Preparation method of high-performance polyethylene / glass fiber composite material and application in modified polypropylene

Abstract

The application discloses a kind of preparation method of high-performance polyethylene / glass fiber composite material and application in modified polypropylene, belong to olefin polymerization and material modification technical field, the preparation method of the polyethylene-glass fiber composite material, including the following steps: glass fiber, toluene, diimine nickel catalyst, Et2 AlCl are added to reaction container in N2 Environment, fill in ethylene gas, carry out polymerization, obtain immediately.There is also proposed a kind of modified PP material, which is composed of the following weight parts of raw materials: polypropylene 65-100 parts, modified filler 5-30 parts and antioxidant 0.1-0.5 parts;Modified filler is the polyethylene-glass fiber composite material described above.A beneficial effect: the application provides a new polyolefin modified PP material and applies it to the preparation of composite material, improves its mechanical, mechanical properties.Based on the basis of modified PP material, polyethylene-glass fiber is used as filling material to prepare a new type of composite material with high elasticity, high strength and environmental protection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of olefin polymerization and material modification, and relates to a preparation method of a high-performance polyethylene / glass fiber composite material and application of the high-performance polyethylene / glass fiber composite material in modified polypropylene. BACKGROUND

[0002] Polyolefins are the largest demand and highest yield polymer in the world. It has the properties of abundant raw materials and low cost, light weight, good processing performance and good chemical corrosion resistance, and is widely used in various fields. Common polyolefins include polyethylene, polypropylene, polybutylene, polybutadiene, ethylene-olefin copolymer and ethylene-cycloolefin copolymer. At present, the global polyolefin production has exceeded 400 million tons per year, most of which are polyethylene and polypropylene. High-end polyolefins (such as ethylene-olefin copolymer and ethylene-cycloolefin copolymer) have excellent performance and high added value, and have become the research focus of current polyolefin new products. Catalysts have a crucial influence on the structure, performance and capacity of polyolefins, especially in the research and development of high-end polyolefins.

[0003] Fiberglass is a kind of inorganic non-metallic material with excellent performance, and has many types. Its advantages are good insulation, strong heat resistance, good corrosion resistance and high mechanical strength, but its disadvantages are brittleness and poor wear resistance. It is made of six kinds of ores, namely, pyrophyllite, quartz sand, limestone, dolomite, boric calcium stone and boric magnesium stone, through high-temperature melting, drawing, winding and weaving processes. The diameter of its single wire is several microns to twenty microns, which is equivalent to 1 / 20-1 / 5 of a hair. Each bundle of fiber filaments is composed of hundreds or even thousands of single wires.

[0004] Polypropylene (PP) is one of the most commonly used plastics, and crystalline polypropylene was prepared in 1951. However, the high crystallinity of PP also causes the following disadvantages: poor low-temperature toughness, large molding shrinkage and large notch sensitivity, which to some extent limits its more extensive application. Blending modification is the most effective way to toughen PP. After that, PP / PE blends were developed. It is a new material that is macroscopically uniform and microscopically phase-separated, which is formed by mechanically blending two or more polymers and additives at a certain temperature. Through the blending modification of PP, the comprehensive performance of PP is greatly improved by overcoming its disadvantages such as brittleness, aging, poor weather resistance, etc., so that it enters the field of engineering plastics and becomes a strong competitor of general-purpose engineering plastics and alloys.

[0005] Chinese patent application document with publication number CN104861295A discloses a preparation method of modified polypropylene material with improved impact strength, which is prepared by one-step blending modification of raw materials including the following components: 100 parts of polypropylene, 20-40 parts of main modifier, 2.5-10 parts of auxiliary modifier, 0.5-5 parts of crosslinking modifier, and 0.5-5 parts of crosslinking auxiliary agent, wherein the main modifier is polyolefin elastomer, the auxiliary modifier is high-density polyethylene, the crosslinking modifier is organic peroxide, and the crosslinking auxiliary agent is divinylbenzene with a content of 50%-60%, and the decomposition temperature of the crosslinking modifier at a half-life period of 1 minute is 1-5℃ different from the melting temperature of PP. The patent can greatly improve the impact strength of modified PP, and endow the composite material with excellent impact resistance, rigidity, aging resistance, cold resistance and gasoline resistance, while the remaining properties are almost unaffected. However, the mechanical properties of the modified polypropylene (PP) material prepared by the patent are still poor, and need to be further improved. SUMMARY

[0006] The technical problem to be solved by the present application is how to solve the problem of poor mechanical properties of the existing modified polypropylene (PP) material.

[0007] The present application solves the above technical problems by the following technical means:

[0008] The first aspect of the present application provides a preparation method of polyethylene-glass fiber composite material, including the following steps:

[0009] The glass fiber, toluene, diimine nickel catalyst and Et2AlCl are added into a reaction container under N2 environment, ethylene gas is filled, and polymerization reaction is carried out, and the product is obtained; the structural formula of the diimine nickel catalyst is

[0010]

[0011] Toluene is used as a reaction solvent, and Et2AlCl (monochlorodioethylaluminum) acts as a cocatalyst,

[0012] Preferably, the use amount ratio of the glass fiber, diimine nickel catalyst and Et2AlCl is (1.0-4.5) g: (1-3) μmol: (300-500) μmol, and further preferably 2.5 g: 2 μmol: 400 μmol.

[0013] Preferably, the temperature of the polymerization reaction is 30-60℃, and the time of the polymerization reaction is 0.3-1h.

[0014] The second aspect of the present application provides a polyethylene-glass fiber composite material prepared by the above preparation method.

[0015] The third aspect of the present application provides a modified PP material, which is composed of the following raw materials in parts by weight: 65-100 parts of polypropylene, 5-30 parts of modified filler and 0.1-0.5 parts of antioxidant; the modified filler is the polyethylene-glass fiber composite material as described above.

[0016] Preferably, the antioxidant is one or more of Irganox 1010, antioxidant 168 and antioxidant 1076.

[0017] The fourth aspect of the present application provides a preparation method of the modified PP material, which comprises the following steps:

[0018] The polypropylene, modified filler and antioxidant are mixed according to the parts by weight, and then melted and extruded to obtain the modified PP material.

[0019] The fifth aspect of the present application provides a diimine ligand, which has the following structural formula:

[0020]

[0021] The sixth aspect of the present application provides a diimine nickel catalyst, which has the following chemical formula:

[0022]

[0023] The seventh aspect of the present application provides a preparation method of the diimine nickel catalyst, which comprises the following steps:

[0024] (1) 4,4-difluorobis(4-fluorophenyl)methanamine and [1,1'-biphenyl]-2-amine are mixed, heated for a period of time, and then hydrochloric acid (HCl) dissolved zinc chloride (ZnCl2) is added, and compound (I) is obtained after reaction;

[0025] (2) Compound (I) is reacted with anthraquinone to obtain compound (II);

[0026] (3) Compound (II) is further reacted with 2,6-dimethylaniline to obtain compound (III);

[0027] (4) Compound (III) is reacted with (DME)NiBr2 under nitrogen atmosphere to obtain the diimine nickel catalyst

[0028]

[0029] The synthesis route is as follows:

[0030]

[0031] Preferably, the molar ratio of compound (II) to dihexamethylaniline in step (3) is 1:1.

[0032] Preferably, the temperature of heating in step (1) is 80-100℃.

[0033] Preferably, the reaction time in step (1) is 2h.

[0034] Preferably, the reaction time in step (2) is 10-14h.

[0035] Preferably, the reaction time in step (3) is 10-14h.

[0036] Preferably, the reaction time in step (4) is 3h.

[0037] An eighth aspect of the present application provides the use of the above-mentioned diimine nickel catalyst in olefin polymerization.

[0038] The present application has the following advantages:

[0039] 1、The present application is directed to a special structure of diimine nickel catalyst, which has a very special space structure. Because the space structure of the catalyst presents a double coordination structure, it has a larger specific surface area, and the change in the coordination number of surface nickel atoms and the valence electron state makes the catalyst have extremely high activity. Because the large steric hindrance of the catalyst is in the same direction, it has a certain conjugation effect, which further improves the activity of the catalyst, and the catalyst also maintains a certain stability. Therefore, polyethylene is prepared by using the high activity of the catalyst, and the prepared polyethylene is subjected to a toughening experiment, and the obtained polyethylene-glass fiber composite material is applied to polypropylene. Thus, a new type of composite material with excellent compression ductility is realized, which also provides a new output path for the diversification development of polyolefin composite materials. It also provides a new method for the synthesis of polyolefin composite materials.

[0040] 2、The main catalyst alpha-diimine asymmetric nickel complex used in the composite material of the present application has the characteristics that the catalyst structure is double coordination and forms a "large-small" arrangement structure. Due to the electronic effect and steric hindrance effect between atoms and the effect of ΠΠ conjugation, the catalyst has its particularity. Therefore, the ligand that provides electrons may have higher activity. Therefore, the catalyst used in the present application has extremely high polymerization activity under the promotion of the "large-small" structure. At the same time, theoretically, the catalyst structure should be "small-small", that is, the large steric hindrance and the small steric hindrance are separated. However, the large steric hindrance of the catalyst is located in one direction, and the small steric hindrance is located in one direction, while maintaining high activity and stability.

[0041] 3. The present application provides a new polyolefin composite material, i.e. polyethylene-glass fiber composite material. The polyethylene of the composite material is obtained by polymerization of ethylene catalyzed by the above-mentioned catalyst, and the polyethylene-glass fiber has certain mechanical properties and also ensures high elasticity.

[0042] 4. The modified (PP) in the present application is blended into polypropylene to form a new polyolefin composite material which is macroscopically uniform and microscopically phase-separated, by using polyethylene-glass fiber composite material. A small amount of polyethylene-glass fiber elastomer can improve the mechanical properties of polypropylene.

[0043] 5. Based on the modified PP material, the present application uses polyethylene-glass fiber composite material as a filling material to prepare a new composite material with high elasticity and high strength. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The H NMR spectrum of the compound (III) of Example 1 of the present application 1

[0045] Figure 2 The C NMR spectrum of the compound (III) of Example 1 of the present application 13

[0046] Figure 3 The X-Ray Crystallography graph of the diimine nickel catalyst of Example 1 of the present application

[0047] Figure 4 The cyclic stress-strain curve graph of the polyethylene-glass fiber composite material prepared in Examples 2-5 of the present application

[0048] Figure 5 The scanning electron microscope graph of the polyethylene-glass fiber composite material prepared in Example 2 of the present application

[0049] Figure 6 The tensile strength and impact resistance test graph of the modified PP material prepared in Examples 6-10 of the present application

[0050] Figure 7 The tensile property test graph of the modified PP material prepared in Examples 6-10 of the present application DETAILED DESCRIPTION

[0051] ​​In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of the present application.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing the specific embodiments only and is not intended to be limiting of the application.

[0053] The test materials and reagents used in the following examples, and the like, can be obtained from commercial channels unless otherwise specified.

[0054] The specific techniques or conditions not specified in the examples can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0055] The performance testing conditions of the products prepared in the following examples and comparative examples are as follows:

[0056] The tensile sample used for the tensile strength test is of the type: (50.0±5.0)mm*(4.0±0.5)mm*(2.5±0.2)mm, and the tensile rate is 50mm / min.

[0057] The notched Izod impact strength sample used for the notched Izod impact strength test is of the type: (80.0±5.0)mm*(10.0±0.5)mm*(4.0±0.2)mm, and the notch is mechanically machined by a sample milling machine, and the notch depth is (2.0±0.2)mm.

[0058] Example 1:

[0059] A preparation method of a diimine nickel catalyst, and the technical route is as follows:

[0060]

[0061] Specifically includes the following steps:

[0062] (1) Synthesis of compound (I): 4, 4-difluorobenzhydrol (13.153g; 60mmol) and benzidine (5.076g; 30mmol) are mixed, heated to 120℃, and then an appropriate amount of hydrochloric acid (HCl) dissolved zinc chloride (2g) (Zncl2) is added, and compound (I) is obtained after reaction, and the reaction formula is as follows:

[0063]

[0064] (2) Synthesis of compound (II): To a mixture of compound I (5.736 g; 10 mmol) and acenaphthenequinone (1.82 g; 10 mmol) was added acetic acid (8 mL). The mixture was heated to 80 °C and stirred for 30 min, then acetonitrile (10 mL) was added and the reaction was allowed to proceed for 24 h. The reaction mixture was cooled to room temperature and extracted with CH2Cl2. The combined organic layers were washed with brine and dried over anhydrous Na2SO4. The solvent was removed under reduced pressure to give a crude product which was purified by flash silica chromatography (EA / PE = 1 / 10 (v / v)). The desired compound (II) was obtained as follows:

[0065]

[0066] (3) Synthesis of compound (III): To compound (II) (7.38 g; 10 mmol) and dihexamethylaniline (1.21 g; 10 mmol) was added toluene (30 mL) slowly at 120 °C and stirred for 30 min, then PTSA (0.5 g) was added and the reaction was allowed to proceed at 80 °C for 24 h. The reaction mixture was cooled to room temperature and extracted with CH2Cl2three times and dried over anhydrous MgSO4. The MgSO4was filtered off and the filtrate was concentrated and column chromatographed to give compound (III) as follows: 1 HNMR spectrum, 13 C NMR spectrum as Figure 1 、 Figure 2 shown)

[0067]

[0068] (4) Synthesis of compound (IV): Compound (III) (0.85 g, 1.0 mmol) synthesized in step (3) was reacted with (DME)NiBr2(0.31 g, 1.0 mmol) in CH2Cl2(20 mL) under nitrogen atmosphere for 6-12 h. The reaction mixture was filtered, washed and dried to give a nickel diimine catalyst of acenaphthenequinone skeleton (i.e. compound (IV)) as follows:

[0069]

[0070] X-Ray Crystallography of compound (IV) is shown in Figure 3 .

[0071] Selected bond lengths and angles [deg]: Br(1)-Ni(1)=2.4144(16), Br(2)-Ni(1)=2.4592(13), Br(3)-Ni(2)=2.4637(13) Br(4)-Ni(2)=2.3959(16); Ni(1)-N(1)=2.059(6), Ni(1)-N(2)=2.130(2), Ni(2)-N(3)=2.070(6), Ni(2)-N(4)=2.134(6), N(1)-C(62)=1.452(9), N(1)-C(98)=1.282(10),

[0072] N(2)-C(97)=1.290(10), N(2)-C(109)=1.457(9); N(3)-C(9)=1.256(5), N(3)-C(7)=1.462(9), N(4)-C(10)

[0073] =1.292(10) N(4)-C(31)=1.464(9); Ni(2)-Br(3)-Ni(1)=92.04(4), N(1)-Ni(1)-Br(2)=155.06(18),

[0074] N(1)-Ni(1)-Br(1)=103.75(17), N(1)-Ni(1)-N(2)=95.99(19), Br(3)-Ni(2)-Br(2)=87.71(5), Br(4)-Ni(2)-Br(3)

[0075] =100.09(5), Br(4)-Ni(2)-Br(2)=99.72(5), N(3)-Ni(2)-Br(3)=159.20(19), N(3)-Ni(2)-Br(2)=93.22(17), N(3)-Ni(2)-Br(4)=100.22(19), N(3)-Ni(2)-N(4)=79.5(2), N(4)-Ni(2)-Br(3)=91.77(17); N(4)-Ni(2)-Br(2)=157.29(18), N(4)-Ni(2)-Br(4)=107.72(18), C(9)-N(3)-Ni(2)=113.4(5), C(9)-N(3)-C(7)=116.1(6),

[0076] C(7)-N(3)-Ni(2)=130.5(5), C(10)-N(4)-Ni(2)=113.2(5), C(10)-N(4)-C(31)=117.7(7), C(31)-N(4)-Ni(2)

[0077] = 128.8(5); C(62)-N(l)-Ni(l)= 127.5(5); C(98)-N(l)-Ni(l)= 114.3(5); C(98)-N(l)-C(62)=

[0078] 118.0(6); C(97)-N(2)-Ni(l)= 129.6(5); C(97)-N(2)-C(109)= 118.8(6); C(109)-N(2)-Ni(l)= 129.6(5)

[0079]

[0080]

[0081] Example 2:

[0082] A method for preparing a polyethylene-glass fiber composite material, comprising the following steps: a 350 mL thick-walled glass pressure vessel is charged with glass fiber (2.5 g), Et2AlCl (400 μmol), toluene (28 mL) and a magnetic stirring rod in a glove box. The pressure vessel is connected to a high-pressure polymerization line, and the solution is degassed. The vessel is heated to 40 °C using an oil bath, and allowed to equilibrate for 5 minutes. The nickel diimine catalyst (2 μmol, prepared in Example 1) in CH2Cl2(2 mL) is injected into the vessel with a syringe. With rapid stirring, the reactor is pressurized and maintained at 8.0 atm of ethylene. After 20 min, the vessel is vented, the polymer is precipitated in acidified ethanol (ethanol / HCl = 50:1 (v / v)), and dried under vacuum at 50 °C for 24 h to give the polyethylene-glass fiber composite material.

[0083] A scanning electron micrograph of the polyethylene-glass fiber composite material prepared in this example is shown in Figure 2, which shows that the material is well mixed. Figure 5

[0084] Example 3:

[0085] This example differs from Example 2 in that the glass fiber is 1.0 g, and the rest is the same as Example 2.

[0086] Example 4:

[0087] This example differs from Example 2 in that the glass fiber is 3.5 g, and the rest is the same as Example 2.

[0088] Example 5:

[0089] This example differs from Example 2 in that the glass fiber is 4.5 g, and the rest is the same as Example 2.​

[0090] The cyclic stress-strain curve of the polyethylene-glass fiber composite material prepared in Examples 2-5 is shown in Fig. 1, from which it can be seen that the tensile strength of the polyethylene-glass fiber (modified filler) first increases and then decreases with the increase of the glass fiber content. The tensile strength of the filler is increased to 6.23 MPa without affecting the tensile elongation of the filler, which facilitates the subsequent modification of polypropylene (PP). Figure 4

[0091] Example 6: (polyethylene-glass fiber composite material content 10%)

[0092] A method for preparing a modified PP material: 90 parts of polypropylene, 10 parts of polyethylene-glass fiber composite material (prepared in Example 2), and 0.2 parts of antioxidant Irganox 168 are weighed according to weight parts and added to a mixer respectively for mixing for 10 minutes to prepare a mixture; the mixture is added to a twin-screw extruder for melting and extrusion to prepare the modified PP material, wherein the temperature and screw speed of each zone of the twin-screw extruder are as follows: the temperature of the upper cavity plate is 140°C, the temperature of the lower cavity plate is 160°C, and the screw speed is 130-180 r / min.

[0093] Example 7: (content 5%)

[0094] The difference between this example and Example 6 is that the polypropylene is 95 parts, the polyethylene-glass fiber composite material is 5 parts, and the other steps are the same as those of Example 6.

[0095] Example 8: (content 15%)

[0096] The difference between this example and Example 6 is that the polypropylene is 85 parts, the polyethylene-glass fiber composite material is 15 parts, and the other steps are the same as those of Example 6.

[0097] Example 9: (content 20%)

[0098] The difference between this example and Example 6 is that the polypropylene is 80 parts, the polyethylene-glass fiber composite material is 20 parts, and the other steps are the same as those of Example 6.

[0099] Example 10: (content 25%)

[0100] The difference between this example and Example 6 is that the polypropylene is 75 parts, the polyethylene-glass fiber composite material is 25 parts, and the other steps are the same as those of Example 6.

[0101] Comparative Example 1: (content 30%)

[0102] ​The difference between the present comparative example and example 6 is that 70 parts of polypropylene and 30 parts of polyethylene-glass fiber composite are used, and other steps are the same as those in example 6.

[0103] Comparative example 2: (incorporation amount 35%)

[0104] The difference between the present comparative example and example 6 is that 65 parts of polypropylene and 35 parts of polyethylene-glass fiber composite are used, and other steps are the same as those in example 6.

[0105] Comparative example 3: (incorporation amount 0%)

[0106] The difference between the present comparative example and example 6 is that no polyethylene-glass fiber composite is added, and other steps are the same as those in example 6.

[0107] The modified PP materials prepared in examples 6-10 and comparative examples 1-3 are injected into a sample bar by an injection molding machine for tensile property test, and the test results are shown in the following table:

[0108]

[0109] In the table, “-” represents that the material morphology is poor, and the sample cannot be prepared for test.

[0110] From the above table, it can be seen that when the incorporation amount of the polyethylene-glass fiber composite is within 25%, the modified PP material can be uniformly blended, and has good performance, but when the incorporation amount is more than 30%, the composite material will have problems such as uneven mixing, and the compatibility becomes poor, and cannot be tested.

[0111] The tensile strength and impact resistance test results of the modified PP materials prepared in examples 6-10 are shown in Figure 6 , and the tensile property test results are shown in Figure 7 . From Figure 6 , it can be seen that with the increase of the modified filler, the tensile strength of the modified polypropylene (PP) has a trend of first increasing and then decreasing, and when the incorporation amount is 10%, the tensile strength reaches the highest.

[0112] From Figure 7 , it can be seen that when the incorporation amount of the modified filler is 10%, the tensile strength of the polypropylene (PP) can be increased by 2.41 times without affecting the tensile elongation of the polypropylene (PP).

[0113] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a polyethylene-glass fiber composite material, characterized in that: Includes the following steps: Glass fiber, toluene, nickel diimide catalyst, and Et₂AlCl were added to a reaction vessel under N₂ atmosphere, and ethylene gas was introduced to carry out the polymerization reaction, thus obtaining the product; the structural formula of the nickel diimide catalyst is as follows: ； The ratio of glass fiber, nickel diimide catalyst, and Et2AlCl is (1.0-4.5) g: (1-3) μmol: (300-500) μmol; the polymerization temperature is 30-60℃, and the polymerization time is 0.3-1 h.

2. The preparation method according to claim 1, characterized in that: The ratio of glass fiber, nickel diimide catalyst, and Et2AlCl is 2.5 g: 2 μmol: 400 μmol.

3. The preparation method according to claim 1, characterized in that: The polymerization reaction was carried out at a temperature of 40°C for 20 minutes.

4. The polyethylene-glass fiber composite material prepared by the preparation method according to any one of claims 1-3.

5. A modified PP material, characterized in that: It is composed of the following raw materials in parts by weight: 65-100 parts of polypropylene, 5-30 parts of modified filler and 0.1-0.5 parts of antioxidant; the modified filler is the polyethylene-glass fiber composite material according to claim 4; the antioxidant is one or more of Irganox 1010, antioxidant 168 and antioxidant 1076.

6. The modified PP material according to claim 5, characterized in that: The antioxidant is designated as Irganox1010.

7. A diimine ligand, characterized in that: Its structural formula is 。 8. A nickel diimine catalyst, characterized in that: Its structural formula is 。 9. The method for preparing the diimine nickel catalyst according to claim 8, characterized in that: Includes the following steps: (1) Mix 4,4-difluorodiphenylmethanol and benzidine, heat for a period of time, and then add zinc chloride dissolved in hydrochloric acid. After the reaction, compound (I) is obtained. (2) Compound (I) was reacted with acenaphthoquinone to obtain compound (II); (3) Compound (II) is then reacted with dihexamethylaniline to obtain compound (III); (4) Compound (III) was reacted with (DME)NiBr2 under a nitrogen atmosphere to obtain a diimine nickel catalyst. (IV).

10. The application of the nickel diimine catalyst according to claim 8 in olefin polymerization.

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