Aminated tung oil-based polyvinyl alcohol, preparation method thereof and application thereof in PBAT

Abstract

The present invention discloses aminated tung oil-based polyvinyl alcohol, its preparation method and its application in PBAT. The preparation method of the composite material comprises the following steps: first, alcoholysis of tung oil is carried out with ethanol, and then, under the action of the catalyst cobalt(II) terephthalate, diethylenetriamine is added to aminate the alcoholyzed tung oil to obtain aminated tung oil; the aminated tung oil and polyvinyl alcohol are uniformly mixed and reacted to obtain an aminated tung oil-plasticized polyvinyl alcohol material; the above plasticized polyvinyl alcohol material and PBAT are mixed and melt-extruded to obtain a tung oil-based polyvinyl alcohol / PBAT composite material. The present invention uses aminated tung oil to plasticize polyvinyl alcohol, through chemical grafting and physical hydrogen bond methods. At the same time, the large tung oil molecules can inhibit the outward migration of the plasticizer and maintain the internal plasticization performance of polyvinyl alcohol. The aminated tung oil-based polyvinyl alcohol can also form stable chemical bonds with PBAT, improving the compatibility between the two and enhancing the mechanical effect of the composite material.

Description

Technical Field

[0001] The present invention relates to the technical field of polyvinyl alcohol composite materials, and particularly to aminated tung oil-based polyvinyl alcohol, a preparation method thereof, and an application thereof in PBAT. Background Art

[0002] Polyvinyl alcohol (PVA) is a white, stable, non-toxic polymer, in the form of a powder, flake or flocculent solid. It has good biodegradability, water solubility and barrier properties. Therefore, PVA is regarded as an environmentally friendly polymer material, and it is of great significance to realize the substitution of conventional petrochemical-derived polymers. However, there are strong intermolecular and intramolecular hydrogen bonds between PVAs, and the structural regularity of the —OH groups on the PVA main chain is very high, resulting in high crystallinity and melting point, approaching or higher than its decomposition temperature. Therefore, the thermal processing of PVA is very difficult, which is the main challenge in the production of PVA products. There are two main strategies for the treatment of PVA. One main solution is to introduce additional side groups or incorporate comonomers through new polymerization techniques to disrupt the chain regularity and hydrogen bond network. Another strategy is to add plasticizers, which form hydrogen bonds with the hydroxyl groups of PVA, and can effectively reduce the inherent intermolecular and intramolecular hydrogen bonds of PVA, thereby realizing the thermal processing of PVA. Poly(butylene adipate-co-terephthalate) (PBAT) is a thermoplastic degradable plastic with good ductility and elongation at break, but its low crystallinity, poor rheological properties and low melt strength limit its development in the application field. It is expected that the performance of the composite material can be improved by mixing PVA and PBAT, broadening the scope of use and expanding the market scale.

[0003] The introduction of plasticizers will reduce the intermolecular interaction between PVAs, promote the reduction of the crystallinity and melting point of PVA, thereby expanding the processing window and easily realizing the melt processing ability of PVA. For example, glycerol is often used as a traditional plasticizer for PVA plasticization because it contains hydroxyl groups in polyols. However, its disadvantage is that it is easy to precipitate, and migration and oiling phenomena are likely to occur. Another example is to add plasticizers such as plasticized starch, polylactic acid, polyvinyl alcohol and phthalate esters to improve the overall effect of the blend system. For the plasticization of polyvinyl alcohol materials, it is changed by physical hydrogen bonds, and the plasticization effect is not obvious. Also, degradable plastics such as PBAT, PVA and polylactic acid are directly melt-extruded to obtain recycled plastic particles, but they have defects in compatibility and little improvement in mechanical properties. Summary of the Invention

[0004] Based on the technical problems existing in the background art, the present invention proposes aminated tung oil-based polyvinyl alcohol, a preparation method thereof, and an application thereof in PBAT, enhancing the performance of the composite material.

[0005] The preparation method of the aminated tung oil-based polyvinyl alcohol proposed by the present invention comprises the following method steps:

[0006] S1: The tung oil and absolute ethanol are subjected to alcoholysis reaction under the action of a catalyst to obtain ethyl tungate.

[0007] S2: The ethyl tungate and diethylenetriamine are subjected to amination reaction to obtain aminated tung oil.

[0008] S3: The aminated tung oil and polyvinyl alcohol are mixed and kneaded, and then extruded and pelletized to obtain aminated tung oil-based polyvinyl alcohol.

[0009] Preferably, the catalyst is cobalt(II) terephthalate.

[0010] Preferably, the mass ratio of tung oil, absolute ethanol and the catalyst is 2 - 5:1:0.001 - 0.003; the alcoholysis reaction temperature is 40 - 55 °C, and the time is 4 - 6 h.

[0011] Preferably, the mass ratio of ethyl tungate, diethylenetriamine and absolute ethanol is 1:3 - 6:8 - 9; the amination reaction temperature is 65 - 80 °C, and the time is 6 - 8 h.

[0012] Preferably, the mass ratio of aminated tung oil and polyvinyl alcohol is 0.10 - 0.40:1; the kneading temperature is 175 - 185 °C, the time is 6 - 10 min, and the rotation speed is 40 - 60 r / min.

[0013] The aminated tung oil-based polyvinyl alcohol proposed by the present invention is prepared by the above preparation method.

[0014] The present invention proposes the application of the above aminated tung oil-based polyvinyl alcohol in PBAT.

[0015] The present invention proposes a preparation method of a PBAT composite material, and the method steps are as follows: Poly(butylene adipate-co-terephthalate) and the above aminated tung oil-based polyvinyl alcohol are uniformly mixed and melt-extruded to obtain a composite material.

[0016] Preferably, the mass ratio of aminated tung oil-based polyvinyl alcohol and poly(butylene adipate-co-terephthalate) is 1:1 - 4; the mixing temperature is 40 - 55 °C, and the time is 1 - 2 h.

[0017] Preferably, the melt-extrusion conditions are: the screw rotation speed is 100 - 130 rpm, the feeding speed is 5 - 7 Hz, and the extrusion temperature zones are set at 165, 170, 170, 175, 180, 180, 175, 170 °C.

[0018] The beneficial technical effects of the present invention:

[0019] In the present invention, aminated tung oil is used as a plasticizer for polyvinyl alcohol. The tung oil-based macromolecules inhibit migration and maintain the properties of the polyvinyl alcohol material after plasticization. The amino groups in the aminated tung oil can react with the hydroxyl groups of polyvinyl alcohol to form chemical bonds, destroying the internal and external structures of the polyvinyl alcohol molecules, weakening the intermolecular forces, making them more mobile, and thus increasing the plasticity of polyvinyl alcohol.

[0020] In the present invention, the aminated tung oil-based polyvinyl alcohol after plasticization treatment has C=O and -NH structures, which can form more stable hydrogen bonds with -OH in polyvinyl alcohol, breaking the internal hydrogen bond network of the polyvinyl alcohol material, and improving the plasticization effect under the dual action of chemical grafting and physical hydrogen bonds.

[0021] In the present invention, the blending modification of plasticized polyvinyl alcohol and poly(butylene adipate-co-terephthalate) has the characteristics of simple process. The plasticized polyvinyl alcohol can form chemical bond connections with the terminal hydroxyl groups of poly(butylene adipate-co-terephthalate), improving the compatibility of the two materials and enhancing the mechanical properties of the composite material. Description of the Drawings

[0022] Figure 1 It is the infrared spectrogram of ATOEE-1, PVA, ATOEE-PVA-1 and ATOEE-PVA / PBAT-1 samples in Example 1 proposed by the present invention;

[0023] Figure 2 It is the schematic diagram of the synthesis mechanism of ATOEE-PVA / PBAT proposed by the present invention. Detailed Embodiments

[0024] The present invention will be further explained below in conjunction with specific embodiments.

[0025] Example 1

[0026] Weigh 2 kg of tung oil (TO) and 1 kg of absolute ethanol (EtOH), mix and stir them, add 1 g of cobalt terephthalate as a catalyst, react at a temperature of 45 °C for 4 h to obtain ethyl tung oil (TOEE). Dissolve 1 kg of TOEE and 3 kg of diethylenetriamine (DETA) in 8 kg of EtOH, react at a temperature of 80 °C for 6 h to obtain aminated tung oil, denoted as ATOEE-1. Mix 0.2 kg of the above ATOEE-1 and 1 kg of PVA by internal mixing, the internal mixing temperature is 185 °C, the time is 8 min, and the rotation speed is 40 r / min for extrusion granulation to obtain an aminated tung oil-based polyvinyl alcohol material, denoted as ATOEE-PVA-1.

[0027] Weigh 1 kg of ATOEE-PVA-1 and 2 kg of poly(butylene adipate-co-terephthalate) (PBAT), and mix them at high speed for 1 h to obtain a masterbatch. Melt-extrude the masterbatch with a screw speed of 120 rpm, a feeding speed of 6 Hz, and the extrusion temperature zones set at 165, 170, 170, 175, 180, 180, 175, 170 °C to obtain a composite material, denoted as ATOEE-PVA / PBAT-1.

[0028] Example 2

[0029] Weigh 2 kg of TO and 1 kg of EtOH, mix and stir them, add 1 g of cobalt(II) terephthalate as a catalyst, react at a temperature of 45 °C for 4 h to obtain TOEE. Dissolve 1 kg of TOEE and 5 kg of DETA in 8 kg of EtOH, react at a temperature of 80 °C for 6 h to obtain amino-functionalized tung oil, denoted as ATOEE-2. Mix 0.2 kg of the above ATOEE-2 and 1 kg of PVA by internal mixing, with an internal mixing temperature of 185 °C, a time of 8 min, and a rotation speed of 40 r / min for extrusion granulation to obtain an amino-functionalized tung oil-based polyvinyl alcohol material, denoted as ATOEE-PVA-2.

[0030] S2: Weigh 1 kg of ATOEE-PVA-2 and 2 kg of PBAT, mix them at high speed for 1 h to obtain a masterbatch. Melt-extrude the masterbatch with a screw speed of 120 rpm, a feeding speed of 6 Hz, and the extrusion temperature zones set at 165, 170, 170, 175, 180, 180, 175, 170 °C to obtain a composite material, denoted as ATOEE-PVA / PBAT-2.

[0031] Example 3

[0032] Weigh 1 kg of ATOEE-PVA-1 and 1 kg of PBAT, mix them at high speed for 1 h to obtain a masterbatch. Melt-extrude the masterbatch with a screw speed of 120 rpm, a feeding speed of 6 Hz, and the extrusion temperature zones set at 165, 170, 170, 175, 180, 180, 175, 170 °C to obtain a composite material, denoted as ATOEE-PVA / PBAT-3.

[0033] Comparative Example 1

[0034] Weigh 1 kg of PVA and 2 kg of PBAT, mix them at high speed for 1 h to obtain a masterbatch. Melt-extrude the masterbatch with a screw speed of 120 rpm, a feeding speed of 6 Hz, and the extrusion temperature zones set at 165, 170, 170, 175, 180, 180, 175, 170 °C to obtain a composite material, denoted as PVA / PBAT-1.

[0035] Comparative Example 2

[0036] Weigh 0.2 kg of TO, 1 kg of PVA, and 2 kg of PBAT, and mix them at high speed for 1 h to obtain the masterbatch; melt-extrude the masterbatch with a screw speed of 120 rpm, a feeding speed of 6 Hz, and the extrusion temperature zones set at 165, 170, 170, 175, 180, 180, 175, 170 °C to obtain the composite material, denoted as PVA / PBAT-2.

[0037] Comparative Example 3

[0038] Weigh 2 kg of TO and 1 kg of EtOH, mix and stir them, add 1 g of cobalt(II) terephthalate as a catalyst, react at a temperature of 45 °C for 4 h to obtain TOEE. Dissolve 1 kg of TOEE and 3 kg of DETA in 8 kg of EtOH, react at a temperature of 80 °C for 6 h to obtain ATOEE. Mix 0.4 kg of the above ATOEE and 1 kg of PVA by internal mixing, with an internal mixing temperature of 185 °C, a time of 8 min, and a rotation speed of 40 r / min for extrusion granulation to obtain ATOEE-PVA-3.

[0039] Weigh 1 kg of ATOEE-PVA-3 and 2 kg of PBAT, and mix them at high speed for 1 h to obtain the masterbatch; melt-extrude the masterbatch S1 with a screw speed of 120 rpm, a feeding speed of 6 Hz, and the extrusion temperature zones set at 165, 170, 170, 175, 180, 180, 175, 170 °C to obtain the composite material, denoted as ATOEE-PVA / PBAT-4.

[0040] The present invention conducts mechanical property tests on the samples prepared in Examples 1-3 and Comparative Examples 1-3, and the results are shown in Table 1. Among them, the standards for tensile strength and elongation at break tests are GB / T 1040.1-2018 "Plastics - Determination of tensile properties"; the standards for flexural strength and flexural modulus tests are GB / T 9341-2008 "Plastics - Determination of flexural properties".

[0041] Table 1 Mechanical properties of the samples

[0042]

[0043] As can be seen from Table 1, the sample prepared in Example 1 has the best mechanical properties, with a tensile strength of 32.18 Mpa, an elongation at break of 620%, a flexural strength of 22.67 Mpa, and a flexural modulus of 2.35 GPa. From Comparative Examples 1 and 2, it can be seen that the mechanical properties of the composite materials obtained by directly mixing PVA and PBAT or directly adding TO are not prominent. By comparing Example 1 with Comparative Example 3, it is proved that the larger the addition amount of ATOEE, the better the mechanical properties are not achieved, and an appropriate proportion condition still needs to be satisfied. In the examples, the tensile strength of the composite material obtained by melt extrusion of plasticized and post-treated PVA and PBAT increased by up to 71.28%, and the flexural strength increased by up to 46.73%. This is because the aminated tung oil chemically grafted the hydroxyl groups inside the PVA molecules, reducing the hydroxyl groups and weakening the strong intermolecular and intramolecular hydrogen bond interactions, promoting its processability. The plasticized ATOEE-PVA can also form chemical bonds with PBAT at the same time, improving the compatibility of the two materials, and thus showing a more obvious improvement effect in terms of mechanics.

[0044] In the present invention, infrared detection and analysis were respectively carried out on the ATOEE-1, PVA, ATOEE-PVA-1, and ATOEE-PVA / PBAT-1 samples in Example 1, and the results are as Figure 1 shown. As can be seen from the figure, the absorption peak appearing at 1732 cm -1 in the spectrum is the C=O stretching vibration. At the same time, -NH peaks appear at 3413 cm -1 and 3469 cm -1 , which may be its stretching vibration. The absorption peak at 1634 cm -1 represents the rocking vibration of N-H, and the absorption peak at 1025 cm -1 corresponds to the C-N vibration. The peak at 622 cm -1 is attributed to the twisting vibration of N-H, indicating the formation of ATOEE. The main characteristic absorption peaks of PVA are the -OH stretching vibration absorption peak at 3311 cm -1 , the -CH -1 stretching vibration absorption peak at 2921 cm 2 , and the C-O-C stretching vibration absorption peak at 1086 cm -1 . In the spectrum of ATOEE-PVA, the characteristic peaks of ATOEE appear, indicating that ATOEE is successfully introduced into the PVA material. In ATOEE-PVA / PBAT, the absorption peak at 1732 cm -1 becomes sharp and strong, representing that the aminated tung oil-based PVA reacts with the terminal hydroxyl groups of PBAT to produce ester groups, and there is a chemical connection between PBAT and the ATOEE-PVA material.

[0045] Figure 2It is a schematic diagram of the preparation mechanism of the ATOEE-PVA / PBAT composite material proposed by the present invention. As Figure 2 shown, first, in step ①, tung oil is alcoholyzed with absolute ethanol to form larger TOEE molecules; next, in step ②, the obtained TOEE is aminated. In cobalt(II) terephthalate, the divalent cobalt ion can serve as the active center of the catalyst, effectively activating the amino group of DETA and catalyzing the reaction between the amino group and the ester group of TOEE to obtain aminoated tung oil, that is, ATOEE. In the next step, in step ③, PVA polymer is added, and ATOEE and PVA are mixed by kneading. The -NH 2 of the aminoated tung oil can chemically graft with the -OH of PVA to form a stable chemical bond connection, breaking the hydrogen bond structure of PVA and plasticizing the PVA material, thereby obtaining ATOEE-PVA. Finally, in step ④, the above-mentioned aminoated tung oil-based PVA and PBAT are under the condition of melt extrusion. After plasticization, the carboxyl bond of PVA can connect with the terminal hydroxyl chemical bond of PBAT to form an ATOEE-PVA / PBAT composite material with good compatibility.

[0046] Although the embodiments of the present application have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application. The scope of the present application is defined by the appended claims and their equivalents and should be included within the protection scope of the present application.

Claims

1. A method for preparing aminated tung oil-based polyvinyl alcohol, characterized in that: The steps are as follows: S1: Tung oil and anhydrous ethanol undergo alcoholysis reaction under the action of a catalyst to obtain tung oil ethyl ester; S2: Tung oil ethyl ester and diethylenetriamine undergo amination reaction to obtain aminated tung oil; S3: aminated tung oil and polyvinyl alcohol are mixed and kneaded, and extruded and granulated to obtain aminated tung oil-based polyvinyl alcohol; The catalyst is cobalt(II) terephthalate; Among them, the structural formula of tung oil is as follows: The structural formula of tung oil ethyl ester is as follows: The structural formula of aminated tung oil is as follows: The structural formula of aminated tung oil-based polyvinyl alcohol is as follows: 。 2. The method for preparing aminated tung oil-based polyvinyl alcohol according to claim 1, characterized in that: The mass ratio of tung oil, anhydrous ethanol and catalyst is 2-5:1:0.001-0.003; the alcoholysis reaction temperature is 40-55°C, and the time is 4-6 h.

3. The method for preparing aminated tung oil-based polyvinyl alcohol according to claim 1, characterized in that: The mass ratio of tung oil ethyl ester, diethylenetriamine and anhydrous ethanol is 1:3-6:8-9; the amination reaction temperature is 65-80 ℃, and the time is 6-8 h.

4. The method for preparing aminated tung oil-based polyvinyl alcohol according to claim 1, characterized in that: The mass ratio of aminated tung oil to polyvinyl alcohol is 0.10-0.40:1; the banburying temperature is 175-185°C, the time is 6-10 min, and the speed is 40-60 r / min.

5. An aminated tung oil-based polyvinyl alcohol, characterized in that: The method is prepared according to any one of claims 1 to 4.

6. Use of the aminated tung oil-based polyvinyl alcohol as claimed in claim 5 in PBAT.

7. A method for preparing a PBAT composite material, characterized in that: The method comprises the following steps: uniformly mixing polybutylene terephthalate-adipate and the aminated tung oil-based polyvinyl alcohol as claimed in claim 5, and melt-extruding to obtain a composite material.

8. The method for preparing the PBAT composite material according to claim 7, characterized in that: The mass ratio of aminated tung oil-based polyvinyl alcohol to polybutylene terephthalate-adipate is 1:1-4; the mixing temperature is 40-55°C, and the mixing time is 1-2 h.

9. The method for preparing the PBAT composite material according to claim 7, characterized in that: The melt extrusion conditions were as follows: screw speed of 100-130 rpm, feed rate of 5-7 Hz, and extrusion temperature zones of 165, 170, 170, 175, 180, 180, 175, 170 °C.

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