CN111253596B

CN111253596B - Preparation method of polyetherimide micro-nano particles with controllable particle sizes

Info

Publication number: CN111253596B
Application number: CN201911073196.6A
Authority: CN
Inventors: 朱鹏; 张华鹏; 丁新波
Original assignee: Zhejiang Sci Tech University ZSTU
Current assignee: Zhejiang Sci Tech University ZSTU
Priority date: 2019-11-05
Filing date: 2019-11-05
Publication date: 2023-03-10
Anticipated expiration: 2039-11-05
Also published as: CN111253596A

Abstract

The invention relates to the technical field of engineering plastics, and provides a preparation method of polyetherimide micro-nano particles with controllable particle sizes, aiming at solving the problems that a high-boiling-point organic solvent is difficult to remove, the energy consumption is high, the process is complex, and the particle sizes cannot be accurately controlled in the traditional nano particle preparation process. The method has the advantages of simple operation, low energy consumption, low requirement on equipment and no auxiliary agent except components.

Description

Preparation method of polyetherimide micro-nano particles with controllable particle sizes

Technical Field

The invention relates to the technical field of engineering plastics, in particular to a preparation method of polyetherimide micro-nano particles with controllable particle sizes.

Background

Polyetherimide (PEI for short) has excellent mechanical property, electrical insulation property, irradiation resistance, high and low temperature resistance and wear resistance, and can transmit microwaves. The glass fiber, the carbon fiber or other fillers are added to achieve the purpose of enhancing and modifying. It can also be combined with other engineering plastics to form heat-resisting high-molecular alloy.

The preparation method of the polymer micro-nano particles mainly comprises the following steps: emulsion polymerization, microemulsion polymerization, self-assembly method, dendrimer method, dispersion copolymerization method, mechanical pulverization method, micro-nano particle formation by polymer post-dispersion, template method and the like. The polymer is dispersed to form micro-nano particles, namely the micro-nano particles are prepared by utilizing a polymerized polymer material, wherein three methods are mainly adopted: a) Solvent evaporation method: dissolving a polymer in a low-boiling-point organic solvent such as dichloromethane, chloroform and the like, emulsifying in a water system containing an emulsifier to form O/W type emulsion, evaporating and removing the organic solvent by heating, decompressing or continuously stirring and the like, and finally forming a water dispersion system of the polymer nano/micro nano particles; b) A solvent diffusion method: dissolving a polymer in a hydrophilic organic solvent (such as low-boiling-point organic solvents such as acetone, methanol and the like), then dropwise adding the polymer into water, wherein the hydrophilic organic solvent can be diffused into a water system and generate turbulence so as to form micro-nano particles, then evaporating and removing the organic solvent in a heating, decompression or continuous stirring mode and the like, and finally forming a water dispersion system of the polymer micro-nano particles; c) The polymer is dissolved in an organic solvent, is pressurized by a pump and atomized by a nozzle, is mixed with supercritical carbon dioxide in a precipitation kettle, the organic solvent is quickly diffused into supercritical fluid, and the polymer is precipitated from the mixed solvent to form micro-nano particles.

The three methods are not suitable for preparing PEI micro-nano particles and have the following defects:

the method a) adopts a two-phase system by a solvent evaporation method, is only suitable for preparing the polymer micro-nano particles dissolved in the low-boiling-point organic solvent, and firstly removes the low-boiling-point solvent in the preparation process to obtain a water dispersion system of the polymer nano particles; the boiling point of the common PEI solvent is higher than that of water, and the organic solvent cannot be removed by adopting the method, so that the method is not applicable;

method b) solvent diffusion: as above PEI is often soluble in high boiling point organic solvents which are difficult to remove by solvent diffusion methods.

Method c): the supercritical method is theoretically feasible, but the equipment requirement is high, the process is complex, and reports are not available for a while.

In the prior art, only PEI (polyetherimide) micron-sized particles (more than 50 microns) are reported, PEI is mostly dissolved by adopting an organic solvent, a surfactant is matched, ultrasonic or high-speed shearing dispersion is carried out, and finally spray drying is carried out to obtain the micron-sized particles. The disadvantages of the above method are: the addition of additional auxiliary agents results in high energy consumption, complex process, and inability to precisely control particle size and prepare nano-scale PEI particles.

Disclosure of Invention

The invention provides a preparation method of PEI micro/nano particles with controllable particle sizes (80 nm-6 microns), aiming at overcoming the problems that when the traditional nano particle preparation process is applied to the preparation of PEI micro/nano particles, high-boiling-point organic solvents are difficult to remove, energy consumption is large, the process is complex, and the particle sizes cannot be accurately controlled.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for preparing Polyetherimide (PEI) micro-nano particles with controllable particle sizes comprises the steps of dissolving polyetherimide in an organic solvent, then placing the organic solvent on a platform deck, and evaporating until the solvent is completely removed to obtain the PEI micro-nano particles.

The invention uses polymerized PEI as a raw material, the preparation method of the invention is obviously different from the preparation method of the polymer, and the preparation of PEI particles with micro-nano scale is not mentioned in the patent and the literature.

Preferably, the organic solvent is one selected from the group consisting of N-methylpyrrolidone (NMP), N-Dimethylformamide (DMF), N-Dimethylacetamide (DMA), dichloromethane, trichloroethane and dimethylsulfoxide.

Preferably, the PEI is added in an amount of 0.005 to 10wt% based on the total mass of the organic solvent. When the concentration of the PEI in the organic solvent is too low, particles can be formed because the PEI cannot overcome the adsorption force with the carrier, and when the concentration of the PEI in the organic solvent is too high, molecular chains are intertwined to form a film-shaped object, and the particles cannot be formed; therefore, the addition amount of PEI must be strictly controlled within the above range, so as to realize the controllability of the particle size of PEI micro/nano particles.

Preferably, the evaporation temperature is controlled to be-20 to 210 ℃. The evaporation temperature is greater than the boiling point of the organic solvent.

Preferably, the evaporation mode is gas flow evaporation, and the gas flow is compressed air flow or inert gas flow.

Preferably, the evaporation environment is an open environment.

The evaporation environment has great influence on the preparation process of the PEI micro-nano particles, if a closed environment is adopted, an undersized closed evaporation space can form saturated steam, so that the evaporation process is prevented; even if a closed environment is selected, the evaporation space must be large enough to satisfy the evaporation process without forming saturated vapor. If a vacuum environment is used, the vacuum degree has an influence on the evaporation rate, which affects the distribution, size and morphology of the particles. The open environment is often a fume hood. Precise environmental control can also be performed with the use of the graphical device.

Preferably, the flow rate of the gas is controlled to be 0 to 10m/s. The evaporation rate is controlled by the gas flow rate, thereby adjusting the preparation time.

Preferably, the stage is a planar stage or an open carrier. The surface of the plane carrier (aluminum foil, polytetrafluoroethylene coating or glass slide) can be placed in a dropping or spraying mode, and the liquid can also be directly injected into the open carrier.

Preferably, the particle size of the PEI micro-nano particles is 80 nm-6 μm.

Therefore, the invention has the following beneficial effects:

(1) The preparation material only needs PEI and a corresponding solvent, and PEI micro/nano particles can be obtained by simple natural evaporation;

(2) The particle size of the obtained micro-nano particles can be controlled by the concentration of PEI;

(3) Simple operation, low energy consumption, low requirement on equipment and no auxiliary agent except components.

Drawings

FIG. 1 is an SEM image of PEI particles made in example 1.

FIG. 2 is a TEM image of PEI particles made in example 1.

FIG. 3 is an SEM image of PEI particles made in example 2.

FIG. 4 is an SEM image of PEI particles made in example 3.

FIG. 5 is an SEM image of PEI particles made in example 4.

FIG. 6 is an SEM image of PEI particles made in example 5.

FIG. 7 is a schematic diagram of a preparation system with air as the gas source.

FIG. 8 is an SEM image of PEI particles made in example 6.

FIG. 9 is an SEM image of PEI particles made in example 7.

FIG. 10 is a schematic view of a manufacturing system using compressed gas as a gas source.

FIG. 11 is an SEM image of PEI particles made in example 8.

FIG. 12 is a plot of the average particle size of PEI particles prepared by the process of the present invention versus the concentration of PEI.

FIG. 13 is an SEM image of PEI particles made in comparative example 1.

FIG. 14 is an SEM image of PEI particles made in comparative example 2.

In the figure, a magnetic stirring heating instrument 1, an air extracting device 2, a carrying platform 3, an opening carrier 4, a liquid dripping, spraying or injecting device 5, an air purifying device 6, an air flow valve 7 and a compressed gas storage device 8.

Detailed Description

The technical solution of the present invention is further specifically described below by using specific embodiments and with reference to the accompanying drawings.

In the present invention, all the equipment and materials are commercially available or commonly used in the art, and the methods in the following examples are conventional in the art unless otherwise specified.

Example 1

PEI is dissolved in NMP by using air as a gas source and a common fume hood, and stirred and heated to obtain a high polymer solution (0.2% of mass fraction of the solvent), the high polymer solution is placed on a carrying table or in an open carrier, the high polymer solution is placed in the fume hood at room temperature, air flow with the flow rate of 0.8m/s is controlled until the solvent is completely evaporated, and PEI particles are obtained, wherein an SEM picture of the PEI particles is shown in FIG. 1, and the particle size of the PEI particles is about 206nm as can be seen from FIG. 1. The TEM image is shown in FIG. 2, and it can be seen from FIG. 2 that the resulting particles are spherical solid particles.

Example 2

PEI is dissolved in DMF by using air as a gas source and a common fume hood, the solution is stirred and heated to obtain a high polymer solution (0.005 percent of mass fraction to the solvent), the high polymer solution is placed on an aluminum foil and placed in the fume hood at room temperature, air flow with the flow rate of 0.8m/s is controlled until the solvent is completely evaporated, and PEI particles are obtained, wherein an SEM picture of the PEI particles is shown in figure 3, and the particle size of the PEI particles is about 80nm.

Example 3

Dissolving PEI in trichloroethane by using air as a gas source and utilizing a common fume hood, stirring and heating to obtain a high polymer solution (10% of mass fraction of the solvent), placing the high polymer solution on the surface of a glass slide, placing the high polymer solution in the fume hood at room temperature, controlling air flow at the flow rate of 0.8m/s until the solvent is completely evaporated to obtain PEI particles, wherein the SEM picture of the PEI particles is shown in figure 4, and the particle size of the PEI particles is about 6 mu m.

Example 4

Dissolving PEI in a corresponding solvent, stirring and heating to obtain a high polymer solution (0.2% of the mass fraction of the solvent), placing the high polymer solution on a loading table or in an open carrier, and placing the high polymer solution in a refrigerated cabinet at the temperature of-20 ℃ until the solvent is completely evaporated to obtain PEI particles, wherein the SEM picture of the PEI particles is shown in figure 5.

Example 5

Using air as a gas source, dissolving the PEI in dichloromethane by using a common fume hood, stirring and heating to obtain a high polymer solution (0.2% by mass fraction to the solvent), placing the solution on a carrying table or in an open carrier, setting a heating device below the solution at 210 ℃, placing the solution in the fume hood, and controlling air flow at a flow rate of 0.8m/s until the solvent is completely evaporated to obtain PEI particles, wherein an SEM picture of the PEI particles is shown in fig. 6.

Example 6

Using air as a gas source, using a device shown in fig. 7 to dissolve PEI in DMF, stirring and heating to obtain a high polymer solution (0.2% relative to the mass fraction of the solvent), placing the high polymer solution on a carrying table or in an open carrier, placing the high polymer solution in the device 1 at room temperature, closing a ventilation device, and controlling the air flow rate to be approximately 0m/s until the solvent is completely evaporated, thereby obtaining PEI particles, wherein an SEM image of the PEI particles is shown in fig. 8.

Example 7

Using air as a gas source, using the device shown in fig. 7 to dissolve PEI in DMA, stirring and heating to obtain a high polymer solution (0.2% by mass fraction to solvent), placing the solution on a carrier or in an open carrier, placing the solution in the device at room temperature, turning on a ventilation device, controlling the air flow rate at 10m/s until the solvent is completely evaporated, and obtaining PEI particles, wherein an SEM image of the PEI particles is shown in fig. 9.

Example 8

Using inert gas as a gas source, using a device shown in fig. 10 to dissolve PEI in dimethyl sulfoxide, stirring and heating to obtain a high polymer solution (0.2% by mass fraction of solvent), placing the high polymer solution on a carrier or in an open carrier, placing the high polymer solution in the device at room temperature, opening an airflow valve, and controlling the flow rate of air to be 2m/s until the solvent is completely evaporated, thereby obtaining PEI particles, wherein an SEM picture of the PEI particles is shown in fig. 11.

Fig. 12 is a graph showing the correspondence between the average particle size of PEI particles prepared by the process of the present invention and the concentration of PEI, and it can be seen from fig. 12 that the average particle size of PEI particles is linearly related to the concentration of PEI, so that the particle size of PEI particles can be precisely controlled by using the concentration of PEI in the solution.

Comparative example 1

Comparative example 1 is different from example 1 in that the evaporation environment is a vacuum environment, and the other conditions are identical, and the SEM image of the obtained PEI particles is shown in fig. 13.

Comparative example 2

Comparative example 2 is different from example 1 in that the evaporation environment is 250 c and the other conditions are identical, and the SEM image of the resulting PEI particles is shown in fig. 14.

As can be seen from fig. 13 and 14, the evaporation environment has a great influence on the preparation process of PEI micro-nano particles, and the PEI micro-nano particles are not uniformly distributed in the vacuum environment or at an excessively high temperature in the evaporation environment, so that the product cannot be successfully prepared.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.

Claims

1. The preparation method of the polyetherimide micro-nano particles with the controllable particle size is characterized by dissolving polyetherimide in an organic solvent, then placing the solvent on a carrying table, and evaporating until the solvent is completely removed to obtain the polyetherimide micro-nano particles, wherein the organic solvent is one of N-methyl pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dichloromethane, trichloroethane and dimethyl sulfoxide, the total mass of the organic solvent is taken as a reference, the addition amount of the polyetherimide is 0.005-10wt%, the evaporation temperature is controlled to be-20-210 ℃, the evaporation mode is airflow evaporation, the airflow is compressed air airflow or inert gas airflow, the evaporation environment is an open environment, the carrying table is a plane carrying table or an open carrier, and the particle size of the polyetherimide micro-nano particles is 80nm-6 microns.

2. The preparation method of the polyetherimide micro-nano particles with controllable particle sizes, according to claim 1, is characterized in that the flow rate of the air flow is controlled to be 0-10m/s.