CN117024873A - Preparation method of modified polypropylene plastic - Google Patents

Abstract

The invention provides a method for preparing modified polypropylene plastic, which is prepared by blending polypropylene and modified polyetherketone, wherein the modified polyetherketone is modified by carbon nanotubes and prepared by in-situ polymerization. get. In this way, the dispersion of carbon nanotubes in the polypropylene matrix resin is improved, thereby improving the overall performance of the prepared material.

Description

A kind of preparation method of modified polypropylene plastic

Technical field

The invention relates to a method for preparing modified polypropylene plastic, in particular to a method for preparing modified polypropylene plastic through nanocarbon materials.

Background technique

As a commonly used industrial plastic, polypropylene has excellent properties, such as high strength, high hardness, good impact resistance, strong corrosion resistance and good formability, so it is widely used in various fields.

Carbon nanotubes have excellent mechanical properties and electrical conductivity and can be added to polypropylene to improve its properties. Direct modification of polypropylene with carbon nanotubes can improve the mechanical strength, electrical conductivity, thermal stability and flame retardancy of polypropylene, thus expanding the application fields of polypropylene. However, since carbon nanotubes themselves are difficult to disperse uniformly in the polypropylene matrix, direct modification has limited improvement in the performance of polypropylene.

Patent CN115850869A discloses a polypropylene modified thermoplastic shielding material and its preparation method. The patent uses polypropylene, polyolefin elastomer and modified resin as the matrix, and adds conductive fillers, antioxidants, lubricants, and processing aids. In blending modification, the added carbon nanotubes are not further modified, but are directly added to the matrix resin for modification, thereby improving the various properties of the material.

Patent CN114539667A discloses a durable antibacterial polypropylene composition and its preparation method and application. This patent promotes better dispersion of carbon nanotubes in the polypropylene matrix by grafting carbon nanotubes onto hyperbranched polyester. , improve the performance of polypropylene.

The existing technology adds carbon nanotubes to polypropylene resin through different methods, but the technical effects are not the same. The present invention attempts to provide a carbon nanotube-modified polypropylene material that is different from the existing technology and has good comprehensive properties.

Contents of the invention

The invention provides a method for preparing modified polypropylene plastic, which is prepared by blending polypropylene and modified polyetherketone, wherein the modified polyetherketone is modified by carbon nanotubes and prepared by in-situ polymerization. get. In this way, the dispersion of carbon nanotubes in the polypropylene matrix resin is improved, thereby improving the overall performance of the prepared material.

The technical solutions provided by the present invention are as follows:

A method for preparing modified polypropylene plastic, which is prepared by blending polypropylene and modified polyetherketone, wherein the modified polyetherketone is modified by carbon nanotubes and prepared by in-situ polymerization.

In the present invention, carbon nanotubes are selected to modify polypropylene. However, if carbon nanotubes are directly added to polypropylene, due to poor dispersion, the prepared modified polypropylene plastic will have poor performance. After extensive research, the inventor found that carbon nanotubes were added to polyetherketone through in-situ polymerization, so that the carbon nanotubes were first pre-dispersed in polyetherketone; then the prepared modified polyetherketone was mixed with polypropylene After blending, the properties of the modified polypropylene plastic obtained are better than those of samples in which carbon nanotubes directly modify polypropylene.

It should be noted that the modification of polyetherketone by carbon nanotubes through in-situ polymerization is a technology that has been disclosed in the prior art. For example, patent CN110183647A discloses a carbon nanotube/polyetherketone composite material and its preparation method and application. , but the blending and modification of carbon nanotube-modified polyetherketone and polypropylene materials as described in the present invention is not disclosed in the prior art.

The raw materials for preparing the modified polyetherketone include 4,4-difluorobenzophenone, 4,4-dihydroxybenzophenone and carbon nanotubes.

The preparation method of the modified polyetherketone is:

Step 1: Add carbon nanotubes and organic solvent into the reactor and disperse them evenly to obtain a carbon nanotube dispersion liquid for later use;

Step 2: Add solvent, 4,4'-dihydroxybenzophenone, 4,4'-difluorobenzophenone, salt-forming agent and the carbon nanotube dispersion into the reactor under an inert gas atmosphere , start stirring, control the reactor temperature at 170-310°C, carry out the reaction for 2-6 hours, discharge the material, and obtain the modified polyetherketone after cooling, washing and drying.

In a preferred example of the present invention, in the second step of the preparation method of the modified polyetherketone, after the reaction raw materials are added to the reactor, the reaction system is sequentially reacted at 140-180°C for 1-2 hours, and at 210-210°C React at 230°C for 2 to 3 hours, at 240 to 280°C for 2 to 3 hours, and at 300 to 310°C for 0.5 to 1 hour.

The inert gas can be an inert gas commonly used in this field, such as nitrogen, argon, etc., and these gases can be used alone or in combination.

The salt-forming agent can be a salt-forming agent commonly used in the art for preparing polyetherketone, such as potassium carbonate, sodium carbonate, calcium carbonate, magnesium carbonate, lithium carbonate, etc. Such salt-forming agents can be used alone or in combination. In a preferred example of the present invention, the salt-forming agent is potassium carbonate and sodium carbonate, wherein the molar ratio of potassium carbonate and sodium carbonate is 1:10.

The content of the preparation method of the modified polyetherketone is not further limited, and the process steps, raw material types and dosages can also be adjusted according to the technical solutions commonly used in the field. For example, the organic solvent in step one can be toluene, xylene, acetone, butanone, diethyl ether, chloroform, divinylbenzene, etc.; the solvent in step two can be diphenyl sulfone, biphenyl, anthracene, etc. Quinone, dibutyl phthalate, silicone oil, etc.

In the preparation method of the modified polyetherketone, the step one is: adding carbon nanotubes, 4,4'-diphenyldimethylbisphenol, and organic solvent into the reactor to disperse them evenly to obtain dispersed carbon nanotubes. Liquid for later use.

In the preparation method of the modified polyetherketone, a small amount of reactive compounds can be introduced to regulate the properties of the polyetherketone and promote their dispersion through a stacking effect with carbon nanotubes. Such reactive compounds are preferably compounds with a hydroxyl group and a benzene ring structure, especially compounds with a dihydroxyl group and a benzene ring structure, such as bisphenolfluorene and the like. When this type of reactive compound is simply used in the preparation of polyetherketone, it is only necessary to consider whether its chemical structure is suitable for the synthesis of polyetherketone. However, when applied to the technical solution of the present invention, that is, carbon nanotube modified polypropylene In addition to the impact on polyetherketone, it is also necessary to consider the material properties after blending polyetherketone and polypropylene. The present invention preferably uses 4,4'-diphenylmethylbisphenol as a reactive compound to modify polyetherketone. On the one hand, it can promote the dispersion of carbon nanotubes in the synthesis process of polyetherketone and improve the polyetherketone synthesis process. The properties of ether ketone itself, on the other hand, the modified polyether ketone prepared by this method has better compatibility when blended with polypropylene, and the obtained modified polypropylene has better properties.

In the preparation method of the modified polyetherketone, the 4,4'-diphenylmethylene bisphenol, 4,4'-dihydroxybenzophenone, and 4,4'-difluorobenzophenone The molar ratio is 0.01~0.1:0.9~0.99:1~1.2; preferably 0.1:0.9:1.05.

The mass ratio of the carbon nanotubes and 4,4'-diphenylmethylbisphenol is 0.1-1:1, preferably 0.5-0.8:1.

In a preferred example of the present invention, the prepared modified polyetherketone needs to be pulverized and blended with polypropylene in the form of small particles or powder. The modified polyetherketone is preferably crushed into powder. During the melt blending process of polyetherketone and polypropylene, polypropylene is the matrix resin, and the processing temperature should be set within the applicable range of polypropylene. However, the melt flow temperature of polyetherketone is relatively high, so polyetherketone The smaller the particle size, the better the compatibility with polypropylene.

The carbon nanotubes can be selected from carbon nanotubes commonly used in the field, preferably non-functionalized carbon nanotubes, that is, multi-walled carbon nanotubes and/or single-walled carbon nanotubes. Functionalized carbon nanotubes, that is, carbon nanotubes that have been modified, have active groups in their structure, such as hydroxyl, carboxyl and other groups. The structure of this type of carbon nanotubes has been damaged to a certain extent through modification, and its strength has decreased. , which may lead to a decrease in the performance of the final material.

The mass ratio of polypropylene and modified polyetherketone is 10:1-3.

The polypropylene can be selected from polypropylene commonly used in this field, such as homopolymerized polypropylene, copolymerized polypropylene, etc.

The method of blending polypropylene and modified polyetherketone can adopt technical solutions commonly used in this field. In a preferred example of the present invention, the polypropylene and modified polyetherketone are premixed by a high-speed mixer, and then blended and prepared by a twin-screw extruder. The rotating speed of the twin-screw extruder is 200 to 900 rpm, and the screw The temperature is 180~230℃.

Detailed ways

The present invention will be further described below in conjunction with specific examples. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

The raw materials used in the examples and comparative examples of the present invention are as follows:

Polypropylene, H309F, SK Chemical;

Carbon nanotubes, XFM04, multi-walled carbon nanotubes, Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.

Preparation method of carbon nanotube dispersion 1: add 17.62 parts by mass of carbon nanotubes, 35.24 parts by mass of 4,4'-diphenylmethylenebisphenol, and 300 parts by mass of xylene into the reactor, perform magnetic stirring and Ultrasonic for 2 hours, then discharge and set aside.

Preparation method of carbon nanotube dispersion 2: add 28.19 parts by mass of carbon nanotubes, 35.24 parts by mass of 4,4'-diphenylmethylenebisphenol, and 300 parts by mass of xylene into the reactor, perform magnetic stirring and Ultrasonic for 2 hours, then discharge and set aside.

Preparation method of carbon nanotube dispersion 3: Add 28.03 parts by mass of carbon nanotubes, 35.04 parts by mass of bisphenol fluorene, and 300 parts by mass of xylene into the reactor, perform magnetic stirring and ultrasonic for 2 hours, and discharge the materials for later use.

Preparation method of carbon nanotube dispersion 4: add 28.19 parts by mass of carbon nanotubes and 300 parts by mass of xylene into the reactor, perform magnetic stirring and ultrasonic for 2 hours, and discharge the materials for later use.

The salt-forming agent 1 uses a composite salt-forming agent with a mass of potassium carbonate and sodium carbonate of 1:10.

The salt-forming agent 2 uses a composite salt-forming agent with a mass of potassium carbonate and sodium carbonate of 1:100.

The preparation method of modified polyetherketone is: under an argon atmosphere, combine diphenyl sulfone, salt-forming agent, 4,4-dihydroxybenzophenone, 4,4'-difluorobenzophenone, and carbon nanoparticles. Pipe dispersion (if any) is added to the reactor, control the reactor temperature at 180°C, start stirring and condensation reflux, react for 2 hours, react at 230°C for 2 hours, exclude xylene, react at 280°C for 2 hours, and React at 310°C for 0.5 hours, discharge, and obtain modified polyetherketone after crushing, washing, and drying.

The types and amounts of raw materials used in the modified polyetherketone used in the examples and comparative examples are listed in Table 1, based on the relative mass parts between each component.

Table 1 Types and amounts of raw materials (parts by mass) of modified polyetherketone

Examples and Comparative Example 1 The preparation method of modified polypropylene plastic samples is as follows: mix polypropylene, modified polyetherketone, and antioxidant 1010 in advance through a high-speed mixer, then add them to a twin-screw extruder for extrusion and granulation. The extrusion conditions are that the screw speed is 300 rpm, and the screw temperature is set to 190°C, 190°C, 200°C, 200°C, 210°C, 220°C, 230°C, 220°C, 190°C, 185°C in sections from the feed port to the machine head. ℃, 180℃. Among them, polypropylene is in the form of pellets, and modified polyetherketone is crushed into powder in advance.

The preparation method of the modified polypropylene plastic sample of Comparative Example 2 is as follows: mix polypropylene, carbon nanotubes (the amount of carbon nanotubes added is 0.6% of the mass of polypropylene), and antioxidant 1010 in advance through a high-speed mixer, and then add The twin-screw extruder is used for extrusion and granulation. The extrusion conditions are as follows: the screw speed is 300 rpm, and the screw temperature is set from the feed port to the machine head to 190°C, 190°C, 200°C, 200°C, 210°C, 220°C, 230℃, 220℃, 190℃, 185℃, 180℃.

The amounts of polypropylene and modified polyetherketone used in Examples and Comparative Example 1 are listed in Table 2, based on the relative mass parts between each component.

Table 2 Examples and Comparative Examples Raw Material Amount (mass parts)

category Example 1 Example 2 Example 3 Example 4 Example 5 Comparative example 1 Polypropylene 10 10 10 10 10 10 Modified polyetherketone 1 3 Modified polyetherketone 2 1 Modified polyetherketone 3 1 Modified polyetherketone 4 1 Modified polyetherketone 5 1 Modified polyetherketone 6 1

It should be noted that Comparative Example 2 did not add modified polyetherketone, but the polypropylene pellets used underwent the same processing steps for performance comparison.

Perform performance tests on the samples of the examples and comparative examples. The tensile strength test standard is ISO 527, the spline size is 130mm*10mm*0.8mm, and the tensile rate is 50mm/min; the impact strength test standard is ISO 179 test, cantilever beam, Spline size 80mm*10mm*4mm, A-shaped notch.

Table 3 Examples and Comparative Examples Performance Test Results

It should be noted that the types and amounts of raw materials, process steps, etc. that are not explained in the examples and comparative examples of the present invention are all commonly used raw materials and processes in this field, and these unexplained contents are in the examples and comparative examples. All remain consistent, and do not affect the horizontal comparison between the examples and comparative examples, nor the technical effects of the present invention.

Claims (7)

1. The preparation method of the modified polypropylene plastic is characterized by comprising the step of blending polypropylene and modified polyether ketone, wherein the modified polyether ketone is prepared in an in-situ polymerization mode by modifying carbon nano tubes.

2. The preparation method according to claim 1, wherein the preparation raw material of the modified polyether ketone comprises 4, 4-difluorobenzophenone, 4-dihydroxybenzophenone, and carbon nanotubes.

3. The preparation method of the modified polyether ketone according to claim 2, wherein the preparation method comprises the following steps:

adding the carbon nano tube and an organic solvent into a reactor to uniformly disperse, and obtaining a carbon nano tube dispersion liquid for standby;

and step two, adding a solvent, 4 '-dihydroxybenzophenone, 4' -difluorobenzophenone, a salifying agent and the carbon nanotube dispersion liquid into a reactor under the inert gas atmosphere, starting stirring, controlling the temperature of the reactor to be 170-310 ℃ for reaction for 2-6 hours, discharging, cooling, washing and drying to obtain the modified polyether ketone.

4. The method according to claim 3, wherein in the method for producing the modified polyether ketone, the first step is: adding the carbon nano tube, 4' -diphenyl methylene bisphenol and an organic solvent into a reactor for uniform dispersion to obtain a carbon nano tube dispersion liquid for standby.

5. The method according to claim 4, wherein in the method for producing the modified polyether ketone, the molar ratio of the 4,4' -dibenzylidene bisphenol, the 4,4' -dihydroxybenzophenone, and the 4,4' -difluorobenzophenone is 0.01 to 0.1:0.9 to 0.99:1 to 1.2; preferably 0.1:0.9:1.05.

6. the preparation method according to claim 5, wherein the mass ratio of the carbon nanotubes to the 4,4' -dibenzylidene bisphenol is 0.1 to 1:1, preferably 0.5 to 0.8:1.

7. the preparation method according to any one of claims 1 to 6, wherein the mass ratio of the polypropylene to the modified polyether ketone is 10:1 to 3.