Bio-based elastomers, bio-based 3d-printed elastomers, and methods of making and using the same

Abstract

This invention discloses a bio-based elastomer, a bio-based 3D-printed elastomer, its preparation method, and its applications. The bio-based elastomer, by weight, comprises the following components: 1-12 parts of poly(hexanediol) itaconic acid, 1-12 parts of itaconic acid-modified epoxidized soybean oil, 0-10 parts of pentaerythritol tetramercaptoacetate, and 0.1-10 parts of photoinitiator; the mass ratio of poly(hexanediol) itaconic acid and itaconic acid-modified epoxidized soybean oil is 0.5-1.5:1. Furthermore, this invention also provides a bio-based 3D-printed elastomer. The bio-based elastomer and bio-based 3D-printed elastomer provided by this invention exhibit excellent tensile strength and elongation at break.

Description

Technical Field

[0001] This invention belongs to the technical field of photocurable polymer materials, and more specifically, relates to bio-based elastomers, bio-based 3D printed elastomers, their preparation methods and applications. Background Technology

[0002] Bio-based resins are renewable, low-carbon, and highly safe materials, increasingly used in the production of various products. Currently, research on bio-based photosensitive resins is relatively limited, with most studies focusing on petroleum-based photosensitive resins. Commercially available bio-based elastomer photosensitive materials typically contain 50-65% bio-based carbon. Developing high-content, high-performance 3D-printed elastomers with high bio-based carbon content has become an important research direction. Furthermore, combining 3D printing technology to manufacture sustainably sourced, non-toxic, high-strength, and high-toughness personalized custom parts will help broaden the range of consumables available for 3D printing, significantly promoting the adaptation of various fields to 3D printing technology and its green development.

[0003] Patent publication number CN105801406A discloses an epoxidized soybean oil coating ester, which introduces photocurable active double bonds into the molecular structure of epoxidized soybean oil. This increases the interaction between soybean oil-based oligomers and other components and substrates in coatings, thereby improving the overall performance of the coatings. However, the aforementioned modified epoxidized soybean oil is only used in the coating field and has not been used to prepare photocurable elastomers with excellent elongation at break and tensile strength. Summary of the Invention

[0004] In view of the above-mentioned existing technical problems, the primary objective of the present invention is to provide a bio-based elastomer with good elongation at break and tensile strength.

[0005] A second objective of this invention is to provide a method for preparing a bio-based elastomer.

[0006] A third objective of this invention is to provide a bio-based 3D printed elastomer.

[0007] The fourth objective of this invention is to provide a method for preparing a bio-based 3D printed elastomer.

[0008] A fifth objective of this invention is to provide the application of bio-based elastomers or bio-based 3D printed elastomers in the fabrication of elastomer devices.

[0009] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0010] A bio-based elastomer, by weight, comprises the following components: 1-12 parts of poly(hexanediol) itaconic acid, 1-12 parts of itaconic acid-modified epoxidized soybean oil, and 0.1-10 parts of photoinitiator.

[0011] The structural formula of the poly(hexanediol) itaconic acid is:

[0012] In the formula, n is 45 to 65;

[0013] The structural formula of the monomer of the itaconic acid modified epoxidized soybean oil is:

[0014] In the formula, R and R′ are both

[0015] The mass ratio of poly(hexanediol) itaconic acid to itaconic acid-modified epoxidized soybean oil is 0.5–1.5:1.

[0016] This invention provides a bio-based elastomer using itaconic acid-modified epoxidized soybean oil as a photosensitive resin. The structure incorporates photocurable groups, making it suitable for the 3D printing industry and improving the reactivity of the photosensitive resin material to meet the application requirements of 3D printing. Each alkyl segment in the itaconic acid-modified epoxidized soybean oil monomer contains three active double bonds, which can be used for cross-linking reactions. This results in a highly cross-linked network formed by the cured resin, and also enables the formation of a complex cross-linked network after photocuring, thereby improving the printing accuracy and mechanical properties of the bio-based elastomer.

[0017] Furthermore, the inventors discovered through research that a specific mass ratio of poly(hexanediol) itaconic acid to itaconic acid-modified epoxidized soybean oil exhibits superior tensile strength and elongation at break. A lower ratio results in lower mechanical strength of the bio-based elastomer, affecting its elongation at break and causing premature fracture. Conversely, a higher ratio leads to a sharp decrease in the average elongation at break, hindering its application. Moreover, the poly(hexanediol) itaconic acid used in this invention contains numerous unsaturated double bonds, which significantly increases the crosslinking density during photocuring, thereby limiting the deformation of the bio-based elastomer.

[0018] Preferably, the bio-based elastomer comprises, by weight, the following components: 5-10 parts of poly(hexanediol) itaconic acid, 5-10 parts of itaconic acid-modified epoxidized soybean oil, and 0.15-0.5 parts of photoinitiator.

[0019] Preferably, the mass ratio of poly(hexanediol) itaconic acid to itaconic acid-modified epoxidized soybean oil is 0.8–1.2:1. More preferably, the mass ratio of poly(hexanediol) itaconic acid to itaconic acid-modified epoxidized soybean oil is 1.0–1.2:1.

[0020] Preferably, the photoinitiator is selected from one or more of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-ethoxy-phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and ethyl 2,4,6-trimethylbenzoylphenylphosphonate. More preferably, the photoinitiator is ethyl 2,4,6-trimethylbenzoylphenylphosphonate.

[0021] Preferably, by weight, the itaconic acid modified epoxidized soybean oil comprises: 30 parts epoxidized soybean oil, 10-40 parts itaconic acid, 0.5-5 parts alkali catalyst, 0.1-5 parts polymerization inhibitor, and 30-60 parts solvent.

[0022] Preferably, by weight, the itaconic acid modified epoxidized soybean oil comprises: 30 parts epoxidized soybean oil, 10-20 parts itaconic acid, 0.5-1.0 parts alkaline catalyst, 0.1-1.0 parts polymerization inhibitor, and 35-45 parts solvent.

[0023] Preferably, the alkaline catalyst is one or more of triphenylphosphine, triethylamine, dimethylimidazole, tetrabutylammonium bromide, or a chromium-based catalyst. More specifically, the chromium-based catalyst includes, but is not limited to, chromium acetate. Even more preferably, the alkaline catalyst is triphenylphosphine.

[0024] Preferably, the polymerization inhibitor is a phenolic polymerization inhibitor. More specifically, the phenolic polymerization inhibitor is a hydroquinone compound and / or an alkoxyphenol compound. More specifically, the polymerization inhibitor is selected from one or more of 4-methoxyphenol, hydroquinone, and 2-tert-butylhydroquinone.

[0025] Preferably, the solvent is selected from one or more of ethyl acetate, butyl acetate, ethanol, N,N'-dimethylformamide, n-butanol and isobutanol.

[0026] Preferably, the present invention provides a method for preparing itaconic acid modified epoxidized soybean oil, comprising the following steps: mixing and reacting epoxidized soybean oil, itaconic acid, an alkaline catalyst, a polymerization inhibitor and a solvent to obtain the itaconic acid modified epoxidized soybean oil.

[0027] Preferably, the reaction temperature is 80–100°C, and the reaction time is 6–12 h.

[0028] Preferably, before the reaction, itaconic acid and soybean oil are dissolved in a solvent and pre-reacted at room temperature for 30-60 minutes. This pre-reaction can increase the reaction rate for preparing itaconic acid-modified epoxidized soybean oil.

[0029] Furthermore, this invention claims protection for a method for preparing a bio-based elastomer, wherein poly(hexanediol) itaconic acid, itaconic acid-modified epoxidized soybean oil, and a photoinitiator are mixed uniformly to obtain a prepolymer, and the prepolymer is subjected to light irradiation to obtain the bio-based elastomer.

[0030] Preferably, the illumination conditions are: light intensity 5–30 mW / cm². 2 .

[0031] Furthermore, the present invention claims protection for a bio-based 3D printed elastomer, comprising, by weight, the following components: 1-5 parts of poly(hexanediol) itaconic acid, 1-5 parts of itaconic acid-modified epoxidized soybean oil, 0.1-10 parts of photoinitiator, and 1-40 parts of reactive diluent.

[0032] The structural formula of the poly(hexanediol) itaconic acid is:

[0033] In the formula, n is 45 to 65;

[0034] The structural formula of the monomer of the itaconic acid modified epoxidized soybean oil is:

[0035] In the formula, R and R′ are both

[0036] The mass ratio of poly(hexanediol) itaconic acid to itaconic acid-modified epoxidized soybean oil is 0.5–1.5:1.

[0037] In addition to the advantages of bio-based elastomers, the aforementioned bio-based 3D printed elastomers also incorporate reactive diluents. These reactive diluents dilute the viscosity of the resin system, increasing its fluidity during 3D printing and thus improving printing accuracy. They also enhance the double bond conversion rate in the reaction system, thereby increasing crosslinking density and gradually improving thermal stability. Within a certain range, reactive diluents can improve the strength and elongation at break of bio-based 3D printed elastomers.

[0038] Preferably, the reactive diluent is selected from one or more of pentaerythritol tetramercaptoacetate, isobornyl acrylate, β-carboxyethyl acrylate, 1,6-hexanediol diacrylate, and pentaerythritol tetra(3-mercaptopropionic acid) ester. More preferably, the reactive diluent is pentaerythritol tetramercaptoacetate.

[0039] Preferably, the mass ratio of poly(hexylene itaconic acid), itaconic acid-modified epoxidized soybean oil, and reactive diluent is 0.5–1.5:1:0.25–0.5.

[0040] Furthermore, this invention claims protection for a method for preparing a bio-based 3D printed elastomer, wherein poly(hexanediol) itaconic acid, itaconic acid-modified epoxidized soybean oil, a photoinitiator, and an active diluent are mixed uniformly to obtain a prepolymer, and the prepolymer is 3D printed to obtain the bio-based 3D printed elastomer.

[0041] Preferably, the 3D printing conditions are: ultraviolet light intensity of 3–10 mW / cm². 2 The printing layer thickness is 50–150 μm, and the exposure time is 10–20 s.

[0042] Furthermore, this invention claims protection for the application of the aforementioned bio-based elastomer or the aforementioned bio-based 3D-printed elastomer in the fabrication of elastomer devices. More specifically, the elastomer devices can be artificial blood vessels, artificial ligaments, and medical sealing materials, etc.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] This invention uses itaconic acid-modified epoxidized soybean oil as a photosensitive resin and adds poly(hexanediol itaconic acid) to increase the crosslinking density. Within a specific ratio range, the prepared bio-based elastomer exhibits excellent tensile strength and elongation at break. Based on this, this invention adds an active diluent to the above system to prepare a bio-based 3D-printed elastomer, which also exhibits excellent mechanical strength and elongation at break. Attached Figure Description

[0045] Figure 1 The Fourier transform infrared (FTIR) spectrum of the monomer of the itaconic acid-modified epoxidized soybean oil prepared in Example 1 is shown.

[0046] Figure 2 The images show the nuclear magnetic resonance (NMR) spectra of the monomers of the epoxidized soybean oil and itaconic acid-modified epoxidized soybean oil from Example 1. Figure 2 (a) is the nuclear magnetic resonance spectrum of epoxidized soybean oil; Figure 2 (b) is the NMR spectrum of the monomer of itaconic acid modified epoxidized soybean oil.

[0047] Figure 3 The image shows gel chromatograms of the products from different reaction times in Example 1.

[0048] Figure 4 This is a comparison chart of the reaction times required for different catalyst systems in Example 1.

[0049] Figure 5 The image shows the stress-strain curve of the bio-based elastomer prepared in Example 1.

[0050] Figure 6The image shows the stress-strain curve of the bio-based 3D printed elastomer prepared in Example 2. Detailed Implementation

[0051] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0052] Example 1: Preparation of a bio-based elastomer

[0053] (1) Add 12g of itaconic acid and 40g of ethanol solvent to a 250ml three-necked flask equipped with a thermometer and a stirrer. Stir at room temperature for 30min to dissolve the itaconic acid until it becomes transparent. Then add 30g of epoxidized soybean oil, 0.6g of triphenylphosphine, and 0.6g of 4-methoxyphenol. Stir for 10min.

[0054] (2) The temperature was raised to 90℃ for reaction. A small amount of the reaction solution was taken every hour for infrared testing to observe the characteristic peak of the epoxy and analyze the degree of reaction. The reaction was stopped when the characteristic peak of the epoxy disappeared. The product of the catalyst reaction system was detected by infrared spectroscopy to ensure that the epoxy groups reacted completely. The required reaction time was recorded as 6 hours. The product was collected. 15 mL of dichloromethane and 30 mL of deionized water were added to the product for extraction and washing. The washing step was repeated two to three times to remove the catalyst and unreacted small molecule reactants from the product. After rotary evaporation of the dichloromethane phase, a light yellow transparent product was obtained, which is the desired bio-based photosensitive resin itaconic acid modified epoxidized soybean oil, 24.66 g. The Fourier transform infrared (FTIR) spectrum of the monomer of itaconic acid modified epoxidized soybean oil is shown in the figure. Figure 1 As shown. The nuclear magnetic resonance (NMR) spectra of epoxidized soybean oil and its itaconic acid-modified epoxidized soybean oil monomers are shown below. Figure 2 As shown.

[0055] (3) Take 7.5 parts of itaconic acid modified epoxidized soybean oil prepared in step (2), 7.5 parts of poly(hexanediol itaconic acid) (PHI), and 0.3 parts of ethyl 2,4,6-trimethylbenzoyl phosphate, stir at room temperature for 15 minutes to obtain a photocurable prepolymer.

[0056] The structural formula of poly(hexanediol) ester is as follows:

[0057] In the formula, n is 50;

[0058] The photocurable prepolymer was filled into a 2mm thick dumbbell-shaped stretching die using a photocurable track machine (light source: 405nm wavelength, light intensity: 15mW / cm²). 2The material is repeatedly photocured twice via a conveyor belt to obtain a bio-based elastomer.

[0059] Example 2: Preparation of a bio-based 3D printed elastomer

[0060] The difference between this embodiment and Embodiment 1 is that:

[0061] Take 7.5 parts of itaconic acid modified epoxidized soybean oil prepared in step (2), 7.5 parts of poly(hexanediol itaconic acid) (PHI), 0.3 parts of ethyl 2,4,6-trimethylbenzoyl phosphate, and 1.875 parts of pentaerythritol tetramercaptoacetate (PETMA) and mix them. Stir at room temperature for 30 minutes to obtain a photocurable prepolymer.

[0062] The photopolymer was added to an LCD 3D printer (W5501, Shenzhen Viseetec Technology Co., Ltd., China) for 3D printing (3D printing parameters: UV irradiation source wavelength of 405nm, UV light intensity of 5mW / cm²). 2 The bio-based 3D printed elastomer was obtained by printing a layer with a thickness of 100 μm and an exposure time of 15 s.

[0063] Examples 3-6: Preparation of a bio-based elastomer

[0064] The difference between Examples 3-6 and Example 1 is that in step (1), triethylamine, dimethylimidazole, tetrabutylammonium bromide and chromium acetate are used to replace triphenylphosphine.

[0065] Examples 7-10: Preparation of a bio-based elastomer

[0066] The difference between Examples 7-10 and Example 1 is that:

[0067] Example 7 specifically consists of: 0 parts of poly(hexylene itaconic acid) glycol ester and 15 parts of itaconic acid-modified epoxidized soybean oil; Example 7 corresponds to PI (0.0:1) in the figure.

[0068] Example 8 specifically consists of 5 parts of poly(hexylene itaconic acid) glycol ester and 10 parts of itaconic acid-modified epoxidized soybean oil; Example 8 corresponds to PI (0.5:1) in the figure;

[0069] Example 9 specifically consists of 9 parts of poly(hexanediol) itaconic acid and 6 parts of itaconic acid-modified epoxidized soybean oil; Example 9 corresponds to PI (1.5:1) in the figure;

[0070] Example 10 specifically consists of 10 parts of poly(hexanediol) itaconic acid and 5 parts of itaconic acid-modified epoxidized soybean oil; Example 10 corresponds to PI (2.0:1) in the figure.

[0071] Examples 11-14: Preparation of a bio-based 3D printed elastomer

[0072] The difference between Examples 11-14 and Example 2 is as follows:

[0073] Example 11 specifically consists of: 0 parts of pentaerythritol tetramercaptoacetate; Example 11 corresponds to the PIP (1:1:0.00) in the figure;

[0074] Example 12 specifically comprises: 3.75 parts of pentaerythritol tetramercaptoacetate; PIP (1:1:0.50) corresponding to Example 12 in the figure;

[0075] Example 13 specifically comprises: 5.625 parts of pentaerythritol tetramercaptoacetate; the corresponding PIP (1:1:0.75) in the figure for Example 13;

[0076] Example 14 specifically consists of 7.5 parts of pentaerythritol tetramercaptoacetate; the corresponding PIP (1:1:1.00) in the figure for Example 14.

[0077] Test case

[0078] (1) The molecular weight (Mw) and distribution (PDI) of itaconic acid modified epoxidized soybean oil (IESO) were determined by gel permeation chromatography (GPC) (Agilent PL-GPC220, polystyrene as standard). Tetrahydrofuran was used as the eluent, the flow rate was 1 mL / min, and the test temperature was 25 °C.

[0079] Depend on Figure 3 It is observed that the molecular weight of IESO increases rapidly in the initial stage of the reaction. After 6 hours, the increase in molecular weight slows down. This is because most of the epoxy groups in the reaction system have been consumed, the proportion of the main reaction decreases, and side reactions such as epoxy ring-opening and double bond self-polymerization become dominant, reducing the double bond content of the product and leading to a decrease in resin performance. Therefore, it is necessary to select an appropriate reaction time to prepare IESO with excellent performance.

[0080] Depend on Figure 4 It is evident that the required reaction time varies depending on the base catalyst used. When triphenylphosphine, dimethylimidazole, or tetrabutylammonium bromide is used, the reaction can be completed in a shorter time.

[0081] (2) According to the national standard GB / T 1040-2018, the mechanical properties were tested at 25℃ using dumbbell-shaped specimens (15mm long, 4mm wide, and 1mm thick at the narrowest part) on a SANS CMT 6000 universal testing machine with a clamping speed of 10mm / min. Five specimens were tested in each group, and the average value was taken. The specimens were the bio-based elastomer prepared in Example 1 and the bio-based 3D printed elastomer prepared in Example 2.

[0082] Figure 5This is a stress-strain curve of the bio-based elastomer prepared in Example 1. In the figure, PI refers to the mass ratio of poly(hexanediol) itaconic acid (PHI) to itaconic acid-modified epoxidized soybean oil (IESO). Figure 5 It can be observed from the tensile test that PHI increases the tensile strength of the photocurable system. The average tensile strength of the sample without added PHI was only 0.7 MPa, and the average elongation at break was only 37.4%. As the amount of PHI added increased, the average tensile strength of the sample gradually increased to 21 MPa, but the elongation at break decreased to 27.7%. Among these, when the mass ratio of PHI to IESO was 1.0:1, the sample exhibited the best mechanical properties, with an average elongation at break of approximately 94% and an average tensile strength of approximately 8 MPa. Figure 5 It is evident that the mass ratio of PHI to IESO needs to be controlled within a specific range to obtain products with superior average elongation at break and average tensile strength. A smaller mass ratio results in lower mechanical strength, premature fracture, and reduced elongation at break. Conversely, a larger mass ratio leads to a sharp decrease in the average elongation at break, making the system unsuitable for practical applications.

[0083] Figure 6 This is a stress-strain curve of the bio-based 3D printed elastomer prepared in Example 2. In the figure, PIP refers to the mass ratio of poly(hexanediol) itaconic acid (PHI), itaconic acid-modified epoxidized soybean oil (IESO), and pentaerythritol tetramercaptoacetate (PETMA). Figure 6 As observed in the tensile tests, the tensile strength and elongation at break of the samples significantly improved with increasing PETMA content. This is attributed to the large number of flexible bonds generated by the reaction of mercaptoene, which effectively enhances the tensile properties of the material. However, due to the relatively weak mechanical properties of the flexible bonds formed by the reaction of mercaptoene, the mechanical properties of the samples decreased to some extent after excessive addition. With the addition of PETMA, the tensile strength of the samples decreased from a maximum of 8.3 MPa to 3.9 MPa. However, the elongation at break of the material increased to 120.7%. This indicates that the flexible bonds generated by the reaction of mercaptoene play an excellent role. The optimal mechanical properties were observed when the mass ratio of PIP was 1:1:0.50.

[0084] The foregoing examples are merely illustrative, used to explain some features of the method described in this invention. The appended claims are intended to claim the broadest possible scope, and the embodiments presented herein are demonstrated by the applicant's actual experimental results. Therefore, the applicant intends that the appended claims are not limited by the selection of examples illustrating the features of the invention. Some numerical ranges used in the claims also include sub-ranges within them, and variations within these ranges should also be interpreted as being covered by the appended claims where possible.

Claims

1. A bio-based elastomer, characterized in that, By weight, it includes the following components: 1-12 parts of poly(hexylene itaconic acid), 1-12 parts of itaconic acid-modified epoxidized soybean oil, and 0.1-10 parts of photoinitiator. The structural formula of the poly(hexanediol) itaconic acid is: In the formula, n is 45 to 65; The structural formula of the monomer of the itaconic acid modified epoxidized soybean oil is: In the formula, R and R′ are both The mass ratio of poly(hexanediol) itaconic acid to itaconic acid-modified epoxidized soybean oil is 0.5–1.5:

1.

2. The bio-based elastomer according to claim 1, characterized in that, The photoinitiator is selected from one or more of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-ethoxy-phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and ethyl 2,4,6-trimethylbenzoylphenylphosphonate.

3. The bio-based elastomer according to claim 1, characterized in that, By weight, the itaconic acid-modified epoxidized soybean oil comprises: 30 parts epoxidized soybean oil, 10-40 parts itaconic acid, 0.5-5 parts alkali catalyst, 0.1-5 parts polymerization inhibitor, and 30-60 parts solvent.

4. The bio-based elastomer according to claim 3, characterized in that, The alkaline catalyst is one or more of triphenylphosphine, triethylamine, dimethylimidazole, tetrabutylammonium bromide, or a chromium-based catalyst.

5. The bio-based elastomer according to claim 3, characterized in that, The polymerization inhibitor is a phenolic polymerization inhibitor.

6. A method for preparing the bio-based elastomer according to any one of claims 1 to 5, characterized in that, Poly(hexanediol) itaconic acid, itaconic acid-modified epoxidized soybean oil, and a photoinitiator are mixed evenly to obtain a prepolymer. The prepolymer is then irradiated with light to obtain the bio-based elastomer.

7. A bio-based 3D printed elastomer, characterized in that, By weight, it includes the following components: 1-12 parts of poly(hexylene itaconic acid), 1-12 parts of itaconic acid-modified epoxidized soybean oil, 0.1-10 parts of photoinitiator, and 1-40 parts of reactive diluent. The structural formula of the poly(hexanediol) itaconic acid is: In the formula, n is 45 to 65; The structural formula of the monomer of the itaconic acid modified epoxidized soybean oil is: In the formula, R and R′ are both The mass ratio of poly(hexanediol) itaconic acid to itaconic acid-modified epoxidized soybean oil is 0.5–1.5:

1.

8. The bio-based 3D printed elastomer according to claim 7, characterized in that, The active diluent is selected from one of pentaerythritol tetramercaptoacetate, trimethylolpropane tris(3-mercaptopropionic acid) ester, and pentaerythritol tetra(3-mercaptopropionic acid) ester.

9. The bio-based 3D printed elastomer according to claim 7, characterized in that, The mass ratio of poly(hexylene itaconic acid) to reactive diluent is 0.5–1.5:0.25–0.

5.

10. The use of the bio-based elastomer according to any one of claims 1 to 5 or the bio-based 3D printed elastomer according to any one of claims 7 to 9 in the fabrication of elastomer devices.

Images