Process method for improving barrier property and degradation time of biomass all-component film

Abstract

The invention relates to the technical field of film materials, and discloses a process method for improving barrier property and degradation time of a biomass all-component film, which comprises the following steps of: performing blade coating on a solution obtained by dissolving biomass all components to form a film, gelatinizing the film in air, and then transferring the film into a coagulating bath for regeneration to obtain the biomass all-component film. The obtained biomass all-component film is soaked in a mixed solution composed of epoxy grease and coagulating bath, and then the hydrophobic biomass all-component film with high barrier and low degradation rate is obtained through heating and drying. According to the method, an epoxy open ring in epoxy grease reacts with hydroxyl in a biomass component, hydrophilic hydroxyl is shielded, and a hydrophobic epoxy grease bionic skin layer is constructed on the surface of a membrane in situ; meanwhile, the epoxy grease is self-polymerized to fill pores in the film body, so that the compactness of the film is remarkably improved. The obtained film has excellent hydrophobicity and gas barrier property, is controllable in degradation time, and can be used in the fields of degradable packaging, agricultural mulching films and functional bio-based degradable materials.

Description

Technical Field

[0001] This invention relates to the field of thin film materials technology, and specifically to a process method for improving the barrier properties and degradation time of biomass full-component thin films. Background Technology

[0002] With the increasing demand for plastic products, the "white pollution" generated by traditional petroleum-based plastic waste has become a serious problem. Plastic films, due to their low cost, suitable mechanical properties and barrier properties, are widely used in food packaging, agricultural mulch films, and biomedical materials. However, the large-scale use of disposable plastic films has generated waste that is difficult to degrade, resulting in a heavy environmental burden. Therefore, renewable, abundant, and mechanically sound biomass such as cellulose, lignocellulose, and starch have become a research hotspot for the preparation of sustainable films. However, these films, due to the large number of hydroxyl groups in components such as cellulose or hemicellulose, suffer from problems such as poor hydrophobicity (Compos Part B Eng, 2024. 274: 111285), insufficient gas barrier properties (Chem Eng J, 2024. 495: 153500), and uncontrollable degradation rate (carbohyd polym, 2023. 322: 121312).

[0003] Currently, there are three main strategies to enhance the barrier properties of lignocellulose-based films: First, adding montmorillonite (such as CN120082108A), graphene oxide (CN113956541A), cellulose nanocrystals and other nanofillers (CN111574752B) to improve performance by forming tortuous gas diffusion paths (e.g., adding octadecylamine-grafted graphene oxide can reduce the water vapor diffusion rate by more than 20% (ACS omega, 2019. 4(1):509-517)). However, since the nanofillers do not have chemical interactions with biomass molecules, the barrier properties decrease significantly under high humidity. Second, reducing hydrophilic hydroxyl groups through chemical modifications such as acylation, esterification, and etherification (e.g., after grafting octadecyl chloride onto cellulose nanofibers, the water vapor permeability is reduced by 62.4% (Cellulose, 2019). 26(5),3271-3284), but toxic reagents and complex processes reduce biodegradability and sustainability; thirdly, commercial coating technologies (such as functionalized polylactic acid coatings that reduce paper water vapor transmission rate by 95% (ACS omega, 2025. 10(11), 11483-11497)) have problems such as complex preparation, increased thickness leading to decreased optical performance, and interface layer structure differences causing delamination during deformation. Summary of the Invention

[0004] This invention addresses the problems of existing technologies by providing a process method to improve the barrier properties and degradation time of biomass whole-component films. The specific scheme is as follows: A solution obtained by dissolving the biomass whole components is coated onto a film and then gelled in air. The film is then regenerated and washed in a coagulation bath to remove the solvent. The resulting biomass whole-component film is immersed in a mixed solution of epoxy grease and the coagulation bath for a period of time, followed by heating and drying to obtain a hydrophobic film with high barrier properties and a low degradation rate. This method utilizes the ring-opening of the epoxy in the epoxy grease to react with the hydroxyl groups in the biomass components, shielding the hydrophilic hydroxyl groups and constructing a hydrophobic epoxy grease biomimetic skin layer in situ on the film surface. Simultaneously, the epoxy grease self-polymerizes and fills the internal pores of the film, significantly improving its density. The resulting film exhibits excellent hydrophobicity and gas barrier properties. Since all components are derived from nature, the film has the characteristic of natural degradation.

[0005] The technical solution adopted in this invention is: A process for improving the barrier properties and degradation time of biomass full-component films includes the following steps: Step 1: Preparation of the complete biomass solution: The biomass complete component solution comprises: 5-50 wt% organic base, 0-90 wt% dimethyl sulfoxide, and 1-50 wt% biomass complete component; wherein the organic base is one or more of alkyl quaternary ammonium / phosphorus bases mixed in any proportion; Step 2: Preparation of biomass full-component thin films: The biomass whole component solution was coated into a film and then gelled in air for 1-6 hours to obtain a gel film; The gel membrane was regenerated by immersing it in a coagulation bath and then washed to remove the solvent, thus obtaining a biomass full-component membrane. Step 3: Preparation of hydrophobic films with high barrier properties and low degradation rate: The biomass whole-component film obtained in step 2 was immersed in a mixed solution of epoxy grease and coagulation bath for 0.1-6 h, and then dried by heating to obtain a hydrophobic biomass whole-component film with high barrier properties and low degradation rate. The epoxy grease content in the mixed solution accounts for 1 to 80 wt% of the total mass of the mixed solution, the heating temperature range is 20 to 200℃, and the heating time is 0.1 to 24 h.

[0006] Furthermore, the biomass components are composed of one or more of cellulose, hemicellulose, lignin, lignocellulose, starch, and chitosan, mixed in any proportion.

[0007] Furthermore, the coagulation bath is composed of one or more of ethyl acetate, acetone, ethanol, tetrahydrofuran, and dimethyl sulfoxide in any proportion.

[0008] Furthermore, the epoxy oil is composed of one or more of the following: epoxidized soybean oil, epoxidized castor oil, epoxidized cottonseed oil, epoxidized rice bran oil, and epoxidized sunflower oil, mixed in any proportion.

[0009] Furthermore, the mixed solution of the epoxy grease and the coagulation bath also includes a catalyst, which is one or more of Lewis acids, organic amines, titanates, zinc acetate, and zinc oxide mixed in any proportion.

[0010] Furthermore, the alkyl quaternary ammonium / phosphorus base is composed of one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, triethylbenzylammonium hydroxide, tetramethylphosphorus hydroxide, tetraethylphosphorus hydroxide, tetrapropylphosphorus hydroxide, and tetrabutylphosphorus hydroxide, mixed in any proportion.

[0011] The beneficial effects of this invention are: This invention utilizes the ring-opening reaction of epoxy resin in the epoxy grease with the hydroxyl groups in the biomass components to reduce the exposure of hydrophilic groups such as hydroxyl groups on the surface. Simultaneously, a hydrophobic biomimetic skin layer of epoxy grease is constructed in situ on the membrane surface. Furthermore, the epoxy grease self-polymerizes and fills the internal pores of the membrane, significantly improving its density. The resulting biomass-based full-component membrane exhibits excellent hydrophobicity and gas barrier properties. Since all components are derived from nature, the membrane is biodegradable. This method is simple and can be widely applied in packaging and agricultural films.

[0012] This invention uses a biomass full-component film as the structural strength framework. Through ring-opening polymerization of epoxy oil molecules and biomass components during heating, a biomass full-component film with a skin-like biomimetic structure is prepared. By adjusting the epoxy oil loading, the epidermal layer thickness is controlled within the range of 1 to 100 μm. Correspondingly, the water contact angle of the film is adjusted from 34.8° to 120°, and the water vapor transmission rate (WVTR) is increased from 2000 g / m². 2 Adjust to 50 g / m² over 24 hours. 2 • Oxygen permeability (OTR) increased from 10.00 cm³ / h over 24 hours. 3 / (m 2 Adjust the pressure (0.1 MPa) to 0.10 cm (24 h). 3 / (m 2 (24 h, 0.1 MPa), and the biodegradation time under soil burial was adjusted from 10 to 200 days. This provides a sustainable approach for developing high-performance packaging materials for a variety of applications. Attached Figure Description

[0013] Figure 1 The degradation performance of the untreated film and the films obtained in Examples 1-5 of this invention is compared.

[0014] Figure 2 This is a schematic diagram of the method flow of the present invention. Detailed Implementation

[0015] Specific embodiments of the present invention are given below to further illustrate the technical solution of the present invention. The performance details of the embodiments and comparative examples are shown in Table 1, and their general process steps are as follows: Figure 2 As shown: The solution obtained by dissolving the whole biomass components is coated into a film and then gelled in the air. The film is then regenerated and washed in a coagulation bath to remove the solvent. The resulting whole biomass film is then immersed in a mixed solution of epoxy grease and coagulation bath for a period of time, and then heated and dried to obtain a hydrophobic whole biomass film with high barrier properties and low degradation rate.

[0016] Example 1 A process for improving the barrier properties and degradation time of biomass full-component films includes the following steps: Step 1: Preparation of the complete biomass solution: The complete biomass solution comprises: 20 wt% tetrabutylammonium hydroxide, 50 wt% dimethyl sulfoxide, 10 wt% cellulose, and the remainder being water; Step 2: Preparation of biomass full-component thin films: The biomass whole component solution was coated into a film and then gelled in air for 3 hours to obtain a gel film; The gel membrane was regenerated by immersing it in a coagulation bath and then washed to remove the solvent, thus obtaining a biomass full-component membrane. Step 3: Preparation of hydrophobic films with high barrier properties and low degradation rate: The biomass whole-component film obtained in step 2 was immersed in a mixed solution of epoxy grease and coagulation bath for 1 hour, heated at 60 °C for 4 hours, and dried to obtain a hydrophobic biomass whole-component film with high barrier properties and low degradation rate.

[0017] The mixed solution includes: 95 parts of epoxidized soybean oil, 5 parts of ethyl acetate, and 0.1 parts of aluminum chloride (catalyst); the above components are mixed evenly at 25°C to obtain an epoxidized oil solution.

[0018] Example 2 A process for improving the barrier properties and degradation time of biomass full-component films includes the following steps: Step 1: Preparation of the complete biomass solution: The complete biomass solution comprises: 5 wt% tetraethyl phosphorus hydroxide, 60 wt% dimethyl sulfoxide, 8 wt% lignocellulose, and the remainder being water; Step 2: Preparation of biomass full-component thin films: The biomass whole component solution was coated into a film and then gelled in air for 3 hours to obtain a gel film; The gel membrane was regenerated by immersing it in a coagulation bath and then washed to remove the solvent, thus obtaining a biomass full-component membrane. Step 3: Preparation of hydrophobic films with high barrier properties and low degradation rate: The biomass full-component film obtained in step 2 was immersed in a mixed solution of epoxy grease and coagulation bath for 1 hour, heated at 60 °C for 4 hours, and dried to obtain the hydrophobic biomass full-component film with the desired high barrier and low degradation rate.

[0019] The mixed solution includes: 10 parts of epoxidized soybean oil, 90 parts of ethyl acetate, and 0.1 parts of aluminum chloride (catalyst); the above components are mixed evenly at 25°C to obtain an epoxidized oil solution.

[0020] Example 3 A process for improving the barrier properties and degradation time of biomass full-component films includes the following steps: Step 1: Preparation of the complete biomass solution: The complete biomass solution comprises: 50 wt% tetrapropylammonium hydroxide, 20 wt% dimethyl sulfoxide, 2 wt% hemicellulose, and the balance being water; Step 2: Preparation of biomass full-component thin films: The biomass whole component solution was coated into a film and then gelled in air for 6 hours to obtain a gel film; The gel membrane was regenerated by immersing it in a coagulation bath and then washed to remove the solvent, thus obtaining a biomass full-component membrane. Step 3: Preparation of hydrophobic films with high barrier properties and low degradation rate: The biomass whole-component film obtained in step 2 was immersed in a mixed solution of epoxy grease and coagulation bath for 1 hour, heated at 200 °C for 0.1 hours, and dried to obtain a hydrophobic biomass whole-component film with high barrier properties and low degradation rate.

[0021] The mixed solution includes: 20 parts of epoxidized soybean oil, 80 parts of ethyl acetate, and 0.1 parts of aluminum chloride (catalyst); the above components are mixed evenly at 25°C to obtain an epoxidized oil solution.

[0022] Example 4 A process for improving the barrier properties and degradation time of biomass full-component films includes the following steps: Step 1: Preparation of the complete biomass solution: The complete biomass solution comprises: 20 wt% tetrapropylphosphine hydroxide, 50 wt% dimethyl sulfoxide, 10 wt% cellulose, and the remainder being water; Step 2: Preparation of biomass full-component thin films: The biomass whole component solution was coated into a film and then gelled in air for 3 hours to obtain a gel film; The gel membrane was regenerated by immersing it in a coagulation bath and then washed to remove the solvent, thus obtaining a biomass full-component membrane. Step 3: Preparation of hydrophobic films with high barrier properties and low degradation rate: The biomass whole-component membrane obtained in step 2 was immersed in a mixed solution of epoxy grease and coagulation bath for 0.1 h, heated at 60 ℃ for 4 hours, and dried to obtain a hydrophobic biomass whole-component membrane with high barrier properties and low degradation rate.

[0023] The mixed solution includes: 30 parts of epoxidized soybean oil, 70 parts of ethyl acetate, and 0.1 parts of aluminum chloride (catalyst); the above components are mixed evenly at 25°C to obtain an epoxidized oil solution.

[0024] Example 5 A process for improving the barrier properties and degradation time of biomass full-component films includes the following steps: Step 1: Preparation of the complete biomass solution: The complete biomass solution comprises: 20 wt% tetrapropylphosphine hydroxide, 50 wt% dimethyl sulfoxide, 10 wt% cellulose, and the remainder being water; Step 2: Preparation of biomass full-component thin films: The biomass whole component solution was coated into a film and then gelled in air for 3 hours to obtain a gel film; The gel membrane was regenerated by immersing it in a coagulation bath and then washed to remove the solvent, thus obtaining a biomass full-component membrane. Step 3: Preparation of hydrophobic films with high barrier properties and low degradation rate: The biomass whole-component film obtained in step 2 was immersed in a mixed solution of epoxy grease and coagulation bath for 1 hour, heated at 60 °C for 4 hours, and dried to obtain a hydrophobic biomass whole-component film with high barrier properties and low degradation rate.

[0025] The mixed solution includes: 40 parts of epoxidized soybean oil, 60 parts of ethyl acetate, and 0.1 parts of aluminum chloride (catalyst); the above components are mixed evenly at 25°C to obtain an epoxidized oil solution.

[0026] Example 6 A process for improving the barrier properties and degradation time of biomass full-component films includes the following steps: Step 1: Preparation of the complete biomass solution: The complete biomass solution comprises: 20 wt% tetrapropylphosphine hydroxide, 50 wt% dimethyl sulfoxide, 10 wt% cellulose, and the remainder being water; Step 2: Preparation of biomass full-component thin films: The biomass whole component solution was coated into a film and then gelled in air for 3 hours to obtain a gel film; The gel membrane was regenerated by immersing it in a coagulation bath and then washed to remove the solvent, thus obtaining a biomass full-component membrane. Step 3: Preparation of hydrophobic films with high barrier properties and low degradation rate: The biomass full-component film obtained in step 2 was immersed in a mixed solution of epoxy grease and coagulation bath for 1 hour, heated at 20 °C for 24 hours, and dried to obtain a hydrophobic biomass full-component film with high barrier properties and low degradation rate.

[0027] The mixed solution includes: 20 parts of epoxidized castor oil, 60 parts of ethyl acetate, and 0.2 parts of triethylamine (catalyst); the above components are mixed evenly at 25°C to obtain an epoxy oil solution.

[0028] Example 7 A process for improving the barrier properties and degradation time of biomass full-component films includes the following steps: Step 1: Preparation of the complete biomass solution: The complete biomass solution comprises: 20 wt% tetrapropylphosphine hydroxide, 50 wt% dimethyl sulfoxide, 10 wt% cellulose, and the remainder being water; Step 2: Preparation of biomass full-component thin films: The biomass whole component solution was coated into a film and then gelled in air for 3 hours to obtain a gel film; The gel membrane was regenerated by immersing it in a coagulation bath and then washed to remove the solvent, thus obtaining a biomass full-component membrane. Step 3: Preparation of hydrophobic films with high barrier properties and low degradation rate: The biomass full-component film obtained in step 2 was immersed in a mixed solution of epoxy grease and coagulation bath for 1 hour, heated at 20 °C for 24 hours, and dried to obtain a hydrophobic biomass full-component film with high barrier properties and low degradation rate.

[0029] The mixed solution includes: 40 parts of epoxidized sunflower seed oil, 60 parts of ethyl acetate, and 0.5 parts of zinc acetate (catalyst); the above components are mixed evenly at 25°C to obtain an epoxy oil solution.

[0030] Comparative Example 1 The materials and process flow used were the same as in Example 1, except that the biomass full-component film was not soaked in epoxy grease solution. The resulting film had a water contact angle of 34.8° and a water vapor transmission rate of 1951.4 g / m³. 2 • Oxygen permeability over 24 hours: 9.0854 cm³ 3 / (m 2·24 h·0.1 MPa), the disintegration period is 10 days.

[0031] Comparative Example 2 The materials and process flow used were the same as in Example 2, except that coagulation bath regeneration and washing to remove the solvent from all components of the biomass were not employed. The resulting biomass membrane had a water contact angle of 68.8° and a water vapor transmission rate of 1021.7 g / m³. 2 • Oxygen permeability over 24 hours: 7.4721 cm³ 3 / (m 2 ·24 h·0.1 MPa), the disintegration period is 10 days.

[0032] Comparative Example 3 The materials and process flow used were the same as in Example 3, except that epoxidized soybean oil was not added. The resulting biomass full-component film had a water contact angle of 35.1° and a water vapor transmission rate of 1932.2 g / m³. 2 • Oxygen permeability over 24 hours: 9.0634 cm³ 3 / (m 2 ·24 h·0.1 MPa), the disintegration period is 10 days.

[0033] Comparison Example 4 The materials and process flow used were the same as in Example 4, except that aluminum chloride catalyst was not added. The resulting biomass full-component thin film had a water contact angle of 34.1° and a water vapor permeability of 1926.9 g / m³. 2 • Oxygen permeability over 24 hours: 9.0783 cm³ 3 / (m 2 ·24 h·0.1 MPa), the disintegration period is 10 days.

[0034] Table 1 shows the water contact angle, water vapor transmission rate (WVTR), oxygen transmission rate (OTR), and disintegration period of the films obtained in Examples 1-5 and the comparative examples of the present invention.

[0035] Table 1. Test results of Examples 1-5 and comparative examples.

[0036] As shown in Table 1, the water contact angle of the untreated film (Control Example 1) was 34.8°, while the water contact angle obtained in Example 5 was 114.6°, indicating a significant improvement in hydrophobicity. The water vapor transmission rate of the film obtained in Example 5 was 63.4 g / m³. 2 • After 24 hours, the untreated film (Control Example 1) had a g / m³ of 1951.42 g / m³. 2After 24 hours, the water vapor permeability was 3.25% of that of the untreated membrane, demonstrating a high water vapor barrier effect. The oxygen permeability of the membrane was 0.3216 cm⁻¹. 3 / (m 2 (24 h, 0.1 MPa), the untreated film (Control Example 1) had a thickness of 9.0854 cm⁻¹. 3 / (m 2 (24 h, 0.1 MPa), the oxygen permeability of the film obtained in Example 1 was 3.54% of that of the untreated film (Control Example 1), showing a high oxygen barrier effect.

[0037] Figure 1 The figures show the degradation results of the untreated film (Comparative Example 1) and the films obtained in Examples 1-5 of this invention. As can be seen from the figures, the film obtained by this invention exhibits controllable degradation within 180 days, demonstrating good degradability.

Claims

1. A process for improving the barrier properties and degradation time of biomass full-component films, characterized in that, Includes the following steps: Step 1: Preparation of the complete biomass solution: The complete biomass solution comprises: 5-50 wt% organic base, 0-90 wt% dimethyl sulfoxide, and 1-50 wt% complete biomass components; wherein the organic base is one or more of alkyl quaternary ammonium bases or quaternary phosphorus bases mixed in any proportion; Step 2: Preparation of biomass full-component thin films: The biomass whole component solution was coated into a film and then gelled in air for 1-6 hours to obtain a gel film; The gel membrane was regenerated by immersing it in a coagulation bath and then washed to remove the solvent, thus obtaining a biomass full-component membrane. Step 3: Preparation of hydrophobic films with high barrier properties and low degradation rate: The biomass full-component film obtained in step 2 is immersed in a mixed solution of epoxy grease and coagulation bath for 0.1-6 hours, and then dried by heating to obtain the hydrophobic biomass full-component film with the desired high barrier and low degradation rate. The epoxy grease content in the mixed solution accounts for 1 to 80 wt% of the total mass of the mixed solution, the heating temperature range is 20 to 200℃, and the heating time is 0.1 to 24 h.

2. The process method for improving the barrier properties and degradation time of biomass full-component films according to claim 1, characterized in that, The biomass composition consists of one or more of the following: cellulose, hemicellulose, lignin, lignocellulose, starch, and chitosan, mixed in any proportion.

3. The process method for improving the barrier properties and degradation time of biomass full-component films according to claim 1, characterized in that, The coagulation bath is composed of one or more of ethyl acetate, acetone, ethanol, tetrahydrofuran, and dimethyl sulfoxide in any proportion.

4. The process method for improving the barrier properties and degradation time of biomass full-component films according to claim 1, characterized in that, The epoxy oil is composed of one or more of the following: epoxidized soybean oil, epoxidized castor oil, epoxidized cottonseed oil, epoxidized rice bran oil, and epoxidized sunflower oil, mixed in any proportion.

5. The process method for improving the barrier properties and degradation time of biomass full-component films according to claim 1, characterized in that, The mixed solution of the epoxy grease and the coagulation bath also includes a catalyst, which is one or more of Lewis acids, organic amines, titanates, zinc acetate, and zinc oxide mixed in any proportion.

6. The process method for improving the barrier properties and degradation time of biomass full-component films according to claim 1, characterized in that, The alkyl quaternary ammonium / phosphorus base is composed of one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, triethylbenzylammonium hydroxide, tetramethylphosphorus hydroxide, tetraethylphosphorus hydroxide, tetrapropylphosphorus hydroxide, and tetrabutylphosphorus hydroxide, mixed in any proportion.

Images