Modified hdpe composite material, its preparation method and application in power communication pipeline

Abstract

The application belongs to the technical field of high polymer composite materials, and discloses a modified HDPE composite material, a preparation method thereof and application of the modified HDPE composite material in power communication pipes. The preparation method of the modified HDPE composite material comprises the following steps: adding an HDPE base material, an organic silicon cross-linked polybutadiene modifier, a flame retardant and an initiator into a banbury mixer, carrying out a melt mixing reaction under a protective atmosphere, then injection molding into a mold to form a modified HDPE composite material. The organic silicon cross-linked polybutadiene modifier is used to modify the HDPE material, so that the strength, toughness and aging resistance of the HDPE material can be improved at the same time. The modified HDPE composite material can be used for preparing power communication pipes.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials technology, specifically relating to a modified HDPE composite material, its preparation method, and its application in power communication pipelines. Background Technology

[0002] The main organic polymer materials used in power and communication pipelines are polyvinyl chloride (PVC) and polyethylene (PE). PVC has the advantages of being lightweight and inexpensive, but its high temperature resistance and impact resistance are relatively poor. PE is mainly divided into high-density polyethylene (HDPE) and low-density polyethylene (LDPE). HDPE has higher strength and hardness characteristics because its molecular chains are arranged linearly with very few branches and high crystallinity, but its aging resistance and toughness are slightly worse.

[0003] Organosilicon has wide applications in the modification of polyethylene materials due to its good aging resistance and flexibility. For example, Li Qiaojuan et al. modified low-density polyethylene with organosilicon grafting to improve the flexibility, heat resistance, weather resistance, and electrical properties of polyethylene materials (Li Qiaojuan et al.: Research on Organosilicon Grafting Modification of Low-Density Polyethylene. Insulation Materials. 2004 No.1). However, current chemical grafting modification is mainly used for LDPE because LDPE has higher reactivity, and chemical grafting modification does not affect its overall structure and crystallinity. HDPE, on the other hand, has fewer molecular chains and a more regular structure, resulting in lower reactivity and lower modification efficiency. Furthermore, conventional chemical grafting modification can affect its molecular structure and crystallinity, leading to a reduction in its original advantageous properties. Summary of the Invention

[0004] In view of the shortcomings and deficiencies of the existing technology, the purpose of this invention is to provide a modified HDPE composite material, its preparation method, and its application in power communication pipelines.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for preparing a modified HDPE composite material includes the following steps:

[0007] S1. Preparation of organosilicon crosslinked polybutadiene modifier: An organic solvent was added to a reaction vessel, and after deoxygenation by nitrogen, liquid polybutadiene, terminal hydrogen silicone oil, and caster platinum complex catalyst (1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex) were added sequentially and mixed and dissolved. Then, the temperature was raised to 70~90℃ and the reaction was maintained until the silicon-hydrogen bond reaction was complete. The reaction mixture was then transported to a rotary dryer for drying and granulation to obtain organosilicon crosslinked polybutadiene modifier.

[0008] S2. Preparation of modified HDPE composite material: HDPE matrix, organosilicon crosslinked polybutadiene modifier, flame retardant and initiator are added to a mixer and melt-mixed under a protective atmosphere. Then, the mixture is injected into a mold to form a modified HDPE composite material.

[0009] Preferably, the organic solvent in step S1 is a mixture of toluene and tetrahydrofuran with a volume ratio of 2 to 4:1. Using this mixture of toluene and tetrahydrofuran promotes better miscibility between the liquid polybutadiene and the terminal hydrogen silicone oil. Furthermore, the addition of the polar tetrahydrofuran solvent further enhances the hydrosilylation reaction between the terminal hydrogen silicone oil and polybutadiene, thereby improving reaction efficiency.

[0010] Preferably, the liquid polybutadiene in step S1 is any one of Evonik POLYVEST 110, POLYVEST 130, or POLYVEST MV nonfunctionalized polybutadiene; more preferably, it is POLYVEST MV.

[0011] The nonfunctionalized polybutadienes POLYVEST 110 and POLYVEST 130 mainly consist of 1,4-double bonds, while POLYVESTMV contains a high content of 1,2-vinyl double bonds. The 1,2-vinyl double bonds exhibit lower steric hindrance and higher reactivity with terminal hydrogen silicone oil, resulting in higher reaction efficiency.

[0012] Preferably, the molecular structure of the hydrogen-terminated silicone oil in step S1 is as follows:

[0013] In the formula, n is an integer from 10 to 50.

[0014] Under the above conditions, the number-average molecular weight of the hydrogen-terminated silicone oils ranges from 800 to 4000. The organosilicon crosslinked polybutadiene modifier prepared using hydrogen-terminated silicone oils within this chain length range exhibits good compatibility with HDPE substrates, has minimal impact on the HDPE structure, and achieves better modification results.

[0015] This application further reveals that using conventional side-chain hydrogen-containing silicone oil to crosslink liquid polybutadiene as a modifier has an adverse effect on the mechanical strength of HDPE composites. This is because side-chain hydrogen-containing silicone oil has significant steric hindrance, requiring increased hydrogen content to promote the crosslinking reaction. Furthermore, the crosslinking process involves entanglement and coating of the polybutadiene backbone, leading to an increased proportion of polysiloxane chains at the modifier interface. This results in poor compatibility with the HDPE substrate and disrupts the structural regularity of HDPE, leading to reduced mechanical strength. In contrast, using the terminal hydrogen-containing silicone oil of this invention for crosslinking primarily generates a crosslinked structure with internal polysiloxane chains and an external polyolefin layer. This structure exhibits better compatibility with HDPE and has less impact on the HDPE structure, thus achieving a better modification effect. The principle of the crosslinking reaction using the terminal hydrogen-containing silicone oil of this invention is as follows:

[0016] .

[0017] The above reaction principle is only a general example of a reaction under normal circumstances.

[0018] Preferably, the amount of terminal hydrogen silicone oil added in step S1 is 40% to 80% of the mass of liquid polybutadiene. Increasing the amount of terminal hydrogen silicone oil can achieve better aging resistance and flexibility, but too much terminal hydrogen silicone oil will lead to incomplete reaction. Uncrosslinked terminal hydrogen silicone oil is prone to phase separation in HDPE substrate, thereby reducing the modification effect.

[0019] Preferably, the amount of organosilicon crosslinked polybutadiene modifier used in step S2 is 0.5% to 8% of the mass of the HDPE substrate. If the amount of modifier is too small, the modification effect will be insignificant; if the amount of modifier is too large, it will lead to too many crosslinked branched structures in the system, thereby destroying the linear regular structure of HDPE and reducing mechanical strength.

[0020] Preferably, the flame retardant in step S2 is hexaphenoxycyclotriphosphazene. The present invention uses hexaphenoxycyclotriphosphazene as a flame retardant, which has good compatibility with HDPE substrate and causes less damage to the structural regularity of HDPE compared to inorganic flame retardants. While possessing good flame retardant properties, it also has minimal impact on the mechanical properties of the material.

[0021] Preferably, the amount of flame retardant used in step S2 is 2% to 10% of the mass of the HDPE substrate.

[0022] Preferably, the initiator in step S2 is dicumyl peroxide or di-tert-butyl peroxide; the amount of initiator is 0.05% to 0.2% of the mass of the HDPE substrate.

[0023] The initiator of this invention enables the unsaturated bonds introduced by the modifier to undergo further cross-linking reaction, thereby further improving the material strength and thermo-oxidative aging performance.

[0024] A modified HDPE composite material was prepared by the above method.

[0025] Application of the above-mentioned modified HDPE composite material in power communication pipelines.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] (1) The present invention uses an organosilicon crosslinked polybutadiene modifier to modify HDPE material, which can simultaneously improve the strength, toughness and aging resistance of HDPE material.

[0028] (2) The preparation method of the organosilicon crosslinked polybutadiene modifier of the present invention is simple, the raw materials are widely available, and good modification effect can be achieved with a low addition amount, and the production and application costs are low.

[0029] (3) The present invention uses a novel hexaphenoxycyclotriphosphazene flame retardant, which has good compatibility with the HDPE substrate of the present invention. Compared with inorganic flame retardants, it causes less damage to the structural regularity of HDPE. While having good flame retardant properties, it has less impact on the mechanical properties of the material. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0031] Example 1

[0032] A method for preparing a modified HDPE composite material includes the following steps:

[0033] S1. Preparation of organosilicon crosslinked polybutadiene modifier: Toluene and tetrahydrofuran were added to a reactor at a volume ratio of 3:1. After deoxygenation with nitrogen, liquid polybutadiene (Evonik POLYVEST 110), terminal hydrogen silicone oil (Mn 2000, hydrogen content 0.1%), and Castel platinum complex catalyst (1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex) were added sequentially and mixed and dissolved. The amount of terminal hydrogen silicone oil added was 60% of the mass of liquid polybutadiene. The temperature was then raised to 80℃ and maintained for 6 hours. The silicon hydrogen content in the product was not detected, indicating that the reaction was complete. The reaction mixture was then transferred to a rotary dryer for drying and granulation to obtain the organosilicon crosslinked polybutadiene modifier.

[0034] S2. Preparation of modified HDPE composite material: By mass, 100 parts of HDPE substrate, 5 parts of organosilicon crosslinked polybutadiene modifier, 6 parts of flame retardant hexaphenoxycyclotriphosphazene and 0.1 parts of dicumyl peroxide initiator were added to a mixer and melt-mixed under nitrogen protection (the temperature of the internal mixing melt-mixing reaction was controlled at 180~220℃ and the time was 30min). Then, the mixture was injected into a mold for molding (the injection temperature was controlled at 220~240℃) to obtain the modified HDPE composite material.

[0035] Example 2

[0036] A method for preparing a modified HDPE composite material includes the following steps:

[0037] S1. Preparation of organosilicon crosslinked polybutadiene modifier: Toluene and tetrahydrofuran were added to a reactor at a volume ratio of 3:1. After deoxygenation with nitrogen, liquid polybutadiene (Evonik POLYVEST 130), terminal hydrogen silicone oil (Mn 2000, hydrogen content 0.1%), and Castel platinum complex catalyst (1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex) were added sequentially and mixed and dissolved. The amount of terminal hydrogen silicone oil added was 60% of the mass of liquid polybutadiene. The temperature was then raised to 80℃ and maintained for 6 hours. The silicon hydrogen content in the product was not detected, indicating that the reaction was complete. The reaction mixture was then transferred to a rotary dryer for drying and granulation to obtain the organosilicon crosslinked polybutadiene modifier.

[0038] Step S2 is the same as in Example 1.

[0039] Example 3

[0040] A method for preparing a modified HDPE composite material includes the following steps:

[0041] S1. Preparation of organosilicon crosslinked polybutadiene modifier: Toluene and tetrahydrofuran were added to a reactor at a volume ratio of 3:1. After deoxygenation with nitrogen, liquid polybutadiene (Evonik POLYVEST MV), terminal hydrogen silicone oil (Mn 2000, hydrogen content 0.1%), and Castel platinum complex catalyst (1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex) were added sequentially and mixed and dissolved. The amount of terminal hydrogen silicone oil added was 60% of the mass of liquid polybutadiene. The temperature was then raised to 80℃ and maintained for 3 hours. The product was sampled and the silane content was not detected, indicating that the reaction was complete. The reaction mixture was then transferred to a rotary dryer for drying and granulation to obtain the organosilicon crosslinked polybutadiene modifier.

[0042] Step S2 is the same as in Example 1.

[0043] Example 4

[0044] A method for preparing a modified HDPE composite material includes the following steps:

[0045] S1. Preparation of organosilicon crosslinked polybutadiene modifier: Toluene and tetrahydrofuran were added to a reactor at a volume ratio of 2:1. After deoxygenation with nitrogen, liquid polybutadiene (Evonik POLYVEST MV), terminal hydrogen silicone oil (Mn 4000, hydrogen content 0.05%), and Castel platinum complex catalyst (1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex) were added sequentially and mixed and dissolved. The amount of terminal hydrogen silicone oil added was 80% of the mass of liquid polybutadiene. The temperature was then raised to 80℃ and maintained for 3 hours. The silicon hydrogen content in the product was not detected, indicating that the reaction was complete. The reaction mixture was then transferred to a rotary dryer for drying and granulation to obtain the organosilicon crosslinked polybutadiene modifier.

[0046] S2. Preparation of modified HDPE composite material: By mass, 100 parts of HDPE substrate, 8 parts of organosilicon crosslinked polybutadiene modifier, 2 parts of flame retardant hexaphenoxycyclotriphosphazene and 0.1 parts of dicumyl peroxide initiator were added to a mixer and melt-mixed under nitrogen protection (the temperature of the internal mixing melt-mixing reaction was controlled at 180~220℃ and the time was 30min). Then, the mixture was injected into a mold for molding (the injection temperature was controlled at 220~240℃) to obtain the modified HDPE composite material.

[0047] Example 5

[0048] A method for preparing a modified HDPE composite material includes the following steps:

[0049] S1. Preparation of organosilicon crosslinked polybutadiene modifier: Toluene and tetrahydrofuran were added to a reactor at a volume ratio of 4:1. After deoxygenation with nitrogen, liquid polybutadiene (Evonik POLYVEST MV), terminal hydrogen silicone oil (Mn 800, hydrogen content 0.25%), and Castel platinum complex catalyst (1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex) were added sequentially and mixed and dissolved. The amount of terminal hydrogen silicone oil added was 40% of the mass of liquid polybutadiene. The temperature was then raised to 80℃ and maintained for 3 hours. The silicon hydrogen content in the product was not detected, indicating that the reaction was complete. The reaction mixture was then transferred to a rotary dryer for drying and granulation to obtain the organosilicon crosslinked polybutadiene modifier.

[0050] S2. Preparation of modified HDPE composite material: By mass, 100 parts of HDPE substrate, 3 parts of organosilicon crosslinked polybutadiene modifier, 8 parts of flame retardant hexaphenoxycyclotriphosphazene and 0.1 parts of dicumyl peroxide initiator were added to a mixer and melt-mixed under nitrogen protection (the temperature of the internal mixing melt-mixing reaction was controlled at 180~220℃ and the time was 30min). Then, the mixture was injected into a mold for molding (the injection temperature was controlled at 220~240℃) to obtain the modified HDPE composite material.

[0051] Example 6

[0052] A method for preparing a modified HDPE composite material includes the following steps:

[0053] S1. Preparation of organosilicon crosslinked polybutadiene modifier: Toluene and tetrahydrofuran were added to a reactor at a volume ratio of 3:1. After deoxygenation with nitrogen, liquid polybutadiene (Evonik POLYVEST MV), terminal hydrogen silicone oil (Mn 1000, hydrogen content 0.20%), and Castel platinum complex catalyst (1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex) were added sequentially and mixed and dissolved. The amount of terminal hydrogen silicone oil added was 70% of the mass of liquid polybutadiene. The temperature was then raised to 80℃ and maintained for 3 hours. The silicon hydrogen content in the product was not detected, indicating that the reaction was complete. The reaction mixture was then transferred to a rotary dryer for drying and granulation to obtain the organosilicon crosslinked polybutadiene modifier.

[0054] S2. Preparation of modified HDPE composite material: By mass, 100 parts of HDPE substrate, 0.5 parts of organosilicon crosslinking polybutadiene modifier, 10 parts of flame retardant hexaphenoxycyclotriphosphazene and 0.1 parts of dicumyl peroxide initiator are added to a mixer and melt-mixed under nitrogen protection (the temperature of the internal mixing melt-mixing reaction is controlled at 180~220℃ and the time is 30min). Then, it is injected into a mold for molding (the injection temperature is controlled at 220~240℃) to obtain the modified HDPE composite material.

[0055] Comparative Example 1

[0056] A method for preparing a modified HDPE composite material includes the following steps:

[0057] By weight, 100 parts of HDPE substrate, 5 parts of liquid polybutadiene (Evonik POLYVEST MV) modifier, 6 parts of flame retardant hexaphenoxycyclotriphosphazene, and 0.1 parts of dicumyl peroxide initiator were added to an internal mixer and melt-mixed under nitrogen protection (the internal melting reaction temperature was controlled at 180~220℃ for 30 min). Then, the mixture was injected into a mold for molding (the injection temperature was controlled at 220~240℃) to obtain the modified HDPE composite material.

[0058] Comparative Example 2

[0059] A method for preparing a modified HDPE composite material includes the following steps:

[0060] S1. Preparation of organosilicon crosslinked polybutadiene modifier: Toluene and tetrahydrofuran were added to a reactor at a volume ratio of 3:1. After deoxygenation with nitrogen, liquid polybutadiene (Evonik POLYVEST MV), side-chain hydrogen-containing silicone oil (Mn 2000, hydrogen content 0.8%), and Castel platinum complex catalyst (1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex) were added sequentially and mixed and dissolved. The amount of side-chain hydrogen-containing silicone oil added was 60% of the mass of liquid polybutadiene. The temperature was then raised to 80℃ and maintained for 3 hours. The silicon hydrogen content in the product was measured to be 0.22% (calculated to be approximately 26.7% of the silicon hydrogen bonds involved in the crosslinking reaction). The reaction mixture was then transferred to a rotary dryer for drying and granulation to obtain the organosilicon crosslinked polybutadiene modifier.

[0061] Step S2 is the same as in Example 3.

[0062] The tensile strength, impact strength, and thermo-oxidative aging properties (forced ventilation thermo-aging chamber, 100℃*168h, recording the change rate of tensile strength and the change rate of impact strength) of the modified HDPE composite material and the unmodified HDPE material obtained in the above examples and comparative examples were tested, and the results are shown in Table 1 below.

[0063] Table 1

[0064] test sample Tensile strength / MPa Impact strength / kJ / m² Tensile strength change rate / % Impact strength change rate / % Example 1 33.6 28.5 -7.5 -6.4 Example 2 33.0 28.2 -7.9 -6.7 Example 3 32.4 30.3 -6.8 -5.5 Example 4 29.5 31.4 -5.4 -4.6 Example 5 33.5 27.3 -8.4 -8.7 Example 6 32.8 26.7 -11.1 -12.6 Comparative Example 1 32.8 23.9 -21.5 -25.3 Comparative Example 2 24.1 25.6 -17.8 -16.9 Unmodified HDPE 28.7 22.5 -25.4 -31.2

[0065] The results in Table 1 show that the modification of HDPE using an organosilicon crosslinked polybutadiene modifier significantly improves the strength, toughness, and aging resistance of the composite material. Comparative Example 1 shows that simple modification with crosslinked polybutadiene has no significant effect on improving toughness and aging resistance. Comparative Example 2 shows that the polybutadiene modifier with side-chain hydrogen-containing silicone oil crosslinking has an adverse effect on the strength of the composite material, and its improvement effect on the toughness and aging resistance is significantly lower compared to the polybutadiene modifier with terminal hydrogen silicone oil crosslinking.

[0066] The above embodiments are merely explanations of this application and are not intended to limit this application. Those skilled in the art can make simple substitutions or modifications to this invention as needed after reading this specification, and all such modifications are included within the protection scope of this invention.

Claims

1. A method of making a modified HDPE composite material, characterized by: Comprising the following steps: S1. Preparation of silicone cross-linked polybutadiene modifier: organic solvent is added into a reaction kettle, after nitrogen deoxygenation, liquid polybutadiene, terminal hydrogen silicone oil and Karsted platinum complex catalyst are sequentially added and dissolved, then the temperature is raised to 70-90℃ and kept for reaction until the silicon hydrogen bond reaction is complete, the reaction mixture is transported to a rotary dryer for drying and granulation to obtain the silicone cross-linked polybutadiene modifier; S2. Preparation of modified HDPE composite material: HDPE base material, silicone cross-linked polybutadiene modifier, flame retardant and initiator are added into a banbury mixer, melt mixing reaction is carried out under a protective atmosphere, then injection molding is carried out in a mold to form a modified HDPE composite material; The molecular structure formula of the terminal hydrogen silicone oil in the S1 step is as follows: wherein n is an integer from 10 to 50.

2. The method for preparing a modified HDPE composite material according to claim 1, characterized in that: The organic solvent in the S1 step is a mixed solvent of toluene and tetrahydrofuran with a volume ratio of 2-4:

1.

3. The method for preparing a modified HDPE composite material according to claim 1, characterized in that: The liquid polybutadiene in the S1 step is any one of Wanhao POLYVEST 110, POLYVEST 130 and POLYVEST MV non-functionalized polybutadiene.

4. The method for preparing a modified HDPE composite material according to claim 1, characterized in that: The amount of the terminal hydrogen silicone oil added in the S1 step is 40%-80% of the mass of the liquid polybutadiene.

5. The method for preparing a modified HDPE composite material according to claim 1, characterized in that: The amount of the silicone cross-linked polybutadiene modifier in the S2 step is 0.5%-8% of the mass of the HDPE base material.

6. The method for preparing a modified HDPE composite material according to claim 1, characterized in that: The flame retardant in the S2 step is hexaphenoxycyclotriphosphazene; the amount of the flame retardant is 2%-10% of the mass of the HDPE base material.

7. The method for preparing a modified HDPE composite material according to claim 1, characterized in that: The initiator in the S2 step is dicumyl peroxide or di-tert-butyl peroxide; the amount of the initiator is 0.05%-0.2% of the mass of the HDPE base material.

8. A modified HDPE composite material, characterized by Prepared by the method of any one of claims 1-7.

9. Application of the modified HDPE composite material of claim 8 in power communication pipelines.

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