BIO-BASED EPOXY CHAIN EXTENDER AND PREPARATION METHOD THEREOF

Abstract

The present disclosure provides a bio-based epoxy chain extender and a preparation method thereof, belonging to the technical field of chain extenders, and the preparation method includes the following steps: (1) mixing ESO and CD and carrying out catalytic reaction to obtain ESO.sub.n-CD; and (2) mixing and heating the ESO.sub.n-CD with concentrated sulfuric acid, dropwise adding a mixture of glacial acetic acid and hydrogen peroxide for stirring reaction, and after the stirring reaction, carrying out extraction and separation to remove a solvent to obtain the bio-based epoxy chain extender. The present disclosure also provides a bio-based epoxy chain extender prepared by the preparation method.

Claims

1. A preparation method of a bio-based epoxy chain extender, comprising following steps: (1) mixing ESO and CD and carrying out catalytic reaction to obtain ESO.sub.n-CD; and (2) mixing and heating the ESO.sub.n-CD with concentrated sulfuric acid, dropwise adding a mixture of glacial acetic acid and hydrogen peroxide for stirring reaction, and after a reaction, carrying out extraction and separation to remove a solvent to obtain the bio-based epoxy chain extender; wherein the ESO is epoxidized soybean oil; and the CD is cardanol.

2. The preparation method of the bio-based epoxy chain extender according to claim 1, wherein a molar ratio of the ESO to the CD in step (1) is 3-6:1; and a catalyst in a process of the catalytic reaction is hydrochloric acid.

3. The preparation method of the bio-based epoxy chain extender according to claim 1, wherein a temperature of the catalytic reaction in the step (1) is 200 C. and a reaction duration is 30 min.

4. The preparation method of the bio-based epoxy chain extender according to claim 1, wherein an addition ratio of the ESO.sub.n-CD, the concentrated sulfuric acid, the glacial acetic acid and the hydrogen peroxide in step (2) is 100 g:2 mL:10 mL:20 mL.

5. The preparation method of the bio-based epoxy chain extender according to claim 4, wherein a mass concentration of the concentrated sulfuric acid is 98%; a concentration of the glacial acetic acid is 3 equivalents; and a mas concentration of the hydrogen peroxide is 30%.

6. The preparation method of the bio-based epoxy chain extender according to claim 1, wherein a heating temperature in step (2) is 65 C.; and a duration of the stirring reaction is 4 h.

7. A bio-based epoxy chain extender prepared by the preparation method of the bio-based epoxy chain extender according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which constitute a part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application, and do not constitute an improper limitation of this application. In the attached drawings:

[0033] FIG. 1 shows schematic diagrams of the structural formulas of the reactants ESO and CD, and the product ESO.sub.n-ECD in Embodiments 1 and 2;

[0034] FIG. 2 shows the structural formula of BASF ADR4468;

[0035] FIG. 3 is a photograph showing ESO.sub.n-CD, ESO.sub.n-ECD and ESO obtained in Embodiments 1 and 2;

[0036] FIG. 4 is the NMR spectra of ESO.sub.n-CD and ESO.sub.n-ECD obtained in Embodiments 1 and 2;

[0037] FIG. 5 illustrates the thermogravimetric curves of ESO.sub.n-CD and ESO.sub.n-ECD obtained in Embodiments 1 and 2;

[0038] FIG. 6 shows SEM images of sections of PBS/PGA injection molded samples obtained from Embodiment 5, Comparative embodiment 1 and Comparative embodiment 4;

[0039] FIG. 7 shows physical diagrams of PBS/PGA composite films obtained in Embodiments 11-12 and Comparative embodiments 6-7;

[0040] FIG. 8 shows SEM images of the longitudinal section (MD direction) of the PBS/PGA composite films obtained from Embodiment 11 and Comparative embodiments 6-7;

[0041] FIG. 9 shows SEM images of the longitudinal section (TD direction) of the PBS/PGA composite films obtained from Embodiment 11 and Comparative embodiments 6-7.

[0042] FIG. 10 shows a process illustrating the preparation method of the bio-based epoxy chain extender.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] In the following, the technical schemes in the embodiments of the present disclosure are clearly and completely described with reference to the attached drawings. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, but not the whole embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without creative labor belong to the scope of protection of the present disclosure.

[0044] In order to make the above objectives, features and advantages of the present disclosure more obvious and easy to understand, the present disclosure will be further described in detail with the attached drawings and specific embodiments.

[0045] Some sources of raw materials used in the embodiments of the present disclosure are as follows: [0046] CD (cardanol): Dining Huakai Resin Biochemical Co., Ltd. of Shandong, China; [0047] ESO (epoxidized soybean oil): Macklin Co., Ltd. of Shanghai, China; [0048] ADR4468: BASF; [0049] PBS (polybutylene succinate): Showa Denko, Japan, with mark of 1001MD; [0050] PGA (polyglycolic acid, high barrier material): Shanghai Pujing Chemical Technology Co., Ltd.

[0051] The present disclosure provides a preparation method of a bio-based epoxy chain extender, including the following steps as shown in FIG. 10: [0052] (1) mixing epoxidized soybean oil (ESO) and cardanol (CD) and carrying out catalytic reaction to obtain ESO.sub.n-CD; and [0053] (2) mixing and heating the ESO.sub.n-CD with concentrated sulfuric acid, dropwise adding a mixture of glacial acetic acid and hydrogen peroxide for stirring reaction, and after the stirring reaction, carrying out extraction and separation to remove a solvent to obtain the bio-based epoxy chain extender.

Embodiment 1

[0054] The preparation method of the bio-based epoxy chain extender, including the following steps: [0055] (1) mixing ESO and CD in a molar ratio of 3:1 in a three-necked flask equipped with a magnetic stirrer, adding a drop of concentrated hydrochloric acid as a catalyst, and then reacting at a constant temperature of 200 C. for 30 min to obtain the product ESO.sub.3-CD; and [0056] (2) mixing 100 g of ESO.sub.3-ECD with 2 mL of H.sub.2SO.sub.4 (98 wt. %) and heating to 65 C., then dropwise adding a mixture of 10 mL of glacial acetic acid (3 equivalents) and 20 mL of H.sub.2O.sub.2 (30 wt. %), and then magnetically stirring the mixed solution for 4 h at 65 C.; after reaction, extracting and separating the product from the organic phase in dichloromethane, and then removing the organic phase by rotary evaporation to obtain the bio-based epoxy chain extender ESO.sub.3-ECD.

[0057] The yield of the obtained bio-based epoxy chain extender ESO.sub.3-ECD is 90% and the epoxy value is 6.62%.

Embodiment 2

[0058] The preparation method of the bio-based epoxy chain extender, including the following steps: [0059] (1) mixing ESO and CD in a molar ratio of 6:1 in a three-necked flask equipped with a magnetic stirrer, adding a drop of concentrated hydrochloric acid as a catalyst, and then reacting at a constant temperature of 200 C. for 30 min to obtain the product ESO.sub.6-CD; and [0060] (2) mixing 100 g of ESO.sub.6-ECD with 2 mL of H.sub.2SO.sub.4 (98 wt. %) and heating to 65 C., then dropwise adding a mixture of 10 mL of glacial acetic acid (3 equivalents) and 20 mL of H.sub.2O.sub.2 (30 wt. %), and then magnetically stirring the mixed solution for 4 h at 65 C.; after reaction, extracting and separating the product from the organic phase in dichloromethane, and then removing the organic phase by rotary evaporation to obtain the bio-based epoxy chain extender ESO.sub.6-ECD.

[0061] The yield of the obtained bio-based epoxy chain extender ESO.sub.6-ECD is 92% and the epoxy value is 4.78%.

[0062] The structural formulas of the reactants ESO and CD used in Embodiments 1-2 and the products ESO.sub.n-ECD are shown in FIG. 1. The chemical structures of the ADR4468 is shown in FIG. 2; and the pictures of the two chain extenders ESO.sub.3-ECD and ESO.sub.6-ECD prepared in Embodiments 1-2 as well as ESO.sub.3-CD, ESO.sub.6-CD and ESO synthesized in the step (1) are shown in FIG. 3. By comparison, it is observed that the color of ESO.sub.n-ECD obtained in step (2) is deeper than that of ESO.sub.n-CD, indicating the successful occurrence of oxidation reaction.

Embodiment 3

[0063] The preparation method of the PBS/PGA composite material includes the following steps: [0064] mixing PBS, PGA and the bio-based epoxy chain extender obtained in Embodiment 1, and then melting, extruding and granulating with a twin screw to obtain composite master batch, where the temperature of the extruder from the feeding area to the head area is 195-225 C.; among them, the mass ratio of PBS to PGA is 4:1, and the addition amount of the bio-based epoxy chain extender obtained in Embodiment 1 is 0.3% of the total mass of PBS and PGA; then, carrying out injection molding to the composite master batch at 200 C. by using an injection molding machine to obtain PBS/PGA composite spline.

Embodiments 4-6

[0065] The preparation method of PBS/PGA composite material is different from Embodiment 3 in that the addition amount of bio-based epoxy chain extender obtained in Embodiment 1 is 0.5%, 0.7% and 1.0% of the total mass of PBS and PGA in turn.

Embodiment 7

[0066] The preparation method of the PBS/PGA composite material includes the following steps: [0067] mixing PBS, PGA and the bio-based epoxy chain extender obtained in Embodiment 2, and then melting, extruding and granulating with a twin screw to obtain composite master batch, where the temperature of the extruder from the feeding area to the die area is 195-225 C.; among them, the mass ratio of PBS to PGA is 4:1, and the bio-based epoxy chain extender obtained in Embodiment 1 accounts for 0.3% of the total mass of PBS and PGA; then, carrying out injection molding to the composite master batch at 200 C. by using an injection molding machine to obtain PBS/PGA composite spline.

Embodiments 8-10

[0068] The preparation method of the PBS/PGA composite material is different from Embodiment 7 in that the bio-based epoxy chain extender obtained in Embodiment 2 accounts for 0.5%, 0.7% and 1.0% of the total mass of PBS and PGA in turn.

Comparative Embodiment 1

[0069] The preparation method of PBS/PGA composite material is different from Embodiment 3 in that the bio-based epoxy chain extender obtained in Embodiment 1 is not added.

Comparative Embodiment 2

[0070] The preparation method of the PBS/PGA composite material includes the following steps: [0071] mixing PBS, PGA and BASF ADR4468, and then melting, extruding and granulating with a twin screw to obtain composite master batch, where the temperature of the extruder from the feeding area to the head area is 195-225 C.; among them, the mass ratio of PBS and PGA is 4:1, and the amount of ADR4468 is 0.3% of the total mass of PBS and PGA; then, carrying out injection molding to the composite master batch at 200 C. by using an injection molding machine to obtain PBS/PGA composite spline.

Comparative Embodiments 3-5

[0072] The preparation method of the PBS/PGA composite material is different from Embodiment 7 in that the addition amount of BASF ADR4468 is 0.5%, 0.7% and 1.0% of the total mass of PBS and PGA in turn.

Embodiment 11

[0073] The preparation method of the PBS/PGA composite film includes the following steps: [0074] mixing PBS, PGA and the bio-based epoxy chain extender obtained in Embodiment 1, and then melting, extruding and granulating with a twin screw to obtain composite master batch, where the temperature of the extruder from the feeding area to the head area is 195-225 C.; among them, the mass ratio of PBS to PGA is 4:1, and the bio-based epoxy chain extender obtained in Embodiment 1 accounts for 0.7% of the total mass of PBS and PGA; then, carrying out blow-molding to the composite master batch by a blow molding machine at 180-200 C. to obtain the PBS/PGA composite film.

Embodiment 12

[0075] The preparation method of PBS/PGA composite film is different from Embodiment 11 in that the bio-based epoxy chain extender obtained in Embodiment 2 is used.

Comparative Embodiment 6

[0076] The preparation method of PBS/PGA composite film is different from Embodiment 11 in that no chain extender is used.

Comparative Embodiment 7

[0077] The preparation method of PBS/PGA composite film is different from Embodiment 11 in that BASF ADR4468 is used instead of the bio-based epoxy chain extender obtained in Embodiment 1.

Technical Effects

[0078] 1. The products prepared in each embodiment are characterized by the following methods.

[0079] (1)

[0080] Proton nuclear magnetic resonance (.sup.1H NMR) spectroscopy is performed on a Broker Avance 400 instrument with a frequency of 400 MHz, using CDCl.sub.3 as the solvent.

[0081] The thermal stability of each bio-based epoxy chain extender is measured by thermogravimetric analysis (TGA) in STA7200 (Hitachi, Japan). Specifically, under the condition of nitrogen purging, the heating rate is 20 C./min, and the measuring temperature range is 40-500 C. The weight loss rate of each chain extender with the increase of temperature is recorded.

[0082] (2) On the electronic universal testing machine controlled by microcomputer (CMT6104, China), the mechanical properties of injection-molded splines and films are tested according to GB/T1040.1-2006, and the elongation at break (EB, %) and tensile strength (TS, MPa) of the samples are obtained. Among them, the spacing between fixtures is set to 50 mm, the stretching speed is 50 mm/min, and each group of samples is tested for 5-10 times. The average value and the error are calculated.

[0083] Using the same machine, the tear resistance of the film is tested according to the standard of GB/T106578.1-2008. During the test, the distance between fixtures is set to 50 mm, and the tearing rate is 200 mm/min. Each group of samples is tested for 5 times, and the average value is taken according to the effective value.

[0084] (3) Under the condition of JSM-6700F voltage of 10 kV, the microstructure of the sample is analyzed by scanning electron microscope (SEM). Each group of samples is soaked in liquid nitrogen for 15 min, and a thin gold layer is coated on the fracture surface to improve the conductivity of the samples.

[0085] (4) According to ASTM D3985, the O.sub.2 permeability of PBS/PGA composite film is measured by VAC-V2 differential pressure gas permeameter at 23 C. and 30% relative humidity.

[0086] According to GB/T1037, at 38 C. and 90% relative humidity, the water vapor permeability of PBS/PGA composite film is measured by C360M weight loss method with a water vapor permeameter.

[0087] 2. The characterization results and analysis are as follows:

[0088] FIG. 4 shows the .sup.1HNMR spectra of the bio-based epoxy chain extenders obtained in Embodiments 1 and 2.

[0089] By comparing the .sup.1HNMR spectra, it is found that after the oxidation reaction in step (2), the signal peaks of ESO.sub.n-ECD at 5.75 ppm and 5.0 ppm are obviously reduced compared with ESO.sub.n-CD, indicating that the double bond disappears and the epoxidation reaction occurs.

[0090] FIG. 5 shows the thermogravimetric curves of the bio-based epoxy chain extenders obtained in Embodiments 1 and 2, as shown in Table 3. The thermal stability of the synthesized chain extenders is evaluated by TGA. By comparing the weight loss temperature of 5% of the chain extender (T.sub.d-5%), it is found that the thermal stability of ESO.sub.n-ECD is reduced compared to ESO.sub.n-CD, and the thermal stability of ESO.sub.3-ECD is better than that of ESO.sub.6-ECD.

TABLE-US-00001 TABLE 3 Thermal decomposition temperature of chain extender Samples T.sub.d-5%( C.) T.sub.d-10% ( C.) ESO 328.6 364.5 ESO.sub.3-CD 270.3 291.4 ESO.sub.3-ECD 256.4 296.7 ESO.sub.6-CD 342.8 315.7 ESO.sub.6-ECD 218.7 273.8

[0091] The mechanical properties of composite injection-molded splines obtained in Embodiments 3-10 and Comparative embodiments 1-5 are tested, and their tensile properties and impact properties are shown in Table 4, and the compatibilization effects of different chain extenders are studied correspondingly. It is observed from Table 4 that the addition of ADR or ESO.sub.n-ECD may improve the tensile strength and elongation at break of the composite material compared with the compatibilized blends, which proves that the addition of chain extender is capable of enhancing the interfacial bonding force. The epoxy group in the chain extender reacts with carboxyl and/or hydroxyl groups of PBS and PGA, thus promoting effective immobilization between phases. With the content of chain extender increasing from 0.3% to 0.7%, the tensile strength, elongation at break, tensile modulus and impact strength of the composite material are all increased. However, when the content of chain extender continues to increase to 1.0%, the mechanical properties will decrease, which is mainly caused by excessive chain extender. The excessive chain extender fails to react with the terminal carboxyl group of PBS and PGA, and it plays a plasticizing role in the composite, which will lead to the decrease of mechanical properties.

[0092] It may be further observed from Table 4 that the component with 0.7% chain extender in the composite material has the best mechanical properties, among which ESO.sub.n-ECD shows a better value than ADR, which may be due to its lower viscosity, as ESO.sub.n-ECD is an oily liquid with a molecular weight of about 1,000, while ADR is in a solid powder state with a molecular weight of about 6,000-7,000. Generally, during melt mixing, the components with lower viscosity in the blend tend to encapsulate other components. Therefore, ESO.sub.n-ECD should be easier to migrate to the phase interface between PGA and PBS, thus serving as a bridge between the two phases. In addition, the addition of ESO.sub.n-ECD also promotes the significant increase of impact strength, which further proves the enhancement of two-phase interface. From the mechanical properties, it is observed the chain extension and compatibilization effect of ESO.sub.3-ECD is better than ESO.sub.6-ECD. This is related to the number of epoxy groups, which increases as the proportion of cardanol increases in ESO.sub.n-ECD, and a higher number of epoxy groups favours a higher efficiency of the reaction and accelerates the chain extension reaction.

TABLE-US-00002 TABLE 4 Tensile and impact properties of PBS/PGA injection moulded samples Tensile Elongation at Tensile modulus Notched impact Samples strength (MPa) break (%) (MPa) strength (KJ/m.sup.2) Comparative 15.3 1.8 205.7 5.6 180.4 3.1 30.7 2.3 embodiment 1 Comparative 16.54 2.34 248.12 82.72 161.45 47.11 34.35 3.31 embodiment 2 Comparative 17.08 1.12 295.83 63.23 148.93 11.48 37.54 2.44 embodiment 3 Comparative 19.58 3.33 348.98 57.94 153.67 67.36 43.36 3.91 embodiment 4 Comparative 18.36 1.67 321.95 33.54 119.73 13.72 30.64 2.62 embodiment 5 Embodiment 3 19.15 2.12 393.58 43.45 134.92 61.19 34.44 2.12 Embodiment 4 19.62 2.55 401.68 50.94 159.38 95.36 42.09 2.23 Embodiment 5 19.44 3.14 410.38 63.45 165.83 32.03 45.59 3.69 Embodiment 6 18.75 2.65 334.76 79.47 128.63 48.34 43.11 4.73 Embodiment 7 18.68 1.87 388.78 95.43 153.33 57.64 40.37 1.31 Embodiment 8 18.85 2.39 394.55 70.23 147.95 29.84 41.75 2.09 Embodiment 9 19.38 1.27 409.23 52.89 155.27 68.82 43.95 3.44 Embodiment 10 19.48 0.96 396.47 38.03 133.62 19.72 42.32 2.84

[0093] FIG. 6 shows SEM images of injection spline sections of the composite materials obtained from Embodiment 5, Comparative embodiment 1 and Comparative embodiment 4, providing the micro-morphology about the compatibilization of PBS/PGA blends. It may be seen that the injection spline section obtained in Comparative embodiment 1 presents a typical sea-island morphology, and PGA is mainly dispersed in PBS matrix in granular form, and obvious phase interface is observed.

[0094] After adding 0.7% ADR or ESO.sub.3-ECD in Comparative embodiment 4 and Embodiment 5, the phase interface is decreased. The composite injection-molded spline obtained in Embodiment 5 shows a small and well-adhered PGA dispersed phase, in addition to improved compatibility and better interface adhesion.

[0095] The composite films obtained in Embodiments 11-12 and Comparative embodiments 6-7 are shown in FIG. 7. From the appearance and morphology of the composite film, it is observed that the composite film with ESO.sub.3-ECD chain extender obtained in Embodiment 1 has a smoother membrane surface, in addition, the film bubbles are larger and the stability is good during production and processing.

[0096] Tables 5 and 6 show the mechanical properties of PBS/PGA composite films obtained in Comparative embodiments 6-7 and Embodiments 11-12. As shown in the results, the tensile and tear properties of the composite films obtained in Embodiment 11 are the best.

TABLE-US-00003 TABLE 5 Tensile properties of PBS/PGA composite film Tensile strength (MPa) Elongation at break (%) Samples MD TD MD TD Comparative embodiment 6 9.52 0.82 4.34 0.39 374.01 68.48 58.33 5.71 Comparative embodiment 7 9.98 1.03 8.39 0.61 377.71 76.41 153.72 23.03 Embodiment 11 12.27 1.42 7.25 1.68 401.99 49.35 179.84 45.22 Embodiment 12 9.05 1.01 5.12 1.03 270.36 60.27 53.97 14.31

TABLE-US-00004 TABLE 6 Tearing properties of PS/PGA composite film Tensile strength (MPa) Elongation at break (%) Samples MD TD MD TD Comparative embodiment 6 9.52 0.82 4.34 0.39 374.01 68.48 58.33 5.71 Comparative embodiment 7 9.98 1.03 8.39 0.61 377.71 76.41 153.72 23.03 Embodiment 11 12.27 1.42 7.25 1.68 401.99 49.35 179.84 45.22 Embodiment 12 9.05 1.01 5.12 1.03 270.36 60.27 53.97 14.31

[0097] FIG. 8 and FIG. 9 are SEM images of longitudinal and transverse sections of PBS/PGA composite films obtained in Comparative embodiments 6-7 and Embodiment 11, respectively. The composite film obtained in Comparative embodiment 6 without compatibilization modification is similar to the results obtained from the SEM section of injection-molded spline, and PGA is dispersed in the PBS matrix in particles. Due to the weak bonding force between phase interfaces, rigid PGA particles will be pulled out from the flexible PBS matrix during the brittle fracture of the sample, thus leaving holes in the cross section of the composite film obtained in Comparative embodiment 6. However, in Embodiment 11, after adding 0.7% ESO.sub.3-ECD, the two-phase interface in the composite film is obviously reduced, and the transverse and longitudinal sections become smooth, which further explains the good compatibilization effect of ESO.sub.3-ECD.

[0098] In addition, as shown in Table 7, the composite film obtained in Embodiment 11 exhibits the lowest oxygen and water vapour permeability and has good barrier properties due to the reduction of the phase interfaces as compared to the unmodified composite film obtained in Comparative embodiment 6.

TABLE-US-00005 TABLE 7 PBS/PGA composite film oxygen and water vapor permeability Oxygen Water vapour permeability permeability Samples (cm.sup.3/m.sup.2 .Math. 24 h) g/(m.sup.2 .Math. day) Comparative embodiment 6 0.082 287 Comparative embodiment 7 0.063 238 Embodiment 11 0.014 202 Embodiment 12 0.045 267

[0099] According to the present disclosure, a bio-based epoxidized compound is prepared from biological cardanol and epoxidized soybean oil as raw materials, and is used as an active compatibilizer/chain extender additive of a PBS/PGA (80:20 wt %) blend, and meanwhile, the effectiveness of the bio-based compound is compared with the petroleum-derived glycidyl ester-based copolymer ADR4468 widely used in the prior art. The results show that compared with unmodified PBS/PGA incompatible blends, adding 0.7 part of ESO.sub.3-ECD may effectively improve the mechanical properties of composite material/films. It may be clearly seen from SEM that the addition of ESO.sub.3-ECD is capable of strengthening the phase interface of the two phases and plays a bridging role. To sum up, ESO.sub.3-ECD has excellent effect on toughening chain-extended PBS/PGA blends.

[0100] The chain extender prepared by the present disclosure is obtained from monomers of biomass origin, which is green and non-toxic, and is also a good substitute for petroleum-based chain extender. It may be directly applied in the field of food packaging, and the bio-based chain extender solves the problem of poor barrier properties of biodegradable films, as well as makes a positive significance for broadening the application field of PBS.

[0101] The above describes only the preferred embodiments of this application, but the protection scope of this application is not limited to this. Any change or replacement that may be easily thought of by a person familiar with this technical field within the technical scope disclosed in this application should be included in the protection scope of this application. Therefore, the protection scope of this application should be based on the protection scope of the claims.