. Excellent resistance to gamma Radiation ability and excellent heat resistance; 3. It is safe and stable, non-toxic and harmless; 4. After the membrane is discarded, it can be decomposed under the action of microorganisms, and will not cause environmental pollution.

The use of regenerated cellulose provides an effective technical means to solve the problem of white pollution, and has bright application prospects. However, the production process of the traditional viscose method and copper ammonia method is seriously polluted, and the plasticity of the film in the dry state is relatively poor, and the elongation at break in the dry state does not exceed 10%. Therefore, it is necessary to develop a green production process of cellulose film and improve the plasticity of cellulose film.

The Chinese patent application with the publication number 101733002A discloses a pH-sensitive cationic regenerated cellulose composite membrane, its preparation method and application. chitosan; it discloses the preparation method of pH-sensitive cationic regenerated cellulose composite membrane, comprising the following steps: 1), after degassing the cellulose solution, salivate into a solution layer on the substrate, then solidify to obtain cellulose Solution layer; 2), dissolving chitosan in a solvent to obtain a chitosan solution; 3), immersing the solidified cellulose solution layer in step 1) in the chitosan solution, and the cellulose will regenerate and separate out into a film , and dried after washing, the pH-sensitive cationic regenerated cellulose composite membrane is prepared. Although the pH-sensitive cationic regenerated cellulose composite membrane has good biocompatibility, bacteriostasis and degradability, its outstanding point is that it has outstanding bacteriostasis performance, but its mechanical properties, especially the toughness and strength are obviously biased. Low, there are technical problems.

In the prior art, some cellulose green solvent systems have been developed, such as LiCl/DMAC, LiCl/DMF and LiCl/DMSO, LiCl/DMAC solvent system is one of them, and the pretreatment process using LiCl/DMAC solvent system includes the following Steps: add the cellulose to the LiCl/DMAC solvent system, heat and stir in an oil bath at 160°C for 30-60 minutes, then squeeze and dry at low temperature for later use. In particular, low-temperature drying requires a freeze dryer, which is costly and time-consuming, usually more than 6 hours. It has been limited to the experimental stage and cannot be industrialized, and there are technical defects.

Contents of the invention

The invention provides a regenerated cellulose composite film, which has the characteristics of high toughness, biodegradability, good compatibility and the like.

The invention also provides a preparation method of the regenerated cellulose composite film, which has the characteristics of simple preparation process, good controllability, easy industrial production and the like.

A regenerated cellulose composite film is composed of the following components in mass percentage:

Cellulose 60%～97.5%;

Halogenated polymer 2.5% to 40%.

Described cellulose is natural lignocellulose, specifically can be selected from seaweed cellulose, bacterial cellulose, short cotton linters, flax, hemp, wood pulp, microcrystalline cellulose, cotton, wood, bamboo powder, bagasse One or two or more.

The halogenated polymer is one or more of polymers containing a large amount of fluorine and chlorine atoms such as polyvinylidene fluoride (PVDF) and polyvinylidene chloride (PVDC), and these polymers generally have high toughness and/or high plasticity. The present invention changes the strong hydrogen bond interaction between cellulose molecular chains by adding some macromolecules (small molecular plasticizers are easy to lose) and blends with cellulose, so as to improve the movement ability of cellulose chains at normal temperature, thereby improving Toughness of regenerated cellulose composite membranes. Due to the strong interaction between halogen atoms such as fluorine and chlorine with strong electronegativity on the halogenated polymer chain and hydrogen atoms, the compatibility between halogenated polymers and cellulose is good, which can improve the regenerated cellulose composite membrane. mechanical strength.

The preparation method of described regenerated cellulose composite membrane comprises the following steps:

1) adding cellulose to the pretreated organic solvent, treating it at 155°C to 165°C for 0.5h to 1h, and then pressing to obtain the pretreated cellulose;

2) adding the pretreated cellulose obtained in step 1) into the co-dissolving organic solvent system, stirring at 70°C to 100°C until a gel is formed, and then standing for 12h to 30h to obtain a transparent solution;

3) Add halogenated polymers to the transparent solution obtained in step 2), and stir and blend at 70°C to 100°C for 15min to 40min to obtain a mixed solution;

4) The mixed solution obtained in step 3) is subjected to film-forming and post-film-forming treatment to obtain a regenerated cellulose composite film.

In order to obtain better invention effects of the present invention, the following are further preferred as the present invention:

In step 1), the pretreatment organic solvent is one of dimethylacetamide (DMAC), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), which can avoid the introduction of various organic Solvent affects the preparation of regenerated cellulose composite membrane.

In step 2), the co-solvent organic solvent system is lithium chloride and dimethylacetamide (LiCl/DMAC) organic solvent system, lithium chloride and dimethylformamide (LiCl/DMF) organic solvent system, One of lithium chloride and dimethyl sulfoxide (LiCl/DMSO) organic solvent systems, wherein the mass ratio of lithium chloride to the organic solvent (ie DMAC, DMF, DMSO) is preferably 1/9.

Since in step 1), although the pretreatment organic solvent is added, the removal step of the pretreatment organic solvent is not included, in order to avoid introducing various organic solvents in the preparation process, thus affecting the preparation of the regenerated cellulose composite membrane, the It is best to keep the pretreatment organic solvent consistent with the organic solvent in the co-dissolution organic solvent system, specifically: when the co-dissolution organic solvent system is LiCl/DMAC, then the pretreatment organic solvent is selected as DMAC; when the co-dissolution organic solvent system is LiCl/DMF, at this time, choose DMF as the pretreatment organic solvent; when the co-soluble organic solvent system is LiCl/DMSO, then choose DMSO as the pretreatment organic solvent.

Pressing conditions: the pressure is 3MPa~10MPa, the pressing temperature is 165℃~210℃, and the holding time is 1min~5min. The dissolution of cellulose in the organic solvent can be realized by releasing the pressure and drying after holding the pressure.

In step 3), the halogenated polymer is added in the form of powder. The adding method is simple and can uniformly disperse the halogenated polymer in the transparent mixed solution. Alternatively, the powder of the halogenated polymer is stirred at 70°C to 100°C for 10min to 30min and dissolved in another co-solvent organic solvent system before being added to the mixed solution. This addition method can make the halogenated polymer better Dispersed in a transparent mixed solution, and the addition of halogenated polymer powder is relatively easy to control.

In step 4), the film formation and post-film formation treatment include: forming a film at 20°C to 40°C, placing it for 0.5h to 3h after film formation, then soaking in water for 10h to 20h, and changing the water 2 to 8 times .

After specific film-forming steps and film-forming post-treatment, a regenerated cellulose composite film with stable comprehensive properties is obtained, which has higher mechanical strength and is better decomposed under the action of microorganisms after the film is discarded, without causing environmental pollution. Therefore, the use of regenerated cellulose membranes brings bright prospects for solving the white pollution problem.

Compared with prior art, the present invention has following advantage:

The regenerated cellulose composite membrane of the present invention adopts cellulose as the main raw material, which is a renewable resource and has good biodegradability; by adding high toughness or plastic halogenated polymers, it has a relatively high molecular weight with cellulose polymers. Good compatibility, the prepared regenerated cellulose composite film has high toughness, its elongation at break is greatly improved compared with pure regenerated cellulose composite film, and its mechanical properties are excellent.

The preparation method of the regenerated cellulose composite membrane of the present invention simplifies the pretreatment process of the traditional LiCl/DMAC solvent system, and removes the time-consuming and energy-consuming step of low-temperature drying, so that the preparation process of the present invention is simple, easy to operate, and can be used. The controllability is good, and because the pretreatment process is simplified, the preparation method of the regenerated cellulose composite film of the present invention can realize industrial production relatively easily, and is beneficial to reduce the cost of industrial production.

Description of drawings

Fig. 1 is the scanning electron micrograph of the regenerated cellulose composite membrane that embodiment 1 prepares;

Fig. 2 is the scanning electron micrograph of the regenerated cellulose composite membrane that embodiment 3 prepares;

FIG. 3 is a scanning electron micrograph of the regenerated cellulose composite membrane prepared in Example 4.

Detailed ways

The present invention will be described in further detail below in conjunction with the examples, but not limited to the examples.

Comparative example 1

1) Pretreatment of cellulose

Add 1 gram of cellulose (Dezhou Tianma Cellulose Co., Ltd., refined cotton, degree of polymerization (DP) = 800) into 100 grams of DMAC, activate it at 160°C for 0.5 hours, and then press it. The pressing conditions: pressure 4MPa, The pressing temperature is 175°C and the holding time is 3 minutes to obtain the pretreated cellulose, and there is almost no loss of cellulose during this process;

2) Dissolution of cellulose

0.9 grams of cellulose obtained in step 1) after the pretreatment was added to 29.1 grams of LiCl/DMAC organic solvent system (the mass ratio of LiCl and DMAC in the LiCl/DMAC organic solvent system was 1:9), at 100 ° C Stir until gel is produced (stir about 3h), then stand at room temperature for 24h to obtain 30 grams of transparent solution, the mass percentage of cellulose in the transparent solution is 3%;

3) Cellulose film formation

Take out 30 grams of the transparent solution obtained in step 2), scrape it into a film at 25°C, place it in the air for 1 hour after the film is formed, then soak it in distilled water for 12 hours, change the distilled water 3 times, and obtain regenerated cellulose The composite film has a thickness of about 30 microns.

The mechanical properties of the regenerated cellulose composite membrane prepared in Comparative Example 1 were tested using a universal material testing machine. The spline standard is 10mm wide with a fixture length of 50mm. The stretching speed was 5 mm/min. The test results are shown in Table 1.

Example 1

1) Pretreatment of cellulose

Add 0.9 grams of cellulose (Dezhou Tianma Cellulose Co., Ltd., refined cotton, DP=800) into 100 grams of DMAC, treat it at 160°C for 0.5 hours, and then squeeze it. The pressing conditions: pressure is 4MPa, pressing temperature is 175°C , The holding time is 3 minutes, and the pretreated cellulose is obtained, and there is almost no loss of cellulose in this process;

2) Dissolution of cellulose

0.9 grams of cellulose obtained in step 1) after the pretreatment was added to 29.1 grams of LiCl/DMAC organic solvent system (the mass ratio of LiCl and DMAC in the LiCl/DMAC organic solvent system was 1:9), at 100 ° C Stir until gel (stirring about 3h) is produced, then stand at room temperature for 24h to obtain 30 grams of transparent solution, and the mass percentage of cellulose in the transparent solution is 3%;

3) Dissolution and blending of PVDF

Dissolve the powder of PVDF (FR-904, Mn=475637, Shanghai Sanaifu Co., Ltd.) in the LiCl/DMAC organic solvent system (the mass ratio of LiCl to DMAC in the LiCl/DMAC organic solvent system is 1: 9) after that, it is 3% PVDF solution containing PVDF mass percentage concentration; Add PVDF solution in the transparent solution that obtains in step 2), stir and blend at 80 ℃ for 40min, obtain transparent mixed solution; Transparent solution and PVDF The mass ratio of the solution is 97.5: 2.5;

4) Cellulose film formation

Get 30 grams of the mixed solution in step 3) and cool to 25°C to form a film, place it in the air for 1 hour after film formation, then soak in distilled water for 12 hours, change distilled water 3 times, and obtain a regenerated cellulose composite film with a thickness of 20um, its scanning electron microscope picture is shown in Figure 1. It can be seen from Figure 1 that the prepared regenerated cellulose composite film has good compatibility between cellulose and PVDF.

The regenerated cellulose composite membrane prepared in Example 1 was tested for elongation at break, tensile strength and modulus in the same manner as Comparative Example 1, and the test results are shown in Table 1.

Example 2

1) Pretreatment of cellulose

Add 0.9 grams of cellulose (Dezhou Tianma Cellulose Co., Ltd., refined cotton, DP=800) into 100 grams of DMAC, treat it at 160°C for 0.5 hours, and then squeeze it. The pressing conditions: pressure is 4MPa, pressing temperature is 175°C , The holding time is 3 minutes, and the pretreated cellulose is obtained, and there is almost no loss of cellulose in this process;

2) Dissolution of cellulose

0.9 grams of cellulose obtained in step 1) after the pretreatment was added to 29.1 grams of LiCl/DMAC organic solvent system (the mass ratio of LiCl and DMAC in the LiCl/DMAC organic solvent system was 1:9), at 100 ° C Stir until gel is produced (stir about 3h), then stand at room temperature for 24h to obtain 30 grams of transparent solution, the mass percentage of cellulose in the transparent solution is 3%;

3) Dissolution and blending of PVDF

Dissolve the PVDF (FR-904, Mn=475637, Shanghai Sanaifu Co., Ltd.) powder in another LiCl/DMAC organic solvent system (the mass ratio of LiCl to DMAC in the LiCl/DMAC organic solvent system) was stirred at 80°C for 20 min After 1:9), the PVDF solution containing PVDF mass percent concentration of 3% was obtained; the PVDF solution was added to the transparent solution obtained in step 2), and stirred and blended at 80° C. for 40 min to obtain a transparent mixed solution; transparent The mass ratio of solution and PVDF solution is 80: 20;

4) Cellulose film formation

Get 30 grams of the mixed solution in step 3) and cool to 20°C to form a film, place it in the air for 1 hour after film formation, then soak in distilled water for 12 hours, change distilled water 3 times, and obtain a regenerated cellulose composite film with a thickness of 20um.

The regenerated cellulose composite film prepared in Example 2 was tested for elongation at break, tensile strength and modulus in the same manner as Comparative Example 1, and the test results are shown in Table 1.

Example 3

1) Pretreatment of cellulose

Add 0.9 grams of cellulose (Dezhou Tianma Cellulose Co., Ltd., refined cotton, DP=800) into 100 grams of DMAC, treat it at 160°C for 0.5 hours, and then squeeze it. The pressing conditions: pressure is 4MPa, pressing temperature is 175°C , The holding time is 3 minutes, and the pretreated cellulose is obtained, and there is almost no loss of cellulose in this process;

2) Dissolution of cellulose

0.9 grams of cellulose obtained in step 1) after the pretreatment was added to 29.1 grams of LiCl/DMAC organic solvent system (the mass ratio of LiCl and DMAC in the LiCl/DMAC organic solvent system was 1:9), at 100 ° C Stir until gel is produced (stir about 3h), then stand at room temperature for 24h, to obtain 30 grams of transparent solution, the mass percent of cellulose contained in the solution is 3%;

3) Dissolution and blending of PVDF

Dissolve the PVDF (FR-904, Mn=475637, Shanghai Sanaifu Co., Ltd.) powder in another LiCl/DMAC organic solvent system (the mass ratio of LiCl to DMAC in the LiCl/DMAC organic solvent system) was stirred at 80°C for 20 min After 1:9), the PVDF solution containing PVDF mass percent concentration of 3% was obtained; the PVDF solution was added to the transparent solution obtained in step 2), and stirred and blended at 80° C. for 40 min to obtain a transparent mixed solution; transparent The mass ratio of solution and PVDF solution is 60:40;

4) Cellulose film formation

Take 30 grams of the mixed solution in step 3) and cool to 40°C to form a film, place it in the air for 1 hour after film formation, then soak in distilled water for 12 hours, change the distilled water 3 times, and obtain a regenerated cellulose composite film with a thickness of 20um. Its scanning electron microscope picture is shown in Figure 2. It can be seen from Figure 2 that the prepared regenerated cellulose composite film has good compatibility between cellulose and PVDF.

The regenerated cellulose composite membrane prepared in Example 3 was tested for elongation at break, tensile strength and modulus by the method of Comparative Example 1, and the test results are shown in Table 1 for details.

Example 4

1) the pretreatment of cellulose is the same as embodiment 1

2) the dissolving of cellulose is with embodiment 1

3) Dissolution and blending of PVDC

The powder of PVDC (Saran168, DOW Chemical Company) was dissolved in another LiCl/DMAC organic solvent system (the mass ratio of LiCl to DMAC in the LiCl/DMAC organic solvent system was 1:9) at 80 ° C for 20 min to obtain A PVDC solution with a PVDC mass percentage concentration of 3%; add the PVDC solution to the transparent solution obtained in step 2), and stir and blend at 80° C. for 40 minutes to obtain a transparent mixed solution; the mass ratio of the transparent solution to the PVDC solution is 97.5 : 2.5;

4) Cellulose film formation

Take 30 grams of the mixed solution in step 3) and cool to 40°C to form a film, place it in the air for 1 hour after film formation, then soak in distilled water for 12 hours, change the distilled water 3 times, and obtain a regenerated cellulose composite film with a thickness of 20um, its scanning electron microscope picture is shown in Figure 3, it can be seen from Figure 3 that the prepared regenerated cellulose composite film has good compatibility between cellulose and PVDC.

The regenerated cellulose composite membrane prepared in Example 4 was tested for elongation at break, tensile strength and modulus by the same method as Comparative Example 1, and the test results are shown in Table 2.

Example 5

1) the pretreatment of cellulose is the same as embodiment 1

2) the dissolving of cellulose is with embodiment 1

3) Dissolution and blending of PVDC

The powder of PVDC (Saran168, DOW Chemical Company) was dissolved in another LiCl/DMAC organic solvent system (the mass ratio of LiCl to DMAC in the LiCl/DMAC organic solvent system was 1:9) at 80°C for 20 min with stirring to obtain A PVDC solution with a PVDC mass percentage concentration of 3%; add the PVDC solution to the transparent solution obtained in step 2), stir and blend at 80° C. for 40 minutes to obtain a transparent mixed solution; the mass ratio of the transparent solution to the PVDC solution is 80 :20;

4) Cellulose film formation

Get 30 grams of the mixed solution in step 3) and cool to 30°C to form a film, place it in the air for 1 hour after film formation, then soak in distilled water for 12 hours, change the distilled water 3 times, and obtain a regenerated cellulose composite film with a thickness of 20um.

The regenerated cellulose composite film prepared in Example 5 was tested for elongation at break, tensile strength and modulus by the same method as Comparative Example 1, and the test results are shown in Table 2.

Example 6

1) the pretreatment of cellulose is the same as embodiment 1

2) the dissolving of cellulose is with embodiment 1

3) Dissolution and blending of PVDC

The powder of PVDC (Saran168, DOW Chemical Company) was dissolved in another LiCl/DMAC organic solvent system (the mass ratio of LiCl to DMAC in the LiCl/DMAC organic solvent system was 1:9) at 80 ° C for 20 min to obtain A PVDC solution with a PVDC mass percentage concentration of 3%; add the PVDC solution to the transparent solution obtained in step 2), stir and blend at 80° C. for 40 minutes to obtain a transparent mixed solution; the mass ratio of the transparent solution to the PVDC solution is 60 : 40;

4) Cellulose film formation

Get 30 grams of the mixed solution in step 3) and cool it to 25°C to form a film, place it in the air for 1 hour after film formation, then soak it in distilled water for 12 hours, change the distilled water 3 times, and obtain a regenerated cellulose composite film with a thickness of 20um.

The regenerated cellulose composite film prepared in Example 6 was tested for elongation at break, tensile strength and modulus by the same method as Comparative Example 1, and the test results are shown in Table 1.

Comparative example 2

1) Pretreatment of cellulose

Add 1 gram of cellulose (Dezhou Tianma Cellulose Co., Ltd., refined cotton, DP=800) into 100 grams of DMF, treat it at 155°C for 0.5 hours, and then press it. The pressing conditions: pressure 4MPa, pressing temperature 165°C , The holding time is 3 minutes, and the pretreated cellulose is obtained, and there is almost no loss of cellulose in this process;

2) Dissolution of cellulose

0.9 grams of cellulose obtained in step 1) after the pretreatment was added to 29.1 grams of LiCl/DMF organic solvent system (the mass ratio of LiCl to DMF in the LiCl/DMF organic solvent system was 1:9), and the Stir until gel is produced (stir about 3h), then stand at room temperature for 24h to obtain 30 grams of transparent solution, the mass percentage of cellulose in the transparent solution is 3%;

3) Cellulose film formation

Take out 30 grams of the transparent solution obtained in step 2), and scrape it into a film at a room temperature of 25°C. After the film is formed, place it in the air for 1 hour, then soak it in distilled water for 12 hours, change the distilled water 3 times, and obtain the regenerated fiber The plain composite film has a thickness of about 30 μm.

The mechanical properties of the regenerated cellulose composite membrane prepared in Comparative Example 2 were tested using a universal material testing machine. The spline standard is 10mm wide with a fixture length of 50mm. The stretching speed was 5 mm/min. The test results are shown in Table 1.

Example 7

1) The pretreatment of cellulose is the same as Comparative Example 2

2) The dissolving of cellulose is the same as Comparative Example 2

3) Dissolution and blending of PVDF

Dissolve the PVDF (FR-904, Mn=475637, Shanghai Sanaifu Co., Ltd.) powder in another LiCl/DMF organic solvent system (the mass ratio of LiCl to DMF in the LiCl/DMF organic solvent system) was stirred at 80°C for 20 min. After 1:9), the PVDF solution containing PVDF mass percent concentration of 3% was obtained; the PVDF solution was added to the transparent solution obtained in step 1), and stirred and blended at 80° C. for 40 min to obtain a transparent mixed solution; transparent The mass ratio of the solution to the PVDF solution is 97.5: 2.5;

4) Cellulose film formation

Get 30 grams of the mixed solution in step 3) and cool to 25°C to form a film, place it in the air for 1 hour after film formation, then soak in distilled water for 12 hours, change distilled water 3 times, and obtain a regenerated cellulose composite film with a thickness of 20um.

The regenerated cellulose composite film prepared in Example 7 was tested for elongation at break, tensile strength and modulus in the same manner as Comparative Example 2, and the test results are shown in Table 1.

Example 8

1) The pretreatment of cellulose is the same as Comparative Example 2

2) The dissolving of cellulose is the same as Comparative Example 2

3) Dissolution and blending of PVDF

Dissolve the PVDF (FR-904, Mn=475637, Shanghai Sanaifu Co., Ltd.) powder in another LiCl/DMF organic solvent system (the mass ratio of LiCl to DMF in the LiCl/DMF organic solvent system) was stirred at 80°C for 20 min. After 1:9), the PVDF solution containing PVDF mass percent concentration of 3% was obtained; the PVDF solution was added to the transparent solution obtained in step 1), and stirred and blended at 80° C. for 40 min to obtain a transparent mixed solution; transparent The mass ratio of solution and PVDF solution is 80: 20;

4) Cellulose film formation

Get 30 grams of the mixed solution in step 3) and cool to 30°C to form a film, place it in the air for 1 hour after film formation, then soak in distilled water for 12 hours, change the distilled water 3 times, and obtain a regenerated cellulose composite film with a thickness of 20um.

The regenerated cellulose composite film prepared in Example 8 was tested for elongation at break, tensile strength and modulus in the same manner as Comparative Example 1, and the test results are shown in Table 1.

Comparative example 3

1) Pretreatment of cellulose

Add 1 gram of cellulose (Dezhou Tianma Cellulose Co., Ltd., refined cotton, DP=800) into 100 grams of DMSO, treat it at 165°C for 0.5 hours, and then press it. The pressing conditions: pressure 4MPa, pressing temperature 165°C , The holding time is 3 minutes, and the pretreated cellulose is obtained, and there is almost no loss of cellulose in this process;

2) Dissolution of cellulose

0.9 grams of cellulose obtained in step 1) after the pretreatment was added to 29.1 grams of LiCl/DMSO organic solvent system (the mass ratio of LiCl and DMSO in the LiCl/DMSO organic solvent system was 1:9), at 100 ° C Stir until gel is produced (stir about 3h), then stand at room temperature for 24h to obtain 30 grams of transparent solution, the mass percentage of cellulose in the transparent solution is 3%;

3) Cellulose film formation

Take out the transparent solution obtained in step 2), scrape it into a film at a room temperature of 25°C, place it in the air for 1 hour after film formation, then soak it in distilled water for 12 hours, change the distilled water 3 times, and obtain a regenerated cellulose composite film, the thickness of which is about 30 microns.

The mechanical properties of the regenerated cellulose composite membrane prepared in Comparative Example 3 were tested using a universal material testing machine. The spline standard is 10mm wide with a fixture length of 50mm. The stretching speed was 5 mm/min. The test results are shown in Table 1.

Example 9

1) The pretreatment of cellulose is the same as Comparative Example 3

2) The dissolving of cellulose is the same as Comparative Example 3

3) Dissolution and blending of PVDF

Dissolve the powder of PVDF (FR-904, Mn=475637, Shanghai Sanaifu Co., Ltd.) in another LiCl/DMSO organic solvent system (the mass ratio of LiCl to DMSO in the LiCl/DMSO organic solvent system) was stirred at 80°C for 20 min After 1:9), the PVDF solution containing PVDF mass percent concentration of 3% was obtained; the PVDF solution was added to the transparent solution obtained in step 1), and stirred and blended at 80° C. for 40 min to obtain a transparent mixed solution; transparent The mass ratio of the solution to the PVDF solution is 97.5: 2.5;

4) Cellulose film formation

Take 30 grams of the mixed solution in step 3) and cool it to room temperature at 25°C to form a film. After the film is formed, place it in the air for 1 hour, then soak it in distilled water for 12 hours, and change the distilled water 3 times to obtain a regenerated cellulose composite film. It is 20um.

The regenerated cellulose composite film prepared in Example 9 was tested for elongation at break, tensile strength and modulus in the same manner as Comparative Example 3, and the test results are shown in Table 1.

Example 10

1) The pretreatment of cellulose is the same as Comparative Example 3

2) The dissolving of cellulose is the same as Comparative Example 3

3) Dissolution and blending of PVDF

Dissolve the powder of PVDF (FR-904, Mn=475637, Shanghai Sanaifu Co., Ltd.) in another LiCl/DMSO organic solvent system (the mass ratio of LiCl to DMSO in the LiCl/DMSO organic solvent system) was stirred at 80°C for 20 min After 1:9), the PVDF solution containing PVDF mass percent concentration of 3% was obtained; the PVDF solution was added to the transparent solution obtained in step 1), and stirred and blended at 80° C. for 40 min to obtain a transparent mixed solution; transparent The mass ratio of solution and PVDF solution is 60:40;

4) Cellulose film formation

Take 30 grams of the mixed solution in step 3) and cool it to room temperature at 25°C to form a film. After the film is formed, place it in the air for 1 hour, then soak it in distilled water for 12 hours, and change the distilled water 3 times to obtain a regenerated cellulose composite film. It is 20um.

The regenerated cellulose composite membrane prepared in Example 10 was tested for elongation at break, tensile strength and modulus in the same manner as Comparative Example 3, and the test results are shown in Table 1.

Table 1

As can be seen from Table 1, the regenerated cellulose composite film prepared in Examples 1-6 is compared with the regenerated cellulose film prepared in Comparative Example 1, and the regenerated cellulose composite film prepared in Examples 7-8 is compared with the regenerated fiber prepared in Comparative Example 2. Compared with the regenerated cellulose composite film prepared in Examples 9-10 and the regenerated cellulose film prepared in Comparative Example 3, when the strength and modulus were maintained, the regenerated fiber prepared in Examples 1-10 The elongation at break of the plain composite film is generally increased by 3 to 4 times.

Claims (10)

1. regenerated cellulose composite film, form by following component by mass percent:

Mierocrystalline cellulose 60%～97.5%;

Halo polymer 2.5%～40%.

2. regenerated cellulose composite film according to claim 1; Its spy is being, described Mierocrystalline cellulose is a kind of or two or more in seaweed fiber element, bacteria cellulose, short velveteen, flax, hemp, wood pulp, Microcrystalline Cellulose, cotton, timber, bamboo powder, the bagasse.

3. regenerated cellulose composite film according to claim 1, its spy is being, described halo polymer is a kind of in polyvinylidene difluoride (PVDF), the polyvinylidene dichloride or two kinds.

4. according to the preparation method of each described regenerated cellulose composite film of claim 1～3, may further comprise the steps:

1) Mierocrystalline cellulose is joined in the pre-treatment organic solvent, handle 0.5h～1h, through squeezing, obtain pretreated Mierocrystalline cellulose again at 155 ℃～165 ℃;

2) the pretreated Mierocrystalline cellulose that obtains in the step 1) is joined be dissolved with altogether in the machine solvent system, until producing gel, leave standstill 12h～30h again, obtain clear solution 70 ℃～100 ℃ stirrings;

3) to step 2) in add the halo polymer in the clear solution that obtains, at 70 ℃～100 ℃ blended under agitation 15min～40min, obtain mixing solutions;

4) mixing solutions that step 3) is obtained obtains regenerated cellulose composite film through film forming and film forming aftertreatment.

5. the preparation method of regenerated cellulose composite film according to claim 4 is characterized in that, in the step 1), described pre-treatment organic solvent is a kind of in N,N-DIMETHYLACETAMIDE, dimethyl formamide, the dimethyl sulfoxide (DMSO).

6. the preparation method of regenerated cellulose composite film according to claim 4 is characterized in that, in the step 1), and squeezing condition: pressurize 1min～5min under 3MPa～10MPa pressure and 165 ℃～210 ℃ conditions.

7. the preparation method of regenerated cellulose composite film according to claim 4; It is characterized in that; Step 2) in, the described machine solvent system that is dissolved with altogether is a kind of in lithium chloride and N,N-DIMETHYLACETAMIDE organic solvent system, lithium chloride and dimethyl formamide organic solvent system, lithium chloride and the dimethyl sulfoxide (DMSO) organic solvent system.

8. the preparation method of regenerated cellulose composite film according to claim 4 is characterized in that, in the step 3), described halo polymer adds with form of powder.

9. the preparation method of regenerated cellulose composite film according to claim 4; It is characterized in that; In the step 3), the high molecular powder of described halo stirs at 70 ℃～100 ℃ and adds in the clear solution after 10min～30min is dissolved in the machine that is dissolved with the altogether solvent system of getting in addition again.

10. the preparation method of regenerated cellulose composite film according to claim 4 is characterized in that, in the step 4); Described film forming and film forming aftertreatment comprise: 20 ℃～40 ℃ following film forming; Place 0.5h～3h after the film forming, in water, soak 10h～20h again, change water 2～8 times.

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