A porous biodegradable gel filter, its preparation method and use

Abstract

In order to solve the problem that traditional filter material is difficult to degrade, the application discloses a kind of porous biodegradable gel filter material and its preparation method and application, the gel filter material includes chitosan, polyethylene glycol 4000 and polysorbate 80, and the mass ratio is 10-30:1-10:1-10.The gel filter material prepared by the application has good ventilation, adsorption performance, biodegradability and biocompatibility, realizes the double functions of "filtration+degradation", and can be used as a new green material for cigarette filter, and has potential application value in the production and manufacturing process of new type cigarettes.

Description

Technical Field

[0001] This invention relates to the field of materials, and more particularly to a porous biodegradable gel filter material, its preparation method, and its application. Background Technology

[0002] Cigarette filters, an indispensable part of cigarettes, were initially designed to prevent cigarette paper from sticking to the lips and tobacco from entering the mouth. With increasing health awareness, the industry has continuously improved filters to reduce the release of tar and harmful substances. However, the widely used cellulose acetate is difficult to degrade, placing a burden on the environment. Therefore, developing new green filter materials that are both effective in filtration and biodegradable has become a key focus of the industry. In recent years, naturally degradable materials such as polylactic acid have entered the research field, but most are only used as additives, and their performance remains limited. Therefore, there is an urgent need to invent a new type of tobacco gel filter material that is low-cost, non-toxic to humans, biodegradable, and has good interception performance of harmful components, thereby achieving the dual function of "filtration + degradation" to reduce the inhalation of harmful components in cigarette smoke, reduce the pollution and damage of cigarette waste, and protect the ecological environment. Summary of the Invention

[0003] To address the problem of traditional tobacco filter materials being difficult to degrade, this invention provides a porous, biodegradable gel filter material and its preparation method.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A porous, biodegradable gel filter material comprising chitosan, polyethylene glycol 4000, and polysorbate 80.

[0006] Furthermore, in the gel filter material, the mass ratio of chitosan, polyethylene glycol 4000, and polysorbate 80 is 10–30:1–10:1–10.

[0007] The present invention discloses a method for preparing a porous biodegradable gel filter material, comprising the following steps:

[0008] Step (1): Dissolve chitosan in glacial acetic acid and stir for 8-10 hours. After filtration, obtain a chitosan solution.

[0009] Step (2): Add polyethylene glycol 4000 and polysorbate 80 to the chitosan solution and stir evenly at 20-28℃ to obtain a mixed solution;

[0010] Step (3): After degassing the mixed solution by low-speed centrifugation, freeze for 8-9 hours and then freeze-dry to obtain a porous biodegradable gel filter material.

[0011] Further, in step (2), the mass concentration of chitosan in the mixed solution is 1.0% to 3.0% (w / v), the mass concentration of polyethylene glycol 4000 is 0.1% to 1.0% (w / v), and the mass concentration of polysorbate 80 is 0.1% to 1.0% (w / v).

[0012] In step (1), the stirring speed is 300-500 r / min; in step (2), the stirring time is 1-3 h; in step (3), the low-speed centrifugation speed is 1200-1500 r / min, the centrifugation time is 8-10 min; and the freezing temperature is -80℃.

[0013] The porous biodegradable gel filter material of this invention can be applied to cigarette filters.

[0014] Furthermore, the porous biodegradable gel filter material of the present invention, when applied to cigarette filters, can remove harmful components such as nicotine, phenol, and crotonaldehyde from mainstream cigarette smoke.

[0015] By adopting the above technical solution, the present invention has the following beneficial effects:

[0016] 1. By using a specific ratio of chitosan, polyethylene glycol 4000, and polysorbate 80, combined with freeze polymerization, a three-dimensional gel network with high porosity and uniform pore structure is constructed. Chitosan forms the framework structure, polyethylene glycol 4000 improves the material's flexibility and regulates the pore structure, and polysorbate 80 reduces surface tension and guides pore formation. As a result, the obtained material simultaneously possesses good mechanical stability, air permeability, and adsorption performance, thus improving the overall structural performance of the filter material.

[0017] 2. Through the synergistic effect of the above three components, this invention can simultaneously and efficiently intercept multiple harmful components in flue gas. Chitosan provides multi-site adsorption, polysorbate 80 improves wettability and promotes the capture of harmful substances, and polyethylene glycol 4000 optimizes the mass transfer process, thereby significantly improving filtration performance. Under the optimal ratio of chitosan 2.0%, polyethylene glycol 4000 0.4%, and polysorbate 80 0.15% (w / v), the reduction rates of nicotine, phenol, and crotonaldehyde reach 27.0%, 58.8%, and 50.0%, respectively, the hazard index is reduced by 45.0%, the filtration efficiency reaches 76%, and the cell survival rate of the material exceeds 96%, demonstrating good biocompatibility.

[0018] 3. Through the hydrophilic network structure constructed by chitosan and the synergistic effect of polyethylene glycol 4000, the material can achieve good degradation performance while filtering flue gas. In a simulated soil environment, the degradation rate reaches 69% after 180 days, which is significantly better than traditional cellulose acetate filter materials (about 10%). Thus, it achieves the dual function of "filtration + degradation", reduces environmental residues, and has good innovation and application value. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the sample appearance under the optimal parameter conditions of this invention.

[0020] Figure 2 The results are scanning electron microscopy characterizations of the internal aperture under the optimal parameter conditions of this invention.

[0021] Figure 3 This is a trend chart of biodegradation rate in this invention. Detailed Implementation

[0022] The technical solutions in the embodiments of this invention will be described in detail and completely below. The following content is only for illustrative purposes and explanation of the inventive concept. Any supplements, modifications, or substitutions made by those skilled in the art to the specific embodiments described herein without creative effort shall fall within the protection scope of this invention.

[0023] In this embodiment of the invention, the evaluation of the adsorption of harmful components in the mainstream cigarette smoke using a porous biodegradable gel filter material was carried out by smoking cigarettes under the standard conditions specified in YC / T 29-1996191 using a self-made smoking device. The total particulate matter (TPM) in the mainstream cigarette smoke was captured by a Cambridge filter and then calculated and evaluated.

[0024] The scanning electron microscope (SEM) was performed using a Sigma 300 field emission scanning electron microscope from Zeiss GmbH, Germany. Before testing, the samples were sputtered with gold and accelerated at a voltage of 20 kV.

[0025] Example 1

[0026] The porous biodegradable gel filter material in this embodiment is prepared according to the following steps:

[0027] A certain mass of chitosan was weighed and dissolved in 2% (v / v) glacial acetic acid. After stirring overnight at 300 rpm, the undissolved chitosan was filtered through four layers of sterile gauze to remove the undissolved chitosan, thus obtaining a chitosan solution. Another certain mass of the chitosan solution was weighed, and polyethylene glycol 4000 and a certain mass of polysorbate 80 were added. The mixture was stirred at room temperature for 2 hours to ensure thorough mixing. The component ratios were: chitosan 1.0%–3.0% (w / v), polyethylene glycol 4000 0.1%–1.0% (w / v), and polysorbate 80 0.1%–1.0% (w / v). The mixture was degassed by centrifugation at 1500 rpm for 10 minutes and then frozen at -80°C for 9 hours.

[0028] The frozen sample is placed in a vacuum freeze dryer for freeze drying, which produces a porous, biodegradable gel filter material.

[0029] Following the above method, when the mass concentrations of chitosan, polyethylene glycol 4000, and polysorbate in the mixed solution are 2.0%, 0.4%, and 0.15%, the gel exhibits a slightly milky white appearance and good mechanical stability and air permeability. At this point, the porous gel filter material reaches its optimal quality, and therefore this is determined to be the best parameter combination for the porous gel filter material of this invention. Its appearance is shown in [the image / description]. Figure 1 .

[0030] Example 2

[0031] The scanning electron microscope characterization results of the porous biodegradable gel filter material obtained under the optimal parameter conditions in Example 1 are shown in the figure. Figure 2 .

[0032] like Figure 2 As shown, the material exhibits a continuous and uniform three-dimensional porous network structure with relatively uniform and interconnected pores, forming obvious open channels. The pore size is in the micrometer range, and the pore walls are intact without obvious collapse or fracture, indicating that the material has good structural stability and molding quality. This structure originates from the synergistic effect of the three components: chitosan constructs a continuous framework through molecular chain entanglement and hydrogen bonding; polyethylene glycol 4000 regulates interchain forces and improves pore wall flexibility, thereby preventing structural brittleness; and polysorbate 80 promotes the formation of a uniform porous structure by reducing the surface tension of the system and guiding phase separation during gelation. The above porous structure facilitates gas transport within the material and provides more adsorption sites, thus achieving good ventilation performance and pollutant capture capacity during flue gas filtration.

[0033] Example 3

[0034] The porous, biodegradable gel filter material obtained under the optimal parameters in Example 1 was evaluated for its filtration performance using a breakthrough test. The gel filter material was placed in the cigarette filter tip, with a standard Cambridge filter connected in series behind it to completely capture the remaining mainstream smoke that penetrated the filter material. After puffing, the weight gains (G2 and G1) of the gel filter material and the Cambridge filter were weighed separately, and the filtration efficiency was calculated using Formula 1. The tar content in the remaining smoke captured by the Cambridge filter was analyzed. Under the condition of a constant total smoke generation, the lower the nicotine content measured in the Cambridge filter, the better the adsorption and retention effect of the gel filter material.

[0035] Formula 1: Filter efficiency of the filter for flue gas:

[0036]

[0037] Preferably, the filter tip has a filtration efficiency of 76% for flue gas, and the tar content in the filter element is 2.4 mg. That is, the porous, biodegradable gel filter material has good filtration performance for flue gas.

[0038] The porous biodegradable gel filter material obtained under the optimal parameter conditions in Example 1 was analyzed for harmful components in cigarettes. Nicotine, phenol, and crotonaldehyde were used as indicators to calculate its hazard index. With conventional cigarette products as a control, the reduction in harmful components and hazard index of the experimental group samples was calculated.

[0039] Compared with the control group, the release of nicotine, phenol, and crotonaldehyde in the experimental samples of the porous biodegradable gel filter material decreased by approximately 27.0%, 58.8%, and 50.0%, respectively, and its hazard index decreased by approximately 45.0% compared with the control group. This indicates that the porous biodegradable gel filter material of this invention can effectively adsorb various harmful components in mainstream cigarette smoke. This filter material can reduce the hazard index of cigarette smoke without significantly altering the basic physicochemical properties of cigarettes, thereby improving the overall harm reduction performance of cigarette products.

[0040] Example 4

[0041] The porous composite hydrogel material under the optimal parameter conditions in Example 1 was tested against the traditional cellulose acetate material. Natural humus soil was adjusted to a saturated moisture content of 50–60%, and the porous biodegradable hydrogel filter material was shallowly buried (2 cm deep) in a constant temperature chamber at 25°C or room temperature, with the traditional cellulose acetate material as a control. Direct exposure to sunlight or mechanical disturbance was avoided; each sample was individually labeled. Samples were removed at 0, 14, 28, 56, 90, and 180 days. After removal, the soil was gently brushed off, the surface was rinsed with deionized water, freeze-dried to constant weight, and weighed. The initial weight of the sample was recorded as m0, and the weight obtained from each sampling was recorded as mt. The mass loss rate (%) was calculated according to Formula 2, which is the biodegradation rate, and a trend graph was plotted.

[0042] Formula 2 Sample mass loss rate

[0043]

[0044] Depend on Figure 3 As can be seen, the porous composite hydrogel material prepared in Example 1 of the present invention exhibits significant biodegradability in a simulated soil environment. After 28 days of burial, its mass loss rate exceeded 60%, while that of the control material (traditional cellulose acetate) was less than 5%; by 180 days, the degradation rate of the material of the present invention reached approximately 69%, while that of the control material was only approximately 10%.

[0045] Compared with traditional cellulose acetate materials, the porous gel material of the present invention has a biodegradation rate that is at least 6 times higher, and most of the mass loss can be achieved within 180 days, demonstrating excellent biodegradability.

[0046] Example 5

[0047] According to ISO 10993-5 standard, the porous biodegradable gel filter material obtained in Example 1 was evaluated for cytotoxicity. The material was soaked in anhydrous ethanol for 5 min, sterilized by UV irradiation on both sides for 12 h each, and extracted in DMEM at 37°C for 24 h at a ratio of 0.2 g / mL to obtain the stock extract. The stock extract was then diluted to a 50% concentration with DMEM containing 10% fetal bovine serum for later use.

[0048] Using traditional cellulose acetate extract as a control, and lung epithelial cells CC16 as a model, 1×10⁶ cells were extracted per well. 4 Cells were seeded in 96-well plates and cultured for 24 hours until adherence. The culture medium was then replaced with the appropriate extract. Each group had 8 replicates. Cell viability was assessed at 12, 24, and 48 hours using the MTT assay: 100 μL of 0.5 mg / mL MTT solution was added to each well, and after 4 hours of culture, the solution was discarded. 150 μL of LDMSO was added to dissolve the crystals, and the mixture was shaken for 10 minutes. The absorbance was measured at 570 / 630 nm, and the relative cell viability was calculated.

[0049] The experimental results showed that at 12 h, the cell viability of the material group of the present invention was (98.2±3.1)%, which was not significantly different from that of the control group (95.4±2.8)%. However, the difference became apparent with prolonged treatment time. At 24 h, the cell viability of the material group of the present invention remained at (102.3±2.5)%, while that of the control group significantly decreased to (78.6±3.2)%. At 48 h, the cell viability of the material group of the present invention remained at a high level of (96.8±2.1)%, while that of the control group further decreased to (62.4±4.3)%. Statistical analysis showed that the differences in cell viability between the two groups at 24 h and 48 h were statistically significant (p<0.01).

[0050] The results showed that the material of this invention maintained a cell viability rate of over 95% during a 48-hour cell exposure experiment, demonstrating excellent biocompatibility. In contrast, traditional cellulose acetate materials exhibited significant cytotoxicity after 24 hours, with a marked decrease in cell viability. Therefore, the porous biodegradable gel material provided by this invention has lower cytotoxicity and meets safety requirements.

Claims

1. A porous, biodegradable gel filter material, characterized in that, The gel filter material comprises chitosan, polyethylene glycol 4000, and polysorbate 80.

2. The gel filter material according to claim 1, wherein the mass ratio of chitosan, polyethylene glycol 4000 and polysorbate 80 is 10-30:1-10:1-10.

3. The method for preparing gel filter material according to claim 1, characterized in that, The preparation method includes the following steps: (1) Dissolve the chitosan in glacial acetic acid and stir for 8-10 hours. After filtration, obtain a chitosan solution. (2) Add polyethylene glycol 4000 and polysorbate 80 to the chitosan solution and stir evenly at 20-28°C to obtain a mixed solution; (3) After degassing the mixed solution by low-speed centrifugation, freeze for 8-9 hours and then freeze-dry to obtain a porous biodegradable gel filter material.

4. The preparation method according to claim 3, characterized in that, In step (2), the mass concentration of chitosan in the mixed solution is 1.0% to 3.0% (w / v), the mass concentration of polyethylene glycol 4000 is 0.1% to 1.0% (w / v), and the mass concentration of polysorbate 80 is 0.1% to 1.0% (w / v).

5. The preparation method according to claim 3, characterized in that, The stirring speed in step (1) is 300-500 r / min; the stirring time in step (2) is 1-3 h; the low-speed centrifugation speed in step (3) is 1200-1500 r / min and the centrifugation time is 8-10 min; the freezing temperature is -80℃.

6. The porous biodegradable gel filter material according to claim 1, characterized in that, The gel filter material is used in cigarette filters.

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