A rapeseed oil-based high molecular copolymer, a synthesis method and application thereof

Abstract

This invention discloses a rapeseed oil-based polymer copolymer, its synthesis method, and its applications, belonging to the field of fine chemical technology. This invention synthesizes a rapeseed oil-benzyl methacrylate copolymer via solution polymerization under catalyst-free conditions. The synthesis method is simple, feasible, and low-cost, and the resulting chemical structure is clearly defined. By converting edible rapeseed oil into an industrially usable rapeseed oil derivative, the viscosity index and anti-wear properties of lubricating oil can be significantly improved. It can serve as a multifunctional lubricating oil additive, overcoming the disadvantages of traditional petroleum-based lubricating oil additives, such as non-biodegradability and limited functionality, thus filling the research gap in using rapeseed oil-based polymer copolymers as multifunctional lubricating oil additives.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical technology, specifically relating to polymer synthesis and lubricant additive technology, and more specifically to a rapeseed oil-based polymer copolymer, its synthesis method, and its application. Background Technology

[0002] Lubricating oil is a core auxiliary material in modern industry, and additives are key components that determine its performance. While traditional petroleum-based lubricating oil additives offer stable performance, most are difficult to biodegrade, and their leakage or disposal can cause long-term pollution to soil, water, and other ecological environments. Furthermore, some anti-wear additives containing sulfur, phosphorus, and chlorine are ecotoxic, limiting their use. With the advancement of "dual carbon" goals and increasingly stringent environmental regulations, the development of renewable and environmentally friendly lubricating oil additives has become an urgent industry need.

[0003] Vegetable oils, as renewable resources, possess advantages such as high biodegradability, high viscosity index, low volatility, and non-toxicity. The unsaturated double bonds and ester groups in their molecular structure can be chemically modified to optimize performance, making them ideal substitutes for petroleum-based additives. Rapeseed oil is my country's largest domestically produced vegetable oil, with an annual output of approximately 6.2 million tons. Its fatty acid composition features an oleic acid content as high as 56%–64%, exhibiting superior thermal oxidation stability compared to other vegetable oils such as soybean oil and flaxseed oil. Furthermore, it is widely available and has stable costs, demonstrating potential for large-scale application.

[0004] However, using rapeseed oil directly as a lubricant additive has significant drawbacks: the unsaturated double bonds are located in the middle of the fatty acid chain, resulting in large steric hindrance and low polymerization reactivity; simultaneously, it exhibits poor low-temperature fluidity and insufficient oxidative stability, limiting its industrial applications. Existing research largely focuses on the transesterification and esterification modifications of rapeseed oil for the preparation of biodiesel, plasticizers, and other products, while research on the free radical polymerization modification of its unsaturated double bonds and its application in the field of lubricant additives remains relatively scarce.

[0005] There are many types of lubricant additives, such as detergents, dispersants, viscosity index improvers, pour point depressants, and antioxidants. Traditional petroleum-based lubricant additives are difficult to biodegrade, and anti-wear agents containing sulfur, phosphorus, and chlorine can harm the environment or human health, and are therefore prohibited from use in food processing equipment, pharmaceutical production machinery, and other applications. Furthermore, competitive adsorption may occur when different types of additives are blended, making it difficult to achieve the desired overall performance. At the same time, different types of base oils (such as API Groups I, II, and IV) have significant differences in polarity and molecular structure, resulting in inconsistent compatibility of existing additives with different base oils, making it difficult to achieve efficient lubrication across all scenarios.

[0006] Therefore, developing a non-toxic, residue-free, biodegradable, and multifunctional rapeseed oil-based lubricant additive that is compatible with different types of base oils has become an urgent problem for those skilled in the art. Summary of the Invention

[0007] In view of this, the purpose of this invention is to address the problems existing in the prior art by providing a method for synthesizing rapeseed oil-based polymers. This method is simple in process, cost-controllable, and the synthesized copolymer has a clear chemical structure. It can be used as a multifunctional lubricating oil additive, which can improve the viscosity index and anti-wear properties of base oils. It is also non-toxic, residue-free, and has a high biodegradability, making it suitable for different types of base oils and sensitive scenarios such as the food industry.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for synthesizing a rapeseed oil-based polymer includes the following steps: (1) Add rapeseed oil and benzyl methacrylate into a polymerization reaction tube, seal it, connect it to the Schlenk apparatus, stir, evacuate and purge with nitrogen to obtain the reaction material; (2) Stir the reactants in step (1) and heat them at a constant temperature. Under nitrogen protection, inject a xylene solution of initiator azobisisobutyronitrile (AIBN) to react and obtain the rapeseed oil-based polymer copolymer, namely rapeseed oil-benzyl methacrylate copolymer. The reaction formula for the polymerization reaction of rapeseed oil and benzyl methacrylate is as follows:

[0010] in, m The number of repeating units in the benzyl methacrylate segment. n The number of repeating units in the rapeseed oil chain. m / n The range is approximately 0.56 to 36.

[0011] The rapeseed oil used in this invention is refined rapeseed oil, which conforms to the first-grade finished rapeseed oil of GB / T 1536-2021, with an acid value ≤1.5 mg KOH / g and a peroxide value ≤0.125 g / 100g.

[0012] The beneficial effects of the present invention are as follows: The method for synthesizing rapeseed oil-based polymers of the present invention involves polymerizing rapeseed oil and benzyl methacrylate using a solution polymerization method under catalyst-free conditions to obtain rapeseed oil-based polymers.

[0013] It is worth noting that rapeseed oil has advantages such as high viscosity index and good biodegradability, but it also has disadvantages such as poor oxidative stability and poor low-temperature fluidity. To fully utilize the advantages of vegetable oil while compensating for its shortcomings, it is necessary to modify and alter it. Existing technologies mainly involve chemical modification of rapeseed oil through transesterification, esterification, and epoxidation to prepare rapeseed oil-based polyols, polyurethanes, and fatliquoring agents. Simultaneously, rapeseed oil can also undergo thermal polymerization, cationic polymerization, or free radical polymerization with monomers such as acrylates to obtain various products ranging from elastomers to rigid polymers.

[0014] This invention effectively synthesizes rapeseed oil-based polymers under catalyst-free conditions, filling the research gap in rapeseed oil-based polymers as multifunctional lubricant additives and expanding the application scope of rapeseed oil-based copolymers in the industrial field.

[0015] Considering that rapeseed oil is an edible vegetable oil, it still possesses irreplaceable advantages as a polymerization raw material. On the one hand, its supply scale and structure provide ample room for non-edible utilization; on the other hand, the molecular structure of rapeseed oil endows it with excellent polymerization modification potential. Therefore, rapeseed oil-based polymers obtained by polymerizing rapeseed oil as a reaction raw material can serve as multifunctional lubricating oil additives with certain biodegradability. The synthesis method is simple, the cost is low, and the economic advantages are obvious, making it a promising candidate for application in the field of lubricating oil additives.

[0016] Furthermore, in step (1), the mass ratio of rapeseed oil to benzyl methacrylate is (1-9):(9-1). In step (2), the amount of azobisisobutyronitrile (AIBN) fed is 0.1%-2.0% of the total mass of rapeseed oil and benzyl methacrylate in step (1).

[0017] Furthermore, in step (2), the constant temperature heating temperature is 60-100℃, and the constant temperature heating time is 4-12h.

[0018] Furthermore, in step (2), the xylene solution of azobisisobutyronitrile contains azobisisobutyronitrile at a concentration of 0.001~0.02 g / mL.

[0019] Further, after the reaction in step (2) is completed, the polymerization reaction tube is placed in an ice-water bath to terminate the reaction. Then, the reactants are poured into industrial alcohol with a concentration of 95wt%, allowed to stand, filtered, purified, and dried to obtain the product.

[0020] The present invention also provides a rapeseed oil-based polymer copolymer synthesized by the synthesis method described above; Its structural formula is shown in equation (I):

[0021] Formula (I).

[0022] The present invention also provides the application of the synthetic rapeseed oil-based polymer as described above in lubricating oil additives.

[0023] Furthermore, the rapeseed oil-based polymer is added to the lubricating oil base oil at a mass fraction of 0.01%-0.10%, which increases the viscosity index of the lubricating oil by 22-65 and reduces the wear scar diameter of the lubricating oil by 0.098-0.356 mm.

[0024] The beneficial effects of this invention are as follows: Adding the rapeseed oil-based polymer to the base oil of lubricating oil can significantly improve the viscosity index and anti-wear performance of the lubricating oil, increasing the viscosity index by 22-65 and reducing the wear scar diameter by 0.098-0.356 mm. It can be used as a multifunctional lubricating oil additive, suitable for different types of base oils of API I, II, and IV.

[0025] When added at a concentration of 0.01% to 0.10% of the lubricating oil base oil by mass, the viscosity index of the lubricating oil base oil can be increased by 22-65. When added at a concentration of 0.03% of the lubricating oil base oil by mass, the viscosity index of API Group I base oil can be increased from 84 to 149, the viscosity index of API Group II base oil from 91 to 140, and the viscosity index of API Group IV base oil from 135 to 137. The wear scar diameter of the lubricating oil base oil can be reduced by 0.098-0.356 mm. This fills the research gap of rapeseed oil-based polymer copolymers as multifunctional lubricating oil additives and expands the application scope of rapeseed oil-based copolymers in the industrial field.

[0026] Furthermore, the synthetic rapeseed oil-based polymer copolymer is used in food industry lubrication, pharmaceutical industry lubrication, environmental protection industry lubrication, agricultural machinery lubrication, or industrial lubrication.

[0027] The beneficial effects of this invention are as follows: Rapeseed oil-based polymer copolymers, as multifunctional lubricant additives, are suitable for food industry-specific lubrication and can be applied to food processing equipment (such as biscuit production lines, edible oil pressing equipment, dairy product mixing machinery), food packaging machinery, food conveying equipment, etc., especially lubrication parts that come into direct or indirect contact with food. The advantages of this application are that the copolymers do not contain toxic elements such as sulfur, phosphorus, and chlorine, have a high biodegradability rate, meet the requirements of food-grade regulations such as GB 4853, and do not release toxic or harmful substances during lubrication, thus avoiding food contamination. Thermogravimetric analysis shows that the copolymers can operate stably in a wide temperature range of 25℃ to 437℃, making them suitable for different process scenarios such as high-temperature sterilization.

[0028] Rapeseed oil-based polymer copolymers can also be adapted for lubrication in the pharmaceutical industry, and can be used in pharmaceutical preparation production equipment (such as capsule filling machines, tablet compressors), pharmaceutical packaging machinery, and aseptic workshop conveying machinery. Their advantages include being non-toxic, odorless, and non-volatile, meeting the GMP certification requirements of the pharmaceutical industry, avoiding the impact of lubricating contaminants on drug purity, and exhibiting good biodegradability, thus aligning with the environmental compliance needs of the pharmaceutical industry. Performance tests show that under high-frequency operating conditions of pharmaceutical equipment, a stable lubricating film can be formed, exhibiting excellent anti-wear properties, reducing equipment maintenance frequency, and extending equipment lifespan.

[0029] Rapeseed oil-based polymer copolymers can also be adapted for environmentally friendly industrial lubrication and applied in sewage treatment equipment, waste incineration power generation machinery, and environmentally friendly engineering machinery (such as electric excavators and new energy sanitation vehicles). The advantages of this application are its high biodegradability, which will not cause soil or water pollution after leakage, and it meets the "zero pollution emission" requirements of environmental protection equipment. The raw material is renewable vegetable oil, which is in line with the "dual carbon" policy. Performance tests show that it has good viscosity-temperature stability and can maintain excellent lubrication performance under harsh working conditions such as high temperature.

[0030] Rapeseed oil-based polymer copolymers can also be adapted for agricultural machinery lubrication and applied to the engines, gearboxes, and transmission systems of agricultural machinery such as tractors, combine harvesters, and seeders. The advantages of this application are that the raw material comes from agricultural waste (rapeseed), realizing an "agriculture-industry" cycle, with good biodegradability, avoiding farmland soil pollution, and a cost that is more than 30% lower than that of synthetic ester additives. Performance tests show that it has strong anti-wear properties, can withstand the high-load and dusty working environment of agricultural machinery, and has a significantly improved viscosity index, making it suitable for the wide temperature fluctuation requirements of field operations.

[0031] Rapeseed oil-based polymer copolymers can also be adapted to general industrial lubrication and applied to general equipment such as ordinary machinery manufacturing, textile machinery, and small motors. The application advantages are multi-functional integration (viscosity enhancement + anti-wear), eliminating the need for compounding other additives, simplifying lubrication formulas, reducing usage costs, and having better environmental performance than traditional petroleum-based additives. Performance tests show that adding 0.01% to 0.10% copolymer can increase the viscosity index of base oil by 22-65 and reduce the wear scar diameter of base oil by 0.098-0.356 mm, achieving the required overall performance.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention uses rapeseed oil as raw material and carries out free radical solution polymerization reaction with benzyl methacrylate. The structure of the copolymer is characterized by infrared and nuclear magnetic resonance, proving that the rapeseed oil-benzyl methacrylate copolymer was successfully synthesized. 2. This invention is the first to carry out a free radical copolymerization reaction between rapeseed oil and benzyl methacrylate, which has a high biodegradability rate, does not contain toxic elements such as sulfur, phosphorus, and chlorine, and meets the requirements of food-grade and pharmaceutical-grade regulations, filling the gap in green additives for sensitive industries. 3. The rapeseed oil-based copolymer prepared by this invention has both the functions of improving viscosity index and anti-wear, without the need for compounding other additives, thus solving the problems of single function and compounding conflicts of traditional additives. The amount added is small (0.03% can achieve the best effect), the cost of use is low, and it is easy to carry out industrial-scale production. 4. The rapeseed oil-based copolymer prepared by this invention performs excellently in API Group I and II base oils, and still has a certain modification effect in API Group IV base oils, making it suitable for lubrication needs in multiple scenarios and covering a wide market. 5. The rapeseed oil-based copolymer prepared by this invention is suitable for multiple fields such as food, medicine, environmental protection, agriculture, and general industry, especially sensitive scenarios where traditional additives are limited, with a wide market coverage and great industrialization potential; 6. The method for synthesizing rapeseed oil-based polymer copolymers used in this invention is simple, cost-controllable, and avoids catalyst residue pollution. It has broad application prospects in the preparation of biodegradable oil additives and expands the application scope of rapeseed oil-based copolymers. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of unsaturated fatty acids in rapeseed oil.

[0035] Figure 2 The images are infrared spectra, where (a) is rapeseed oil; (b) is benzyl methacrylate; (c) is polybenzyl methacrylate; and (d) is rapeseed oil-benzyl methacrylate copolymer. Figure 3 The images are NMR spectra, where (a) is rapeseed oil; (b) is benzyl methacrylate; (c) is polybenzyl methacrylate; and (d) is rapeseed oil-benzyl methacrylate copolymer. Figure 4 This is a gel permeation chromatogram of rapeseed oil-benzyl methacrylate copolymer.

[0036] Figure 5 This is a thermogravimetric analysis (TGA) diagram of rapeseed oil-benzyl methacrylate copolymer. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] The rapeseed oil used in this invention is refined rapeseed oil, conforming to the first-grade finished rapeseed oil of GB / T 1536-2021, with an acid value ≤1.5 mg KOH / g and a peroxide value ≤0.125 g / 100g. The industrial alcohol has an ethanol concentration of 95wt%.

[0039] Example 1 The synthesis method of rapeseed oil-based polymers specifically includes the following steps: At room temperature, 1.20 g of rapeseed oil and 1.80 g of benzyl methacrylate were added to a polymerization tube, sealed, and connected to a Schlenk apparatus. The mixture was stirred (300 r / min), and the system vacuum was maintained at 90-100 kPa through continuous evacuation. Then, the nitrogen valve was slowly opened, and nitrogen was introduced at a flow rate of 120 mL / min until the system pressure returned to atmospheric pressure (101 kPa). This evacuation-nitrogen circulation cycle was repeated three times. During the final nitrogen purging, 0.015 g of azobisisobutyronitrile (0.5% of the total monomer mass) was dissolved in 3 mL of xylene and injected into the polymerization reaction tube under nitrogen protection. The polymerization reaction tube was placed in a 90°C constant-temperature heating device, and the reaction was allowed to proceed for 6 hours. After the reaction, the polymerization tube was placed in an ice-water bath to terminate the reaction. The resulting product was allowed to settle for 24 hours after being exposed to 50 mL of room-temperature industrial alcohol. h, filter under normal pressure, pour the precipitate onto qualitative filter paper with a pore size of 10-12μm, and after the solvent has drained naturally, transfer the filter paper and filter cake together into a vacuum drying oven at 40℃ and dry for 24 h to obtain rapeseed oil-benzyl methacrylate copolymer.

[0040] The reaction formula for the polymerization of rapeseed oil and benzyl methacrylate is as follows:

[0041] in, m= 67, n= 9.

[0042] The synthesized rapeseed oil-benzyl methacrylate copolymer was subjected to infrared spectroscopy, and the results are as follows: Figure 2 As shown.

[0043] Infrared analysis revealed that the =CH stretching vibration and -C=C stretching vibration of the conjugated unsaturated double bonds in rapeseed oil fatty acids occurred at wavenumber 3008 cm⁻¹. -1 and 1650cm -1 At this point, the stretching vibration absorption peaks of methyl (―CH3) and methylene (―CH2―) appear at wavenumber 2927 cm⁻¹. -1 and 2856cm -1 At this point, the characteristic peak of the stretching vibration of the ester carbonyl group (C=O) appears at wavenumber 1750 cm⁻¹. -1 The =CH stretching vibration peak of the benzyl methacrylate benzene ring appears at wavenumbers 3091-3034 cm⁻¹. -1 At this point, the skeletal stretching vibration peak of the benzene ring appears at wavenumber 1498 cm⁻¹. -1 and 1455 cm -1 If the polymer product is polybenzyl methacrylate, then 1637cm -1 The C=C doublet at that point will disappear. Meanwhile, compared to rapeseed oil and benzyl methacrylate, 3008 cm⁻¹... -1 =CH stretching vibration peak and 1650cm -1 The C=C stretching vibration peak was significantly weakened at 1637 cm⁻¹. -1 The weakening of the C=C stretching vibration peak indicates that the obtained polymer is a copolymer of rapeseed oil and benzyl methacrylate.

[0044] The synthesized rapeseed oil-benzyl methacrylate copolymer was subjected to... 1 H NMR characterization, results as follows Figure 5 As shown.

[0045] NMR analysis revealed that if the polymer product were polybenzyl methacrylate, no proton peaks would appear at chemical shifts of 5.59 and 6.16. However, due to... Figure 3 As can be seen, proton peaks of the triglyceride structure appeared at chemical shifts of 5.26 and 4.15–4.27; methylene peaks of the fatty acid structure appeared at chemical shifts of 1.26–1.60; terminal methyl peaks of the fatty acid structure appeared at chemical shifts of 0.90 and 0.74; characteristic peaks of benzene ring protons appeared at chemical shifts of 7.33–7.37; a proton peak on a tertiary carbon appeared at chemical shift of 2.32; and a methylene peak connected to the benzene ring appeared at chemical shift of 4.77. The proton peak corresponding to the unsaturated double bond in the fatty acid chain at chemical shift 5.35 was significantly weakened, and the vinyl proton peaks corresponding to the methacrylate group at chemical shifts of 5.59 and 6.16 were weakened, indicating that the obtained polymer is a copolymer of rapeseed oil and benzyl methacrylate.

[0046] Based on the results of infrared and nuclear magnetic resonance analysis, the structure of the rapeseed oil-benzyl methacrylate copolymer is shown in formula (I).

[0047]

[0048] Formula (I) Finally, this experiment obtained optimized polymerization conditions by changing factors such as the monomer ratio of rapeseed oil to benzyl methacrylate, the amount of initiator, the polymerization temperature, and the polymerization time: a rapeseed oil to benzyl methacrylate monomer mass ratio of 4:6, ω(AIBN) = 0.5%, T = 90℃, and t = 6h. The relative molecular mass and polydispersity index of the rapeseed oil-based polymer synthesized under the optimized conditions were determined. The number-average relative molecular mass M of the obtained rapeseed oil-based polymer copolymer was... n =2.07×10 4 The polydispersity index (PDI) is 1.55.

[0049] Example 2 The specific steps for synthesizing rapeseed oil-based polymers are as follows: At room temperature, 0.60 g of rapeseed oil and 2.40 g of benzyl methacrylate were added to a polymerization tube, sealed, and connected to a Schlenk apparatus. The mixture was stirred (300 r / min), and the system vacuum was continuously evacuated to maintain a pressure of 90-100 kPa. Then, the nitrogen valve was slowly opened, and nitrogen gas was introduced at a flow rate of 120 mL / min until the system pressure returned to atmospheric pressure (101 kPa). This vacuum-nitrogen-purging cycle was repeated three times. During the final nitrogen purging, 0.015 g of azobisisobutyronitrile (0.5% of the total monomer mass) was dissolved in 3 mL of xylene and injected into the polymerization reaction tube under nitrogen protection. The polymerization reaction tube was placed in a 90°C constant-temperature heating device, and the reaction was allowed to proceed for 6 hours. After the reaction, the polymerization tube was placed in an ice-water bath to terminate the reaction. The resulting product was allowed to settle for 24 hours after being exposed to 50 mL of room-temperature industrial alcohol. h, filter under normal pressure, pour the precipitate onto qualitative filter paper with a pore size of 10-12μm, and after the solvent has drained naturally, transfer the filter paper and filter cake together into a vacuum drying oven at 40℃ and dry for 24 h to obtain rapeseed oil-benzyl methacrylate copolymer.

[0050] Example 3 The synthesis method of rapeseed oil-based polymers specifically includes the following steps: At room temperature, 2.70 g of rapeseed oil and 0.30 g of benzyl methacrylate were added to a polymerization tube, sealed, and connected to a Schlenk apparatus. The mixture was stirred (300 r / min), and the system vacuum was maintained at 90-100 kPa through continuous evacuation. Then, the nitrogen valve was slowly opened, and nitrogen was introduced at a flow rate of 120 mL / min until the system pressure returned to atmospheric pressure (101 kPa). This evacuation-nitrogen-introduction cycle was repeated three times. During the final nitrogen induction, 0.015 g of azobisisobutyronitrile (0.5% of the total monomer mass) was dissolved in 3 mL of xylene and injected into the polymerization reaction tube under nitrogen protection. The polymerization reaction tube was placed in a 90°C constant-temperature heating device, and the reaction was carried out for 6 hours. After the reaction, the polymerization tube was placed in an ice-water bath to terminate the reaction. The resulting product was allowed to settle for 24 hours after being exposed to 50 mL of room-temperature industrial alcohol. h, filter under normal pressure, pour the precipitate onto qualitative filter paper with a pore size of 10-12μm, and after the solvent has drained naturally, transfer the filter paper and filter cake together into a vacuum drying oven at 40℃ and dry for 24 h to obtain rapeseed oil-benzyl methacrylate copolymer.

[0051] Example 4 The synthesis method of rapeseed oil-based polymers specifically includes the following steps: At room temperature, 1.20 g of rapeseed oil and 1.80 g of benzyl methacrylate were added to a polymerization tube, sealed, and connected to a Schlenk apparatus. The mixture was stirred (300 r / min), and the system vacuum was maintained at 90-100 kPa through continuous evacuation. Then, the nitrogen valve was slowly opened, and nitrogen was introduced at a flow rate of 120 mL / min until the system pressure returned to atmospheric pressure (101 kPa). This evacuation-nitrogen circulation cycle was repeated three times. During the final nitrogen purging, 0.0003 g of azobisisobutyronitrile (0.1% of the total monomer mass) was dissolved in 3 mL of xylene and injected into the polymerization reaction tube under nitrogen protection. The polymerization reaction tube was placed in a 90°C constant-temperature heating device, and the reaction was carried out for 6 hours. After the reaction, the polymerization tube was placed in an ice-water bath to terminate the reaction. The resulting product was allowed to settle for 24 hours after being exposed to 50 mL of room-temperature industrial alcohol. h, filter under normal pressure, pour the precipitate onto qualitative filter paper with a pore size of 10-12μm, and after the solvent has drained naturally, transfer the filter paper and filter cake together into a vacuum drying oven at 40℃ and dry for 24 h to obtain rapeseed oil-benzyl methacrylate copolymer.

[0052] Example 5 The synthesis method of rapeseed oil-based polymers specifically includes the following steps: At room temperature, 1.20 g of rapeseed oil and 1.80 g of benzyl methacrylate were added to a polymerization tube, sealed, and connected to a Schlenk apparatus. The mixture was stirred (300 r / min), and the system vacuum was maintained at 90-100 kPa through continuous evacuation. Then, the nitrogen valve was slowly opened, and nitrogen was introduced at a flow rate of 120 mL / min until the system pressure returned to atmospheric pressure (101 kPa). This evacuation-nitrogen circulation cycle was repeated three times. During the final nitrogen purging, 0.060 g of azobisisobutyronitrile (2.0% of the total monomer mass) was dissolved in 3 mL of xylene and injected into the polymerization reaction tube under nitrogen protection. The polymerization reaction tube was placed in a 90°C constant-temperature heating device, and the reaction was carried out for 6 hours. After the reaction, the polymerization tube was placed in an ice-water bath to terminate the reaction. The resulting product was allowed to settle for 24 hours after being exposed to 50 mL of room-temperature industrial alcohol. h, filter under normal pressure, pour the precipitate onto qualitative filter paper with a pore size of 10-12μm, and after the solvent has drained naturally, transfer the filter paper and filter cake together into a vacuum drying oven at 40℃ and dry for 24 h to obtain rapeseed oil-benzyl methacrylate copolymer.

[0053] Example 6 The synthesis method of rapeseed oil-based polymers specifically includes the following steps: At room temperature, 1.20 g of rapeseed oil and 1.80 g of benzyl methacrylate were added to a polymerization tube, sealed, and connected to a Schlenk apparatus. The mixture was stirred (300 r / min), and the system vacuum was maintained at 90-100 kPa through continuous evacuation. Then, the nitrogen valve was slowly opened, and nitrogen was introduced at a flow rate of 120 mL / min until the system pressure returned to atmospheric pressure (101 kPa). This evacuation-nitrogen-introduction cycle was repeated three times. During the final nitrogen induction, 0.015 g of azobisisobutyronitrile (0.5% of the total monomer mass) was dissolved in 3 mL of xylene and injected into the polymerization reaction tube under nitrogen protection. The polymerization reaction tube was placed in a 90°C constant-temperature heating device, and the reaction was carried out for 12 h. After the reaction, the polymerization tube was placed in an ice-water bath to terminate the reaction. The resulting product was allowed to settle for 24 hours after being exposed to 50 mL of room-temperature industrial alcohol. h, filter under normal pressure, pour the precipitate onto qualitative filter paper with a pore size of 10-12μm, and after the solvent has drained naturally, transfer the filter paper and filter cake together into a vacuum drying oven at 40℃ and dry for 24 h to obtain rapeseed oil-benzyl methacrylate copolymer.

[0054] Example 7 The synthesis method of rapeseed oil-based polymers specifically includes the following steps: At room temperature, 1.20 g of rapeseed oil and 1.80 g of benzyl methacrylate were added to a polymerization tube, sealed, and connected to a Schlenk apparatus. The mixture was stirred (300 r / min), and the system vacuum was continuously evacuated to maintain a pressure of 90-100 kPa. Then, the nitrogen valve was slowly opened, and nitrogen was introduced at a flow rate of 120 mL / min until the system pressure returned to atmospheric pressure (101 kPa). This vacuum-nitrogen cycle was repeated three times. During the final nitrogen purging, 0.015 g of azobisisobutyronitrile (0.5% of the total monomer mass) was dissolved in 3 mL of xylene and injected into the polymerization tube under nitrogen protection. The polymerization tube was placed in an 80°C constant-temperature heating device, and the reaction was carried out for 6 hours. After the reaction, the polymerization tube was placed in an ice-water bath to terminate the reaction. The resulting product was allowed to settle for 24 hours after being exposed to 50 mL of room-temperature industrial alcohol. h, filter under normal pressure, pour the precipitate onto qualitative filter paper with a pore size of 10-12μm, and after the solvent has drained naturally, transfer the filter paper and filter cake together into a vacuum drying oven at 40℃ and dry for 24 h to obtain rapeseed oil-benzyl methacrylate copolymer.

[0055] The effects of different reaction conditions on the yield of the synthesized copolymer are shown in Table 1. By changing the monomer mass ratio of rapeseed oil to benzyl methacrylate, the initiator mass fraction, the reaction temperature, and the reaction time, and taking into account factors such as polymer yield and the proportion of renewable raw materials, the optimal process conditions for polymerization were obtained: a rapeseed oil to benzyl methacrylate monomer mass ratio of 4:6, and an initiator mass fraction of... w (AIBN) = 0.5 wt%, reaction temperature 90℃, reaction time 6 h. Under these conditions, the yield of sample rapeseed oil-benzyl methacrylate copolymer No. 4 reached 68%.

[0056] Table 1. Effects of polymerization process conditions on copolymerization reaction

[0057] It should be noted that post-transition metals can effectively catalyze the free radical polymerization of esters. When Cu and Ni-based complexes are used as catalysts to catalyze the synthesis reaction of this invention, the copolymer yield decreases by 10-20%, and the complexity and cost of the reaction increase. Therefore, under catalyst-free conditions, by adjusting the synthesis conditions and post-processing methods, the synthesis of rapeseed oil-based copolymers was effectively carried out. The table below shows the comparative experiments with and without catalysts under the same conditions.

[0058] Table 2 Effect of catalyst on the yield of rapeseed oil-benzyl methacrylate copolymer

[0059] The performance of the synthesized rapeseed oil-based polymeric copolymer as a lubricating oil additive will be further verified below: (I) To investigate the application effect of the rapeseed oil-based polymer copolymer provided by this invention, the kinematic viscosity of the oil at 40℃ and 100℃ was determined according to GB 265-88 "Determination of Kinematic Viscosity and Calculation of Dynamic Viscosity of Petroleum Products"; the viscosity index (VI) of the oil was calculated according to GB / T 1995-1998 "Calculation of Kinematic Viscosity Index of Petroleum Products". The testing and calculation process is as follows: (1) The kinematic viscosity at 40℃ and 100℃ was measured using a capillary viscometer.

[0060] (2) If the viscosity index of the tested oil is less than 100 or equal to 100, the viscosity index calculation formula is as follows: VI = [(L - U) / (L - H)] × 100 Note: In the formula, U—kinematic viscosity of the oil sample at 40℃ (ν) 40 mm 2 / s; L—kinematic viscosity (mm) of the oil with the same kinematic viscosity as the sample at 100℃ and a viscosity index of 0 at 40℃. 2 / s; H—kinematic viscosity (mm) of the oil with a viscosity index of 100 at 40°C, which is the same as the kinematic viscosity of the sample at 100°C. 2 / s.

[0061] (3) If the viscosity index of the tested oil is greater than 100, the formula for calculating the viscosity index is as follows: N = (logH - logU) / logY VI={[(antilogN)-1] / 0.00715}+100 Note: In the formula, Y—kinematic viscosity of the sample at 100℃ (ν) 100 mm 2 / s; antilogN means antilogN.

[0062] Specifically, the copolymer obtained in Example 1 under optimized conditions was added to the lubricating oil fraction of Yumen crude oil (350~390℃) in different proportions to investigate the effect of copolymer addition on the viscosity-temperature properties of the lubricating oil. The results are shown in Table 3.

[0063] Table 3. Effect of different copolymer addition amounts on the viscosity index of lubricating oils

[0064] Table 3 shows that the improvement in viscosity index of the lubricating oil fraction first increases and then decreases with increasing copolymer content, reaching its maximum at 0.03%. This is likely because although the viscosity of the lubricating oil decreases with increasing temperature, the polymer molecules expand, resulting in larger micelles in the oil, which compensates for the decrease in viscosity. As the polymer concentration increases, the total volume of polymer micelles in the oil increases, leading to a higher viscosity index. Excessive copolymer addition limits chain expansion at high temperatures, thus reducing the viscosity index improvement effect.

[0065] The copolymer obtained in Example 1 under optimized conditions was added to API Group I, II, and IV lubricating oil base oils at an addition amount of 0.03% to investigate the effect of the copolymer on the viscosity-temperature properties of different types of base oils. The results are shown in Table 4.

[0066] Table 4. Effects of copolymers on viscosity-temperature properties of different types of base oils

[0067] As shown in Table 4, the viscosity index of API Group I base oils increased by 65 units, API Group II base oils by 49 units, while API Group IV base oils only increased by 2 units. This may be due to the differences in the polarity and molecular structure of the base oils. API Group I base oils are rich in aromatic hydrocarbons and cycloalkanes, which form strong intermolecular interactions with polar groups (such as ester groups) and long alkyl chains in copolymers, thus significantly improving solubility and viscosity-temperature properties. In contrast, hydrotreated API Group II base oils have a lower aromatic hydrocarbon content and mainly interact with copolymers through weak physical forces, resulting in a smaller increase in viscosity index. API Group IV base oils are composed of nonpolar saturated hydrocarbons, lack chemisorption, have poor compatibility, and their performance improvement is almost negligible.

[0068] (III) To investigate the application effect of rapeseed oil-based copolymers as anti-wear agents, the wear scar diameter (WSD) of the copolymers was determined according to NB / SH / T0189-2017 "Determination of Anti-wear Properties of Lubricating Oils (Four-Ball Method)". The specific test steps are as follows: (1) Put the clean steel ball into the oil box of the four-ball machine, and then add oil to the oil box. The liquid level after adding the oil should cover the surface of the steel ball, and ensure that there are no air bubbles in the oil in the oil box.

[0069] (2) Under the test conditions of test load 392 N, rotation speed 1200 r / min and test temperature 75℃, the test was run for 1 h.

[0070] (3) Take out the oil box, extract the experimental oil from the oil box, remove the oil from the surface of the steel ball after the experiment, place the oil box under a special microscope to measure the wear mark diameter and vertical wear mark diameter of each steel ball.

[0071] (4) The arithmetic mean of the above measurements is the wear scar diameter (WSD).

[0072] Specifically, the copolymer obtained in Example 1 under optimized conditions was added to the lubricating oil fraction of Yumen crude oil (350~395 ℃) in different proportions. The effect of copolymer addition on the anti-wear performance of the lubricating oil was investigated by taking the decrease in wear scar diameter (WSD) before and after the addition of copolymer (ΔWSD) as the standard. The results are shown in Table 5.

[0073] Table 5. Effects of different copolymer addition amounts on the anti-wear properties of lubricating oils

[0074] Table 5 shows that the wear scar diameter initially decreases and then increases with increasing copolymer content. When the additive content is 0.03%, the wear scar diameter decreases by 0.356 mm, indicating good anti-wear performance. This may be because the polar ester oxygen groups of the copolymer adsorb onto the steel ball surface, forming a dense adsorption film, thereby reducing friction between the steel balls and decreasing the wear scar diameter. However, as the copolymer content increases, the desorption rate on the steel ball surface exceeds the adsorption rate, leading to a decrease in anti-wear effect.

[0075] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for synthesizing a rapeseed oil-based polymer, characterized in that, Includes the following steps: (1) Add rapeseed oil and benzyl methacrylate into a polymerization reaction tube, seal it and connect it to the Schlenk apparatus, stir, evacuate and purge with nitrogen to obtain the reaction material; (2) The reactants in step (1) are heated at a constant temperature and a xylene solution of azobisisobutyronitrile is injected under nitrogen protection to react and obtain the rapeseed oil-based polymer copolymer, namely rapeseed oil-benzyl methacrylate copolymer. The synthetic route for the polymerization reaction of rapeseed oil and benzyl methacrylate is as follows: in, m The number of repeating units in the benzyl methacrylate segment. n The number of repeating units in the rapeseed oil chain. m / n The range is approximately 0.56 to 36.

2. The method for synthesizing a rapeseed oil-based polymer according to claim 1, characterized in that, In step (1), the mass ratio of rapeseed oil to benzyl methacrylate is (1-9):(9-1). In step (2), the amount of azobisisobutyronitrile (AIBN) fed is 0.1%-2.0% of the total mass of rapeseed oil and benzyl methacrylate in step (1).

3. The method for synthesizing a rapeseed oil-based polymer according to claim 1, characterized in that, In step (2), the constant temperature heating temperature is 60-100℃, and the constant temperature heating time is 4-12h.

4. The method for synthesizing a rapeseed oil-based polymer according to claim 1, characterized in that, In step (2), the xylene solution of azobisisobutyronitrile contains azobisisobutyronitrile at a concentration of 0.001~0.02 g / mL.

5. The method for synthesizing a rapeseed oil-based polymer according to claim 1, characterized in that, After the reaction in step (2) is completed, the polymerization reaction tube is placed in an ice-water bath to terminate the reaction. Then, the reactants are poured into industrial alcohol with a concentration of 95wt%, allowed to stand, filtered, purified, and dried to obtain the product.

6. A rapeseed oil-based polymer synthesized by the synthesis method according to any one of claims 1-5; Its structural formula is shown in equation (I): Formula (I).

7. The application of the synthetic rapeseed oil-based polymer as described in claim 6 in a lubricating oil additive.

8. The application of the synthetic rapeseed oil-based polymer according to claim 7 in lubricating oil additives, characterized in that, The rapeseed oil-based polymer is added to the lubricating oil base oil at a mass fraction of 0.01%-0.10%.

9. The application of the synthetic rapeseed oil-based polymer according to claim 7 in lubricating oil additives, characterized in that, The synthetic rapeseed oil-based polymer copolymer is used in food industry lubrication, pharmaceutical industry lubrication, environmental protection industry lubrication, agricultural machinery lubrication, or industrial lubrication.

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