Nucleating / chain extending agent for PBAT, preparation method and application

Abstract

The present invention discloses a nucleating / chain extending agent for PBAT, a preparation method and an application thereof, and the preparation method steps are as follows: S1: dissolving isophthalic acid dihydrazide in N,N-dimethylformamide; S2: adding 1,6-hexanediol diglycidyl ether to the mixed solution of S1 for reaction; S3: precipitating, rotary evaporating, drying and grinding the product after the reaction of S2 to obtain a nucleating / chain extending agent for PBAT. The synthesis process of the present invention is simple, and it can overcome the problems of poor compatibility of existing additives with PBAT, low nucleation efficiency and poor chain extension effect, and it can improve the crystallinity of PBAT and reduce the melt index of PBAT.

Description

Technical Field

[0001] The present invention relates to the technical field of polybutylene terephthalate-adipate functional additives, and in particular to a nucleating / chain extending agent for PBAT, a preparation method and application thereof. Background Art

[0002] Due to the many problems caused by the development and use of traditional non-biodegradable polymer materials, such as white pollution, difficult disposal of waste plastics, and great harm to organisms, the development and application of biodegradable polymer materials can better solve the above problems and conform to the concept of green environmental protection. Therefore, biodegradable polymer materials are receiving more and more attention. PBAT (polybutylene terephthalate-adipate) is an aromatic-fatty polymer material with many advantages such as good flexibility, complete biodegradability, high toughness, excellent tear resistance and good biocompatibility. It is very suitable for film materials and toughening modification of hard and brittle materials such as polylactic acid. However, the disadvantages of PBAT such as low crystallinity, poor rheological properties, low strength and modulus, and low melt strength also greatly limit its application in the above two fields. Therefore, in view of the shortcomings of PBAT itself, it is necessary to perform nucleation modification and chain extension modification on PBAT to improve the mechanical properties, crystallization properties and heat resistance of PBAT and broaden the application range of PBAT.

[0003] At present, for the nucleation modification of PBAT, it is necessary to add a nucleating agent to improve the crystallinity of the polymer and shorten the crystallization time, and improve the crystallization performance and heat resistance of PBAT. For example, the patent with the publication number CN113549305A improves the performance of PBAT by adding at least one of carbon nanotubes, graphene, talcum powder, modified calcium carbonate, carbon black and montmorillonite as an inorganic nucleating agent. However, the inorganic nucleating agent has poor dispersibility in the matrix resin, is easy to agglomerate, and its performance is easily affected by factors such as particle size and shape, which easily leads to the performance degradation or instability of plastic products. For the chain extension modification of PBAT, it is necessary to add a chain extender to improve its melt strength and rheological properties. For example, the patent with the publication number CN108102122A uses a long-chain polyurethane prepolymer terminated with diisocyanate as a chain extender; however, the isocyanate chain extender is highly toxic, which limits the application of PBAT in food. Summary of the invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a nucleating / chain extending agent for PBAT, a preparation method and an application thereof, which has a simple synthesis process and can overcome the problems of poor compatibility between existing additives and PBAT, low nucleating efficiency and poor chain extension effect, and can improve the crystallinity of PBAT and reduce the melt index of PBAT.

[0005] The preparation method of the nucleating / chain extending agent for PBAT proposed by the present invention comprises the following steps:

[0006] S1: dissolving isophthalic acid dihydrazide in N,N-dimethylformamide;

[0007] S2: adding 1,6-hexanediol diglycidyl ether to the mixed solution of S1 to carry out reaction;

[0008] S3: The product after the reaction of S2 is precipitated, rotary evaporated, dried and ground to obtain a nucleating / chain extending agent for PBAT.

[0009] Preferably, the mass volume ratio of isophthalic acid dihydrazide to N,N-dimethylformamide in S1 is 1 g:10-30 mL.

[0010] Preferably, the mass ratio of isophthalic acid dihydrazide to 1,6-hexanediol diglycidyl ether in S2 is 1:4-5.

[0011] Preferably, the reaction temperature in S2 is 110-150° C., the reaction time is 0.5-5 h, and the stirring speed is 200-300 rpm.

[0012] Preferably, the rate of adding 1,6-hexanediol diglycidyl ether is 1-3 drops / second.

[0013] Preferably, the temperature of the rotary evaporation in S3 is 75-85° C. and the rotation speed is 80-120 rpm.

[0014] Preferably, the drying temperature in S3 is 50-70° C. and the drying time is 3-5 h.

[0015] The present invention provides a nucleating / chain extending agent for PBAT prepared by the above method.

[0016] The present invention proposes the use of the above-mentioned PBAT nucleating / chain extending agent in PBAT modification.

[0017] Preferably, the method steps are as follows: melt-extrude PBAT with a nucleating / chain extender and PBAT, the screw speed is 50-100 rpm, and the extrusion temperature zone is set to 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, and 185°C.

[0018] Beneficial technical effects of the present invention:

[0019] (1) The IPH-4HDE prepared by using IPH and HDE as reaction raw materials in the present invention has multiple hydroxyl groups and multiple epoxy functional groups, and has the dual functions of nucleation and chain extension.

[0020] (2) The dropping rate of HDE in the present invention is 1-3 drops / second to prevent insufficient reaction due to too fast a dropping rate and gelation of the product due to too slow a dropping rate.

[0021] (3) In the present invention, the mass ratio of IPH to HDE is controlled to be 1:(4-5), and the synthesized product has four epoxy functional groups, which is easier to form a network structure during the chain extension process, and the melt strength is greatly improved.

[0022] (4) When the nucleation and chain extension integrated functional additive prepared by the present invention is melt-blended with PBAT, it can form multiple hydrogen bonds with the additive to enhance the interaction force between the additive and PBAT, thereby promoting the crystallization of PBAT.

[0023] (5) The additive prepared by the present invention has multiple epoxy functional groups, which can react with the terminal carboxyl groups of PBAT to extend the molecular chain and thus significantly improve its molecular weight and melt strength. At the same time, the reaction can also reduce the acid value and improve the thermal stability of PBAT. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The synthetic reaction formula of IPH-4HDE proposed by the present invention is:

[0025] Figure 2 IR comparison diagram proposed in the present invention; wherein (a) is pure IPH, (b) is pure HDE, and (c) is IPH-4HDE prepared in Example 1;

[0026] Figure 3 It is a comparison diagram of the crystallization / melting curves of the PBAT raw material proposed in the present invention, comparative example 1, comparative example 2, and embodiment 1; wherein (a) is a cooling crystallization process, and (b) is a heating melting process;

[0027] Figure 4 The hydrogen bonding mechanism of PBAT / IPH-4HDE proposed in the present invention;

[0028] Figure 5 This is the chain extension mechanism of PBAT / IPH-4HDE proposed in the present invention. DETAILED DESCRIPTION

[0029] Example 1

[0030] The preparation method of the nucleating / chain extending agent for PBAT proposed by the present invention comprises the following steps:

[0031] S1: Preparation of IPH solution

[0032] First, 50 mL of DMF was measured and placed in a three-necked flask; secondly, 2.91 g of IPH was weighed and dissolved in DMF, and then the temperature was raised to 120 °C, and IPH was completely dissolved using a magnetic stirrer at a stirring speed of 200 rpm.

[0033] S2: Preparation of nucleating / chain extending agents

[0034] First, 13.80 g of HDE was weighed and placed in a constant pressure funnel, and then HDE was added to the IPH solution at a rate of 2 drops / second, the stirring speed was controlled to 250 rpm, the reaction temperature was maintained at 130 °C, and the reaction was carried out for 0.5 h to obtain an IPH-4HDE solution.

[0035] S3: Product processing

[0036] 50 mL of PX was added to the solution in S2 to precipitate the product, and the suspension was placed in a rotary evaporator with the temperature and speed set to 80 °C and 100 rpm, respectively. The product after rotary evaporation was dried in an oven at 60 °C for 4 h. Finally, the dried product was fully ground to obtain IPH-4HDE.

[0037] The method steps of PBAT modification proposed by the present invention are as follows:

[0038] First, weigh 1 kg PBAT and 10 g IPH-4HDE and mix them evenly in a mixer; then, melt-extrude the evenly mixed raw materials at an extrusion speed of 60 rpm, set the extrusion temperature zones to 175, 180, 185, 190, 195, 195, 190, 185 °C, and set the feeding speed to 2 rpm.

[0039] Example 2

[0040] The preparation method of the nucleating / chain extending agent for PBAT proposed by the present invention comprises the following steps:

[0041] S1: Preparation of IPH solution

[0042] First, 50 mL of DMF was measured and placed in a three-necked flask; secondly, 2.91 g of IPH was weighed and dissolved in DMF, and then the temperature was raised to 120 °C, and IPH was completely dissolved using a magnetic stirrer at a stirring speed of 200 rpm.

[0043] S2: Preparation of nucleating / chain extending agents

[0044] First, 12.21 g of HDE was weighed and placed in a constant pressure funnel, and then HDE was added to the IPH solution at a rate of 2 drops / second, the stirring speed was controlled to 250 rpm, the reaction temperature was maintained at 130 °C, and the reaction was carried out for 0.5 h to obtain an IPH-4HDE solution.

[0045] S3: Product processing

[0046] 50 mL of PX was added to the solution in S2 to precipitate the product, and the suspension was placed in a rotary evaporator with the temperature and speed set to 80 °C and 100 rpm, respectively. The product after rotary evaporation was dried in an oven at 60 °C for 4 h. Finally, the dried product was fully ground to obtain IPH-4HDE.

[0047] The method steps of PBAT modification proposed by the present invention are as follows:

[0048] First, weigh 1 kg PBAT and 10 g IPH-4HDE and mix them evenly in a mixer; then, melt-extrude the evenly mixed raw materials at an extrusion speed of 60 rpm, set the extrusion temperature zones to 175, 180, 185, 190, 195, 195, 190, 185 °C, and set the feeding speed to 2 rpm.

[0049] Example 3

[0050] The preparation method of the nucleating / chain extending agent for PBAT proposed by the present invention comprises the following steps:

[0051] S1: Preparation of IPH solution

[0052] First, 50 mL of DMF was measured and placed in a three-necked flask; secondly, 2.91 g of IPH was weighed and dissolved in DMF, and then the temperature was raised to 120 °C, and IPH was completely dissolved using a magnetic stirrer at a stirring speed of 200 rpm.

[0053] S2: Preparation of nucleating / chain extending agents

[0054] First, 14.53 g of HDE was weighed and placed in a constant pressure funnel, and then HDE was added to the IPH solution at a rate of 2 drops / second, the stirring speed was controlled to 250 rpm, the reaction temperature was maintained at 130 °C, and the reaction was carried out for 0.5 h to obtain an IPH-4HDE solution.

[0055] S3: Product processing

[0056] 50 mL of PX was added to the solution in S2 to precipitate the product, and the suspension was placed in a rotary evaporator with the temperature and speed set to 80 °C and 100 rpm, respectively. The product after rotary evaporation was dried in an oven at 60 °C for 4 h. Finally, the dried product was fully ground to obtain IPH-4HDE.

[0057] The method steps of PBAT modification proposed by the present invention are as follows:

[0058] First, 1 kg PBAT and 10 g IPH-4HDE were weighed and mixed evenly in a mixer; then, the evenly mixed raw materials were melt-extruded at an extrusion speed of 60 rpm, the extrusion temperature zones were set to 175, 180, 185, 190, 195, 195, 190, 185 °C, and the feeding speed was set to 2 rpm.

[0059] Comparative Example 1

[0060] The method steps of PBAT modification proposed by the present invention are as follows:

[0061] First, 1 kg PBAT and 10 g IPH were weighed and mixed evenly in a mixer; then, the evenly mixed raw materials were melt-extruded, the extrusion speed was 60 rpm, the extrusion temperature zones were set to 175, 180, 185, 190, 195, 195, 190, 185 °C, and the feeding speed was set to 2 rpm.

[0062] Comparative Example 2

[0063] The method steps of PBAT modification proposed by the present invention are as follows:

[0064] First, 1 kg PBAT and 10 g HDE were weighed and mixed evenly in a mixer; then, the evenly mixed raw materials were melt-extruded at an extrusion speed of 60 rpm, the extrusion temperature zones were set to 175, 180, 185, 190, 195, 195, 190, 185 °C, and the feeding speed was set to 2 rpm.

[0065] The IPH-4HDE prepared by using IPH and HDE as reaction raw materials has multiple hydroxyl groups and multiple epoxy functional groups, and has the dual functions of nucleation and chain extension. The specific reaction formula is as follows: Figure 1 shown.

[0066] The present invention performs infrared detection and analysis on pure IPH, pure HDE and IPH-4HDE respectively. The results are as follows: Figure 2 shown. Figure 2 (a) shows the infrared spectrum of pure IPH, where the -1 -NH in the hydrazide group 2 Infrared absorption peak of Figure 2 (b) shows the infrared spectrum of pure HDE, where 900 cm -1 is the antisymmetric stretching vibration absorption peak of the epoxy group, 1250 cm -1 It is the symmetrical stretching vibration absorption peak of the epoxy group; Figure 2 (c) shows the infrared spectrum of IPH-4HDE. It can be seen that at 3300cm -1 -NH 2The absorption peak at 3500 cm -1 -OH is generated at 913 cm -1 The presence of a large number of epoxy functional groups proves that IPH-4HDE was successfully synthesized.

[0067] The present invention performs differential thermal scanning tests on PBAT / IPH samples, PBAT / HDE samples and PBAT / IPH-4HDE samples. The results are as follows: Figure 3 The crystallization parameters of the samples are shown in Table 1. Figure 3 (a) It can be seen that when IPH-4HDE is added to the system, its crystallization temperature increases significantly, and the crystallization peak moves closer to the high temperature zone. This is because during the cooling process, IPH-4HDE can provide crystal nuclei at higher temperatures and induce PBAT molecular chains to attach to them for growth, thus playing the role of a nucleating agent. Figure 3 (b) It can be seen that when IPH-4HDE is added to the system, the melting temperature increases and the melting peak area increases significantly, indicating that IPH-4HDE can effectively improve the thermal properties of PBAT materials. It can also be seen from Table 1 that when IPH-4HDE is added, the crystallinity of PBAT materials is significantly improved.

[0068] Table 1 Crystallization parameters of samples

[0069]

[0070] The present invention performs melt index test and terminal carboxyl content test on PBAT / IPH samples, PBAT / HDE and PBAT / IPH-4HDE samples, and the results are shown in Table 2. As can be seen from Table 2, after the melt blending reaction of IPH-4HDE and PBAT, the melt index and terminal carboxyl content are significantly reduced. This is because the epoxy functional groups in the IPH-4HDE molecules react with the terminal carboxyl groups of PBAT to increase the length of the PBAT molecular chain and reduce the terminal carboxyl content of PBAT. Moreover, since there are more epoxy functional groups in the IPH-4HDE molecules, the chain extension effect on PBAT is more obvious, significantly improving its melt strength and thermal stability.

[0071] Table 2 Melt index and terminal carboxyl content of samples

[0072]

[0073] Through the study of the nucleation mechanism of PBAT / IPH-4HDE, Figure 4 The mechanism diagram is shown. Figure 4It can be seen that NH and OH in the IPH-4HDE molecule will form multiple hydrogen bonds with O on PBAT, which increases the interaction between IPH-4HDE and PBAT. Therefore, during the cooling crystallization process of the PBAT / IPH-4HDE sample, IPH-4HDE can provide crystal nuclei at a higher temperature and induce the PBAT molecular chain to grow tightly attached thereto through hydrogen bonding, thereby promoting the crystallization of PBAT.

[0074] Through the exploration of the chain extension mechanism of PBAT / IPH-4HDE, Figure 5 The mechanism diagram is shown. Figure 5 It can be seen that during the melt blending process of IPH-4HDE and PBAT, the epoxy functional group in the IPH-4HDE molecule undergoes a ring-opening reaction with the terminal carboxyl group of PBAT, which lengthens the PBAT molecular chain to increase its molecular weight, while also reducing the PBAT acid value to improve its thermal stability.

Claims

1. Preparation method of nucleating / chain extending agent for PBAT, It is characterized in that The steps are as follows: S1: dissolving isophthalic acid dihydrazide in N,N-dimethylformamide; S2: adding 1,6-hexanediol diglycidyl ether to the mixed solution of S1 to carry out reaction; S3: precipitating, rotary evaporating, drying and grinding the product after the reaction in S2 to obtain a nucleating / chain extending agent for PBAT; The synthetic reaction formula of PBAT nucleating / chain extending agent is as follows: Among them, IPH is isophthalic acid dihydrazide; HDE is 1,6-hexanediol diglycidyl ether; IPH-4HDE is a nucleating / chain extender for PBAT.

2. The method for preparing the nucleating / chain extending agent for PBAT according to claim 1, It is characterized in that The mass volume ratio of phthalic acid dihydrazide and N,N-dimethylformamide in S1 is 1g:10-30mL.

3. The method for preparing the nucleating / chain extending agent for PBAT according to claim 1, It is characterized in that The mass ratio of isophthalic acid dihydrazide to 1,6-hexanediol diglycidyl ether in S2 is 1:4-5.

4. The method for preparing a nucleating / chain extending agent for PBAT according to claim 1, It is characterized in that The reaction temperature in S2 is 110-150°C, the reaction time is 0.5-5h, and the stirring speed is 200-300rpm.

5. The method for preparing a nucleating / chain extending agent for PBAT according to claim 1, It is characterized in that The rate of addition of 1,6-hexanediol diglycidyl ether is 1-3 drops / second.

6. The method for preparing the nucleating / chain extending agent for PBAT according to claim 1, It is characterized in that The temperature of the rotary evaporation in S3 is 75-85°C and the rotation speed is 80-120rpm.

7. The method for preparing a nucleating / chain extending agent for PBAT according to claim 1, It is characterized in that The drying temperature in S3 is 50-70°C and the drying time is 3-5h.

8. A nucleating / chain extending agent for PBAT prepared by the method according to any one of claims 1 to 7.

9. Use of the PBAT nucleating / chain extending agent as claimed in claim 8 in PBAT modification.

10. Use of the PBAT nucleating / chain extending agent according to claim 9 in PBAT modification, It is characterized in that The method steps are as follows: melt-extrude PBAT with a nucleating / chain extender, the screw speed is 50-100 rpm, and the extrusion temperature zone is set to 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, and 185°C.

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