Beta crystalline polypropylene composite and method for producing the same

Abstract

This invention discloses a β-crystalline polypropylene composite material and its preparation method. The β-crystalline polypropylene composite material includes the following raw materials: polypropylene and polythiophene. By adding polythiophene to polypropylene, this invention can induce polypropylene to form more β-crystalline polypropylene. Polythiophene has high induction efficiency and low addition amount, which solves the problem of poor nucleation induction efficiency of polymer-type nucleating agents.

Description

Technical Field

[0001] This invention belongs to the field of polypropylene composite material technology, and particularly relates to a β-crystalline polypropylene composite material and its preparation method. Background Technology

[0002] In 1954, Natta first synthesized polypropylene with high stereoregularity, subsequently enabling its industrial production and ushering in a new era in polymer science and engineering. Its excellent thermal and mechanical properties make polypropylene widely used in many fields, such as injection molding, film production, and fiber manufacturing.

[0003] Under different crystallization conditions, polypropylene can form various crystal forms such as α, β, and γ, as well as smectic structures, among which the α crystal form is the most common and stable. The β crystal form belongs to the trigonal crystal system and is thermodynamically metastable, easily undergoing phase transformation during heating or stretching. Under high pressure conditions, the γ crystal form is preferentially formed.

[0004] Compared to α-crystalline and other crystalline forms of polypropylene, β-crystalline polypropylene has advantages such as lower elastic modulus and yield strength, higher impact strength and heat distortion temperature, and better toughness and ductility under high-speed tensile conditions. Furthermore, β-crystals can increase the porosity of polypropylene, improving the printability and coatability of polypropylene products. Therefore, obtaining β-crystalline polypropylene or increasing the β-crystal content in polypropylene has become one of the hot topics in materials science research in recent years.

[0005] Adding a β-nucleating agent to induce β-crystal formation is a simple, reproducible, and currently the only industrially feasible method for obtaining high-content β-crystalline polypropylene. Since the research on the dye γ-quinacridone (E3B) as a β-nucleating agent for polypropylene, significant progress has been made in basic research on β-nucleating agents, and they have also demonstrated considerable commercial value. Currently available β-nucleating agents include: fused-ring compounds with quasi-planar structures, aromatic amine compounds, complexes of alkaline earth metals and diacids, rare earth compounds, polymer-type nucleating agents, and compound nucleating agents. Small-molecule nucleating agents currently have certain drawbacks; for example, they are prone to aggregation and poor dispersibility during polymer processing. Some nucleating agents require surface treatment or the addition of dispersants to achieve better dispersion, while others are more prone to deposition.

[0006] Polymer-based nucleating agents differ significantly from small-molecule nucleating agents. First, the former has a much larger relative molecular mass and better compatibility with the polymer matrix. Second, most polymers, such as polystyrene and liquid crystal polymers, are amorphous, and their nucleation mechanisms cannot be explained by the lattice size matching theory used in small-molecule-induced nucleation. Therefore, research on polymer-based β-nucleating agents is not only of significant theoretical importance but also holds potential for application. For polymer-based nucleating agents, because the relative molecular mass of macromolecular nucleating agents is much greater than that of small-molecule nucleating agents, the content of nucleating agents is relatively high. However, the β-nucleation induction efficiency of polymers is generally low, and the addition amount is usually greater than 1%. Summary of the Invention

[0007] To address the shortcomings of the existing technology, a β-crystalline polypropylene composite material is provided. By adding polythiophene to polypropylene, more β-crystalline polypropylene can be induced to form. Polythiophene has high induction efficiency and low addition amount, thus solving the problem of poor nucleation induction efficiency of polymer-type nucleating agents.

[0008] The purpose of this invention is to provide a β-crystalline polypropylene composite material, comprising the following raw materials: polypropylene and polythiophene.

[0009] In some embodiments of the present invention, the polythiophene is selected from polymers with any of the following structures:

[0010] , , , ;

[0011] The number-average molecular weight ranges from 4.7 to 17.3 kDa.

[0012] In some embodiments of the present invention, the structure of the polythiophene is as follows:

[0013] ;

[0014] The number-average molecular weight is 6.5~8.9 kDa.

[0015] In some embodiments of the present invention, the structure of the polythiophene is as follows:

[0016] ;

[0017] The number-average molecular weight is 9.7~17.3 kDa.

[0018] In some embodiments of the present invention, the structure of the polythiophene is as follows:

[0019] ;

[0020] The number-average molecular weight ranges from 4.7 to 13.8 kDa.

[0021] In some embodiments of the present invention, the structure of the polythiophene is as follows:

[0022] ;

[0023] The number-average molecular weight is 7.5~13.5 kDa.

[0024] In some embodiments of the present invention, the hexylthiophene segment of the polythiophene accounts for 80% to 97.1% of the molar percentage of the polythiophene segment.

[0025] In some embodiments of the present invention, the isotacticity of the polythiophene is ≥80%.

[0026] In some embodiments of the present invention, the isotacticity of the polythiophene is ≥90%.

[0027] In some embodiments of the present invention, the amount of polythiophene used is 300ppm to 1000ppm of the polypropylene by mass percentage.

[0028] In some embodiments of the present invention, the amount of polythiophene used is 500ppm to 800ppm of the polypropylene by weight percentage.

[0029] In some embodiments of the present invention, the crystallization temperature of the β-crystalline polypropylene composite material is 118~119℃.

[0030] In some embodiments of the present invention, the crystallinity of the β-crystalline polypropylene composite material is 38.8~51.3%.

[0031] In some embodiments of the present invention, the β-crystalline polypropylene content in the β-crystalline polypropylene composite material is 6.4 to 53.5% of the total crystalline material, by mass percentage.

[0032] Another object of the present invention is to provide a method for preparing the β-crystalline polypropylene composite material, comprising the following steps:

[0033] S1. Pulverize polypropylene into powder, take a portion of the polypropylene powder and mix it with tetrachloroethane, heat to 120~160℃, dissolve, and obtain a polypropylene solution;

[0034] S2. Mix polythiophene and tetrachloroethane, heat to 120~160℃ to dissolve, and obtain a polythiophene solution;

[0035] S3. Mix the polypropylene solution and the polythiophene solution to form a homogeneous solution, add a poor solvent, precipitate, and obtain the matrix material;

[0036] S4. Blend the matrix material with the remaining polypropylene powder, melt extrude to obtain a β-crystalline polypropylene composite material.

[0037] In some embodiments of the present invention, in S2, the amount of the polypropylene powder used is no more than 1% of the total mass of the polypropylene powder;

[0038] In some embodiments of the present invention, in S3, the undesirable solvent is selected from at least one of methanol and ethanol.

[0039] In some embodiments of the present invention, in S3, the volume ratio of the homogeneous solution to the poor solvent is 1:100~500.

[0040] In some embodiments of the present invention, in S4, the temperature of the melt extrusion is 180-230°C.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] This invention solves the problem of poor nucleation induction efficiency of polymer-type nucleating agents by adding polythiophene to polypropylene. Polythiophene has a highly efficient induction effect, which can induce polypropylene to form more β-crystalline polypropylene. Polythiophene has the advantages of high induction efficiency and low addition amount. Attached Figure Description

[0043] Figure 1 The image shows the DSC secondary temperature rise spectrum of the β-crystalline polypropylene composite material in Example 5.

[0044] Figure 2 The image shows the DSC secondary temperature rise spectrum of the β-crystalline polypropylene composite material of Comparative Example 1. Detailed Implementation

[0045] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0046] Example 1

[0047] This embodiment provides a β-crystalline polypropylene composite material, and the specific preparation steps are as follows:

[0048] S1. Pulverize polypropylene into powder, take a portion of the polypropylene powder and mix it with tetrachloroethane, heat to 120~160℃, dissolve, and obtain a polypropylene solution;

[0049] S2. Mix polythiophene with an isotacticity of 91% and tetrachloroethane, heat to 120~160℃ to dissolve, and obtain a polythiophene solution;

[0050] S3. Mix the polypropylene solution and the polythiophene solution to form a homogeneous solution, add methanol, the volume ratio of the homogeneous solution to methanol is 1:100, precipitate, and take the precipitate to obtain the matrix material;

[0051] S4. Blend the matrix material with the remaining polypropylene powder, and melt-extrude at 180-230℃ to obtain a β-crystalline polypropylene composite material;

[0052] Of which, the amount of polythiophene used, by mass percentage, is 300 ppm of polypropylene.

[0053] The amount of polypropylene powder used is 0.1% of the total mass of polypropylene powder;

[0054] The structure of the polythiophene is shown below:

[0055] ;

[0056] The number-average molecular weight (Mn) was 8.9 kDa, the PDI was 2.61, x = 4.7 mmol%, and y = 95.3 mmol.

[0057] Example 2

[0058] This embodiment provides a β-crystalline polypropylene composite material, and the specific preparation steps are as follows:

[0059] S1. Pulverize polypropylene into powder, take a portion of the polypropylene powder and mix it with tetrachloroethane, heat to 120~160℃, dissolve, and obtain a polypropylene solution;

[0060] S2. Mix polythiophene with an isotacticity of 92% and tetrachloroethane, heat to 120~160℃ to dissolve, and obtain a polythiophene solution;

[0061] S3. Mix the polypropylene solution and the polythiophene solution to form a homogeneous solution, add ethanol, the volume ratio of the homogeneous solution to ethanol is 1:500, precipitate, and take the precipitate to obtain the matrix material;

[0062] S4. Blend the matrix material with the remaining polypropylene powder, and melt-extrude at 180-230℃ to obtain a β-crystalline polypropylene composite material;

[0063] Of which, the amount of polythiophene used, by mass percentage, is 800 ppm of polypropylene.

[0064] The amount of polypropylene powder used is 0.1% of the total mass of polypropylene powder;

[0065] The structure of the polythiophene is shown below:

[0066] ;

[0067] The number-average molecular weight (Mn) was 6.5 kDa, the PDI was 2.67, x = 8.3 mmol%, and y = 91.7 mmol.

[0068] Example 3

[0069] This embodiment provides a β-crystalline polypropylene composite material, and the specific preparation steps are as follows:

[0070] S1. Pulverize polypropylene into powder, take a portion of the polypropylene powder and mix it with tetrachloroethane, heat to 120~160℃, dissolve, and obtain a polypropylene solution;

[0071] S2. Mix polythiophene with an isotacticity of 80% and tetrachloroethane, heat to 120~160℃ to dissolve, and obtain a polythiophene solution;

[0072] S3. Mix the polypropylene solution and the polythiophene solution to form a homogeneous solution, add methanol, the volume ratio of the homogeneous solution to methanol is 1:300, precipitate, and take the precipitate to obtain the matrix material;

[0073] S4. Blend the matrix material with the remaining polypropylene powder, and melt-extrude at 180-230℃ to obtain a β-crystalline polypropylene composite material;

[0074] Of which, the amount of polythiophene used, by mass percentage, is 500 ppm of polypropylene.

[0075] The amount of polypropylene powder used is 0.1% of the total mass of polypropylene powder;

[0076] The structure of the polythiophene is shown below:

[0077] ;

[0078] Among them, the number-average molecular weight Mn is 9.7 kDa, PDI is 3.51, x = 5 mmol%, and y = 95 mmol.

[0079] Example 4

[0080] This embodiment provides a β-crystalline polypropylene composite material, and the specific preparation steps are as follows:

[0081] S1. Pulverize polypropylene into powder, take a portion of the polypropylene powder and mix it with tetrachloroethane, heat to 120~160℃, dissolve, and obtain a polypropylene solution;

[0082] S2. Mix polythiophene with an isotacticity of 84.5% with tetrachloroethane, heat to 120~160℃ to dissolve, and obtain a polythiophene solution;

[0083] S3. Mix the polypropylene solution and the polythiophene solution to form a homogeneous solution, add ethanol, the volume ratio of the homogeneous solution to ethanol is 1:200, precipitate, and take the precipitate to obtain the matrix material;

[0084] S4. Blend the matrix material with the remaining polypropylene powder, and melt-extrude at 180-230℃ to obtain a β-crystalline polypropylene composite material;

[0085] Of which, the amount of polythiophene used, by mass percentage, is 1000 ppm of polypropylene.

[0086] The amount of polypropylene powder used is 0.1% of the total mass of polypropylene powder;

[0087] The structure of the polythiophene is shown below:

[0088] ;

[0089] The number-average molecular weight Mn was 17.3 kDa, the PDI was 3.82, x = 11.8 mmol%, and y = 88.2 mmol.

[0090] Example 5

[0091] This embodiment provides a β-crystalline polypropylene composite material, and the specific preparation steps are as follows:

[0092] S1. Pulverize polypropylene into powder, take a portion of the polypropylene powder and mix it with tetrachloroethane, heat to 120~160℃, dissolve, and obtain a polypropylene solution;

[0093] S2. Mix polythiophene with an isotacticity of 85% and tetrachloroethane, heat to 120~160℃ to dissolve, and obtain a polythiophene solution;

[0094] S3. Mix the polypropylene solution and the polythiophene solution to form a homogeneous solution, add methanol, the volume ratio of the homogeneous solution to methanol is 1:250, precipitate, and take the precipitate to obtain the matrix material;

[0095] S4. Blend the matrix material with the remaining polypropylene powder, and melt-extrude at 180-230℃ to obtain a β-crystalline polypropylene composite material;

[0096] Of which, the amount of polythiophene used, by mass percentage, is 600 ppm of polypropylene.

[0097] The amount of polypropylene powder used is 0.1% of the total mass of polypropylene powder;

[0098] The structure of the polythiophene is shown below:

[0099] ;

[0100] The number-average molecular weight Mn is 13.8 kDa, PDI is 2.2, x = 4.3 mmol%, and y = 95.7 mmol.

[0101] Example 6

[0102] This embodiment provides a β-crystalline polypropylene composite material, and the specific preparation steps are as follows:

[0103] S1. Pulverize polypropylene into powder, take a portion of the polypropylene powder and mix it with tetrachloroethane, heat to 120~160℃, dissolve, and obtain a polypropylene solution;

[0104] S2. Mix polythiophene with an isotacticity of 83% and tetrachloroethane, heat to 120~160℃ to dissolve, and obtain a polythiophene solution;

[0105] S3. Mix the polypropylene solution and the polythiophene solution to form a homogeneous solution, add ethanol, the volume ratio of the homogeneous solution to ethanol is 1:400, precipitate, and take the precipitate to obtain the matrix material;

[0106] S4. Blend the matrix material with the remaining polypropylene powder, and melt-extrude at 180-230℃ to obtain a β-crystalline polypropylene composite material;

[0107] Of which, the amount of polythiophene used, by mass percentage, is 700 ppm of polypropylene.

[0108] The amount of polypropylene powder used is 0.1% of the total mass of polypropylene powder;

[0109] The structure of the polythiophene is shown below:

[0110] ;

[0111] The number-average molecular weight Mn is 4.7 kDa, the PDI is 1.3, x = 20 mmol%, and y = 80 mmol.

[0112] Example 7

[0113] This embodiment provides a β-crystalline polypropylene composite material, and the specific preparation steps are as follows:

[0114] S1. Pulverize polypropylene into powder, take a portion of the polypropylene powder and mix it with tetrachloroethane, heat to 120~160℃, dissolve, and obtain a polypropylene solution;

[0115] S2. Mix polythiophene with an isotacticity of 87% and tetrachloroethane, heat to 120~160℃ to dissolve, and obtain a polythiophene solution;

[0116] S3. Mix the polypropylene solution and the polythiophene solution to form a homogeneous solution, add methanol, the volume ratio of the homogeneous solution to methanol is 1:350, precipitate, and take the precipitate to obtain the matrix material;

[0117] S4. Blend the matrix material with the remaining polypropylene powder, and melt-extrude at 180-230℃ to obtain a β-crystalline polypropylene composite material;

[0118] Of which, the amount of polythiophene used, by mass percentage, is 900 ppm of polypropylene.

[0119] The amount of polypropylene powder used is 0.1% of the total mass of polypropylene powder;

[0120] The structure of the polythiophene is shown below:

[0121] ;

[0122] Among them, the number-average molecular weight Mn is 13.5 kDa, PDI is 2.5, x = 2.5 mmol%, and y = 97.5 mmol.

[0123] Example 8

[0124] This embodiment provides a β-crystalline polypropylene composite material, and the specific preparation steps are as follows:

[0125] S1. Pulverize polypropylene into powder, take a portion of the polypropylene powder and mix it with tetrachloroethane, heat to 120~160℃, dissolve, and obtain a polypropylene solution;

[0126] S2. Mix polythiophene with an isotacticity of 89% and tetrachloroethane, heat to 120~160℃ to dissolve, and obtain a polythiophene solution;

[0127] S3. Mix the polypropylene solution and the polythiophene solution to form a homogeneous solution, add ethanol, the volume ratio of the homogeneous solution to ethanol is 1:450, precipitate, and take the precipitate to obtain the matrix material;

[0128] S4. Blend the matrix material with the remaining polypropylene powder, and melt-extrude at 180-230℃ to obtain a β-crystalline polypropylene composite material;

[0129] Of which, the amount of polythiophene used, by mass percentage, is 400 ppm of polypropylene.

[0130] The amount of polypropylene powder used is 0.1% of the total mass of polypropylene powder;

[0131] The structure of the polythiophene is shown below:

[0132] ;

[0133] Among them, the number-average molecular weight Mn is 7.5 kDa, PDI is 2.1, x = 13.9 mmol%, and y = 86.1 mmol.

[0134] Comparative Example 1

[0135] Polypropylene powder from any of Examples 1 to 5 was used without adding polythiophene.

[0136] Performance testing:

[0137] The performance of the β-crystalline polypropylene composites of Examples 1-8 and the polypropylene of Comparative Example 1 were tested, and the results are shown in Table 1.

[0138] Table 1. Properties of β-crystalline polypropylene composites and polypropylene.

[0139]

[0140] As shown in Table 1, by comparing Examples 1-8 and Comparative Example 1, it can be seen that the present invention, by adding polythiophene to polypropylene, has the advantages of high induction efficiency and low addition amount, thus solving the problem of poor nucleation induction efficiency of polymer-type nucleating agents.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading this application specification, they can still modify or make equivalent substitutions to the specific implementation of the present invention, but these modifications or changes do not depart from the protection scope of the pending claims of the present invention.

Claims

1. A β-crystalline polypropylene composite material, characterized in that, The raw materials include: polypropylene and polythiophene; The amount of polythiophene used is 300ppm to 1000ppm of the polypropylene. The polythiophene is selected from polymers with any of the following structures, and its number average molecular weight is 4.7~17.3 kDa: 、 、 、 。 2. The β-crystalline polypropylene composite material as described in claim 1, characterized in that, The hexylthiophene segment of the polythiophene accounts for 80% to 97.1% of the total polythiophene segments.

3. The β-crystalline polypropylene composite material as described in claim 1, characterized in that, The isotacticity of the polythiophene is ≥80%.

4. The β-crystalline polypropylene composite material according to any one of claims 1 to 3, characterized in that, The crystallization temperature of the β-crystalline polypropylene composite material is 118~119℃.

5. The β-crystalline polypropylene composite material according to any one of claims 1 to 3, characterized in that, The crystallinity of the β-crystalline polypropylene composite material is 38.8~51.3%.

6. The β-crystalline polypropylene composite material according to any one of claims 1 to 3, characterized in that, The β-crystalline polypropylene content in the β-crystalline polypropylene composite material is 6.4-53.5% of the total crystalline material, based on mass percentage.

7. The method for preparing the β-crystalline polypropylene composite material according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Pulverize polypropylene into powder, take a portion of the polypropylene powder and mix it with tetrachloroethane, heat to 120~160℃, dissolve, and obtain a polypropylene solution; S2. Mix polythiophene and tetrachloroethane, heat to 120~160℃ to dissolve, and obtain a polythiophene solution; S3. Mix the polypropylene solution and the polythiophene solution to form a homogeneous solution, add a poor solvent, precipitate, and obtain the matrix material; S4. The matrix material is blended with the remaining polypropylene powder and melt-extruded to obtain the β-crystalline polypropylene composite material.

8. The method for preparing the β-crystalline polypropylene composite material according to claim 7, characterized in that, The amount of polypropylene powder used shall not exceed 1% of the total mass of the polypropylene powder; And / or, the temperature of the melt extrusion is 180-230°C.

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