Poly(malic acid) and kh550 synergistically modified acetylene carbon black, its preparation method and application

Abstract

The application discloses synergistically modified ethyne carbon black by poly malic acid and KH550, a preparation method and application thereof, and the method comprises the following steps: blending poly malic acid, gamma-aminopropyl triethoxysilane and ethyne carbon black in a mass ratio of (0.5-5):(1-10):100, and then performing reaction to obtain ethyne carbon black synergistically modified by poly malic acid and gamma-aminopropyl triethoxysilane. The ethyne carbon black is synergistically modified by poly malic acid and gamma-aminopropyl triethoxysilane (KH550), an esterification reaction occurs between the carboxyl in the poly malic acid molecule and the surface hydroxyl of the ethyne carbon black, meanwhile, a hydroxylamino reaction occurs between the amino group of the KH550 and the hydroxyl, and an amide bond bridge is formed between the poly malic acid and the KH550, thereby realizing ternary synergistic covalent modification. The structure effectively improves the dispersion stability of the ethyne carbon black, the chain-like or grape-like high specific surface area structure of the ethyne carbon black can be fully utilized, the ethyne carbon black is more uniformly dispersed in a polymer matrix, and the interface is more closely combined.

Description

Technical Field

[0001] This invention relates to acetylene black, specifically to an acetylene black synergistically modified with polymalic acid and KH550, its preparation method, and its application. Background Technology

[0002] In the structural design of power cables, semiconductor electrical wrapping tape, as an important component of the cable shielding layer, plays a crucial role in balancing the electric field distribution, preventing partial discharge, and ensuring the long-term safe and stable operation of the cable. Acetylene black, due to its excellent conductivity and high structural integrity, has become a key functional filler in the preparation of semiconductive wrapping tape, and its addition can effectively impart the required semiconductive properties to the tape. However, several technical bottlenecks still need to be addressed in the practical application of acetylene black: First, due to its extremely high specific surface area and surface energy, acetylene black particles are prone to agglomeration, making it difficult to achieve uniform dispersion in the polymer matrix and easily forming weak points in the conductive network; Second, acetylene black has strong surface chemical inertness, resulting in poor interfacial compatibility and weak bonding with common polymer matrices (such as ethylene-vinyl acetate copolymer, polyethylene, etc.). During subsequent processing, winding, or use, it is prone to "powdering" due to mechanical or thermal stress, which not only pollutes the production environment but also leads to a decrease in the conductivity of the wrapping tape, seriously affecting the reliability and service life of cable products.

[0003] To improve the dispersibility and compatibility of acetylene black with the matrix, physical or chemical modification methods are commonly employed. Physical modification methods mainly include mechanical ball milling, high-speed shearing, and ultrasonic dispersion. These methods can disrupt aggregates and reduce particle size to some extent, but the effects are mostly temporary and cannot fundamentally improve interfacial bonding. Furthermore, excessive mechanical force may introduce structural defects, and these methods are accompanied by high energy consumption and low efficiency. Chemical modification is a more commonly used strategy, such as surface treatment of acetylene black using surfactants or polymer grafting. However, modification with a single coupling agent often only provides a single type of chemical bond, and the modified layer may still experience interfacial slippage or damage under complex stress. In addition, some modifiers may have poor environmental friendliness or be costly. Summary of the Invention

[0004] To address the common problems of poor compatibility and environmental pollution in existing acetylene black modification technologies, this invention provides an acetylene black synergistically modified with polymalic acid and KH550, its preparation method, and its application. This method not only significantly improves the compatibility between modified acetylene black and semiconductive wrapping tape, but also the entire reaction process is green and pollution-free, making it suitable for the industrial manufacturing of power cables.

[0005] To achieve the above objectives, the present invention provides a method for preparing acetylene black synergistically modified with polymalic acid and KH550, comprising the following steps: mixing polymalic acid, γ-aminopropyltriethoxysilane and acetylene black in a mass ratio of (0.5 ~ 5): (1 ~ 10): 100 and then reacting them to obtain acetylene black synergistically modified with polymalic acid and γ-aminopropyltriethoxysilane.

[0006] The modification mechanism lies in the fact that the abundant carboxyl groups in the polymalic acid molecular chain can undergo esterification with the hydroxyl groups on the surface of acetylene black to form stable ester bonds; simultaneously, the amino groups in KH550 can also undergo hydroxyamination with the hydroxyl groups on the surface of acetylene black to achieve covalent bonding. Furthermore, the amino groups of KH550 can also undergo acylation with the carboxyl groups of polymalic acid to generate amide bonds, thereby constructing a robust synergistic bridging network among acetylene black, polymalic acid, and KH550.

[0007] After this modification, acetylene black can not only be firmly loaded into the polymalic acid-KH550 composite system through chemical bonding, but its surface properties are also significantly optimized. The modified acetylene black can generate stronger interactions with functional groups (such as amide groups) in the semiconductive coating matrix (e.g., Figure 2 As shown, acetylene black can be connected to the semiconductive wrapping tape via polymalic acid, or via KH550, or even via a combination of polymalic acid and KH550. This greatly improves its dispersion and interfacial compatibility in the wrapping tape, fundamentally alleviating the problem of powder shedding and extending the service life of the cable.

[0008] Preferably, the mass ratio of polymalic acid, γ-aminopropyltriethoxysilane and acetylene black is 1:5:100.

[0009] Specifically, the reaction temperature is 50 ~ 200°C. o C, reaction time is 0.5 ~ 3 h, reaction pressure is 1 ~ 2 kPa.

[0010] Reaction temperature has a direct impact on the properties of the product and the reaction time; temperatures below 50°C... o C, the reaction hardly occurs, above 200 o The reaction is unstable at temperature C. Preferably, the reaction temperature is 90°C. o C, the reaction time is 1.5 h, which can ensure the reaction occurs to the greatest extent with the lowest energy consumption.

[0011] Preferably, the reaction temperature is 110°C. o C, the reaction time is 1.5 h, and the reaction pressure is 1.5 kPa.

[0012] The second aspect of the present invention provides acetylene black synergistically modified with polymalic acid and γ-aminopropyltriethoxysilane obtained by the above preparation method.

[0013] The third aspect of the present invention provides the application of the above-mentioned polymalic acid and γ-aminopropyltriethoxysilane synergistically modified acetylene black in the preparation of semiconductive wrapping tape for cables.

[0014] Through the above technical solution, the present invention achieves the following beneficial effects:

[0015] 1. This invention employs polymalic acid and γ-aminopropyltriethoxysilane (KH550) to synergistically modify acetylene black. The carboxyl groups in polymalic acid undergo esterification with the hydroxyl groups on the surface of acetylene black, while the amino groups in KH550 undergo hydroxylamineization. An amide bond bridge is formed between polymalic acid and KH550, achieving ternary synergistic covalent modification. This structure effectively improves the dispersion stability of acetylene black, fully utilizing its chain-like or grape-like high specific surface area structure, resulting in more uniform dispersion and tighter interfacial bonding within the polymer matrix. The low apparent density of acetylene black (0.2~0.3 g / cm³) is also addressed. 3 It also helps in the preparation of lightweight semiconductive wrapping materials.

[0016] 2. Through the aforementioned diversified chemical bonding, the modified acetylene black can be firmly loaded into the composite system, is not easily detached, and significantly improves its dispersibility and interfacial compatibility in the packaging tape. This modification strategy effectively suppresses dust shedding while improving the mechanical properties and durability of the composite system.

[0017] 3. The introduction of polymalic acid and KH550 not only enhances the chemical compatibility between acetylene black and the semiconductive tape matrix (such as polyolefins), but also significantly improves interfacial adhesion through the formation of strong bonds such as amide and ester bonds. Experiments show that when modified acetylene black is composited with colloids and coated onto semiconductive tapes, the peel strength can reach nearly 100N, demonstrating excellent compatibility and adhesion performance.

[0018] 4. The raw materials used in this invention are environmentally friendly, the reaction conditions are mild, no toxic byproducts are generated during the process, the process is simple and easy to control, and it has good potential for industrial production.

[0019] 5. This method significantly solves the problems of easy powdering and poor dispersion of acetylene black in the application of semiconductive wrapping tape. It is suitable for the preparation of semiconductive shielding layers for high-performance high voltage and ultra-high voltage power cables and has important engineering application value and market prospects. Attached Figure Description

[0020] Figure 1These are photographs illustrating the dispersed microstructure of acetylene black synergistically modified with polymalic acid and γ-aminopropyltriethoxysilane, prepared using the methods of Example 1 and Comparative Example 1 of this invention.

[0021] Figure 2 This is a chemical connection diagram between acetylene black synergistically modified with polymalic acid and γ-aminopropyltriethoxysilane, prepared by the method of Example 1 of this invention, and the semiconductive wrapping tape. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in detail below with reference to examples. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0023] Example 1

[0024] Polymalic acid, γ-aminopropyltriethoxysilane, and acetylene black in a mass ratio of 1:5:100 were added to a reaction vessel, and the mixture was reacted at a temperature of 110°C. o C. Under a pressure of 1.5 kPa and a reaction time of 1.5 h, an acetylene carbon black synergistically modified by polymalic acid and γ-aminopropyltriethoxysilane can be obtained.

[0025] Examples 2 to 3:

[0026] The same steps as in Example 1 were used, except that the mass ratio of polymalic acid, γ-aminopropyltriethoxysilane and acetylene black was changed (see table below).

[0027]

[0028] Examples 8 to 10:

[0029] The same steps as in Example 1 were used, except that the reaction temperature was changed (see table below).

[0030]

[0031] Examples 11 to 13:

[0032] The same steps as in Example 1 were used, except that the reaction time was changed (see table below).

[0033]

[0034] Examples 14 to 15:

[0035] The same steps as in Example 1 were used, except that the reaction pressure was changed (see table below).

[0036]

[0037] Comparative Example 1

[0038] Other conditions are the same as in Example 1, except that the reaction temperature is adjusted to 40°C. o C.

[0039] Comparative Example 2

[0040] All other conditions are the same as in Example 1, except that the reaction temperature is adjusted to 250°C. o C.

[0041] Comparative Example 3

[0042] Other conditions are the same as in Example 1, except that the reaction time is adjusted to 0.4 h.

[0043] Comparative Example 4

[0044] Other conditions are the same as in Example 1, except that the reaction time is adjusted to 4 hours.

[0045] Comparative Example 5

[0046] Other conditions are the same as in Example 1, except that the reaction pressure is adjusted to 0.5 kPa.

[0047] Comparative Example 6

[0048] Other conditions are the same as in Example 1, except that the reaction pressure is adjusted to 3 kPa.

[0049] Comparative analysis:

[0050] The acetylene black obtained in the above examples and comparative examples was combined with a colloid (50% concentration acrylic acid solution and acetylene black were mixed at a mass ratio of 1:3 and stirred evenly).

[0051] like Figure 1 As shown, the synergistically modified acetylene black obtained in Example 1, after being blended with the conductive colloid, exhibits very uniform dispersion and excellent compatibility with the semiconductive wrapper. In contrast, the modified acetylene black obtained in Comparative Example 1, after being blended with the colloid, shows uneven dispersion and poor compatibility with the semiconductive wrapper.

[0052] Additionally, considering the powder shedding rate (a 1 kg iron ball falling freely from a height of 1 m, impacting at a depth of 0.1 m)... 2 The compatibility of the finished semiconductive tape is evaluated by assessing the percentage of acetylene black that has fallen off from the center of the tape (the percentage of total acetylene black filling).

[0053] Peeling force: Use a tensile testing machine to peel acetylene black from a 5*2cm semi-conductive tape and measure the maximum tensile force during peeling.

[0054] The table below compares the performance of the samples prepared in the above embodiments and comparative examples.

[0055]

[0056] As can be seen from the table above:

[0057] 1) The reaction temperature of polymalic acid, H550, and acetylene black is particularly critical. When the reaction temperature is 110°C... o At temperature C, the material obtained has the lowest dust loss rate, which indicates that the prepared bridging modified acetylene black has the best compatibility.

[0058] 2) When the mass ratio of polymalic acid, H550 and acetylene black is 1: 5: 100, polymalic acid, H550 and acetylene black can react completely and have the lowest powder loss rate.

[0059] 3) When the reaction time of polymalic acid, H550 and acetylene black is less than 0.5 h, there is almost no reaction and the powder loss rate is also high.

[0060] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0061] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0062] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing acetylene black synergistically modified with polymalic acid and KH550, characterized in that, The process includes the following steps: Polymalic acid, γ-aminopropyltriethoxysilane, and acetylene black are blended in a mass ratio of (0.5~5):(1~10):100 and then reacted to obtain acetylene black synergistically modified by polymalic acid and γ-aminopropyltriethoxysilane. The reaction temperature is 50~200°C. o C, reaction time is 0.5 ~ 3 h, reaction pressure is 1 ~ 2 kPa.

2. The preparation method according to claim 1, characterized in that, The mass ratio of polymalic acid, γ-aminopropyltriethoxysilane and acetylene black is 1:5:

100.

3. The preparation method according to claim 1, characterized in that, The reaction temperature is 110°C. o C, the reaction time is 1.5 h, and the reaction pressure is 1.5 kPa.

4. Acetylene black synergistically modified with polymalic acid and γ-aminopropyltriethoxysilane by the preparation method according to any one of claims 1 to 3.

5. The application of the synergistic modification of polymalic acid and γ-aminopropyltriethoxysilane as described in claim 4 in the preparation of semiconductive wrapping tape for cables.

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