CN114015119B

CN114015119B - High-thermal-stability cucurbituril-aluminum hypophosphite inclusion compound and preparation method and application thereof

Info

Publication number: CN114015119B
Application number: CN202111415057.4A
Authority: CN
Inventors: 程飞; 张熊; 陆钊申
Original assignee: Jiangsu Tonghe New Material Technology Co ltd; Guangdong Shunde Tongcheng New Materials Technology Co ltd
Current assignee: Jiangsu Tonghe New Material Technology Co ltd; Guangdong Shunde Tongcheng New Materials Technology Co ltd
Priority date: 2021-11-25
Filing date: 2021-11-25
Publication date: 2023-06-30
Anticipated expiration: 2041-11-25
Also published as: CN114015119A

Abstract

The invention discloses a cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability, and a preparation method and application thereof. According to the invention, cucurbituril (CB [ n ]) is used as a main body, aluminum Hypophosphite (AHP) is used as an object, and a dipole-dipole acting force between the main body and the object is utilized to obtain the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability through one-step reaction. The preparation method of the inclusion compound comprises the following steps: (1) Dispersing the CB [ n ] after the activation treatment in a reaction vessel containing a solvent A; (2) And adding AHP into the solution by controlling the mass ratio of CB [ n ] to AHP, stirring for reaction, and performing suction filtration and drying to obtain the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability. According to the invention, the components of CB [ n ] and the proportion of each component are changed to successfully prepare the serial cucurbituril-aluminum hypophosphite inclusion compound, so that the precise regulation and control of the decomposition temperature of AHP are realized, the thermal stability of AHP is obviously improved, and meanwhile, the flame retardant coating has excellent char formation and flame retardance, and has great development potential in the field of high polymer flame retardance.

Description

High-thermal-stability cucurbituril-aluminum hypophosphite inclusion compound and preparation method and application thereof

Technical Field

The invention relates to the technical field of flame retardant materials, in particular to a cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability, and a preparation method and application thereof.

Background

Aluminum Hypophosphite (AHP) is used as a novel halogen-free efficient flame retardant material, and has the advantages of low cost, environmental friendliness, high phosphorus content (about 42%), high flame retardant efficiency, low volatility and the like, so that the aluminum hypophosphite becomes one of the hot spots for research and development at home and abroad. AHP is widely applied to various high polymer materials such as polyamide series (PA 6, PA 66) and polyester series (PBT, PET) as a high-efficiency halogen-free flame retardant, has excellent flame retardant effect and good synergistic flame retardant effect. However, AHP has many drawbacks such as poor thermal stability and corrosiveness to processing equipment, which greatly limits the wide application of AHP in the field of high molecular flame retardance. Wherein poor thermal stability results in AHP producing a toxic and flammable pH during processing ₃ Further, polymer degradation and burning can be caused, which is a fatal defect for use as a highly efficient flame retardant material. Therefore, the preparation of the AHP flame retardant material with high thermal stability has great practical application value and significance.

Cucurbiturils (CB [ n ]) are a class of nitrogen-containing cyclic compounds with hydrophobic cavities and hydrophilic carbonyl ports, which develop after crown ethers, calixarenes, and cyclodextrins, and can form supermolecular self-assembled inclusion compounds by hydrophobic interactions, hydrogen bonds, pi-pi stacking, ion-dipole and dipole-dipole interactions with small organic molecules, biological macromolecules, ionic compounds, and the like. Currently, most studies are to improve the thermal stability of AHP materials by microcapsule technology. However, the method has high cost and large pollution, and the outer layer of the capsule is unstable and is easy to decompose to generate toxic gas, so that the thermal stability of AHP can not be effectively improved, and the application limitation is large. So far, no report has been made on the preparation of high thermal stability cucurbituril-aluminum hypophosphite inclusion compound by changing the components and the proportion of each component of CB [ n ] through systematic research to realize the precise regulation and control of AHP decomposition temperature.

Disclosure of Invention

Aiming at the problems existing in the prior art, the invention aims to provide a cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability, and a preparation method and application thereof.

The technical scheme adopted by the invention is as follows: a preparation method of a cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability comprises the following steps:

(1) Dispersing the CB [ n ] after the activation treatment in a reaction vessel containing a solvent A;

(2) And adding AHP into the solution by controlling the mass ratio of CB [ n ] to AHP, stirring for reaction, and performing suction filtration and drying to obtain the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability.

The cucurbituril-aluminum hypophosphite inclusion compound provided by the invention takes CB [ n ] as a main body and AHP as a guest, and a novel flame retardant with high thermal stability is obtained through one-step reaction by utilizing dipole-dipole acting force between the main body and the guest.

Preferably, the activation temperature of the activation treatment in the step (1) is 90-160 ℃, and the activation time is 4-8 h. The solvent A in the step (1) is selected from more than one of distilled water, tetrahydrofuran, ethanol and methanol.

Preferably, the mass ratio of CB [ n ] after the activation treatment in the step (1) to the solvent A is 1:40-90.

Preferably, the mass ratio of CB [ n ] to AHP in step (2) is from 0.02 to 0.7:1.

Preferably, CB [ n ] in step (2) is selected from two or more of CB [5], CB [6], CB [7], CB [8], CB [9], CB [10] and CB [11 ].

Further preferably, CB [ n ] is selected from two or more of CB [5], CB [6], CB [7] and CB [8], and CB [ n ] is a two-component, three-component or four-component.

In the CB [ n ], the decomposition temperature at the position of the AHP weight loss rate of 1wt% is regulated and controlled at 294-337 ℃ by changing the fraction of the CB [ n ] component and the proportion of each component. The two components CB [ n ] are CB [5] and CB [6], CB [7] and CB [6], CB [8] and CB [6], respectively, and the mass ratio of the fixed former to the latter is (0.3-0.7): 1, a step of; the three components CB [ n ] are CB [5], CB [6] and CB [8], and the mass ratio of the three components is fixed to be (0.08-0.4): (0.3-0.8): 1, a step of; the four components CB [ n ] are CB [5], CB [6], CB [7], CB [8], and the mass ratio of the four components is fixed to be (0.03-0.3): (0.2-0.5): (0.08-0.4): 1.

preferably, the reaction temperature in the step (2) is 40-120 ℃, the reaction time is 3-11 h, and the drying mode is vacuum 70-120 ℃ for 10-15 h.

Preferably, the average particle size of the AHP is 0.5-20 μm, and the pH value of the AHP is 3-5.5.

The invention also protects the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability, which is obtained by the preparation method. CB [ n ] is uniformly coated on the surface of AHP.

The invention also protects the application of the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability in preparation of polyamide flame-retardant materials or polyester flame-retardant materials.

Compared with the prior art, the invention has the advantages that:

(1) The invention not only provides a preparation method of the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability, but also provides a new way for designing and synthesizing a novel thermal stability flame-retardant inclusion compound material.

(2) According to the invention, the components of CB [ n ] and the proportion of each component are changed to successfully prepare the serial cucurbituril-aluminum hypophosphite inclusion compound, so that the precise regulation and control of the decomposition temperature of AHP are realized, the thermal stability of AHP is obviously improved, and meanwhile, the flame retardant coating has excellent char formation and flame retardance, and has great development potential in the field of high polymer flame retardance.

(3) The preparation method provided by the invention has the advantages of economy, environmental protection, mild reaction conditions, good repeatability, easiness in industrialization and the like, and the obtained cucurbituril-aluminum hypophosphite inclusion compound has excellent flame retardant property and is expected to realize large-scale application.

Drawings

FIG. 1 is a schematic diagram of a preparation process of the high thermal stability cucurbituril-aluminum hypophosphite inclusion compound;

fig. 2 is a diagram of the FESEM of example 1 before and after AHP inclusion, wherein: FIG. 2A is an unaddressed AHP surface FESEM image, and FIG. 2B is an AHP surface FESEM image of a CB [ n ] inclusion;

FIG. 3 is a graph showing TG curves of cucurbituril-aluminum hypophosphite inclusion compounds prepared in examples 1 to 5 and comparative example 1;

FIG. 4 is an IR chart of AHP, CB [ n ] and cucurbituril-aluminum hypophosphite inclusion compound prepared in example 1.

Detailed Description

The following examples are further illustrative of the invention and are not intended to be limiting thereof. The reagents proposed in the present invention are all commercially available, unless otherwise specified.

A preparation method of a cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability comprises the following steps:

In the following examples, it is preferable that the specific step of the activation treatment in the step (1) is to heat CB [ n ] at a temperature of 90℃to 160℃for 4 to 8 hours to perform the activation treatment. The solvent A is more than one selected from distilled water, tetrahydrofuran, ethanol and methanol, and more preferably, the solvent A is a mixed solution of water and ethanol, and the volume ratio of the water to the ethanol is 1:1. The mass ratio of CB [ n ] after the activation treatment to the solvent A is 1:40-90, and more preferably, the mass ratio of CB [ n ] after the activation treatment to the solvent A is 1:50.

In the following examples, the mass ratio of CB [ n ] to AHP in step (2) is preferably 0.02 to 0.7:1, and more preferably the mass ratio of CB [ n ] to AHP is 0.1:1. The average particle diameter of AHP is 0.5-20 mu m, and the pH value of AHP is 3-5.5.

CB [ n ] is selected from two or more of CB [5], CB [6], CB [7], CB [8], CB [9], CB [10] and CB [11], more preferably, CB [ n ] is selected from two or more of CB [5], CB [6], CB [7] and CB [8], and CB [ n ] is a two-component, three-component or four-component. In the CB [ n ], the decomposition temperature at the position of the AHP weight loss rate of 1wt% is regulated and controlled at 294-337 ℃ by changing the fraction of the CB [ n ] component and the proportion of each component. The two components CB [ n ] are CB [5] and CB [6], CB [7] and CB [6], CB [8] and CB [6], respectively, and the mass ratio of the fixed former to the latter is (0.3-0.7): 1, it is further preferable that the mass ratio of the former to the latter is fixed to be (0.3 to 0.6): 1, a step of; the three components CB [ n ] are CB [5], CB [6] and CB [8], and the mass ratio of the three components is fixed to be (0.08-0.4): (0.3-0.8): 1, more preferably, the mass ratio of the three is fixed to be (0.1-0.4): (0.2-0.8): 1, a step of; the four components CB [ n ] are CB [5], CB [6], CB [7], CB [8], and the mass ratio of the four components is fixed to be (0.03-0.3): (0.2-0.5): (0.08-0.4): 1.

in the following examples, the reaction temperature in the step (2) is preferably 40 to 120℃and the reaction time is preferably 3 to 11 hours. The drying mode is that the vacuum is between 70 and 120 ℃ for 10 to 15 hours.

Example 1

As shown in figure 1, the high-thermal stability cucurbituril-aluminum hypophosphite inclusion compound and the preparation method thereof specifically comprise the following steps:

heating CB [ n ] for 4 hours at 90 ℃ to perform activation treatment, dispersing 2g of the activated CB [ n ] into 100g of a reaction bottle containing a mixed solution of water and ethanol, wherein the CB [ n ] comprises CB [5] and CB [6], and controlling the mass ratio of the CB [5] to the CB [6] to be 0.6 in the embodiment: 1, weighing AHP according to the mass ratio of 0.1:1, adding into the solution, reacting for 8 hours at 80 ℃ under the stirring speed of 300r/min, cooling to room temperature after the reaction is finished, filtering, and drying for 12 hours at 100 ℃ in vacuum to obtain the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability.

Example 2

the activation treatment of CB [ n ] was the same as in example 1.

2g of activated CB [ n ] is dispersed in 100g of a reaction flask containing a mixed solution of water and ethanol, wherein the CB [ n ] has a composition of CB [5] and CB [6]. In this embodiment, the mass ratio of CB [5] to CB [6] is controlled to be 0.3:1, weighing AHP according to the mass ratio of 0.1:1, adding into the solution, reacting for 8 hours at 80 ℃ under the stirring speed of 300r/min, cooling to room temperature after the reaction is finished, filtering, and drying for 12 hours at 100 ℃ in vacuum to obtain the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability.

Example 3

the activation treatment of CB [ n ] was the same as in example 1.

2g of activated CB [ n ] is dispersed in 100g of a reaction flask containing a mixed solution of water and ethanol, wherein the composition of CB [ n ] is CB [5], CB [6], or CB [8]. In this example, the mass ratio of CB [5], CB [6] and CB [8] is controlled to be 0.4:0.2:1, weighing AHP according to the mass ratio of 0.1:1, adding into the solution, reacting for 8 hours at 80 ℃ under the stirring speed of 300r/min, cooling to room temperature after the reaction is finished, filtering, and drying for 12 hours at 100 ℃ in vacuum to obtain the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability.

Example 4

the activation treatment of CB [ n ] was the same as in example 1.

2g of activated CB [ n ] is dispersed in 100g of a reaction flask containing a mixed solution of water and ethanol, wherein the composition of CB [ n ] is CB [5], CB [6], or CB [8]. In this example, the mass ratio of CB [5], CB [6] and CB [8] is controlled to be 0.1:0.8:1, weighing AHP according to the mass ratio of 0.1:1, adding into the solution, reacting for 8 hours at 80 ℃ under the stirring speed of 300r/min, cooling to room temperature after the reaction is finished, filtering, and drying for 12 hours at 100 ℃ in vacuum to obtain the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability.

Example 5

the activation treatment of CB [ n ] was the same as in example 1.

2g of activated CB [ n ] is dispersed in 100g of a reaction flask containing a mixed solution of water and ethanol, wherein the composition of CB [ n ] is CB [5], CB [6], CB [7], or CB [8]. In this example, the mass ratio of CB [5], CB [6], CB [7], CB [8] is controlled to be 0.1:0.5:0.1:1, weighing AHP according to the mass ratio of 0.1:1, adding into the solution, reacting for 8 hours at 80 ℃ under the stirring speed of 300r/min, cooling to room temperature after the reaction is finished, filtering, and drying for 12 hours at 100 ℃ in vacuum to obtain the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability.

Example 6

CB [ n ] is activated by heating at 160 ℃ for 8 hours, and 2g of CB [ n ] after activation is dispersed in 80g of reaction bottle containing water and ethanol mixed solution, wherein the CB [ n ] is composed of CB [5], CB [6], CB [7] and CB [8]. In this example, the mass ratio of CB [5], CB [6], CB [7], CB [8] is controlled to be 0.03:0.2:0.08:1, weighing AHP according to the mass ratio of 0.02:1, adding into the solution, reacting for 11 hours at 40 ℃ under the stirring speed of 300r/min, cooling to room temperature after the reaction is finished, filtering, and drying for 15 hours at the vacuum of 70 ℃ to obtain the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability.

Example 7

CB [ n ] is activated by heating at 160 ℃ for 8 hours, and 2g of CB [ n ] after activation is dispersed in 180g of reaction bottle containing water and ethanol mixed solution, wherein the CB [ n ] is composed of CB [5], CB [6], CB [7] and CB [8]. In this example, the mass ratio of CB [5], CB [6], CB [7], CB [8] is controlled to be 0.4:0.8:0.4:1, weighing AHP according to the mass ratio of 0.7:1, adding the AHP into the solution, reacting for 3 hours at 120 ℃ under the stirring speed of 300r/min, cooling to room temperature after the reaction is finished, filtering, and drying for 10 hours at the vacuum of 120 ℃ to obtain the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability.

Comparative example 1

Weighing 20g of AHP, adding into 100g of mixed solution containing water and ethanol, reacting for 8 hours at 80 ℃ under the stirring speed of 300r/min, cooling to room temperature after the reaction is finished, filtering, and drying for 12 hours at 100 ℃ in vacuum.

Characterization of cucurbituril-aluminum hypophosphite inclusion compound: the surface morphology, thermal stability and molecular structure of the high thermal stability cucurbituril-aluminum hypophosphite inclusion compound prepared in examples 1 to 5 of the present invention were characterized by using a Field Emission Scanning Electron Microscope (FESEM), a fourier transform infrared spectrometer (IR), and a TA-50H series comprehensive thermal analyzer (TG).

(1) The FESEM results show that: as shown in FIG. 2, the non-inclusion AHP surface morphology is in a sphere shape with small particles accumulated, the small particle water chestnut clearly presents a square block shape (FIG. 2A), and the surface morphology of the CB [ n ] inclusion AHP is smoother and plump (FIG. 2B), which shows that the cucurbituril-aluminum hypophosphite inclusion compound is successfully prepared.

(2) The IR results show: as shown in FIG. 3, part of the infrared characteristic peak of CB [ n ] can be clearly observed in the cucurbituril-aluminum hypophosphite inclusion compound (the dotted line part of FIG. 3), thus further demonstrating that the cucurbituril-aluminum hypophosphite inclusion compound is successfully prepared by the invention.

(3) TG results show: as shown in FIG. 4, compared with comparative example 1, the decomposition temperature of the cucurbituril-aluminum hypophosphite inclusion compound prepared in examples 1 to 5 is greatly increased at the position of 1wt% of weight loss rate, and the decomposition temperature is improved by 21 to 43 ℃, so that the decomposition temperature of AHP can be adjusted by changing the components and the proportion of each component, and the prepared cucurbituril-aluminum hypophosphite inclusion compound has high thermal stability.

Application example flame retardant Performance test

In order to verify that the cucurbituril-aluminum hypophosphite inclusion compound prepared by the invention has excellent flame retardance and char formation, the inclusion compound prepared by the invention is applied to flame retardant polybutylene terephthalate (PBT), the inclusion compound with the mass fraction of 15wt% of PBT particles is added into PBT particles, double-screw melting, extrusion, cooling and granulating are carried out, and the obtained granules are dried at 105 ℃ for 5 hours and then are subjected to injection molding on an injection molding machine to form standard bars required by tests. The material prepared in comparative example 1 was applied to flame retardant PBT in the same way.

Flame retardant Performance test

The vertical burn test (UL-94) was carried out using the GB/T5455-1997 standard with spline dimensions of 130mm by 13mm by 3.2mm. Limiting Oxygen Index (LOI) tests were performed using the GB/T2406-1993 standard with spline sizes of 120mm by 6.5mm by 3.0mm. Thermogravimetric analysis: at N ₂ The temperature rising rate is 10K/min under the atmosphere. Each sample was tested 3 times in parallel and the test results are shown in table 1.

TABLE 1 examples 1-5 flame retardant Property test Table of cucurbituril-aluminum hypophosphite clathrate

Note that: the data in the table are the average of the tests.

As is clear from Table 1, the pure PBT has a limiting oxygen index of 19.8% and a severe dripping, and the char formation amount is only 5.6%. The cucurbituril-aluminum hypophosphite inclusion compound prepared by the method has excellent flame retardance and char formation effects on PBT. When the cucurbituril-aluminum hypophosphite inclusion compound (examples 1 to 5) is added, LOI values are increased, vertical burning grades are changed into V-1 and V-0, the LOI value of comparative example 1 is not obviously increased, the LOI is only increased by 1%, and dripping is serious, so that the cucurbituril-aluminum hypophosphite inclusion compound prepared by the invention has excellent flame retardant effect. The carbon residue at 750 ℃ is observed, and examples 1-5 are obviously larger than pure PBT and comparative example 1, which show that the cucurbituril-aluminum hypophosphite inclusion compound prepared by the invention has excellent carbon forming effect. Possible reasons for the above result are: (1) The cucurbituril-aluminum hypophosphite inclusion compound has the function of catalyzing and forming charcoal; (2) CB [ n ] and AHP can form a compact carbon layer under a certain inclusion proportion, and the compact carbon layer plays a role in physical separation, inhibits the escape of combustible small molecules and finally leads to the improvement of the vertical burning grade of PBT.

In conclusion, the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability has excellent char formation, thermal stability and flame retardance, and meanwhile, the preparation method has the advantages of economy, environmental friendliness, simple equipment, low cost and easiness in industrialization, and is expected to realize large-scale application.

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that the above-mentioned preferred embodiment should not be construed as limiting the invention, and the scope of the invention should be defined by the appended claims. It will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the spirit and scope of the invention, and such modifications and adaptations are intended to be comprehended within the scope of the invention.

Claims

1. The preparation method of the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability is characterized by comprising the following steps of:

(1) Dispersing the CB [ n ] after the activation treatment in a reaction vessel containing a solvent A, wherein the activation temperature of the activation treatment is 90-160 ℃ and the activation time is 4-8 hours, and the solvent A is more than one of distilled water, tetrahydrofuran, ethanol and methanol;

(2) Adding AHP into the solution by controlling the mass ratio of CB [ n ] to AHP, wherein the mass ratio of CB [ n ] to AHP is 0.02-0.7:1, and the CB [ n ] is selected from more than two of CB [5], CB [6], CB [7] and CB [8], stirring, reacting, filtering and drying to obtain the cucurbituril-aluminum hypophosphite inclusion compound with high thermal stability.

2. The method for preparing the high thermal stability cucurbituril-aluminum hypophosphite inclusion compound according to claim 1, wherein the mass ratio of CB [ n ] after the activation treatment to the solvent A in the step (1) is 1:40-90.

3. The method for preparing the high-thermal-stability cucurbituril-aluminum hypophosphite inclusion compound according to claim 1, wherein the reaction temperature in the step (2) is 40-120 ℃, the reaction time is 3-11 h, and the drying mode is vacuum 70-120 ℃ drying for 8-15 h.

4. The method for preparing high thermal stability cucurbituril-aluminum hypophosphite clathrate according to claim 1, wherein the average particle size of the AHP is 0.5-20 μm, and the pH value of the AHP is 3-5.5.

5. The high thermal stability cucurbituril-aluminum hypophosphite clathrate obtained by the preparation method of any one of claims 1 to 4.

6. The use of the high thermal stability cucurbituril-aluminum hypophosphite inclusion compound according to claim 5 for preparing a polyamide flame retardant material or a polyester flame retardant material.