CN108864685B

CN108864685B - Interface assembly structure and method for improving mechanical property of thermoplastic carbon fiber composite material

Info

Publication number: CN108864685B
Application number: CN201810602686.XA
Authority: CN
Inventors: 邹华维; 刘琦; 罗维; 陈洋; 梁梅
Original assignee: Sichuan University
Current assignee: Sichuan University
Priority date: 2018-06-12
Filing date: 2018-06-12
Publication date: 2020-10-30
Anticipated expiration: 2038-06-12
Also published as: CN108864685A

Abstract

The invention provides a method for improving the mechanical property of a thermoplastic carbon fiber composite material, which comprises the following steps: a. uniformly dispersing graphene oxide in water to obtain a graphene oxide solution; b. uniformly dispersing carbon fibers in the graphene oxide solution obtained in the step a, and drying to obtain graphene oxide coated carbon fibers; c. and melting and blending the graphene oxide coated carbon fiber and polyphenyl ether to obtain the composite material. Experimental results prove that the polyphenylene sulfide prepared by the method has high mechanical properties, and the tensile strength and the Young modulus of the polyphenylene sulfide are respectively improved by 116 percent and 193 percent compared with unmodified polyphenylene sulfide; compared with carbon fiber modified polyphenylene sulfide, the carbon fiber modified polyphenylene sulfide is improved by 13% and 17% respectively, and the application prospect is good.

Description

Interface assembly structure and method for improving mechanical property of thermoplastic carbon fiber composite material

Technical Field

The invention relates to a preparation method of a composite material, in particular to an interface assembly structure and method for improving mechanical properties of a thermoplastic carbon fiber composite material.

Background

Polyphenylene Sulfide (PPS), abbreviated as English, is a novel high-performance thermoplastic resin and has the advantages of high mechanical strength, high temperature resistance, chemical resistance, flame retardancy, good thermal stability, excellent electrical property and the like. In order to broaden its application range, its strength or toughness is improved. At present, the polyphenylene sulfide is modified by adopting glass fiber, carbon fiber or aramid fiber to improve the strength of the polyphenylene sulfide.

Compared with polyphenylene sulfide modified by glass fiber and aramid fiber, the polyphenylene sulfide modified by carbon fiber has more excellent comprehensive performance. However, since carbon fibers are chemically inert and have poor interfacial wettability with most resin matrices, they cannot greatly improve the mechanical properties of polyphenylene sulfide, and thus the application of polyphenylene sulfide is limited.

At present, reports of improving the mechanical properties of polyphenylene sulfide composite materials through an interface modifier exist, but the improvement effect is general, for example, the influence of the interface modifier on the mechanical and thermodynamic properties of polyphenylene sulfide/carbon fiber composite materials [ J ] plastic industry, 2013(1): 100-containing 103 ], discloses that epoxy acetone is used as the interface modifier to improve the mechanical properties of polyphenylene sulfide, but the tensile strength is only improved by 3.4%, and the improvement range is not obvious.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a method for improving the mechanical property of a thermoplastic carbon fiber composite material, which comprises the following steps:

a. uniformly dispersing graphene oxide in water to obtain a graphene oxide solution;

b. uniformly dispersing carbon fibers in the graphene oxide solution obtained in the step a, and drying to obtain graphene oxide coated carbon fibers;

c. and melting and blending the graphene oxide coated carbon fiber and polyphenyl ether to obtain the composite material.

Further, in the step a, the weight volume ratio of the graphene oxide to water is 0.1-1: 500 g/ml; the dispersion is ultrasonic dispersion, and the dispersion condition is ultrasonic treatment for 1h at the frequency of 40 kHz.

Further, in the step b, in the carbon fiber coated with the graphene oxide, the weight ratio of the graphene oxide to the carbon fiber is 0.1-1: 15-40;

further, the weight ratio of the graphene oxide to the carbon fiber is 0.1-1: 15.

Further, in the step b, the dispersion is ultrasonic dispersion, and the dispersion condition is ultrasonic treatment for 1h at the frequency of 20 kHz;

further, in step b, the temperature of the drying is 120 ℃.

Further, in the step c, the weight ratio of the carbon fiber coated with graphene oxide to the polyphenylene sulfide is as follows: 15.1-41 parts of carbon fiber coated by graphene oxide and 60-85 parts of polyphenylene sulfide.

Further, the weight ratio of the carbon fiber coated with the graphene oxide to the polyphenylene sulfide is as follows: 15.1-16 parts of carbon fiber coated by graphene oxide and 84-84.9 parts of polyphenylene sulfide.

Further, in step c, the melt blending refers to extrusion granulation and injection molding.

Further, during extrusion, the temperature of each section from the feeding section to the neck ring is 265 ℃, 290 ℃, 295 ℃, 300 ℃ and 300 ℃ respectively; during injection molding, the temperatures from the feeding section to the nozzle are set to be 265 ℃, 295 ℃, 300 ℃ and 300 ℃ respectively.

Experimental results prove that the polyphenylene sulfide prepared by the method has high mechanical properties, and the tensile strength and the Young modulus of the polyphenylene sulfide are respectively improved by 116 percent and 193 percent compared with unmodified polyphenylene sulfide; compared with carbon fiber modified polyphenylene sulfide, the carbon fiber modified polyphenylene sulfide is improved by 13% and 17% respectively, and the application prospect is good.

Obviously, many modifications, substitutions, and variations are possible in light of the above teachings of the invention, without departing from the basic technical spirit of the invention, as defined by the following claims.

The present invention will be described in further detail with reference to the following examples. This should not be understood as limiting the scope of the above-described subject matter of the present invention to the following examples. All the technologies realized based on the above contents of the present invention belong to the scope of the present invention.

Drawings

Fig. 1 is a fourier infrared spectrum of graphene oxide, carbon fiber, and 1 wt% graphene oxide-coated carbon fiber according to example 1 of the present invention.

Fig. 2 is a raman spectrum of the carbon fiber and 1 wt% of graphene oxide-coated carbon fiber in example 1 according to the present invention.

Fig. 3 is a graph showing a thermal weight loss curve of graphene oxide, carbon fiber, and graphene oxide-coated carbon fiber according to example 1 of the present invention.

FIG. 4 is a statistical chart of the length distribution of carbon fibers in the polyphenylene sulfide composite according to test example 1 of the present invention.

Fig. 5 is a drawing cross-sectional morphology diagram of pure polyphenylene sulfide and graphene oxide and carbon fiber reinforced polyphenylene sulfide composite material in experimental example 1 according to the present invention. Wherein (a) is PPS, (b) is GO/PPS, (c) is CF/PPS, (d) is GO/CF/PPS, (e) is 0.1GO-CF/PPS, (f) is 0.3GO-CF/PPS, (g) is 0.5GO-CF/PPS, and (h) is 1 GO-CF/PPS.

FIG. 6 is a DSC melting curve of polyphenylene sulfide and different kinds of graphene oxide or carbon fiber reinforced polyphenylene sulfide composite materials in test example 1 according to the present invention.

FIG. 7 is a DSC cooling crystallization curve of polyphenylene sulfide and different kinds of graphene oxide or carbon fiber reinforced polyphenylene sulfide composite materials in test example 1 according to the present invention.

Fig. 8 is a graph showing tensile strength and young's modulus of carbon fiber reinforced polyphenylene sulfide composites coated with different graphene oxide contents in test example 1 according to the present invention.

Fig. 9 is a graph showing tensile strength and young's modulus of graphene oxide and carbon fiber reinforced polyphenylene sulfide composite materials according to different addition modes in test example 1 of the present invention.

Fig. 10 is a graph showing bending strength and bending modulus of carbon fiber reinforced polyphenylene sulfide composites coated with different graphene oxide contents in test example 1 according to the present invention.

Fig. 11 is a graph showing bending strength and bending modulus of graphene oxide and carbon fiber reinforced polyphenylene sulfide composite materials according to different addition modes in test example 1 of the present invention.

Detailed Description

The raw materials and equipment used in the embodiment of the present invention are known products and obtained by purchasing commercially available products.

Example 1 preparation of polyphenylene sulfide composite according to the invention

Firstly, the preparation method of the composite material of the invention

1. Preparation of graphene oxide coated carbon fiber

According to the proportion shown in table 1, 0.1-1 g of graphene oxide is added into 500ml of deionized water, and ultrasonic treatment is carried out for 1h in a 40kHz rod type ultrasonic instrument, so that the graphene oxide is uniformly dispersed, and a graphene oxide solution is obtained; and then adding 15g of carbon fiber into the graphene oxide solution, carrying out ultrasonic treatment for 1h in a 20kHz ultrasonic water bath, and then placing the carbon fiber in a 100 ℃ air-blast oven for heating treatment for 72h to finally obtain the graphene oxide coated carbon fiber.

TABLE 1 raw material ratio

	Graphene oxide (wt%)	Carbon fiber (wt%)	Polyphenylene sulfide (wt%)
				0.1GO-CF/PPS	0.1	15	84.9
0.3GO-CF/PPS	0.3	15	84.7
				0.5GO-CF/PPS	0.5	15	84.5
1GO-CF/PPS	1.0	15	84

2. Preparation of polyphenylene sulfide composite material

According to the proportion shown in table 1, weighed polyphenylene sulfide is added from a main feed inlet of an extruder, graphene-coated carbon fiber is added from a side feed inlet and is blended and extruded with the polyphenylene sulfide, and then the mixture is cut into particles, and the temperatures of all sections of the extruder from a feed section to a neck ring are respectively set to be 265 ℃, 290 ℃, 295 ℃, 300 ℃, and 300 ℃. And then carrying out injection molding on the extruded granules to obtain a test sample required by the test, setting the injection molding grade temperature from a feeding section to a nozzle to be 265 ℃, 295 ℃, 300 ℃ and 300 ℃, and carrying out annealing treatment on the sample strip in a blast oven at 120 ℃ for 4 hours after injection molding.

Secondly, detecting the property of the composite material

The infrared spectrum, the raman spectrum and the thermal weight loss characterization were performed on the graphene oxide coated carbon fiber, and the results are shown in fig. 1 to 3.

As can be seen from the infrared spectrogram (figure 1) of the graphene oxide coated carbon fiber, the infrared spectrogram is 3407.2cm^-1Is the characteristic peak of bending vibration of the carboxylic acid matrix and water molecules existing on the surface of the graphene oxide, 2916.2cm^-1Corresponding to the C-H asymmetric stretching vibration peak in the alkyl group, 2850.3cm^-1The value of (A) represents the symmetric stretching vibration peak of C-H in alkyl at 1721.8cm^-1Is the peak of the carbonyl group in the carboxyl group, and is 1628.5cm^-1The position corresponds to the absorption peak of the stretching vibration of the carbon-carbon double bond. Further, a characteristic peak of graphene oxide, i.e., 1375.5cm^-1And 1051.2cm^-1The peak is respectively attributable to the bending vibration of C-OH and the bending vibration of O-H. The appearance of these characteristic peaks indicates that the graphene oxide used has a certain degree of oxidation and is rich in different kinds of oxygen-containing functional groups. In the spectrum of 1 wt.% graphene oxide coated carbon fiber, a spectrum at 1721.0cm was observed^-1And 1630.4cm^-1The two peaks are respectively the peak of carbonyl and carbon-carbon double bond at 1051.9cm^-1There is also a distinct peak of bending vibration of the hydroxyl groups. The method shows that compared with untreated carbon fibers, the types of oxygen-containing functional groups on the surface of the carbon fibers coated with the graphene oxide are obviously increased.

As can be seen from the Raman spectrum (figure 2) of the graphene oxide coated carbon fiber, the carbon fiber is 1364cm^-1And 1597cm^-1The peak positions of the carbon fiber coated with 1 wt.% of graphene oxide in the D band and the G band are 1352cm in length^-1And 1581cm^-1To (3). In general, the ratio of the intensities of the D and G bands (I)_D/I_G) Is used to measure the degree of crystallinity or perfection of the carbon structure, I_D/I_GThe larger the ratio, the higher the degree of defect of the carbon structure and the higher the reactivity. I of graphene oxide coated carbon fiber_D/I_GAn increase in the ratio indicates an increase in the reactivity of the modified carbon fiber.

As can be seen from the thermal weight loss curve (fig. 3) of the graphene oxide coated carbon fiber, the graphene oxide has a small mass reduction at about 100 ℃, and the weight loss rate reaches the peak value at 155.6 ℃; the overall weight loss of the carbon fiber is small; the residue of graphene oxide-coated carbon fibers is slightly less important than untreated carbon fibers.

The advantageous effects of the present invention are specifically described below by way of test examples.

Test example 1, Performance test

1. Testing materials:

the material of the invention is as follows: 0.1GO-CF/PPS, 0.3GO-CF/PPS, 0.5GO-CF/PPS, and 1GO-CF/PPS, prepared in example 1.

Comparative materials:

comparative example 1 preparation of graphene oxide/polyphenylene sulfide composite

Weighing 1 wt% of graphene oxide and 99 wt% of polyphenylene sulfide, blending and extruding, and naming the graphene oxide/polyphenylene sulfide as GO/PPS. Comparative example 2 preparation of carbon fiber/polyphenylene sulfide composite Material

Weighing 15 wt% of carbon fiber and 85 wt% of polyphenylene sulfide, blending and extruding, and naming as CF/PPS.

Comparative example 3 preparation of graphene oxide/carbon fiber/polyphenylene sulfide composite material

Weighing 1 wt% of graphene oxide and 84 wt% of polyphenylene sulfide, blending, adding the mixture from a main material port, adding 15 wt% of carbon fiber from a side feeding port, blending and extruding, and naming the mixture as GO/CF/PPS.

2. Test method

1) Scanning Electron Microscope (SEM) testing

After a sample to be tested is placed in vacuum and the surface is sprayed with gold, the internal microstructure of the sample is observed by using a scanning electron microscope with the model number of JSM9600 of Japan Electron corporation, and the accelerating voltage is 5.0 kV.

2) Composite internal fiber length statistics

Placing the extruded composite material particles in a muffle furnace, burning for 2h at 800 ℃ to remove PPS resin, collecting residual fibers, observing by using SEM, taking 20 SEM pictures of each sample, and performing statistical analysis on the fibers in each sample by using image measurement processing software, wherein each sample contains not less than 500 fibers.

3) Differential Scanning Calorimetry (DSC) test

8-10mg of a sample is weighed by using a differential scanning calorimeter of a model DSC-204 produced by German Netzsch company, the temperature is raised from room temperature to 300 ℃ at the speed of 10 ℃/min under the protection of nitrogen, the temperature is kept for 5min to eliminate the thermal history, then the temperature is lowered to room temperature at the speed of 10 ℃/min, and the temperature is raised to 300 ℃ at the speed of 10 ℃/min.

4) Tensile Property test

The tensile properties of the samples were tested according to GB/T1040.2-2006 using an Instron5567 Universal Material testing machine. The sample was a dumbbell-shaped bar having a length of 150mm, a width of 10mm and a thickness of 4mm, and the tensile rate was 50 mm/min.

5) Bending property test

The samples were tested for flexural properties according to GB/T9341-2008 using an Instron5567 Universal Material testing machine. The sample was a rectangular parallelepiped sample having a length of 80mm, a width of 10mm and a thickness of 4mm, and the bending speed was 10 mm/min.

3. Test results

(1) Statistical analysis of fiber length distribution

TABLE 2 number average fiber length and Dispersion index of carbon fibers in PPS composites

Material	Number average fiber length (μm)	Index of dispersibility
			CF/PPS (prepared in comparative example 2)	148.50	1.32
GO/CF/PPS (prepared in comparative example 3)	159.35	1.30
			0.1GO-CF/PPS (inventive Material)	183.83	1.23
0.3GO-CF/PPS (inventive Material)	165.50	1.20
			0.5GO-CF/PPS (inventive Material)	172.40	1.17
1GO-CF/PPS (inventive Material)	190.23	1.15

As can be seen from FIG. 4 and Table 2, the lengths of the carbon fibers in the GO-CF/PPS with four different graphene oxide contents are mainly distributed in the interval of 151-300 μm. The average length of the carbon fibers in CF/PPS and GO/CF/PPS is lower in view of the average length, while the average length of the carbon fibers in GO-CF/PPS with four different graphene oxide contents is increased, wherein the average length of the carbon fibers of 1GO-CF/PPS reaches the maximum value of 190.23 μm.

The experimental results show that the average fiber length of the inventive material is longer.

(2) Scanning Electron Microscope (SEM) analysis

As can be seen from FIG. 5(a), the tensile section of polyphenylene sulfide is smooth; the tensile section in FIG. 5(b) becomes less flat; for the CF/PPS and GO/CF/PPS in FIG. 5(c) (d), it can be observed that the bonding between the carbon fiber and the polyphenylene sulfide matrix is not tight, and the clearance between the carbon fiber and the matrix and the holes left after the carbon fiber is pulled out can be observed at the section of the sample; as can be seen from fig. 5(e) (f) (g), the bonding between the carbon fiber and the polyphenylene sulfide matrix is tight, and there is no gap between the drawn fiber and the matrix. As can be seen from fig. 5(h), the polyphenylene sulfide matrix remaining on the surface of the carbon fiber is large in size. The polarity of the graphene oxide can provide good wettability for the carbon fiber, so that the polyphenylene sulfide matrix can penetrate into defects and holes on the surface of the carbon fiber to form effective mechanical interlocking, and the interface bonding effect between the carbon fiber and the polyphenylene sulfide matrix is enhanced.

The experimental result shows that the carbon fiber treated by the graphene oxide is more tightly combined with the polyphenylene sulfide, and further shows that the interface combination strength of the carbon fiber and the polyphenylene sulfide is enhanced.

(3) Differential Scanning Calorimetry (DSC) analysis

TABLE 3 DSC characteristics of pure PPS and PPS composite materials

As can be seen from fig. 6, 7 and table 3, the melting temperature of polyphenylene sulfide does not change significantly regardless of the addition of graphene oxide or carbon fiber or both. For the maximum crystallization temperature, the CF/PPS of the pure carbon fiber is increased to 210.8 ℃ compared with the 180.0 ℃ of the pure polyphenylene sulfide, and the GO/PPS of the graphene oxide is further increased to 220.4 ℃ on the basis of the maximum crystallization temperature. Adding the graphene oxide coated carbon fiber increases the maximum crystallization temperature to 222 +/-1 ℃.

The experimental result shows that the maximum crystallization temperature and the crystallization rate of the polyphenylene sulfide composite material are both improved.

(4) Analysis of tensile Properties

As is clear from FIG. 8, the tensile strength of CF/PPS was low, and was only 151.38 MPa. After the carbon fiber is coated by the graphene oxide, the tensile strength and Young modulus of polyphenylene sulfide are obviously improved, the carbon fiber is in an increasing trend along with the increase of the coating amount of the graphene oxide, when the content of the graphene oxide coated on the surface of the carbon fiber reaches 1 wt.%, the tensile strength of the composite material reaches the maximum value of 170.62MPa, the improvement amplitude is 12.7%, and the Young modulus is improved by 17.3% compared with that of CF/PPS

As can be seen from fig. 9, the addition of graphene oxide alone has little effect on the mechanical properties of polyphenylene sulfide. The tensile strength of the polyphenylene sulfide can be greatly improved by adding the carbon fiber alone, the tensile strength and the Young modulus of the CF/PPS are respectively improved from 78.84MPa and 2508.44MPa of pure polyphenylene sulfide to 151.14MPa and 6268.30MPa, and the lifting amplitudes respectively reach 91.7 percent and 149.9 percent. And the GO/CF/PPS of the graphene oxide is simultaneously added on the basis of the single addition of the carbon fiber, the tensile property is slightly reduced compared with that of the GO/PPS, and the tensile strength and the Young modulus are respectively 148.89MPa and 5921.52 MPa. When the adding mode of the graphene oxide is changed, namely the graphene oxide is coated on the surface of the carbon fiber and then added together to obtain 1GO-CF/PPS, compared with GO/CF/PPS with the same addition of the graphene oxide and the carbon fiber, the tensile strength and Young modulus are obviously improved to 170.60MPa and 7343.93MPa respectively, and compared with pure polyphenylene sulfide, the lifting amplitude is 116.39% and 192.77% respectively.

The experimental result shows that compared with unmodified polyphenylene sulfide, the tensile strength and the Young modulus of the polyphenylene sulfide composite material are respectively improved by 116 percent and 193 percent; compared with carbon fiber modified polyphenylene sulfide, the carbon fiber modified polyphenylene sulfide is respectively improved by 13% and 17%, and the promotion range is obvious.

(5) Analysis of bending Properties

As can be seen from fig. 10, after the carbon fiber is coated with the graphene oxide, the bending strength of the polyphenylene sulfide is generally improved more than that of a pure carbon fiber reinforced polyphenylene sulfide composite material, and the bending strength of the composite material is increased along with the increase of the graphene oxide coating amount. When only carbon fiber is added, the bending strength of CF/PPS is 182.81MPa, while the bending strength of 1GO-CF/PPS reaches 203.65MPa, and the lifting amplitude reaches 11.4 percent.

As can be seen from fig. 11, the addition of graphene oxide alone rather slightly decreases the bending property of polyphenylene sulfide. After the carbon fiber is introduced, the most excellent performance is 1GO-CF/PPS, and compared with pure polyphenylene sulfide, the bending strength of the composite material is improved by 57%.

The experimental result shows that compared with unmodified polyphenylene sulfide, the bending strength of the polyphenylene sulfide composite material is improved by 56.65%; compared with carbon fiber modified polyphenylene sulfide, the carbon fiber modified polyphenylene sulfide is improved by 11.4%, and the promotion range is obvious.

The experimental results show that the interface bonding force between the carbon fiber treated by the graphene oxide and the polyphenylene sulfide is enhanced. Compared with unmodified polyphenylene sulfide, the tensile strength, the Young modulus and the bending strength of the polyphenylene sulfide composite material are respectively improved by 116%, 193% and 56.65%; compared with carbon fiber modified polyphenylene sulfide, tensile strength, Young modulus and bending strength are respectively improved by 13%, 17% and 11.4%. The polyphenylene sulfide composite material prepared by the invention has more excellent mechanical properties.

In conclusion, compared with unmodified polyphenylene sulfide, the tensile strength, the Young modulus and the bending strength of the polyphenylene sulfide prepared by the method are respectively improved by 116%, 193% and 56.65%; compared with carbon fiber modified polyphenylene sulfide, the tensile strength, the Young modulus and the bending strength are respectively improved by 13%, 17% and 11.4%, and the application prospect is very good.

Claims

1. A method for improving the mechanical property of a thermoplastic carbon fiber composite material is characterized by comprising the following steps: it comprises the following steps:

c. fusing and blending the graphene oxide coated carbon fiber and polyphenylene sulfide to obtain a composite material;

in the step b, in the carbon fiber coated with the graphene oxide, the weight ratio of the graphene oxide to the carbon fiber is 0.1-1: 15;

in the step c, the weight ratio of the carbon fiber coated by the graphene oxide to the polyphenylene sulfide is as follows: 15.1-16 parts of carbon fiber coated by graphene oxide and 84-84.9 parts of polyphenylene sulfide.

2. The method of claim 1, wherein: in the step a, the weight volume ratio of the graphene oxide to water is 0.1-1: 500 g/ml; the dispersion is ultrasonic dispersion, and the dispersion condition is ultrasonic treatment for 1h at the frequency of 40 kHz.

3. The method of claim 1, wherein: in the step b, the dispersion is ultrasonic dispersion, and the dispersion condition is ultrasonic treatment for 1h at the frequency of 20 kHz.

4. The method of claim 1, wherein: in step b, the temperature of the drying is 120 ℃.

5. The method according to any one of claims 1 to 4, wherein: in the step c, the melt blending refers to extrusion granulation and injection molding.

6. The method of claim 5, wherein: during extrusion, the temperature of each section from the feeding section to the neck ring mold is 265 ℃, 290 ℃, 295 ℃, 300 ℃ and 300 ℃ respectively; during injection molding, the temperatures from the feeding section to the nozzle are set to be 265 ℃, 295 ℃, 300 ℃ and 300 ℃ respectively.