Antibacterial, mildew-proof, super-hydrophobic and impermeable PLA degradable composite material and preparation method thereof

Abstract

The invention relates to the field of functional polylactic acid material preparation, in particular to an antibacterial, mildew-proof, super-hydrophobic and anti-permeation PLA degradable composite material and a preparation method thereof. The antibacterial, mildew-proof, super-hydrophobic and anti-permeation PLA degradable composite material is prepared from PLA resin, a plasticizer, cetyltrimethylammonium bromide (CTAB) and a functional filler through a solution method, the functional filler is copper-based Janus particles or copper ion doped type mesoporous silicon dioxide nanospheres; the addition amount of the functional filler is 0.1-5.0 wt%. According to the antibacterial, mildew-proof, super-hydrophobic and anti-permeation PLA degradable composite material, PLA composite master batches are prepared through a solution method, a PLA film is prepared through extrusion blow molding, solution casting, hot press molding, electrostatic spinning, 3D printing, extrusion coating and other methods, and the obtained PLA film has relatively good physical and chemical properties.

Description

Technical Field

[0001] The present application relates to the field of preparation of functional polylactic acid materials, and in particular to an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material and a preparation method thereof. Background Art

[0002] Polylactic acid (PLA), a biodegradable and renewable biopolymer primarily derived from biomass materials such as grain, has enormous commercial potential to replace traditional petroleum-based polymers. Its excellent biodegradability, biocompatibility, non-toxicity, and renewability have led to its widespread application in packaging, textiles, biomedicine, engineering plastics, and agriculture. However, the high regularity of PLA's molecular chains results in less-than-ideal thermal and mechanical properties, as well as poor heat resistance, flame retardancy, flexibility, and biosafety, limiting its functional applications.

[0003] In view of the shortcomings exposed by pure polylactic acid materials themselves, the comprehensive properties of polylactic acid can be effectively improved by compounding organic or inorganic materials with polylactic acid. Polylactic acid is suitable for melt processing methods such as extrusion, injection molding, film drawing, and spinning. Existing melt processing methods usually involve mixing pure polylactic acid and organic or inorganic materials and then melt-extruding granulation, and the resulting polylactic acid masterbatch is made into industrial products through a secondary melt processing method. However, the heat resistance of polylactic acid deviates, and the secondary melt processing method will cause thermal oxidative degradation to destroy the polylactic acid chain length, which will in turn affect the comprehensive properties of the polylactic acid composite material. To this end, the inventors provide a solution-based antibacterial, mildew-proof, and super-hydrophobic and anti-permeability PLA degradable composite material. Summary of the Invention

[0004] In order to solve the problem of decreased comprehensive performance of polylactic acid composite materials caused by conventional secondary melt processing technology, the present invention provides an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material and a preparation method thereof. Pure polylactic acid and organic or inorganic materials are mixed by a solution method to obtain polylactic acid masterbatch, which reduces the melt extrusion granulation process and can be made into industrial products through a single melt processing method, thereby improving the comprehensive performance of polylactic acid composite products.

[0005] The present invention provides an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA biodegradable composite material, which is achieved through the following technical solutions:

[0006] A PLA degradable composite material that is antibacterial, mildew-proof, super-hydrophobic and impermeable is prepared from PLA resin, a plasticizer, cetyltrimethylammonium bromide (CTAB), a functional filler and an organic solvent by a solution method; the functional filler is copper-based Janus particles or copper-ion-doped mesoporous silica nanospheres; and the functional filler is added in an amount of 0.1-5.0 wt%.

[0007] The antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material of the present invention is prepared by a solution method to obtain a PLA composite masterbatch, which can be prepared into a PLA film by methods such as extrusion blow molding, solution casting, hot pressing, electrospinning, 3D printing, and extrusion coating. The antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite film can also be directly prepared by a solution method. The obtained PLA film has relatively good physical and chemical properties.

[0008] Preferably, the copper-based Janus particles are made of nano copper powder, hydrochloric acid, sodium hydroxide, cetyltrimethylammonium bromide (CTAB) and ethyl orthosilicate (TEOS).

[0009] Preferably, the preparation method of the copper-based Janus particles is as follows:

[0010] Step 1: ultrasonically disperse 0.5-1 parts by mass of nano-copper powder in 100-200 parts by mass of pure water at 50-70°C, adjust the pH to 3.4-3.6 with 1-2 mol / L hydrochloric acid aqueous solution, mix and stir under ultrasonic dispersion, and etch for 20-40 minutes;

[0011] Step 2: Subsequently, ultrasonic dispersion is replaced with magnetic stirring, and under magnetic stirring, 0.1-1 mol / L NaOH aqueous solution is added to adjust the pH value of the solution to neutral, and 0.8-1.0 parts by mass of hexadecyltrimethylammonium bromide solution is added to neutralize the solution and stop etching;

[0012] Step 3: Add 0.8-2.4 parts by mass of ethyl orthosilicate (TEOS), raise the temperature to 75-85° C., magnetically stir for 2-4 hours, then centrifuge, wash, and dry to obtain copper-based Janus particles.

[0013] Further preferably, the preparation method of the copper-based Janus particles is as follows:

[0014] Step 1: Ultrasonic dispersion of 1 part by mass of nano-copper powder in 200 parts by mass of pure water at 60±0.5°C, adjusting the pH value to 3.5 with 1 mol / L hydrochloric acid aqueous solution, and etching for 30 minutes under ultrasonic dispersion and mixing;

[0015] Step 2: Subsequently, ultrasonic dispersion is replaced with magnetic stirring, and a 1 mol / L NaOH aqueous solution is added under magnetic stirring at 200-400 r / min to adjust the pH value of the solution to neutral. At the same time, 1.3-1.4 parts by mass of hexadecyltrimethylammonium bromide solution is added to neutralize the solution and stop etching;

[0016] Step 3: Add 1 part by mass of ethyl orthosilicate (TEOS), raise the temperature to 80±0.5° C., stir magnetically at 200-400 rpm for 2-4 hours, then centrifuge, wash, and dry to obtain copper-based Janus particles.

[0017] By adopting the above technical solution,.

[0018] Preferably, the organic solution is a mixed solvent formed by n-butanol and dichloromethane or a mixed solvent formed by n-butanol and chloroform.

[0019] Preferably, the plasticizer is at least one of ethylene glycol, glycerol, propylene glycol, butylene glycol, polyethylene glycol, dioctyl phthalate, tributyl citrate, triphenyl phosphite, dibutyl sebacate, epoxy soybean oil, epoxy soybean oil acrylate, and acetylated mono- and diglycerol fatty acid esters.

[0020] The present invention provides a method for preparing an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA biodegradable composite material, which is achieved through the following technical solutions:

[0021] A method for preparing an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material comprises the following steps:

[0022] S1. Preparation of functional fillers;

[0023] S2. The accurately measured PLA resin, plasticizer, cetyltrimethylammonium bromide CTAB, and functional filler were added to the organic solvent and stirred at room temperature for 2-4 hours to obtain a mixture;

[0024] S3. The obtained mixed solution is subjected to reduced pressure distillation to remove the organic solvent and then crushed to obtain the finished product of antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA biodegradable composite material.

[0025] Preferably, the total mass ratio of the organic solution to the PLA resin, the plasticizer, cetyltrimethylammonium bromide (CTAB), and the functional filler is (10-20):1.

[0026] The raw materials involved in the invention are easily available, the cost is low, the process is simple, and it is easy to realize industrial production.

[0027] The present invention provides a method for preparing copper-based Janus particles and a PLA composite material obtained by a phase separation method, wherein the copper-based Janus particles are uniformly dispersed and have antibacterial, mildew-proof, and super-hydrophobic properties. First, copper-based Janus particles are prepared as nano-antibacterial agents by a sol-gel method. To ensure that the copper-based Janus particles are uniformly mixed in a PLA substrate, the copper-based Janus particles, CTAB, a plasticizer, and PLA particles are added to a mixed solvent of n-butanol and dichloromethane or chloroform and stirred at room temperature for 2-4 hours. Finally, a PLA gel solution is obtained by a phase separation method, wherein the copper-based Janus particles are uniformly dispersed and have antibacterial, mildew-proof, and super-hydrophobic properties. The gel solution can be directly dried to form a film or granulate.

[0028] Preferably, the finished antibacterial, mildew-proof, super-hydrophobic and permeation-proof PLA degradable composite material is prepared by any one of extrusion blow molding, solution casting, hot pressing molding, electrospinning, 3D printing, and extrusion coating to prepare an antibacterial, mildew-proof and super-hydrophobic and permeation-proof PLA film, which can be used in the fields of medical non-woven fabrics to reduce the risk of bacterial infection for medical staff.

[0029] Preferably, a method for preparing an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material comprises the following steps:

[0030] S1. Preparation of functional fillers;

[0031] S2. The accurately measured PLA resin, plasticizer, cetyltrimethylammonium bromide CTAB, and functional filler were added to the organic solvent and stirred at room temperature for 2-4 hours to obtain a mixture;

[0032] S3. The obtained mixture is prepared into an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA film by any one of the following methods: blade coating, spin coating, and roller coating.

[0033] The present invention can directly prepare an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite film by a solution method. The obtained PLA film has relatively good physical and chemical properties compared with the melt-processed film.

[0034] In summary, this application has the following advantages:

[0035] 1. The present invention prepares polylactic acid masterbatch by a solution method, which reduces the melt extrusion granulation process and can be made into industrial products through a single melt processing method, thereby improving the comprehensive performance of polylactic acid composite products.

[0036] 1. The present invention can directly prepare an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite film by a solution method. The obtained PLA film has relatively good physical and chemical properties compared to melt-processed film.

[0037] 2. The raw materials involved in the present invention are easily available, the cost is low, the process is simple, and it is easy to realize industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The contact angle of water droplets dropped on white paper and PLA composited with copper-based Janus particles in different proportions changes within 1 minute.

[0039] Figure 2 This is a graph showing the time variation of the contact angle of water droplets on white paper and different composite surfaces. DETAILED DESCRIPTION

[0040] In order to further understand the creativity and technical advancement of the present invention, the preferred embodiments of the present invention are discussed in detail below in conjunction with examples and comparative examples.

[0041] Example: A PLA biodegradable composite material that is antibacterial, mildew-proof, superhydrophobic, and impermeable is prepared by a solution process from PLA resin, a plasticizer, cetyltrimethylammonium bromide (CTAB), a functional filler, and an organic solvent. The functional filler is added in an amount of 0.1-5.0 wt%.

[0042] The functional filler is copper-based Janus particles or copper ion-doped mesoporous silica nanospheres.

[0043] The organic solvent is a mixed solvent formed by n-butanol and dichloromethane or a mixed solvent formed by n-butanol and chloroform. Preferably, the organic solvent is a mixed solvent formed by n-butanol and dichloromethane.

[0044] The plasticizer is at least one of ethylene glycol, glycerol, propylene glycol, butylene glycol, polyethylene glycol, dioctyl phthalate, tributyl citrate, triphenyl phosphite, dibutyl sebacate, epoxy soybean oil, epoxy soybean oil acrylate, and acetylated mono- and diglycerol fatty acid esters.

[0045] Preferably, an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material comprises 20 parts of PLA resin, 3 parts of plasticizer, 1 part of cetyltrimethylammonium bromide (CTAB), 0.024-1.2 parts of functional filler, and 200-400 parts of organic solvent.

[0046] Copper-based Janus particles are made from nano-copper powder, hydrochloric acid, sodium hydroxide, cetyltrimethylammonium bromide (CTAB), and ethyl orthosilicate (TEOS). The preparation method of copper-based Janus particles is as follows:

[0047] Step 1: ultrasonically disperse 0.5-1 parts by mass of nano-copper powder in 100-200 parts by mass of pure water at 50-70°C, adjust the pH to 3.4-3.6 with 1-2 mol / L hydrochloric acid aqueous solution, mix and stir under ultrasonic dispersion, and etch for 20-40 minutes;

[0048] Step 2: Subsequently, ultrasonic dispersion is replaced with magnetic stirring, and under magnetic stirring, 0.1-1 mol / L NaOH aqueous solution is added to adjust the pH value of the solution to neutral, and 0.8-1.0 parts by mass of hexadecyltrimethylammonium bromide solution is added to neutralize the solution and stop etching;

[0049] Step 3: Add 0.8-2.4 parts by mass of ethyl orthosilicate (TEOS), raise the temperature to 75-85° C., magnetically stir for 2-4 hours, then centrifuge, wash, and dry to obtain copper-based Janus particles.

[0050] Preferably, the preparation method of copper-based Janus particles is as follows:

[0051] Step 1: Ultrasonic dispersion of 1 part by mass of nano-copper powder in 200 parts by mass of pure water at 60±0.5°C, adjusting the pH value to 3.5 with 1 mol / L hydrochloric acid aqueous solution, and etching for 30 minutes under ultrasonic dispersion and mixing;

[0052] Step 2: Subsequently, ultrasonic dispersion is replaced with magnetic stirring, and a 1 mol / L NaOH aqueous solution is added under magnetic stirring at 200-400 r / min to adjust the pH value of the solution to neutral. At the same time, 1.3-1.4 parts by mass of hexadecyltrimethylammonium bromide solution is added to neutralize the solution and stop etching;

[0053] Step 3: Add 1 part by mass of ethyl orthosilicate (TEOS), raise the temperature to 80±0.5° C., stir magnetically at 200-400 rpm for 2-4 hours, then centrifuge, wash, and dry to obtain copper-based Janus particles.

[0054] A method for preparing an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material is as follows:

[0055] S1. Preparation of functional fillers;

[0056] S2. The accurately measured PLA resin, plasticizer, cetyltrimethylammonium bromide CTAB, and functional filler were added to the organic solvent and stirred at room temperature for 2-4 hours to obtain a mixture; the total mass ratio of the organic solution to the PLA resin, plasticizer, cetyltrimethylammonium bromide CTAB and functional filler was (10-20): 1;

[0057] S3. The resulting mixed solution is subjected to reduced pressure distillation to remove the organic solvent and then crushed to obtain a finished antibacterial, mildew-proof, super-hydrophobic, and anti-permeability PLA degradable composite material. The finished antibacterial, mildew-proof, super-hydrophobic, and anti-permeability PLA degradable composite material is prepared by any one of extrusion blow molding, solution casting, hot pressing, electrospinning, 3D printing, and extrusion coating to produce an antibacterial, mildew-proof, super-hydrophobic, and anti-permeability PLA film. The film can be used in fields such as medical nonwovens to reduce the risk of bacterial infection for medical staff.

[0058] Another method for preparing an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA biodegradable composite material is as follows:

[0059] S1. Preparation of functional fillers;

[0060] S2. The accurately measured PLA resin, plasticizer, cetyltrimethylammonium bromide CTAB, and functional filler were added to the organic solvent and stirred at room temperature for 2-4 hours to obtain a mixture; the total mass ratio of the organic solution to the PLA resin, plasticizer, cetyltrimethylammonium bromide CTAB and functional filler was (10-20): 1;

[0061] S3. The obtained mixture is prepared into an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA film by any one of the following methods: blade coating, spin coating, and roller coating.

[0062] Preparation Example 1: The preparation method of copper-based Janus particles is as follows:

[0063] Step 1: Ultrasonic dispersion of 0.5 g of nano-copper powder (diameter: 150-200 nm, dark brown, Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.) in 100 g of 60±0.5°C pure water, with an ultrasonic dispersion power of 400 W and an ultrasonic frequency of 40 kHz. The pH value was adjusted to 3.5 with a 1 mol / L hydrochloric acid aqueous solution, and the mixture was mixed and stirred under ultrasonic dispersion for 30 minutes.

[0064] Step 2: After ultrasonic dispersion, magnetic stirring was switched to agitation. Under magnetic stirring at 240 r / min, a 1 mol / L aqueous solution of NaOH was added to adjust the pH value of the solution to neutral. At the same time, 1.334 g (1 mL) of hexadecyltrimethylammonium bromide solution (analytical grade AR, MacLean Chemical Reagent Company) was added to neutralize the solution and stop etching.

[0065] Step 3: Add 1.4 g of tetraethyl orthosilicate (TEOS) (purity 98%, MacLean Chemical Company), heat to 80±0.5° C., stir magnetically at 240 rpm for 4 hours, then centrifuge, wash, and dry to obtain copper-based Janus particles.

[0066] The difference between Preparation Example 2 and Preparation Example 1 is: Step 1 of the preparation method of copper-based Janus particles: ultrasonically disperse 0.5 g of nano-copper powder in 100 g of 60±0.5°C pure water, with an ultrasonic dispersion power of 400 W and an ultrasonic frequency of 40 kHz. The pH value is adjusted to 3.5 with a 1 mol / L hydrochloric acid aqueous solution, and mixed, stirred and etched for 20 minutes under ultrasonic dispersion.

[0067] The difference between Preparation Example 3 and Preparation Example 1 is: Step 1 of the preparation method of copper-based Janus particles: ultrasonically disperse 0.5 g of nano-copper powder in 100 g of 60±0.5°C pure water, with an ultrasonic dispersion power of 400 W and an ultrasonic frequency of 40 kHz. The pH value is adjusted to 3.5 with a 1 mol / L hydrochloric acid aqueous solution, and mixed, stirred and etched under ultrasonic dispersion for 40 minutes.

[0068] Preparation Example 4: The preparation method of copper ion doped mesoporous silica nano antibacterial agent MSN is as follows:

[0069] S1 were configured with a concentration of 160g / L of industrial-grade copper sulfate solution, a concentration of 13g / L of cetyltrimethylammonium bromide solution, a concentration of 27g / L of NaOH solution, a concentration of 20.0g / L of tetraethyl orthosilicate solution;

[0070] S2. To 100 mL of ultrapure water at a temperature of 60 ° C, 1 mL of 160 g / L industrial-grade copper sulfate solution and 1.0 mL of 13 g / L cetyltrimethylammonium bromide solution were added, mixed and stirred for half an hour, and then 0.25 mL of 27 g / L sodium hydroxide solution was added after thorough mixing. The temperature was raised to 60 ° C and stirring was continued for half an hour to generate a copper hydroxide seed solution;

[0071] S3. Under stirring conditions, 1.0 mL of tetraethyl orthosilicate at a concentration of 20.0 g / L was added to the reactor and the reaction was continued at 60 ° C for 4 hours. After the reaction, the reaction solution in the reactor was cooled and centrifuged to obtain a crude copper ion-doped mesoporous silica nano-antibacterial agent precipitated in the lower layer;

[0072] S4. The crude copper ion-doped mesoporous silica nano-antibacterial agent in S3 is put into a reactor filled with ethanol for washing. The process is carried out at 90°C and the ethanol is stirred and washed for 4 hours. After the process is completed, the centrifugation operation is continued and the filtrate is passed into other reactors for ethanol distillation and recovery. The block solid after centrifugation is then dried, crushed and sieved to obtain the copper ion-doped mesoporous silica nano-antibacterial agent MSN.

[0073] Example 1: An antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material consists of 20g of PLA resin (PLA NatureWorks, USA, particle size 5mm, 4032D powder), 3g of plasticizer-propylene glycol (Aladdin Chemical Reagent Company), 1g of hexadecyltrimethylammonium bromide CTAB, 0.024g of functional filler-copper-based Janus particles, 100mL of n-butanol (Aladdin Chemical Reagent Company), and 200mL of dichloromethane (Aladdin Chemical Reagent Company).

[0074] A method for preparing an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material is as follows:

[0075] S1. Preparation of copper-based Janus particles, see Preparation Example 1 for the preparation of copper-based Janus particles;

[0076] S2. 20 g of PLA resin, 3 g of plasticizer, 1 g of cetyltrimethylammonium bromide CTAB, and 0.024 g of copper-based Janus particles were added to 100 mL of n-butanol and 200 mL of dichloromethane, and the mixture was stirred at room temperature for 4 hours to obtain a mixture;

[0077] S3. The resulting mixed solution is subjected to reduced pressure distillation to remove n-butanol and dichloromethane, and then crushed to obtain a finished antibacterial, mildew-proof, and super-hydrophobic and anti-permeability PLA degradable composite material (masterbatch). The finished antibacterial, mildew-proof, and super-hydrophobic and anti-permeability PLA degradable composite material (masterbatch) is melt-extruded and cast into a film to prepare an antibacterial, mildew-proof, and super-hydrophobic and anti-permeability PLA degradable composite film.

[0078] The difference between Example 2 and Example 1 is that the copper-based Janus particles in Preparation Example 1 are replaced by the copper-based Janus particles in Preparation Example 2.

[0079] The difference between Example 3 and Example 1 is that the copper-based Janus particles in Preparation Example 1 are replaced by the copper-based Janus particles in Preparation Example 3.

[0080] The difference between Example 4 and Example 1 is that the copper-based Janus particles in Preparation Example 1 are replaced by the copper ion-doped mesoporous silica nano-antibacterial agent MSN in Preparation Example 4.

[0081] The difference between Example 5 and Example 1 is that an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material consists of 20g of PLA resin, 3g of plasticizer, 1g of hexadecyltrimethylammonium bromide CTAB, 0.048g of functional filler-copper-based Janus particles, 100mL of n-butanol, and 200mL of dichloromethane.

[0082] The difference between Example 6 and Example 1 is that an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material consists of 20g of PLA resin, 3g of plasticizer, 1g of hexadecyltrimethylammonium bromide CTAB, 0.16g of functional filler-copper-based Janus particles, 100mL of n-butanol, and 200mL of dichloromethane.

[0083] The difference between Example 7 and Example 1 is that an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material consists of 20g of PLA resin, 3g of plasticizer, 1g of hexadecyltrimethylammonium bromide CTAB, 0.32g of functional filler-copper-based Janus particles, 100mL of n-butanol, and 200mL of dichloromethane.

[0084] The difference between Example 8 and Example 1 is that an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material consists of 20g of PLA resin, 3g of plasticizer, 1g of hexadecyltrimethylammonium bromide CTAB, 0.64g of functional filler-copper-based Janus particles, 100mL of n-butanol, and 200mL of dichloromethane.

[0085] The difference between Example 9 and Example 1 is that an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material consists of 20g of PLA resin, 3g of plasticizer, 1g of hexadecyltrimethylammonium bromide CTAB, 1.20g of functional filler-copper-based Janus particles, 100mL of n-butanol, and 200mL of dichloromethane.

[0086] The difference between Example 10 and Example 1 is that: a method for preparing an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material comprises the following steps:

[0087] S1. Preparation of copper-based Janus particles, see Preparation Example 1 for the preparation of copper-based Janus particles;

[0088] S2. 20 g of PLA resin, 3 g of plasticizer, 1 g of cetyltrimethylammonium bromide CTAB, and 0.024 g of copper-based Janus particles were added to 100 mL of n-butanol and 200 mL of dichloromethane, and the mixture was stirred at room temperature for 4 hours to obtain a mixture;

[0089] S3. The obtained mixture is used to prepare an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA film by a doctor blade coating method.

[0090] The difference between Comparative Example 1 and Example 1 is that an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material consists of 20g of PLA resin, 3g of plasticizer, 1g of hexadecyltrimethylammonium bromide CTAB, 100mL of n-butanol and 200mL of dichloromethane.

[0091] The difference between Comparative Example 2 and Example 1 is that an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material consists of 20g of PLA resin, 3g of plasticizer, 1g of hexadecyltrimethylammonium bromide CTAB, 0.048g of nano copper powder, 100mL of n-butanol, and 200mL of dichloromethane.

[0092] The difference between Comparative Example 3 and Example 1 is that an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material consists of 20g of PLA resin, 3g of plasticizer, 1g of hexadecyltrimethylammonium bromide CTAB, 0.012g of functional filler-copper-based Janus particles, 100mL of n-butanol, and 200mL of dichloromethane.

[0093] Performance Testing: 1. Antibacterial Performance Test Method: The film's antibacterial rate was tested in accordance with QB / T 2591-2003, "Test Methods for Antibacterial Performance and Antibacterial Effect of Antibacterial Plastics." Aseptically, pour approximately 15 mL of culture medium into a sterile Petri dish. After the culture solidifies, use a sterile pipette to pipette 100 μL of bacterial suspension onto the surface of the culture medium. Spread the suspension evenly with a sterile applicator, and place the sterile sample in the Petri dish. Bacteria were incubated at 37°C for 24 hours, while molds were incubated at 28°C for 48 hours. Escherichia coli, Staphylococcus aureus, Candida albicans, and Penicillium were tested. Antibacterial efficacy was demonstrated when an inhibition value ≥ 2 or an inhibition rate ≥ 99%. 2. Antifungal Performance Test Method: The film was tested in accordance with GB / T 24128-2009, "Test Methods for Antifungal Performance of Plastics." 3. Mechanical properties test method: Determined in accordance with GB / T 1040.3-2006 "Determination of tensile properties of plastics - Part 3: Test conditions for film and sheeting." 4. Hydrostatic pressure test method: Determined in accordance with GB / T 19082-2023. A hydrostatic pressure ≥1500 mmH20 is marked as Pass, otherwise it is marked as NG.

[0094] Table 1: Test parameters of antibacterial and antifungal properties in Examples 1-10 and Comparative Examples 1-3

[0095]

[0096] Table 2: Test parameters of hydrophobicity in Examples 1-10 and Comparative Examples 1-3

[0097]

[0098]

[0099] Combining Examples 1-10 and Comparative Examples 1-3 with Table 1-2 reveals that a functional filler addition of 0.1 wt% or greater can impart excellent antibacterial and mildew-proof properties to PLA films. As the functional filler addition increases, the mechanical and hydrophobic properties of the PLA film improve. When the functional filler addition reaches 2 wt% or greater, the increase in mechanical and hydrophobic properties decreases. Therefore, a functional filler addition of 1.5-2.5% is ideal to ensure excellent antibacterial, mildew-proof, mechanical, and hydrophobic properties in the PLA film.

[0100] Combining Example 1 and Example 10 and Table 1-2, it can be seen that the PLA film prepared in Example 10 has relatively better mechanical properties, reduces melt extrusion processing, avoids the degradation and aging effects of thermal oxidation on the polylactic acid molecular chain, and can improve the mechanical properties and flexibility of the PLA film.

[0101] In summary, the antibacterial, mildew-resistant, and super-hydrophobic and permeation-resistant PLA degradable composite material of the present invention can be prepared by a solution process to produce a PLA composite masterbatch, which can then be used to prepare PLA films by methods such as extrusion blow molding, solution casting, hot pressing, electrospinning, 3D printing, and extrusion coating. The resulting PLA films have relatively good physical and chemical properties. Alternatively, the present invention can directly produce antibacterial, mildew-resistant, and super-hydrophobic and permeation-resistant PLA degradable composite films by a solution process. The resulting PLA films have relatively good physical and chemical properties compared to melt-processed films.

[0102] Combined with Examples 1-10 and Comparative Examples 1-3 and Tables 1-2 and Figure 1 It can be seen that water droplets were dropped on the surface of white paper and different proportions (0.0%-5.0%) of copper-based Janus particles composite PLA, and the contact angle changes were observed and recorded within 1 minute. The results are as follows Figure 1 As shown in the figure, the contact angle of a water droplet on paper after one minute is approximately 5°, while it is around 95° on the PLA surface. Increasing the filler content from 0.1% to 0.5% significantly changes the contact angle. A 1.0% filler content corresponds to a contact angle of 128°, while increasing the content to 5.0% increases the contact angle to approximately 158°. This is because a higher concentration of copper-based Janus particles makes the composite PLA surface more hydrophobic.

[0103] Combined with Examples 1-10 and Comparative Examples 1-3 and Tables 1-2 and Figure 2As can be seen, the change in the time the water droplets remain on the material surface further demonstrates that the copper-based Janus particles combined with PLA enhance its superhydrophobic properties. The water droplets on the white paper surface essentially lose their spherical shape within 10 minutes, and the contact angle on the pure PLA surface decreases by 7-8°. However, after increasing the contact angle to 70 minutes, the droplet's contact angle decreases by less than 50% after the PLA is filled with copper-based Janus particles, further demonstrating the strong hydrophobicity of the copper-based Janus particles.

[0104] It should be noted that this specific embodiment is merely an explanation of the technical solution of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A PLA degradable composite material that is antibacterial, mildew-proof, super-hydrophobic and anti-permeability, characterized by: The antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material is prepared from PLA resin, plasticizer, cetyltrimethylammonium bromide (CTAB), functional filler and organic solvent by a solution method; the functional filler is copper-based Janus particles or copper ion-doped mesoporous silica nanospheres; and the functional filler is added in an amount of 0.1-5.0 wt%.

2. The antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material according to claim 1, characterized in that: The copper-based Janus particles are made of nano copper powder, hydrochloric acid, sodium hydroxide, hexadecyltrimethylammonium bromide (CTAB) and ethyl orthosilicate (TEOS).

3. The antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material according to claim 2, characterized in that: The preparation method of the copper-based Janus particles is as follows: Step 1: ultrasonically disperse 0.5-1 parts by mass of nano-copper powder in 100-200 parts by mass of pure water at 50-70°C, adjust the pH to 3.4-3.6 with 1-2 mol / L hydrochloric acid aqueous solution, mix and stir under ultrasonic dispersion, and etch for 20-40 minutes; Step 2: Subsequently, ultrasonic dispersion is replaced with magnetic stirring, and under magnetic stirring, 0.1-1 mol / L NaOH aqueous solution is added to adjust the pH value of the solution to neutral, and 0.8-1.0 parts by mass of hexadecyltrimethylammonium bromide solution is added to neutralize the solution and stop etching; Step 3: Add 0.8-2.4 parts by mass of ethyl orthosilicate (TEOS), raise the temperature to 75-85° C., magnetically stir for 2-4 hours, then centrifuge, wash, and dry to obtain copper-based Janus particles.

4. The antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material according to claim 3, characterized in that: The preparation method of the copper-based Janus particles is as follows: Step 1: Ultrasonic dispersion of 1 part by mass of nano-copper powder in 200 parts by mass of pure water at 60±0.5°C, adjusting the pH value to 3.5 with 1 mol / L hydrochloric acid aqueous solution, and etching for 30 minutes under ultrasonic dispersion and mixing; Step 2: Subsequently, ultrasonic dispersion is replaced with magnetic stirring, and a 1 mol / L NaOH aqueous solution is added under magnetic stirring at 200-400 r / min to adjust the pH value of the solution to neutral. At the same time, 1.3-1.4 parts by mass of hexadecyltrimethylammonium bromide solution is added to neutralize the solution and stop etching; Step 3: Add 1 part by mass of ethyl orthosilicate (TEOS), raise the temperature to 80±0.5° C., stir magnetically at 200-400 rpm for 2-4 hours, then centrifuge, wash, and dry to obtain copper-based Janus particles.

5. The antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material according to claim 1, characterized in that: The organic solution is a mixed solvent formed by n-butanol and dichloromethane or a mixed solvent formed by n-butanol and chloroform.

6. The antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material according to claim 1, characterized in that: The plasticizer is at least one of ethylene glycol, glycerol, propylene glycol, butylene glycol, polyethylene glycol, dioctyl phthalate, tributyl citrate, triphenyl phosphite, dibutyl sebacate, epoxy soybean oil, epoxy soybean oil acrylate, and acetylated mono- and diglycerol fatty acid esters.

7. A method for preparing the antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Preparation of functional fillers; S2. The accurately measured PLA resin, plasticizer, cetyltrimethylammonium bromide CTAB, and functional filler were added to the organic solvent and stirred at room temperature for 2-4 hours to obtain a mixture; S3. The obtained mixed solution is subjected to reduced pressure distillation to remove the organic solvent and then crushed to obtain the finished product of antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA biodegradable composite material.

8. The method for preparing an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material according to claim 7, characterized in that: The total mass ratio of the organic solution to the PLA resin, the plasticizer, the hexadecyltrimethylammonium bromide (CTAB), and the functional filler is (10-20):

1.

9. The method for preparing an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material according to claim 7, characterized in that: The finished antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material is prepared by any one of extrusion blow molding, solution casting, hot pressing molding, electrospinning, 3D printing, and extrusion coating to form an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA film, which can be used in the fields of medical non-woven fabrics and the like to reduce the risk of bacterial infection for medical staff.

10. A method for preparing the antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA degradable composite material according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Preparation of functional fillers; S2. The accurately measured PLA resin, plasticizer, cetyltrimethylammonium bromide CTAB, and functional filler were added to the organic solvent and stirred at room temperature for 2-4 hours to obtain a mixture; S3. The obtained mixture is prepared into an antibacterial, mildew-proof, super-hydrophobic and anti-permeability PLA film by any one of the following methods: blade coating, spin coating, and roller coating.

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