Infrared screening method of functionalized environmentally friendly wrapping oil, product and preparation method thereof

Abstract

This invention relates to the field of coated oil materials technology, and discloses an infrared screening method, product, and preparation method for functionalized and environmentally friendly coated oils. The method includes: selecting soybean oil, palm oil, or waste vegetable oil, pre-treating it, and then using infrared spectroscopy to analyze the fingerprint region (1500–900 cm⁻¹). ‑1 Oils containing carboxyl groups were selected as base oils. Acrylic acid was used as a monomer for graft modification, and the grafting rate was calculated using infrared spectroscopy. Modification was considered successful when the grafting rate was ≥15%. The modified oil was then compounded with a chitosan-silane coupling agent, and compatibility was verified using infrared spectroscopy. The optimal ratio was determined through oil film weight loss experiments. This invention utilizes infrared spectroscopy to achieve rapid oil screening and modification effect evaluation, improving screening efficiency by over 80% and accuracy by ≥95%. The prepared composite encapsulated oil exhibits a biodegradability rate ≥90%, a sustained-release period extended by over 30%, and an oil film weight loss rate ≤3% after 7 days, making it suitable for applications in medicine, agriculture, and food.

Description

Technical Field

[0001] This invention relates to the field of coating oil materials technology, and in particular to an infrared screening method, product and preparation method of a functionalized and environmentally friendly coating oil. Background Technology

[0002] Encapsulated oils are widely used in pharmaceutical sustained-release, agricultural controlled-release fertilizers, food preservation, and other fields. Their core function is to encapsulate active ingredients in an oil film, enabling slow release and extending the duration of action. Traditional encapsulated oils often use mineral oils such as paraffin or simple vegetable oils. These encapsulated oils have significant technical drawbacks: firstly, mineral oils such as paraffin have extremely poor biodegradability, and long-term use can lead to cumulative environmental pollution and disrupt the ecological balance; secondly, traditional vegetable oils have limited sustained-release performance and lack targeted functional modifications, making it difficult to meet the precise requirements for sustained-release period, stability, etc., in different scenarios.

[0003] To address the environmental concerns associated with traditional encapsulation oils, existing technologies attempt to replace paraffin with vegetable oils. However, ordinary vegetable oils have low levels of active groups, resulting in poor sustained-release performance when used directly as encapsulation oils, necessitating modification. However, existing oil screening and modification schemes suffer from problems such as low screening efficiency, inaccurate evaluation of modification effects, and significant reliance on haphazard formulation optimization: Firstly, oil source screening often relies on cumbersome chemical analysis methods, failing to quickly identify oils with modification potential; secondly, the verification of modification effects lacks intuitive and rapid characterization methods, making it difficult to establish a correlation between the degree of modification and sustained-release performance; thirdly, during the optimization of composite formulations, the compatibility assessment of functional additives and the oil film lags behind, leading to unreasonable formulation ratios and affecting the overall performance of the encapsulated oil.

[0004] Infrared spectroscopy offers advantages such as speed, accuracy, small sample volume, and non-destructive nature. Its fingerprint region (1500-900 cm⁻¹) -1 Infrared spectroscopy can effectively characterize the functional group structure of substances, providing an ideal technical means for oil screening, modification effect verification, and formulation compatibility analysis. Based on this, this invention proposes a method and formulation for rapidly screening functionalized oils using infrared spectroscopy and optimizing their sustained-release and environmentally friendly synergistic properties, aiming to solve the technical problems of poor biodegradability, low screening efficiency, and blind formulation optimization of traditional encapsulated oils. Summary of the Invention

[0005] The purpose of this invention is to address the problems of poor biodegradability, low screening efficiency, inaccurate modification evaluation, and blind formulation optimization of traditional encapsulated oils (such as paraffin wax). It provides an infrared screening method for functionalized and environmentally friendly encapsulated oils, the product itself, its preparation method, and the functionalized and environmentally friendly encapsulated oils obtained by this method. By rapidly screening functional oils using infrared spectroscopy, the correlation between the degree of modification and sustained-release performance is established, and the composite formulation is optimized to achieve a synergistic improvement in the sustained-release and environmentally friendly properties of the encapsulated oil.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides an infrared screening method for functionalized and environmentally friendly encapsulated oils, comprising the following steps: S1. Oil source pretreatment: Select at least one of soybean oil, palm oil, and waste vegetable oil as candidate oil sources, and obtain refined oil samples by drying and filtering to remove impurities. S2. Infrared fingerprint region analysis and target oil screening: Refined oil samples were tested using a Fourier transform infrared spectrometer, with a focus on analyzing the fingerprint region from 1500 to 900 cm⁻¹. -1 Oils containing carboxyl groups were selected as modified base oils. S3. Modification treatment: using acrylic acid as the grafting monomer and benzoyl peroxide as the initiator, the base oil is grafted and modified to obtain acrylic acid grafted modified oil. S4. Infrared verification of the modification effect: The newly added C=O peak at 1740 cm⁻¹ in the modified oil was detected by infrared spectroscopy. -1 Compared with the original CH peak at 2920 cm⁻¹ -1 The grafting rate is calculated using the absorbance ratio. Grafting rate = (A... 1740 / A 2920 ()×100%, when the grafting rate is ≥15%, it is judged as qualified modification; A 1740 1740 cm -1 The absorbance at the C=O peak, A 2920 2920 cm -1 Absorbance at the CH peak.

[0007] As a preferred technical solution, in step S1, the drying conditions are constant temperature drying at 60-80℃ for 2-4 hours, and the filtration accuracy is 0.22μm.

[0008] As a preferred technical solution, in step S2, the infrared spectral test parameters are: test range 4000~400cm. -1 4 cm resolution -1 The scan was performed 32 times; the screening criterion was the characteristic peak of carboxyl groups in the range of 1720–1700 cm⁻¹. -1 The signal-to-noise ratio is ≥3.

[0009] As a preferred technical solution, in step S3, the mass ratio of base oil:acrylic acid:initiator is 100:10-20:0.5-1.5, and the modification reaction conditions are nitrogen protection and reaction at 80-100℃ for 4-6 hours.

[0010] Secondly, the present invention provides a functionalized and environmentally friendly encapsulating oil, which is a composite of an acrylic graft-modified oil obtained by the method described in the first aspect and a functional additive, and consists of the following components by mass fraction: Acrylic acid grafted modified oil 95.0–99.5%; Functional additives: 0.5%–5.0%; The functional additive is a compound system of chitosan and silane coupling agent, wherein the mass ratio of chitosan to silane coupling agent is 1:2 to 3.

[0011] As a preferred technical solution, the mass fraction of the acrylic grafted modified oil is 97.0% to 98.0%, and the mass fraction of the functional additive is 2.0% to 3.0%.

[0012] Thirdly, the present invention also provides a method for preparing the functionalized environmentally friendly encapsulated oil as described in the second aspect, comprising the following steps: 1) Preparation of composite formulation: The acrylic grafted modified oil is heated to 50-60℃, and functional additives are added while stirring. The functional additives are added by pre-dissolving chitosan in 1% acetic acid solution and adding silane coupling agent directly. The stirring speed is 300-500 r / min, and then the temperature is raised to 60-80℃ and stirring is continued for 1-2 h to remove acetic acid, thus obtaining composite coated oil. 2) Infrared compatibility verification: The composite encapsulated oil was tested using infrared spectroscopy. If the characteristic amino peak of chitosan is 3350 cm⁻¹... -1 The characteristic peak of silane coupling agent Si-O-Si is 1100 cm⁻¹. -1 The offset is ≤5 cm -1 Furthermore, the peak shape is intact, indicating good compatibility; 3) Determining the optimal ratio: By adjusting the amount of functional additives added, composite coating oils with different ratios were prepared and oil film weight loss experiments were conducted. The ratio corresponding to the oil film weight loss rate of ≤3% over 7 days was determined as the ratio of functionalized environmentally friendly coating oil.

[0013] As a preferred technical solution, the oil film prepared in the oil film weight loss experiment is placed in an environment of 25°C and 60% relative humidity for 7 days, and the weight loss rate is calculated.

[0014] As a preferred technical solution, in step 3), the oil film is prepared by applying the composite coating oil to the surface of the substrate by dip coating or spray coating, controlling the dry film thickness to be 5-15 μm, and drying at a constant temperature of 45±2℃ for 40-60 min.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Significantly improved environmental performance The base oils selected in this invention are renewable vegetable oils or waste vegetable oils such as soybean oil and palm oil, with a biodegradability rate of ≥90% (compliant with GB / T 27857-2011 standard), which can replace traditional non-degradable substances such as paraffin and asphalt, effectively reducing environmental pollution; at the same time, the resource utilization of waste cooking oil realizes the transformation of waste into treasure and improves resource utilization rate.

[0016] 2. High screening efficiency and accuracy The infrared spectral fingerprint region is used to quickly identify oils containing active groups, reducing the screening time to less than 2 hours, which is more than 80% more efficient than traditional chemical analysis methods (which require 1 to 2 days). The screening accuracy is ≥95% by determining the signal-to-noise ratio of characteristic peaks, thus avoiding the waste of ineffective oil sources.

[0017] 3. Controllable and excellent sustained-release performance. By precisely controlling the grafting rate using infrared spectroscopy, the slow-release period of the encapsulated oil after grafting modification is extended by more than 30% (e.g., when encapsulating agricultural controlled-release fertilizers, the slow-release period is extended from 20 days to more than 26 days). At the same time, the optimization of the compound formula further improves the stability of the oil film, ensuring that the slow-release process is stable and controllable.

[0018] 4. The formula is optimized and scientifically sound. Infrared spectroscopy analysis was used to analyze the compatibility of functional additives with modified oils, avoiding the blind pursuit of formula optimization. The determined optimal ratio (additive addition amount 2.0%-3.0%) can significantly improve the integrity of the oil film, enabling the oil film to maintain good encapsulation performance in complex environments and further enhance the sustained-release effect.

[0019] 5. Wide range of applications The composite encapsulated oil prepared by this invention is suitable for multiple fields such as pharmaceutical sustained release, agricultural controlled release fertilizer, and food preservation, and has broad application prospects. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased.

[0021] Unless otherwise stated, all percentages in this invention represent mass fractions. Ratios are mass percentages, and concentrations are mass concentrations.

[0022] Unless otherwise specified, all materials, instruments, and equipment used below are conventional materials, instruments, and equipment or obtained through commercial channels; all testing methods used are existing methods unless otherwise specified.

[0023] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments.

[0024] Example 1: Oil Source Screening and Modification 1. Experimental Materials Soybean oil (food grade, purity ≥99%), purchased from (Xiangmanyuan Yihai Kerry Company). Palm oil (food grade, purity ≥99%), purchased from (Tianyijia Taizhou Co., Ltd.); Waste vegetable oil (collected from catering businesses, preliminarily filtered through a 100-mesh sieve to remove food residue). Acrylic acid (analytical grade, purity ≥99%), purchased from (Shanghai Aladdin Biochemical Technology). Benzoyl peroxide (analytical grade, purity ≥98%) was purchased from Haixiang Chemical Co., Ltd. Fourier transform infrared spectrometer (model: Nicolet iS50, Thermo Fisher Scientific, USA).

[0025] 2. Experimental Procedure (1) Oil source pretreatment Soybean oil, palm oil, and waste vegetable oil, three candidate oil sources, were dried in a 70℃ constant temperature oven for 3 hours to remove moisture. Then, they were filtered through a vacuum filter membrane with a pore size of 0.22μm to remove mechanical impurities, and the refined oil samples were numbered as Sample A (soybean oil), Sample B (palm oil), and Sample C (waste vegetable oil), respectively.

[0026] (2) Infrared screening Three refined oil samples were subjected to infrared spectroscopy using a Fourier transform infrared spectrometer. Test conditions: Test range 4000–400 cm⁻¹ -1 4 cm resolution -1 The scan was performed 32 times, with 32 scans for the background and 32 scans for the sample, using Attenuated Total Reflection (ATR) mode.

[0027] Analyze the fingerprint area (1500–900 cm) -1 Characteristic peaks: Sample A (soybean oil): at 1715 cm -1 A characteristic peak of carboxyl groups appears at this location, with a signal-to-noise ratio of 4.2; Sample B (palm oil): at 1712 cm -1 A characteristic peak of carboxyl groups appears at this location, with a signal-to-noise ratio of 3.8; Sample C (waste vegetable oil): at 1710 cm-1 A characteristic peak of carboxyl groups appears at [location], with a signal-to-noise ratio of 3.5.

[0028] The signal-to-noise ratio of the carboxyl characteristic peaks of the three oil samples was ≥3, which met the screening criteria, and all were identified as target base oils.

[0029] (3) Modification treatment Soybean oil was selected as a representative for graft modification. The components were added to a three-necked flask equipped with a stirrer, thermometer, and nitrogen inlet, according to a mass ratio of soybean oil:acrylic acid:benzoyl peroxide = 100:15:1. Nitrogen was introduced to replace the air for 10 minutes, and the temperature was raised to 90°C under nitrogen protection and maintained for 5 hours to obtain acrylic acid-grafted modified soybean oil (sample AM).

[0030] (4) Verification of modification effect Infrared spectroscopy was performed on the modified soybean oil (sample AM) under the same conditions as above.

[0031] Calculate the grafting rate: A 1740 (1740 cm) -1 (Absorbance at C=O peak) = 0.85 A 2920 (2920 cm) -1 (Absorbance at CH peak) = 1.20 Grafting rate G = (0.85 / 1.20) × 100% ≈ 70.8% The grafting rate of 70.8% ≥ 15% meets the qualified standard for modification.

[0032] (5) Validation of sustained-release performance Unmodified soybean oil (sample A) and modified soybean oil (sample AM) were used as coating oils to coat compound fertilizer granules (coating amount 0.5%). The slow-release period (time to reach 80% cumulative nitrogen release) was tested using the water immersion method. The results showed that the slow-release period of unmodified soybean oil coating was 21 days, while the slow-release period of modified soybean oil coating was 28 days, an extension of 33.3%.

[0033] Example 2: Optimization of Compound Formulation 1. Experimental Materials Acrylic acid grafted modified soybean oil prepared in Example 1 (sample AM); Chitosan (molecular weight 50,000-80,000, degree of deacetylation ≥90%) was purchased from Longfukang Biotechnology Co., Ltd. Silane coupling agent (KH-550, γ-aminopropyltriethoxysilane, analytical grade) was purchased from Haoshuo Chemical Co., Ltd. 1% acetic acid solution (homemade: glacial acetic acid to deionized water volume ratio 1:99); Electronic balance (accuracy 0.0001g, MA230 Mettler Toledo). Thermostatic stirrer (LC-OES-60SH, Kelipu Technology Co., Ltd.).

[0034] 2. Experimental Procedure (1) Compound of functional additives Weigh each component according to the mass ratio of chitosan to silane coupling agent = 1:2.5. Dissolve chitosan in 1% acetic acid solution to prepare a 5% chitosan-acetic acid solution, and stir until completely dissolved (about 30 minutes). Then add silane coupling agent KH-550 and continue stirring until homogeneous to obtain the compounded functional additive.

[0035] (2) Preparation of composite coating oils with different ratios Acrylic acid-grafted modified soybean oil was heated to 55°C, and functional additives with mass fractions of 0.5%, 1.0%, 2.0%, 3.0%, 4.0%, and 5.0% were added while stirring (400 r / min). After addition, stirring was continued for 1.5 h, and then the temperature was raised to 70°C and stirring was continued for 1.5 h to remove acetic acid, resulting in six composite coated oils with different ratios, labeled F-0.5, F-1.0, F-2.0, F-3.0, F-4.0, and F-5.0, respectively.

[0036] (3) Infrared compatibility analysis Infrared spectroscopy tests were performed on six different ratios of composite encapsulated oils, under the same conditions as in Example 1.

[0037] Analysis of key characteristic peaks: Chitosan amino characteristic peak (3350 cm⁻¹) -1 In all sample ratios, the peak shift was ≤3 cm. -1 ; Silane coupling agent Si-O-Si characteristic peak (1100 cm⁻¹) -1 In all sample ratios, the peak shift was ≤2 cm. -1 .

[0038] The characteristic peaks of all samples were intact, without any splitting or broadening, indicating that the functional additives and modified oils have good compatibility within the range of ≤5.0% addition.

[0039] (4) Oil film preparation method The oil film used for the weight loss rate test in this embodiment was prepared according to the following method: 1) Sample and substrate preparation Granular compound fertilizer samples were selected, with a particle size controlled between 2.0 and 4.0 mm. Fine powder and broken particles were removed by sieving to ensure uniform and intact granules. A smooth, clean glass plate (2.5 cm × 7.5 cm) was used as the substrate. Before use, the plate was wiped with anhydrous ethanol and dried with cold air to ensure it was free of dust and oil.

[0040] 2) Oil film coating method and thickness control The dip-coating method was used: the composite coating oil was heated to 50±2℃, and the glass slide was completely immersed in the oil sample for 10 seconds. It was then lifted vertically at a speed of 5 mm / s to drain excess oil. The dry film thickness of the oil was controlled to be 8-12 μm (by adjusting the dip-coating speed and the viscosity of the oil sample).

[0041] As an alternative, spray coating can also be used: nozzle diameter 0.5-0.8mm, spraying pressure 0.2-0.3MPa, spraying distance 15-20cm, and spraying 2-3 times at a uniform speed.

[0042] The amount of oil added is 0.3% to 0.8% of the compound fertilizer mass to ensure continuous film formation, no missed coating, and no agglomeration or clumping.

[0043] 3) Drying conditions Pre-drying: Lay the oil-coated substrate flat and let it stand for 15 minutes at room temperature of 23±2℃ and relative humidity of 50±5%.

[0044] Constant temperature drying: Place in a constant temperature drying oven at 45±2℃ and dry for 45 minutes.

[0045] Post-equilibrium: After removal, cool at room temperature for 30 minutes, gently turn the loose particles to prevent them from sticking together, and obtain a uniform and continuous oil film.

[0046] (5) Determining the optimal ratio Oil films with various proportions of composite oil were prepared according to the above oil film preparation method, and then a weight loss test was performed: the glass slides with oil films were placed in a constant temperature and humidity chamber (temperature 25℃, relative humidity 60%), and after 7 days, they were taken out, weighed, and the weight loss rate was calculated. Weight loss rate = (initial oil film mass - oil film mass after 7 days) / initial oil film mass × 100%.

[0047] The test results are shown in Table 1 below: Table 1. 7-day weight loss rate of oil film under different amounts of functional additives Table 1 shows that when the amount of adjuvant added is 2.0%–3.0%, the weight loss rate of the oil film after 7 days is ≤2.3%, and the film integrity is optimal. When the amount of adjuvant added exceeds 3.0%, the weight loss rate increases slightly, which may be related to the formation of microphase separation in the oil film due to excessive adjuvant. Therefore, the optimal formulation is determined to be: 97.0%–98.0% modified soybean oil and 2.0%–3.0% compounded functional adjuvant (chitosan:silane coupling agent = 1:2.5).

[0048] Example 3: Performance Comparison Experiment 1. Experimental Samples The optimal formulation of the composite oil (97.5% modified soybean oil, 2.5% compounded functional additives) determined in Example 2 of this invention group. Control group 1: Traditional paraffin-coated oil (58# fully refined paraffin, melting point 58-60℃); Control group 2: Unmodified soybean oil (sample A from Example 1).

[0049] 2. Testing Methods (1) Biodegradation rate test Referring to GB / T 27857-2011 "Determination of Anaerobic Biodegradable Gas Production of Organic Matter in Digested Sludge," the soil burial method was adopted. Encapsulated oil samples (three replicates for each sample) were mixed with standard soil (pH 7.0±0.5, moisture content 25%±2%, organic matter content ≥10%) at a mass ratio of 1:100 and placed in sealed culture bottles, incubated at a constant temperature of 25±1℃ in the dark for 28 days. After incubation, the remaining oil sample was extracted, dried, weighed, and the biodegradation rate was calculated. Biodegradation rate (%) = (Initial oil sample mass - Residual oil sample mass) / Initial oil sample mass × 100% (2) Sustained-release period test The water immersion method was used. Each oil-coated compound fertilizer granule was coated (coating amount 0.5%, dry film thickness 10±2 μm). 10 g of coated fertilizer was placed in a 250 mL Erlenmeyer flask, 200 mL of deionized water was added, and the flask was sealed and placed in a 25 ℃ constant-temperature shaker (120 r / min). Samples were taken periodically (days 1, 3, 5, 7, 10, 14, 21, 28, and 35) to determine the nitrogen concentration in the aqueous solution. The time when the cumulative nitrogen release rate reached 80% was defined as the slow-release period.

[0050] (3) Oil film weight loss rate test 7 days The oil film preparation method and weight loss rate test method of Example 2 were followed.

[0051] 3. Test Results The test results are shown in Table 2 below: Table 2 Performance Comparison of Different Encapsulated Oils 4. Results Analysis As shown in Table 2: (1) Biodegradability: The biodegradability of the composite-encapsulated oil of the present invention reaches 92.5%, which is significantly higher than the 15.3% of the traditional paraffin-encapsulated oil and better than the 88.6% of the unmodified soybean oil. This shows that the present invention improves other properties by modifying the vegetable oil while maintaining its excellent biodegradability.

[0052] (2) Slow-release performance: The slow-release period of the composite-encapsulated oil of the present invention is 29 days, which is 31.8% longer than that of traditional paraffin-encapsulated oil (22 days) and 38.1% longer than that of unmodified soybean oil (21 days). This shows that the present invention enhances the barrier performance of the oil film against moisture, thereby extending the slow-release period.

[0053] (3) Oil film stability: The 7-day weight loss rate of the composite-encapsulated oil of the present invention is only 2.2%, which is better than that of traditional paraffin-encapsulated oil (4.8%) and unmodified soybean oil (7.5%). This indicates that the chitosan-silane coupling agent combined with functional additives and acrylic acid grafted modified soybean oil synergistically enhances the structural stability of the oil film and reduces the loss rate of the oil film in humid and hot environments.

[0054] In summary, the composite encapsulated oil of this invention achieves a synergistic improvement in sustained-release performance, oil film stability, and environmental performance.

[0055] Example 4: Application of Controlled-Release Fertilizer in Agriculture The optimal formulation of this invention, a composite coating oil (97.5% modified soybean oil and 2.5% compound functional additives), is selected as the coating material for fertilizer granules, so that the nitrogen in the coating is slowly released into the soil according to the crop's growth needs, reducing nutrient loss.

[0056] A corn-soybean intercropping experiment was conducted in the field, with different fertilization treatments where controlled-release nitrogen accounted for 60% of the total nitrogen, and the effects of ordinary urea (PU) and no nitrogen fertilizer (CK) were compared.

[0057] The results showed that the nitrogen utilization rate of controlled-release nitrogen fertilizer treatment was as high as 50.14%–57.98%, far exceeding that of ordinary urea, reducing nitrogen loss into the environment and lowering the risk of non-point source pollution. The above describes and illustrates the basic principles, main features, and advantages of this invention. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made without departing from the spirit and scope of the invention, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An infrared screening method for functionalized and environmentally friendly encapsulated oils, characterized in that, Includes the following steps: S1. Oil source pretreatment: Select at least one of soybean oil, palm oil, and waste vegetable oil as candidate oil sources, and obtain refined oil samples by drying and filtering to remove impurities. S2. Infrared fingerprint region analysis and target oil screening: Refined oil samples were tested using a Fourier transform infrared spectrometer, with a focus on analyzing the fingerprint region from 1500 to 900 cm⁻¹. -1 Oils containing carboxyl groups were selected as modified base oils. S3. Modification treatment: using acrylic acid as the grafting monomer and benzoyl peroxide as the initiator, the base oil is grafted and modified to obtain acrylic acid grafted modified oil. S4. Infrared verification of the modification effect: The newly added C=O peak at 1740 cm⁻¹ in the modified oil was detected by infrared spectroscopy. -1 Compared with the original CH peak at 2920 cm⁻¹ -1 The grafting rate is calculated using the absorbance ratio. Grafting rate = (A... 1740 / A 2920 ()×100%, when the grafting rate is ≥15%, it is judged as qualified modification; A 1740 1740 cm -1 The absorbance at the C=O peak, A 2920 2920 cm -1 Absorbance at the CH peak.

2. The method according to claim 1, characterized in that: In step S1, the drying conditions are constant temperature drying at 60-80℃ for 2-4 hours, and the filtration accuracy is 0.22μm.

3. The method according to claim 1, characterized in that, In step S2, the infrared spectroscopy test parameters are: test range 4000–400 cm⁻¹. -1 4 cm resolution -1 The scan was performed 32 times; the screening criterion was the characteristic peak of carboxyl groups in the range of 1720–1700 cm⁻¹. -1 The signal-to-noise ratio is ≥3.

4. The method according to claim 1, characterized in that: In step S3, the mass ratio of base oil:acrylic acid:initiator is 100:10-20:0.5-1.5, and the modification reaction conditions are nitrogen protection and reaction at 80-100℃ for 4-6 hours.

5. A functionalized and environmentally friendly encapsulating oil, characterized in that, The acrylic grafted modified oil obtained by the method according to any one of claims 1-4 is compounded with functional additives and consists of the following components by mass fraction: Acrylic acid grafted modified oil 95.0–99.5%; Functional additives: 0.5%–5.0%; The functional additive is a compound system of chitosan and silane coupling agent, wherein the mass ratio of chitosan to silane coupling agent is 1:2 to 3.

6. The functionalized environmentally friendly encapsulated oil according to claim 5, characterized in that: The acrylic grafted modified oil has a mass fraction of 97.0% to 98.0%, and the functional additive has a mass fraction of 2.0% to 3.0%.

7. A method for preparing the functionalized environmentally friendly encapsulated oil as described in claim 5, characterized in that, Includes the following steps: 1) Preparation of composite formulation: The acrylic grafted modified oil is heated to 50-60°C, and functional additives are added while stirring. The functional additives are added by pre-dissolving chitosan in 1% acetic acid solution and adding silane coupling agent directly. The stirring speed is 300-500 r / min, and then the temperature is raised to 60-80°C and stirring is continued for 1-2 hours to remove acetic acid, thus obtaining composite coated oil. 2) Infrared compatibility verification: The composite encapsulated oil was tested using infrared spectroscopy. If the characteristic amino peak of chitosan is at 3350 cm⁻¹... -1 The characteristic peak of silane coupling agent Si-O-Si is 1100 cm⁻¹. -1 The offset is ≤5 cm -1 Furthermore, the peak shape is intact, indicating good compatibility; 3) Determining the optimal ratio: By adjusting the amount of functional additives added, composite coating oils with different ratios were prepared and oil film weight loss experiments were conducted. The ratio corresponding to the oil film weight loss rate of ≤3% over 7 days was determined as the ratio of functionalized environmentally friendly coating oil.

8. The preparation method according to claim 7, characterized in that: The oil film prepared in the oil film weight loss experiment was placed in an environment of 25°C and 60% relative humidity for 7 days, and the weight loss rate was calculated.

9. The preparation method according to claim 7, characterized in that: In step 3), the oil film is prepared by applying the composite coating oil to the surface of the substrate by dip coating or spray coating, controlling the dry film thickness to be 5-15 μm, and drying at a constant temperature of 45±2℃ for 40-60 min.

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