A bio-based self-assembling amide nucleating agent and its preparation method and application

Abstract

The invention discloses a bio-based self-assembly amide nucleating agent, which is generated by reacting any one of 4-hydroxyphenylethylamine, 3,4-dihydroxyphenylethylamine or 3,4,5-trihydroxyphenylethylamine with terephthaloyl chloride; the nucleating agent of the present invention is mixed with polylactic acid by a melt blending method, and is extruded or injection molded into a polylactic acid product, and can provide good nucleation efficiency for polylactic acid during the preparation process, and the effect of nucleation is very stable, and the obtained polylactic acid product has the characteristics of biodegradability and excellent mechanical properties. This type of nucleating agent preparation method is simple, the raw materials are derived from bio-based, has sustainable development potential, is easy to achieve large-scale production, and can be widely used in the preparation of industrial polylactic acid plastic products.

Description

Technical Field

[0001] The invention belongs to the technical field of plastic additives, and particularly relates to a bio-based self-assembling amide nucleating agent and a preparation method and application thereof. Background Art

[0002] In the past two decades, the depletion of fossil resources and excessive CO2 emissions have caused global climate and environmental deterioration. Therefore, the development of a low-carbon circular economy has become a global consensus. The promotion and application of biodegradable materials is one of the important ways to solve environmental pollution. Among them, polylactic acid (PLA) has become one of the most industrially produced and commercially consumed biodegradable polymers and is widely used in many fields, such as various plastic products, biomedical materials, food packaging and adhesives. Polylactic acid has attracted much attention due to its good biodegradability, biocompatibility and mechanical properties, and has the potential to replace traditional plastics.

[0003] However, the current application of PLA is still far behind that of traditional plastics, mainly because PLA has a slow crystallization speed during the molding process, resulting in poor heat resistance, which limits its application in many industries. Therefore, improving the crystallization ability of PLA is the key to expanding its application range.

[0004] There are some nucleating agents used to improve the crystallization ability of polylactic acid, such as ester nucleating agents, amide compound nucleating agents, hydrazide compound nucleating agents, organic salt nucleating agents, supramolecular nucleating agents, etc. However, most types of nucleating agents are prepared from petroleum-based compounds and are not biodegradable and biocompatible, which limits the wider use of degradable PLA with a sustainable development strategy. Therefore, from the perspective of environmental issues, the development of environmentally friendly bio-based nucleating agents based on natural resources is an important and valuable task. Summary of the invention

[0005] The purpose of the present invention is to overcome the above technical defects and provide an environmentally friendly bio-based self-assembling amide nucleating agent with biodegradability and biocompatibility, which can accelerate the crystallization rate of PLA during the molding process to improve the crystallinity, heat resistance and impact strength of PLA.

[0006] The present invention is achieved through the following technical solutions:

[0007] A bio-based self-assembling amide nucleating agent, wherein the bio-based self-assembling amide nucleating agent has the following structure:

[0008]

[0009] Wherein, R is -OH, and R is substituted at the 4-position, 3,4-position or 3,4,5-position of the benzene ring;

[0010] When R is substituted at the 4-position of the benzene ring, it is N,N-bis[2-(4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide, and its structure is as follows:

[0011]

[0012] When R is substituted at the 3,4-position of the benzene ring, it is N,N-bis[2-(3,4-dihydroxyphenyl)ethyl]-1,4-benzenedicarbamide, and its structure is as follows:

[0013]

[0014] When R is substituted at the 3, 4, 5-position of the benzene ring, it is N, N-bis[2-(3, 4, 5-dihydroxyphenyl)ethyl]-1, 4-benzenedicarbamide, and its structure is as follows:

[0015]

[0016] The present invention provides a method for preparing a bio-based self-assembling amide nucleating agent, comprising the following steps:

[0017] S1: dissolving any one of 4-hydroxyphenylethylamine, 3,4-dihydroxyphenylethylamine or 3,4,5-trihydroxyphenylethylamine in a solvent, uniformly dispersing by ultrasonication, and dropping an acid-binding agent to obtain a mixed solution;

[0018] S2: adding terephthaloyl chloride to a solvent to obtain a terephthaloyl chloride solution;

[0019] S3: In a nitrogen atmosphere, at a reaction temperature of -10 to 10°C, the terephthaloyl chloride solution of S2 is added dropwise to the mixed solution of S1, and after the addition is completed, the mixture is kept warm under stirring, and then the mixture is transferred to room temperature and stirred for reaction, and the stirring is stopped to obtain a reaction solution;

[0020] S4: The reaction solution of S3 is washed with deionized water, filtered to obtain a filter cake, and then washed with methanol, filtered and dried to obtain a bio-based self-assembling amide nucleating agent.

[0021] Preferably, the molar ratio of any one of 4-hydroxyphenethylamine, 3,4-dihydroxyphenethylamine or 3,4,5-trihydroxyphenethylamine to terephthaloyl chloride is 2-10:1.

[0022] Preferably, in S3, the total time for adding the terephthaloyl chloride solution of S2 to the mixed solution of S1 is 1-3 hours.

[0023] Preferably, the acid-binding agent is selected from one or more of pyridine, triethylamine or diisopropylethylamine.

[0024] Preferably, the solvent is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide or tetrahydrofuran.

[0025] Preferably, the time for transferring to room temperature and continuing stirring the reaction in S3 is 12-36 hours.

[0026] Preferably, in the mixed solution of S1, the molar concentration of any one of 4-hydroxyphenylethylamine, 3,4-dihydroxyphenylethylamine or 3,4,5-trihydroxyphenylethylamine is 0.2-1.2 mol / L, the molar concentration of the acid-binding agent is 0.5-1.5 mol / L; and the molar concentration of the terephthaloyl chloride solution in S2 is 0.1-0.4 mol / L.

[0027] The present invention provides application of the above-mentioned bio-based self-assembling amide nucleating agent for preparing a polylactic acid composition.

[0028] The present invention also provides a polylactic acid composition, comprising the above-mentioned bio-based self-assembly amide nucleating agent and polylactic acid.

[0029] The present invention has the following beneficial effects:

[0030] (1) The present invention uses 4-hydroxyphenylethylamine, 3,4-dihydroxyphenylethylamine or 3,4,5-trihydroxyphenylethylamine and terephthaloyl chloride as raw materials to synthesize a bio-based self-assembling amide nucleating agent, which has a simple synthesis route, low processing cost, and a yield of more than 90%.

[0031] (2) The nucleating agent of the present invention belongs to the bio-based self-assembling amide nucleating agent. The raw materials are derived from bio-based materials. The obtained polylactic acid products are biodegradable and are environmentally friendly biomass nucleating agents. They have a significant effect of promoting the crystallization of PLA in polylactic acid, can provide good nucleation efficiency for polylactic acid during the preparation process, and the nucleation effect is very stable. After adding the nucleating agent of the present application, the crystallization temperature of the polylactic acid composition is increased to 121°C at the highest, and the crystallinity is increased by more than 14% compared with pure PLA.

[0032] (3) After adding the nucleating agent of the present application, the heat deformation temperature (HDT) of PLA is significantly increased, and increases with the extension of annealing time. After annealing for 60 seconds, the HDT of the polylactic acid composition can reach a maximum of 121°C, which is at least 13°C higher than that of pure PLA.

[0033] (4) After adding the nucleating agent of the present application, the impact strength of PLA is improved. This is because the addition of the nucleating agent increases the crystallinity of PLA, thereby increasing the impact strength. The polylactic acid composition prepared by the present application has excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1It is the reaction formula of terephthaloyl chloride and 3,4-hydroxyphenylethylamine of the present invention.

[0035] Figure 2 This is the H NMR spectrum of the nucleating agent N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide.

[0036] Figure 3 This is the H NMR spectrum of the nucleating agent N,N-bis[2-(4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide.

[0037] Figure 4 This is the H NMR spectrum of the nucleating agent N,N-bis[2-(3,4,5-dihydroxyphenyl)ethyl]-1,4-benzenedicarbamide.

[0038] Figure 5 This is the DSC spectrum of N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide nucleating agent added to PLA.

[0039] Figure 6 This is the DSC spectrum of N,N-bis[2-(4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide nucleating agent added to PLA.

[0040] Figure 7 This is the DSC spectrum of N,N-bis[2-(3,4,5-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide nucleating agent added to PLA. DETAILED DESCRIPTION

[0041] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0042] The raw materials used in the present invention are all commercially available.

[0043] Various performance test methods:

[0044] (1) DSC test: According to the determination method of GB1662-81, the non-isothermal crystallization and melting behavior of polylactic acid was studied on a differential scanning calorimeter. The sample amount was 5-10 mg in a nitrogen atmosphere. The temperature was raised from room temperature to 200°C at 20°C / min and kept at that temperature for 5 min; then the temperature was lowered from 200°C to room temperature at a rate of 10°C / min, and the crystallization temperature was recorded; finally, the temperature was raised from room temperature to 200°C at a rate of 10°C / min, and the degree of crystallinity was calculated using the DSC program.

[0045] (2) Heat deformation temperature test: According to GB1634-79 plastic bending load heat deformation temperature test method, a SWB-300D Vicat softening tester was used to test the sample in a three-point simply supported beam mode. The length / width / thickness of the test specimen was 80 / 10 / 4 mm, respectively.

[0046] (3) Impact strength test: The impact test strips obtained by injection molding were subjected to impact test according to GB / T 1843-2008 standard.

[0047] Example 1

[0048] 20 mmol of 3,4-dihydroxyphenylethylamine was dissolved in 100 ml of N-methylpyrrolidone (NMP) solvent, and ultrasonicated until it was evenly dispersed, and then 5 ml of pyridine was added to obtain a mixed solution.

[0049] 10 mmol of terephthaloyl chloride was added to 40 ml of NMP solvent and stirred evenly to obtain a terephthaloyl chloride solution.

[0050] Under nitrogen atmosphere, the terephthaloyl chloride solution was slowly added dropwise to the mixed solution, maintaining the system temperature at 0°C for 1 hour; then the mixture was transferred to room temperature and stirred for 24 hours. The reaction formula is as follows: Figure 1 After the reaction, the solid product was washed once with deionized water and filtered to obtain a solid product. The solid product was washed twice with methanol, and then the white solid product was filtered and dried in a vacuum oven set at 80°C to obtain the nucleating agent N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide with a yield of 93.3%.

[0051] The H NMR spectrum of the nucleating agent N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide is shown in Figure 2 As shown. Among them, the chemical shift at 9.7ppm represents -NH-, the chemical shift at 7.8ppm represents the proton signal peak on C6H4, the chemical shift between 7-6.5ppm represents the proton signal peak on C6H3, the chemical shift at 3.5ppm represents the proton signal peak of CH2 connected to the amide, and the chemical shift at 2.7ppm represents the proton signal peak of CH2 connected to the benzene ring, indicating that N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarboxylic acid amide compound can be directly prepared by coupling reaction.

[0052] Example 2

[0053] 40 mmol of 4-hydroxyphenylethylamine was dissolved in 100 ml of N,N-dimethylformamide solvent, and ultrasonicated until it was evenly dispersed, and then 10 ml of triethylamine was added to obtain a mixed solution.

[0054] 10 mmol of terephthaloyl chloride was added to 40 ml of N,N-dimethylformamide solvent and stirred evenly to obtain a terephthaloyl chloride solution.

[0055] Under nitrogen atmosphere, the terephthaloyl chloride solution was slowly added dropwise to the mixed solution, the system temperature was maintained at -10°C, and the reaction time was 2 hours; then the mixture was transferred to room temperature and stirred for 12 hours. After the reaction, the mixture was washed once with deionized water, and the solid product was filtered out, and the solid product was washed twice with methanol. The white solid product was then filtered out and dried in a vacuum oven set at 80°C to obtain the nucleating agent N,N-bis[2-(4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide, with a yield of 90.2%.

[0056] The H NMR spectrum of the nucleating agent N,N-bis[2-(4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide is shown in Figure 3 As shown. The chemical shift at 9.3ppm represents the proton signal peak of -OH on the benzene ring, the chemical shift at 8.6ppm represents -NH-, the chemical shift at 7.8ppm represents the proton signal peak on C6H4, the chemical shift between 7.3-6.5ppm represents the proton signal peak on C6H4 connected to -OH, the chemical shift at 3.5ppm represents the proton signal peak of CH2 connected to the amide, and the chemical shift at 2.7ppm represents the proton signal peak of CH2 connected to the benzene ring, indicating that N,N-bis[2-(4-hydroxyphenyl)ethyl]-1,4-benzenedicarboxylic acid amide compound can be directly prepared by coupling reaction.

[0057] Example 3

[0058] 60 mmol of 3,4,5-trihydroxyphenylethylamine was dissolved in 100 ml of tetrahydrofuran solvent, and ultrasonicated until it was evenly dispersed, and then 5 ml of diisopropylethylamine was added to obtain a mixed solution.

[0059] 10 mmol of terephthaloyl chloride was added to 40 ml of tetrahydrofuran solvent and stirred evenly to obtain a terephthaloyl chloride solution.

[0060] Under nitrogen atmosphere, the terephthaloyl chloride solution was slowly added dropwise to the mixed solution, the system temperature was maintained at 10°C, and the reaction time was 3 hours; then the mixture was transferred to room temperature and stirred for 36 hours. After the reaction, the mixture was washed once with deionized water, and the solid product was filtered out, and the solid product was washed twice with methanol. The white solid product was then filtered out and dried in a vacuum oven set at 80°C to obtain the nucleating agent N,N-bis[2-(3,4,5-dihydroxyphenyl)ethyl]-1,4-benzenedicarbamide, with a yield of 90.1%.

[0061] The H NMR spectrum of the nucleating agent N,N-bis[2-(3,4,5-dihydroxyphenyl)ethyl]-1,4-benzenedicarbamide is shown in Figure 4 As shown. The chemical shifts at 9.6ppm and 8.7ppm represent the proton signal peaks of -OH, the chemical shift at 8.5ppm represents -NH-, the chemical shift at 8.2ppm represents the proton signal peak on C6H4, the chemical shift at 6.1ppm represents the proton signal peak of C6H2, the chemical shift at 3.5ppm represents the proton signal peak of CH2 connected to the amide, and the chemical shift at 2.8ppm represents the proton signal peak of CH2 connected to the benzene ring, indicating that N,N-bis[2-(2,3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarboxylic acid amide compound can be directly prepared by coupling reaction.

[0062] Example 4

[0063] 40 mmol of 3,4-dihydroxyphenylethylamine was dissolved in 100 ml of N-methylpyrrolidone (NMP) solvent, and ultrasonicated until it was evenly dispersed, and then 5 ml of pyridine was added to obtain a mixed solution.

[0064] 10 mmol of terephthaloyl chloride was added to 40 ml of NMP solvent and stirred evenly to obtain a terephthaloyl chloride solution.

[0065] Under nitrogen atmosphere, the terephthaloyl chloride solution was slowly added dropwise to the mixed solution, the system temperature was maintained at 0°C, and the reaction time was 1 hour; then the mixture was transferred to room temperature and stirred for 24 hours. After the reaction was completed, the mixture was washed once with deionized water, and the solid product was filtered out by suction. The solid product was washed twice with methanol, and then the white solid product was filtered out by suction and dried in a vacuum oven set at 80°C to obtain the nucleating agent N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide, with a yield of 95.1%.

[0066] Example 5

[0067] 60 mmol of 3,4-dihydroxyphenylethylamine was dissolved in 100 ml of N-methylpyrrolidone (NMP) solvent, and ultrasonicated until the mixture was evenly dispersed. Then, 5 ml of pyridine was added to obtain a mixed solution.

[0068] 10 mmol of terephthaloyl chloride was added to 40 ml of NMP solvent and stirred evenly to obtain a terephthaloyl chloride solution.

[0069] Under nitrogen atmosphere, the terephthaloyl chloride solution was slowly added dropwise to the mixed solution, the system temperature was maintained at 0°C, and the reaction time was 1 hour; then the mixture was transferred to room temperature and stirred for 24 hours. After the reaction, the mixture was washed once with deionized water, and the solid product was filtered out, and the solid product was washed twice with methanol. The white solid product was then filtered out and dried in a vacuum oven set at 80°C to obtain the nucleating agent N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide, with a yield of 95.6%.

[0070] Example 6

[0071] 100 mmol of 3,4-dihydroxyphenylethylamine was dissolved in 100 ml of N-methylpyrrolidone (NMP) solvent, and ultrasonicated until it was evenly dispersed, and then 5 ml of pyridine was added to obtain a mixed solution.

[0072] 10 mmol of terephthaloyl chloride was added to 40 ml of NMP solvent and stirred evenly to obtain a terephthaloyl chloride solution.

[0073] Under nitrogen atmosphere, the terephthaloyl chloride solution was slowly added dropwise to the mixed solution, the system temperature was maintained at 0°C, and the reaction time was 1 hour; then the mixture was transferred to room temperature and stirred for 24 hours. After the reaction, the mixture was washed once with deionized water, and the solid product was filtered out, and the solid product was washed twice with methanol. The white solid product was then filtered out and dried in a vacuum oven set at 80°C to obtain the nucleating agent N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide, with a yield of 95.7%.

[0074] Example 7

[0075] 20 mmol of 3,4-dihydroxyphenylethylamine was dissolved in 100 ml of N-methylpyrrolidone (NMP) solvent, and ultrasonicated until it was evenly dispersed, and then 5 ml of pyridine was added to obtain a mixed solution.

[0076] 10 mmol of terephthaloyl chloride was added to 40 ml of NMP solvent and stirred evenly to obtain a terephthaloyl chloride solution.

[0077] Under nitrogen atmosphere, the terephthaloyl chloride solution was slowly added dropwise to the mixed solution, the system temperature was maintained at -5°C, and the reaction time was 1 hour; then the mixture was transferred to room temperature and stirred for 24 hours. After the reaction, the mixture was washed once with deionized water, and the solid product was filtered out, and the solid product was washed twice with methanol. The white solid product was then filtered out and dried in a vacuum oven set at 80°C to obtain the nucleating agent N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide, with a yield of 91.3%.

[0078] Example 8

[0079] 20 mmol of 3,4-dihydroxyphenylethylamine was dissolved in 100 ml of N-methylpyrrolidone (NMP) solvent, and ultrasonicated until it was evenly dispersed, and then 5 ml of pyridine was added to obtain a mixed solution.

[0080] 10 mmol of terephthaloyl chloride was added to 40 ml of NMP solvent and stirred evenly to obtain a terephthaloyl chloride solution.

[0081] Under nitrogen atmosphere, the terephthaloyl chloride solution was slowly added dropwise to the mixed solution, the system temperature was maintained at 5°C, and the reaction time was 1 hour; then the mixture was transferred to room temperature and stirred for 24 hours. After the reaction, the mixture was washed once with deionized water, and the solid product was filtered out, and the solid product was washed twice with methanol. The white solid product was then filtered out and dried in a vacuum oven set at 80°C to obtain the nucleating agent N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide, with a yield of 90.1%.

[0082] Example 9

[0083] The polylactic acid and the nucleating agent obtained in Example 1 were dried in an oven at 60°C for 6 hours, and the PLA and the nucleating agent were fully mixed in a mass ratio of 100:0.03. The temperature zones of the extruder were set to 150, 155, 160, 165, 170, and 180°C. The extruder speed was set to 300r / min. The material was then fed into a twin-screw extruder to obtain a polylactic acid composition with a weight percentage of 0.03wt% of N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide, named PLA / NA-1-0.03wt%.

[0084] Example 10

[0085] The polylactic acid and the nucleating agent obtained in Example 1 were dried in an oven at 60°C for 6 hours, and the PLA and the nucleating agent were fully mixed in a mass ratio of 100:0.05. The temperature zones of the extruder were set to 150, 155, 160, 165, 170, and 180°C. The extruder speed was set to 300r / min. The material was then fed into a twin-screw extruder to obtain a polylactic acid composition with a weight percentage of 0.05wt% of N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide, named PLA / NA-1-0.05wt%.

[0086] Embodiment 11

[0087] The polylactic acid and the nucleating agent obtained in Example 1 were dried in an oven at 60°C for 6 hours, and the PLA and the nucleating agent were fully mixed at a mass ratio of 100:0.1. The temperature zones of the extruder were set to 150, 155, 160, 165, 170, and 180°C. The speed of the extruder was set to 300r / min. The material was then fed into a twin-screw extruder to obtain a polylactic acid composition with a weight percentage of 0.1wt% of N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarboxylic acid, named PLA / NA-1-0.1wt%. The DSC spectrum of the nucleating agent N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarboxylic acid added to PLA is shown in FIG. Figure 5 shown.

[0088] Example 12

[0089] The polylactic acid and the nucleating agent obtained in Example 2 were dried in an oven at 60°C for 6 hours, and the PLA and the nucleating agent were fully mixed at a mass ratio of 100:0.1. The temperature zones of the extruder were set to 150, 155, 160, 165, 170, and 180°C. The speed of the extruder was set to 300r / min. The material was then fed into a twin-screw extruder to obtain a polylactic acid composition with a weight percentage of 0.1wt% of N,N-bis[2-(4-hydroxyphenyl)ethyl]-1,4-benzenedicarboxylic acid, named PLA / NA-2-0.1wt%. The DSC spectrum of the nucleating agent N,N-bis[2-(4-hydroxyphenyl)ethyl]-1,4-benzenedicarboxylic acid added to PLA is shown in Figure 6 shown.

[0090] Example 13

[0091] The polylactic acid and the nucleating agent obtained in Example 3 were dried in an oven at 60°C for 6 hours, and the PLA and the nucleating agent were fully mixed at a mass ratio of 100:0.1. The temperature zones of the extruder were set to 150, 155, 160, 165, 170, and 180°C. The speed of the extruder was set to 300r / min. The material was then fed into a twin-screw extruder to obtain a polylactic acid composition with a weight percentage of 0.1wt% of N,N-bis[2-(3,4,5-dihydroxyphenyl)ethyl]-1,4-benzenedicarboxylic acid, named PLA / NA-3-0.1wt%. The DSC spectrum of the nucleating agent N,N-bis[2-(3,4,5-hydroxyphenyl)ethyl]-1,4-benzenedicarboxylic acid added to PLA is shown in Figure 7 shown.

[0092] Comparative Example 1

[0093] 10 mmol of 3,4-dihydroxyphenylethylamine was dissolved in 100 ml of N-methylpyrrolidone (NMP) solvent, and ultrasonicated until the mixture was evenly dispersed. Then, 5 ml of pyridine was added to obtain a mixed solution.

[0094] 10 mmol of terephthaloyl chloride was added to 40 ml of NMP solvent and stirred evenly to obtain a terephthaloyl chloride solution.

[0095] Under nitrogen atmosphere, the terephthaloyl chloride solution was slowly added dropwise to the mixed solution, the system temperature was maintained at 0°C, and the reaction time was 1 hour; then the mixture was transferred to room temperature and stirred for 24 hours. After the reaction, the mixture was washed once with deionized water, and the solid product was filtered out, and the solid product was washed twice with methanol. The white solid product was then filtered out and dried in a vacuum oven set at 80°C to obtain the nucleating agent N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide, with a yield of 48.1%.

[0096] Comparative Example 2

[0097] 20 mmol of 3,4-dihydroxyphenylethylamine was dissolved in 100 ml of N-methylpyrrolidone (NMP) solvent, and ultrasonicated until it was evenly dispersed, and then 5 ml of pyridine was added to obtain a mixed solution.

[0098] 10 mmol of terephthaloyl chloride was added to 40 ml of NMP solvent and stirred evenly to obtain a terephthaloyl chloride solution.

[0099] Under nitrogen atmosphere, the terephthaloyl chloride solution was slowly added dropwise to the mixed solution, the system temperature was maintained at -15°C, and the reaction time was 1 hour; then the mixture was transferred to room temperature and stirred for 24 hours. After the reaction, the mixture was washed once with deionized water, and the solid product was filtered out, and the solid product was washed twice with methanol. The white solid product was then filtered out and dried in a vacuum oven set at 80°C to obtain the nucleating agent N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide, with a yield of 83.4%.

[0100] Comparative Example 3

[0101] 20 mmol of 3,4-dihydroxyphenylethylamine was dissolved in 100 ml of N-methylpyrrolidone (NMP) solvent, and ultrasonicated until it was evenly dispersed, and then 5 ml of pyridine was added to obtain a mixed solution.

[0102] 10 mmol of terephthaloyl chloride was added to 40 ml of NMP solvent and stirred evenly to obtain a terephthaloyl chloride solution.

[0103] Under nitrogen atmosphere, the terephthaloyl chloride solution was slowly added dropwise to the mixed solution, the system temperature was maintained at 25°C, and the reaction time was 1 hour; then the mixture was transferred to room temperature and stirred for 24 hours. After the reaction, the mixture was washed once with deionized water, and the solid product was filtered out, and the solid product was washed twice with methanol. The white solid product was then filtered out and dried in a vacuum oven set at 80°C to obtain the nucleating agent N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide, with a yield of 82.5%.

[0104] Comparative Example 4

[0105] 20 mmol 3,4-dihydroxyphenylethylamine, 20 mmol ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 10 mmol 1-hydroxybenzotriazole were dissolved in 100 ml N-methylpyrrolidone (NMP) solvent, ultrasonicated until uniformly dispersed, and then 5 ml pyridine was added to obtain a mixed solution.

[0106] 10 mmol of terephthaloyl chloride was added to 40 ml of NMP solvent and stirred evenly to obtain a terephthaloyl chloride solution.

[0107] Under nitrogen atmosphere, the terephthaloyl chloride solution was slowly added dropwise to the mixed solution, the system temperature was maintained at 25°C, and the reaction time was 1 hour; then the mixture was transferred to room temperature and stirred for 24 hours. After the reaction was completed, the solid product was filtered and washed twice with 1M hydrochloric acid solution. The white solid product was then filtered and dried in a vacuum oven set at 80°C to obtain the nucleating agent N,N-bis[2-(3,4-hydroxyphenyl)ethyl]-1,4-benzenedicarbamide, with a yield of 77.6%.

[0108] Comparative Example 5

[0109] The polylactic acid and nucleating agent TMC-300 were dried in an oven at 60°C for 6 hours, and the PLA and the nucleating agent were fully mixed at a mass ratio of 100:0.1. The temperature zones of the extruder were set to 150, 155, 160, 165, 170, and 180°C. The extruder speed was set to 300r / min. The materials were then fed into a twin-screw extruder to obtain a polylactic acid composition with a weight percentage of TMC-300 of 0.1wt%, named PLA / TMC-300-0.1wt%.

[0110] Table 1 Test results of polylactic acid compositions and pure polylactic acid in Examples 9-13 and Comparative Example 5

[0111]

[0112] It can be seen from the results in Table 1 that, by comparing Examples 11-13 with Comparative Example 5, the samples to which the bio-based self-assembling amide nucleating agent of the present application is added are superior to the samples to which the conventional nucleating agent TMC-300 is added in terms of crystallization temperature, crystallinity, heat deformation temperature, and impact strength. In particular, in terms of heat deformation temperature, the heat deformation temperature is increased by more than 19°C compared to the samples to which the conventional nucleating agent TMC-300 is added.

Claims

1. An application of a bio-based self-assembling amide nucleating agent, characterized in that: For preparing a polylactic acid composition, the bio-based self-assembling amide nucleating agent has the following structure: Among them, R is -OH, and R is substituted at the 4-position, 3,4-position or 3,4,5-position of the benzene ring.

2. The use of a bio-based self-assembling amide nucleating agent according to claim 1, characterized in that: The preparation method of the bio-based self-assembling amide nucleating agent comprises the following steps: S1: dissolving any one of 4-hydroxyphenylethylamine, 3,4-dihydroxyphenylethylamine or 3,4,5-trihydroxyphenylethylamine in a solvent, uniformly dispersing by ultrasonication, and dropping an acid-binding agent to obtain a mixed solution; S2: adding terephthaloyl chloride to a solvent to obtain a terephthaloyl chloride solution; S3: In a nitrogen atmosphere, at a reaction temperature of -10 to 10°C, the terephthaloyl chloride solution of S2 is added dropwise to the mixed solution of S1, and after the addition is completed, the mixture is kept warm under stirring, and then the mixture is transferred to room temperature and stirred for reaction, and the stirring is stopped to obtain a reaction solution; S4: The reaction solution of S3 is washed with deionized water, filtered to obtain a filter cake, and then washed with methanol, filtered and dried to obtain a bio-based self-assembling amide nucleating agent.

3. The use of a bio-based self-assembling amide nucleating agent according to claim 2, characterized in that: The molar ratio of any one of 4-hydroxyphenylethylamine, 3,4-dihydroxyphenylethylamine or 3,4,5-trihydroxyphenylethylamine to terephthaloyl chloride is 2-10:

1.

4. The use of a bio-based self-assembling amide nucleating agent according to claim 2, characterized in that: In S3, the total time for adding the terephthaloyl chloride solution of S2 to the mixed solution of S1 is 1-3 hours.

5. The use of a bio-based self-assembling amide nucleating agent according to claim 2, characterized in that: The acid-binding agent is selected from one or more of pyridine, triethylamine or diisopropylethylamine.

6. The use of a bio-based self-assembling amide nucleating agent according to claim 2, characterized in that: The solvent is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide or tetrahydrofuran.

7. The use of a bio-based self-assembling amide nucleating agent according to claim 2, characterized in that: The reaction in S3 is transferred to room temperature and stirred for 12-36 hours.

8. The use of a bio-based self-assembling amide nucleating agent according to claim 2, characterized in that: In the mixed solution of S1, the molar concentration of any one of 4-hydroxyphenylethylamine, 3,4-dihydroxyphenylethylamine or 3,4,5-trihydroxyphenylethylamine is 0.2-1.2 mol / L, and the molar concentration of the acid-binding agent is 0.5-1.5 mol / L; the molar concentration of the terephthaloyl chloride solution in S2 is 0.1-0.4 mol / L.

9. The use of a bio-based self-assembling amide nucleating agent according to claim 1, characterized in that: The polylactic acid composition comprises the bio-based self-assembling amide nucleating agent according to claim 1 and polylactic acid.

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