A functional modifier based on ferulic acid and its preparation and application

Abstract

The application provides a functional modifier based on ferulic acid and preparation and application thereof. The chain extender is prepared by ring-opening esterification reaction of ferulic acid and a polyepoxy compound. The ferulic acid is used as the modifier, is widely sourced and renewable, and solves the non-renewable defect of the petroleum-based hindered phenol. The chain extender simultaneously has a carboxyl group, a carbon-carbon double bond and a conjugated system, improves the antioxidant stability, utilizes the synergistic effect of the conjugated system and the free radical crosslinking capacity of the carbon-carbon double bond to further improve the antioxidant performance of the chain extender, and simultaneously utilizes the reactivity of the carboxyl group and the potential Diels-Alder reaction of the carbon-carbon double bond to realize secondary network construction of the chain extender in the use process, which is beneficial to further improvement of the mechanical property of the polyester material.

Description

Technical Field

[0001] This invention relates to the field of polymer material additives technology, specifically to a novel multifunctional compound obtained by chemically modifying a multifunctional epoxy compound with natural phenolic acid, its preparation method, and its application. Background Technology

[0002] Epoxy compounds are key additives for improving the processing properties of various polyesters such as polyethylene terephthalate (PET), polybutylene succinate (PBS), and polylactic acid (PLA), as well as enhancing their molecular weight, melt strength, toughness, and other mechanical properties. However, traditional epoxy compounds have a limited function; their main role is to "repair" molecular chains broken during polymer processing due to heat, moisture, or shear, but they cannot "inhibit" the thermo-oxidative aging process initiated by free radicals. To improve the long-term thermal stability of polymers, it is usually necessary to add small-molecule antioxidants such as hindered phenols.

[0003] However, the additional hindered phenol and other small molecule antioxidants have many drawbacks. On the one hand, traditional hindered phenol antioxidants are petroleum-based and depend on petroleum resources, which are non-renewable. On the other hand, the additional hindered phenol antioxidants have poor compatibility with polyester and are prone to migration, volatilization and precipitation during use, which greatly affects antioxidant stability.

[0004] To address the technical deficiencies in antioxidant stability, reports indicate that hindered phenols and other small-molecule antioxidants can be reacted with polyepoxides to prepare epoxy compounds with antioxidant properties. However, the functions of these reported antioxidant-modified epoxy compounds are still relatively simple, representing a simple superposition of different functions, and the petroleum dependence of hindered phenols and other small-molecule antioxidants remains unresolved.

[0005] Ferulic acid is a natural phenolic acid widely found in plant cell walls. Its molecular structure contains phenolic hydroxyl groups, carboxyl groups, and carbon-carbon double bonds, making it an ideal source of bio-based functional molecules. Replacing traditional petroleum-based hindered phenolic antioxidants with ferulic acid can solve the problem of petroleum dependence in antioxidants. Furthermore, the carboxyl groups and carbon-carbon double bonds can be utilized as reaction sites, endowing antioxidant-modified epoxy compounds with more functionalities.

[0006] Currently, there are no reports on synthesizing a novel single compound with both chain-extending and antioxidant functions by ring-opening reactions of ferulic acid with polyepoxides. Developing such products is of great significance for simplifying polymer processing formulations, improving the overall performance of materials, and utilizing renewable resources.

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a functional modifier based on ferulic acid, its preparation, and its application. The modified epoxy compound of this invention uses ferulic acid as a modifier, which is widely available and renewable, overcoming the non-renewable nature of petroleum-based hindered phenols. Furthermore, it simultaneously possesses carboxyl groups, carbon-carbon double bonds, and a conjugated system. While improving antioxidant stability, the synergistic effect of the free radical crosslinking ability of the conjugated system and carbon-carbon double bonds further enhances the antioxidant performance of the chain extender. Simultaneously, utilizing the reactivity of the carboxyl groups and the potential Diels-Alder reaction of the carbon-carbon double bonds, secondary network construction can be achieved during the use of the chain extender, which is beneficial for further improving the mechanical properties of polyester materials. Technical solution

[0008] A method for preparing a functional modifier based on ferulic acid involves a ring-opening esterification reaction between ferulic acid and a polyepoxide compound.

[0009] Preferably, in the aforementioned method for preparing the functional modifier based on ferulic acid, the polyepoxide compound is one of ADR-4468, ADR-4400, triglycidyl isocyanurate, tetraglycidyl diaminobenzene, 1,4-butanediol diglycidyl ether, polyethylene glycol diglycidyl ether, and epoxidized soybean oil.

[0010] Preferably, the aforementioned method for preparing the ferulic acid-based functional modifier includes the following steps: Step 1: Dissolve ferulic acid and polyepoxide in an organic solvent and stir until homogeneous; Step 2: Add a catalyst to the solution from Step 1 and heat the solution to induce a ring-opening esterification reaction between the carboxyl group of ferulic acid and the epoxy group of the chain extender. Step 3: Post-process the reaction product from Step 2 to obtain the functional modifier based on ferulic acid.

[0011] Preferably, in the aforementioned method for preparing the functional modifier based on ferulic acid, the molar ratio of ferulic acid to polyepoxide in step one is 1:0.005-1:0.05.

[0012] Preferably, in the aforementioned method for preparing the ferulic acid-based functional modifier, the organic solvent in step one is one of ethyl acetate, 1,4-dioxane, acetone, cyclohexanone, DMF, toluene, xylene, or tetrahydrofuran.

[0013] Preferably, in the aforementioned method for preparing the functional modifier based on ferulic acid, the catalyst in step two is one of an inorganic base, a tertiary amine catalyst, or an imidazole catalyst; the amount of catalyst used is 0.1-0.5% of the total mass of ferulic acid and the polyepoxide compound.

[0014] Preferably, in the aforementioned method for preparing the functional modifier based on ferulic acid, the reaction temperature in step two is 50-70°C, and the reaction time is 3-5 hours.

[0015] Preferably, in the aforementioned method for preparing the functional modifier based on ferulic acid, the post-treatment in step three involves cooling the reaction product, precipitating it in excess petroleum ether, filtering to obtain a crude product, dissolving the crude product in dichloromethane, washing with water to remove the catalyst and unreacted substances, and then drying, filtering, evaporating, and drying the organic phase.

[0016] A functional modifier based on ferulic acid was prepared by the aforementioned method.

[0017] Application of the aforementioned ferulic acid-based functional modifier in biodegradable plastics, medical polymers, coatings, flexible encapsulation materials, or adhesives. The beneficial effects of this invention are: 1. This invention uses natural ferulic acid as a modifier, which solves the problem of non-renewable petroleum-based hindered phenolic antioxidants. It has the advantages of being environmentally friendly and renewable, and is in line with the development concept of green technology.

[0018] 2. This invention grafts ferulic acid onto the side chain of a polyepoxide compound through a ring-opening reaction. Compared with the addition of an additional antioxidant, it has better compatibility with the polyester matrix, stronger dispersibility and binding force, and is less prone to migration, precipitation and volatilization, thus exhibiting good antioxidant stability.

[0019] 3. The chain extender of the present invention contains both carbon-carbon double bonds and a conjugated system. The synergistic effect of the two further enhances the antioxidant properties, thus having the advantage of better antioxidant performance.

[0020] 4. The carbon-carbon double bonds in the chain extender of the present invention can undergo a Diels-Alder reaction under heating conditions to achieve secondary network construction. Combined with the reactivity of the carboxyl group, the mechanical properties of the polyester material can be further improved.

[0021] 5. The preparation method of the present invention is a one-step solution reaction with mild conditions, simple operation and post-processing, inexpensive and readily available catalyst, and high yield, which has good prospects for industrial production.

[0022] Figure 1 The above is a hydrogen nuclear magnetic resonance (NMR) spectrum characterization of the modified chain extender prepared in Example 1 of this invention.

[0023] Figure 2 Infrared spectral characterization of the modified chain extender prepared in Example 1 of this invention.

[0024] Figure 3 The UV-Vis transmittance spectrum of the PBS composite film with the modified chain extender prepared in Example 1 of this invention is shown. Detailed Implementation

[0025] The present invention will be further described below with reference to embodiments, but these embodiments are not intended to limit the scope of the invention. Example 1

[0026] The preparation method using ferulic acid and ADR-4468 epoxy compound as raw materials is as follows: As shown in the reaction formula above, 0.2 mol ferulic acid A (194.18 g / mol) and 0.0027 mol ADR-4468 (7250 g / mol) epoxy compound B were dissolved in 1,4-dioxane. After complete dissolution, 0.3% of triethylamine (based on the total mass of ferulic acid and ADR-4468) was added as a catalyst. The mixed solution was transferred to a three-necked flask and reacted at 60 °C for 4 hours to obtain a milky white mixed product.

[0027] Post-processing: After the reaction was completed and the mixed reactants were cooled to room temperature, they were poured into a large amount of petroleum ether to obtain a white precipitate. The solid-liquid mixture was separated by vacuum filtration in a vacuum filtration flask, and the solid part was dissolved in an appropriate amount of dichloromethane. An appropriate amount of deionized water was added to the dichloromethane, and the mixture was separated by a separatory funnel. The oil layer was removed, and the separation was repeated three times. Anhydrous CaSO4 was added to dry the excess water, and then the mixture was filtered. Finally, the liquid part was separated in a rotary evaporator at 40°C to obtain a white solid product, which was then dried in a 70°C forced-air oven to obtain white product C.

[0028] The proton NMR spectra of product C and reactants A and B are attached. Figure 1 As shown, from Figure 1 As can be seen, ferulic acid (FA) exhibits multiple proton peaks in its 1H NMR spectrum. The proton peak signal at approximately δ=3.92 ppm corresponds to 5-H, 6-H, and 7-H; at approximately δ=6.52 ppm, it corresponds to 2-H; at approximately δ=6.92 ppm, it corresponds to 10-H; at approximately δ=7.16 ppm, it corresponds to 9-H; at approximately δ=7.34 ppm, it corresponds to 4-H; at approximately δ=7.64 ppm, it corresponds to 3-H; at δ=9.57 ppm, it corresponds to 8-OH; and at δ=12.25 ppm, it corresponds to 1-OH. The proton peaks of the structural unit of the ADR-4468 epoxy compound (EP) are mainly contained in the δ=0-4 ppm and δ=6-8 ppm regions. Figure 1The 1H NMR spectrum of product C in -c shows three proton peaks of FA at δ=3.83ppm, and multiple proton peaks of FA in the δ=6-8ppm range. The proton peaks of the 8-OH and 1-OH structural units at δ=9.57ppm and δ=120.25ppm are weakened or disappear, indicating the consumption of their respective groups. Simultaneously, multiple proton peaks of EP are also shown at δ=0-4ppm and δ=6-8ppm, indicating that FA reacted with EP, successfully synthesizing the target product C (FA-EP).

[0029] The infrared spectrum of FA-EP is as follows Figure 2 As shown in the figure, multiple characteristic peaks of EP are displayed, with the peak at 1730 cm⁻¹. -1 It is the stretching vibration of the C=O hydroxyl group in the ester, 910 cm⁻¹ -1 and 845cm -1 The characteristic peak for epoxy groups. FA-EP, compared to the two raw materials, possesses characteristic peaks shared by both EP and FA. At 3200 cm⁻¹ -1 -3600cm -1 The broad peaks within the range are due to the stretching vibrations of -OH and -COOH. Compared to the starting material FA, the characteristic peaks are significantly weakened, indicating that the -OH groups are consumed and participate in the synthesis reaction. At 1400 cm⁻¹ -1 -1600cm -1 Within the range, the skeletal vibrations of the benzene ring indicate that its aromatic ring skeleton was not destroyed during the reaction. Furthermore, its peak intensity is higher than EP but lower than FA, indirectly indicating the success of the synthesis. At 1317 cm⁻¹ -1 At this point, the stretching vibrations of CO and the bending vibrations within the OH plane are observed. Compared to the reactant FA, these vibrations are significantly weaker, indicating that the -COOH groups in FA also participate in the reaction. This corresponds to the results of the 1H NMR spectrum. Finally, at 1131 cm⁻¹... -1 The asymmetric stretching vibration of COC indicates that the core structure of FA (especially the aromatic ether bond) remains intact and undamaged during the reaction. Infrared spectroscopy provides strong evidence for the interaction between FA and EP, synthesizing the product FA-EP. Example 2

[0030] The preparation method using ferulic acid and ADR-4400 epoxy compound as raw materials is as follows: 0.2 mol ferulic acid and 0.01 mol ADR-4400 epoxy compound were dissolved in ethyl acetate. After complete dissolution, 0.1% potassium hydroxide (based on the total mass of ferulic acid and ADR-4400) was added as a catalyst. The mixed solution was transferred to a three-necked flask and reacted at 70°C for 3 hours to obtain a milky white mixed product.

[0031] Post-processing: After the reaction was complete and the mixed reactants were cooled to room temperature, they were poured into a large amount of petroleum ether to obtain a white precipitate. The solid-liquid mixture was separated by vacuum filtration in a vacuum filtration flask, and the solid portion was dissolved in an appropriate amount of dichloromethane. An appropriate amount of deionized water was added to the dichloromethane, and the mixture was separated by a separatory funnel. The oil layer was removed, and the separation was repeated three times. Anhydrous CaSO4 was added to dry the excess water, and then the mixture was filtered. Finally, the liquid portion was separated in a rotary evaporator at 40°C to obtain a white solid product, which was then dried in a 70°C forced-air oven to obtain a white product. Example 3

[0032] The preparation method using ferulic acid and epoxidized soybean oil as raw materials is as follows: 0.3 mol ferulic acid and 0.0015 mol epoxidized soybean oil were dissolved in DMF. After complete dissolution, 0.5% of triethylamine (based on the total mass of ferulic acid and polyepoxides) was added as a catalyst. The mixed solution was transferred to a three-necked flask and reacted at 50°C for 5 hours to obtain a milky white mixed product.

[0033] Post-processing: After the reaction was complete and the mixed reactants were cooled to room temperature, they were poured into a large amount of petroleum ether to obtain a white precipitate. The solid-liquid mixture was separated by vacuum filtration in a vacuum filtration flask, and the solid portion was dissolved in an appropriate amount of dichloromethane. An appropriate amount of deionized water was added to the dichloromethane, and the mixture was separated by a separatory funnel. The oil layer was removed, and the separation was repeated three times. Anhydrous CaSO4 was added to dry the excess water, and then the mixture was filtered. Finally, the liquid portion was separated in a rotary evaporator at 40°C to obtain a white solid product, which was then dried in a 70°C forced-air oven to obtain a white product. Example 4

[0034] Application of the product FA-EP from Example 1 in PBS.

[0035] Take an appropriate amount of PBS and dry it in an oven at 60°C for 8 hours. Weigh an appropriate amount of FA-EP and make its contents 0.2%, 0.4%, 0.6%, 0.8%, and 1.0% of the total amount of PBS. Mix them evenly and then melt-blend and extrude them in a twin-screw mixer. Finally, blow them into film in a blown film machine.

[0036] Comparative Example 1 In Example 4, the 0.4%-FA-EP / PBS sample contained 2.67g of ferulic acid and 1.33g of ADR-4468 per 1000g of PBS. For comparison, 8g of ferulic acid, 4g of ADR-4468, and 3000g of PBS were directly taken, dried at 60°C for 8 hours, mixed thoroughly, and then melt-blended and extruded in a twin-screw extruder, granulated, and finally blown into a film using a blown film extruder. The product was designated 0.4%-FA / EP / PBS. A comparative test was conducted with the sample from Example 4.

[0037] Their performance is compared as follows: I. Tensile property test: The composite film is prepared into specified strips according to GB / T 1040.3 2006 and subjected to tensile property test. The tensile speed is 50 mm / min. At least 5 samples are taken for each group of strips and the average value is calculated.

[0038] Table 1 Mechanical properties of composite films with different FA-EP addition contents As shown in Table 1, the addition of the chain extender FA-EP of this invention produced a significant synergistic modification effect on the mechanical properties of polybutylene succinate (PBS). Specifically, when the amount of FA-EP added was 0.4 wt%, the elongation at break of the PBS composite film reached 832.17% in the transverse direction and 900.25% in the longitudinal direction, which was more than twice that of pure PBS, indicating that the toughness of the material was greatly enhanced. At the same time, its tensile strength (46.24 MPa in the transverse direction and 49.14 MPa in the longitudinal direction) was basically restored to the level of pure PBS (around 50 MPa), maintaining good rigidity. The chain extension reaction between the epoxy groups retained in FA-EP and the end groups of PBS effectively increased the molecular weight and enhanced the interchain entanglement; while the grafted phenolic hydroxyl structure may have synergistically ensured the integrity of mechanical properties by inhibiting thermo-oxidative degradation during processing. After exceeding 0.4 wt%, the mechanical properties showed a downward trend, which is presumably due to local agglomeration or excessive cross-linking caused by excessive addition, which destroyed the continuity of the matrix. The results indicate that the invented FA-EP, as a novel multifunctional additive, can achieve a balanced improvement in the toughness and strength of PBS even at a low addition amount.

[0039] II. Measurement of ferulic acid migration; Refer to the measurement method in the National Food Safety Standard for Determination of Phthalate Esters and Migration in Food Contact Materials and Articles (GB 31604.30-2025). Take 1 dm³ of each sample. 2Weigh out 10cm x 10cm 0.4% FA-EP / PBS and 0.4% FA / EP / PBS films, place them in a round-bottom flask, add 100mL of 95% ethanol, reflux at 40°C, and soak for 3 hours. Remove the soaking solution and measure the concentration of ferulic acid by high-performance liquid chromatography (HPLC). Calculate the amount and migration rate of ferulic acid. The results are shown in the table below: Table 2. Migration resistance test of FA-EP As shown in Table 2, ferulic acid exhibits significantly enhanced anti-migration ability in PBS after conjugation with ADR-4468.

[0040] The UV-Vis transmittance test results for the PBS film are attached. Figure 3 As shown, compared with pure PBS film, the composite film with added FA-EP exhibits significantly reduced transmittance in the 200-400 nm ultraviolet band, and the reduction increases with increasing FA-EP content, indicating that FA-EP effectively imparts excellent ultraviolet shielding performance to PBS. Simultaneously, the composite film maintains high transparency in the 400-800 nm visible light region. This is mainly attributed to the ferulic acid conjugated structural units chemically grafted onto the FA-EP molecule, which efficiently absorb ultraviolet light, thus providing long-lasting photoprotection while maintaining film transparency, helping to delay material photoaging and protect the packaging contents.

[0041] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a functional modifier based on ferulic acid, characterized in that: It is prepared by ring-opening esterification reaction of ferulic acid and polyepoxide.

2. The preparation method of the functional modifier based on ferulic acid according to claim 1, characterized in that: The polyepoxide compound is one of ADR-4468, ADR-4400, triglycidyl isocyanurate, tetraglycidyl diaminobenzene, 1,4-butanediol diglycidyl ether, polyethylene glycol diglycidyl ether, and epoxidized soybean oil.

3. The method for preparing the functional modifier based on ferulic acid according to claim 1, characterized in that, Includes the following steps: Step 1: Dissolve ferulic acid and polyepoxide in an organic solvent and stir until homogeneous; Step 2: Add a catalyst to the solution from Step 1 and heat the solution to induce a ring-opening esterification reaction between the carboxyl group of ferulic acid and the epoxy group of the chain extender. Step 3: Post-process the reaction product from Step 2 to obtain the functional modifier based on ferulic acid.

4. The preparation method of the functional modifier based on ferulic acid according to claim 3, characterized in that: The molar ratio of ferulic acid to polyepoxide in step one is 1:0.005-1:0.

05.

5. The method for preparing the functional modifier based on ferulic acid according to claim 3, characterized in that: The organic solvent mentioned in step one is one of ethyl acetate, 1,4-dioxane, acetone, cyclohexanone, DMF, toluene, xylene, or tetrahydrofuran.

6. The method for preparing the functional modifier based on ferulic acid according to claim 3, characterized in that: The catalyst mentioned in step two is one of an inorganic base, a tertiary amine catalyst, or an imidazole catalyst; the amount of catalyst used is 0.1-0.5% of the total mass of ferulic acid and the polyepoxide compound.

7. The method for preparing the functional modifier based on ferulic acid according to claim 3, characterized in that: The reaction temperature in step two is 50-70℃, and the reaction time is 3-5 hours.

8. The method for preparing the functional modifier based on ferulic acid according to claim 3, characterized in that: The post-treatment described in step three involves cooling the reaction product, precipitating it in excess petroleum ether, filtering to obtain the crude product, dissolving the crude product in dichloromethane, washing with water to remove the catalyst and unreacted substances, and then drying, filtering, evaporating, and drying the organic phase.

9. A functional modifier based on ferulic acid, characterized in that: Prepared by the method according to any one of claims 1-8.

10. The application of a ferulic acid-based functional modifier according to claim 9 in biodegradable plastics, medical polymers, coatings, flexible packaging materials or adhesives.

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