Network cross-linked elastomer toughened PPS composite material and preparation method thereof

Abstract

The invention discloses a network cross-linked elastomer toughened PPS composite material and a preparation method thereof, and belongs to the technical field of high polymer materials, the network cross-linked elastomer toughened PPS composite material comprises the following raw materials by weight: 0-90 parts of PPS, 10-90 parts of a filler, 2-15 parts of a nucleating agent, 2-15 parts of a coupling agent, 2-15 parts of a flexible monomer or an alloying additive, and 0.1-5 parts of an antioxidant. And then a high-speed mixing and twin-screw extrusion process is adopted, so that the components are uniformly dispersed, the reaction conditions are mild, a complex crosslinking process or solvent use is avoided, and the production cost is reduced. The PPS composite material with high strength, high toughness, excellent processability and high temperature resistance is prepared through multiple action mechanisms of interface enhancement, crystallization regulation and network crosslinking, and an innovative solution is provided for application expansion of high-performance engineering plastics.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, and in particular to a network crosslinked elastomer-toughened PPS composite material and its preparation method. Background Technology

[0002] Polyphenylene sulfide (PPS) is a high-performance engineering plastic with excellent mechanical properties, thermal stability, and chemical resistance, making it a promising candidate for high-end applications in automotive, electronics, electrical, and aerospace industries. However, controlling its crystallinity remains a major technical bottleneck restricting its widespread use. For example, highly crystalline PPS typically exhibits higher tensile strength, hardness, thermal stability, and corrosion resistance, making it particularly suitable for harsh environments with high temperatures, high pressures, or extremely corrosive conditions. In contrast, low-crystalline PPS demonstrates superior toughness and flowability, making it suitable for applications requiring lower rigidity and higher molding complexity.

[0003] In existing technologies, optimizing its crystallization properties still faces many challenges, mainly in the following aspects: (1) Difficulty in precisely controlling crystallization rate and crystallinity: Polyphenylene sulfide has a slow crystallization rate and uneven crystallization, which leads to poor dimensional stability and unstable performance of the material during the molding process. In injection molded parts with complex structures, it is difficult to ensure that high crystallinity is achieved while avoiding the effects of excessively fast or slow crystallization rate.

[0004] (2) The balance between mechanical properties and toughness during crystallization: High crystallinity can improve the mechanical properties of PPS, such as tensile strength, hardness and thermal stability, but it will sacrifice its toughness. Conversely, lower crystallinity can improve the toughness and fluidity of the material, but it will affect the mechanical properties and high temperature resistance.

[0005] (3) Effects of nucleating agents and additives on crystallization performance: In the production of PPS, adding nucleating agents or flow modifiers can regulate its crystallization behavior, but the use of nucleating agents usually brings side effects, such as affecting the surface quality of the material or reducing its thermal stability.

[0006] Based on the above problems, a PPS composite material preparation technology is proposed that can effectively enhance interfacial bonding, precisely control crystallization behavior, and achieve synergistic improvement of multiple properties, which has important practical application value. Summary of the Invention

[0007] The purpose of this invention is to provide a network crosslinked elastomer-toughened PPS composite material and its preparation method, so as to solve the problems in the background art.

[0008] To achieve the above objectives, the present invention provides a network crosslinked elastomer-toughened PPS composite material, comprising the following components by weight: 30-90 parts PPS, 10-90 parts filler, 2-15 parts nucleating agent, 2-15 parts coupling agent, 2-15 parts flexible monomer or alloying additive and 0.1-5 parts antioxidant.

[0009] Preferably, the filler is one or a mixture of glass fiber, carbon fiber, and mineral filler.

[0010] Preferably, the nucleating agent is one or a mixture of several of the following: low molecular weight PPS, talc, aluminum hydroxide, silicon dioxide, calcium carbonate, aluminum fluoride, triphenyl phosphate, high molecular weight fatty acid ester, polyester, etc.

[0011] Preferably, the coupling agent is a silane coupling agent or a boric acid-containing organic compound; The silane coupling agent is one or a mixture of several of the following: aminosilane coupling agent, carboxylsilane coupling agent, epoxysilane coupling agent, etc. The boric acid-containing organic compound is one or more of phenylboronic acid, 1,4-phenyldiboronic acid, 4-vinylphenylboronic acid, tetraphenylboronic acid, etc.

[0012] Preferably, the flexible monomer or alloying additive is one or a mixture of several of the following: alkyl or aryl monomers, butadiene, polyamide, polystyrene, polyethylene, etc.

[0013] Preferably, the antioxidant is a phosphite, thiol, phenolic antioxidant, organic acid oxidant, or metal complex.

[0014] This invention also provides a method for preparing the above-mentioned network crosslinked elastomer-toughened PPS composite material, comprising the following steps: PPS, fillers, nucleating agents, coupling agents, antioxidants, flexible monomers or alloying additives are mixed in a high-speed mixer according to the specified ratio; after mixing, the mixture is transferred to a twin-screw extruder for extrusion granulation to obtain a network crosslinked elastomer toughened PPS composite material.

[0015] Preferably, the extrusion granulation temperature is 250~350℃.

[0016] Preferably, the crystallization properties of polyphenylene sulfide are controlled by selecting the types of PPS, fillers, nucleating agents, coupling agents, flexible monomers, or alloying additives.

[0017] Preferably, in the twin-screw extruder, the temperatures in the region from the feed inlet to the die head are set to 230℃, 270℃, 300℃, 300℃, 300℃, 290℃, 285℃, 285℃, 285℃, 285℃, 285℃, 285℃, 300℃, and 300℃, respectively; the screw speed is 300 rpm; and the feed rate is 30 kg / h.

[0018] In this invention, the silane coupling agent can form bonds between PPS and fillers (such as glass fibers, mineral fillers, etc.), thereby improving their compatibility. Through blending, the functional groups of silane can react with the active sites in the PPS chain to form stronger interfacial bonds. This enhanced bonding helps improve the overall mechanical properties of the composite material, especially tensile strength and impact strength. Secondly, the silane coupling agent can improve the melt flowability of PPS, making it more malleable during processing. The addition of the coupling agent can reduce the viscosity of the melt, promote more uniform mixing and molding, thereby reducing processing difficulty and improving production efficiency. At the same time, the silane coupling agent can improve the heat resistance and aging resistance of the composite material, and also improve the oxidation resistance of the material, reducing aging phenomena under high-temperature environments, thereby extending the service life of the material.

[0019] The molecular structure of polyphenylene sulfide (PPS) is one of the fundamental factors determining its crystallization behavior. PPS is a linear polymer composed of benzene rings and sulfur atoms linked by ether bonds, exhibiting relatively strong chain rigidity and a high tendency to crystallize. Its crystallization rate and crystallinity can be controlled by adjusting the molecular structure. High molecular weight PPS has a longer chain length, resulting in more entanglement between molecular chains and factors hindering flow, thus leading to a slower crystallization rate and lower crystallinity. Conversely, lower molecular weight PPS has faster flowability. Considering low molecular weight PPS as a nucleating agent, it crystallizes before high molecular weight PPS, acting as nuclei in the high molecular weight PPS crystallization process. A large and uniform distribution of low molecular weight PPS effectively alleviates the factors hindering flow caused by the entanglement of long chains, significantly increasing the crystallization rate of high molecular weight PPS.

[0020] By introducing flexible monomers with lower rigidity into the polymerization reaction of PPS, the rigidity of the molecular chain can be effectively reduced, and the flexibility of the chain segments can be enhanced. These flexible monomers typically contain large and flexible alkyl, aryl, or oxygen-containing groups, which can reduce the rigidity between chain segments, increase the degree of freedom of chain segment movement, and thus improve its crystallization properties. Introducing highly flexible alkyl or aryl groups into the rigid chain structure of PPS reduces the spatial confinement of the chain, reduces the mutual binding between chain segments, and thus improves the mobility of chain segments, making PPS easier to crystallize.

[0021] The most basic function of nucleating agents is to provide crystallization sites, giving PPS molecular chains an initial ordered region. PPS crystallization usually begins in a liquid or amorphous state, a random process in which molecular chains gradually arrange themselves into crystals as they cool. Nucleating agents, through their crystal structure or chemical properties, provide a relatively stable "starting point" for PPS molecular chains, making it easier for PPS chain segments to begin arranging into a regular lattice structure.

[0022] Sulfur atoms inside PPS can form hydrogen bonds with chemical groups such as amino and hydroxyl groups. At the same time, sulfur atoms also generate interaction forces, especially when the molecular chain is long and the interchain spacing is close. These interactions help crystal growth and stability. Therefore, the introduction of specific additives can qualitatively control the spatial structure of the molecular chain and effectively improve crystallization performance.

[0023] The addition of fillers typically alters the cooling rate and crystallization behavior of PPS. Inorganic fillers, due to their inherent crystallization properties, may accelerate the PPS crystallization process by providing additional nucleation sites, thereby increasing the crystallization rate. Meanwhile, other types of fillers may reduce the PPS crystallization rate by disrupting the ordered arrangement of molecular chains. In general, the addition of fillers can affect the crystallinity of PPS by altering its crystallization behavior, and crystallinity is a crucial factor determining the final properties of PPS (such as mechanical strength, thermal stability, and dimensional stability). The effect of different fillers on crystallinity varies, depending on their chemical properties, morphology, and compatibility with PPS.

[0024] The addition of phosphite and phenolic antioxidants effectively inhibits the oxidative degradation of PPS during high-temperature processing and use, extending the material's service life, and is especially suitable for long-term service scenarios in high-temperature environments.

[0025] Therefore, the present invention provides a network crosslinked elastomer-toughened PPS composite material and its preparation method. Through a multiple mechanism of "interface reinforcement-crystallization regulation-network crosslinking", a PPS composite material with high strength, high toughness, excellent processing performance and high temperature resistance is prepared, providing an innovative solution for expanding the application of high-performance engineering plastics.

[0026] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0027] The technical solution of the present invention will be further described below through embodiments.

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will describe them through embodiments. The technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0029] Example 1 In this embodiment, the raw materials, by weight, are: 49.5 parts commercially available PPS, 45 parts glass fiber, 5 parts epoxy silane coupling agent, 5 parts low molecular weight PPS, 2 parts triphenyl phosphite, 2 parts polyamide, and 2 parts polystyrene. The preparation steps are as follows: All raw materials are mixed evenly in a high-speed mixer, and then transferred to a twin-screw extruder for basic granulation. The temperatures of the extruder zones (from the feed inlet to the die head) are set to 230℃, 270℃, 300℃, 300℃, 300℃, 290℃, 285℃, 285℃, 285℃, 285℃, 285℃, 285℃, 300℃, and 300℃, respectively. The feed rate is 30KG / h, and the extrusion screw speed is 300rpm.

[0030] Example 2 This embodiment is prepared in the same way as Example 1, except that the raw materials are modified as follows: 49.5 parts commercially available PPS, 45 parts glass fiber, 6 parts epoxy silane coupling agent, 6 parts talc, 2 parts triphenyl phosphite, 2 parts polyamide, and 2 parts polystyrene.

[0031] Example 3 This embodiment is prepared in the same way as Example 1, except that the raw materials are modified as follows: 49.5 parts commercially available PPS, 48 parts glass fiber, 0.5 parts epoxy silane coupling agent, 5 parts aluminum hydroxide, 2 parts triphenyl phosphite, 2 parts polyamide, and 2 parts polystyrene.

[0032] Example 4 This embodiment is prepared in the same way as Example 1, except that the raw materials are modified as follows: 49.5 parts commercially available PPS, 49 parts glass fiber, 6 parts epoxy silane coupling agent, 5 parts silica, 2 parts triphenyl phosphite, 2 parts polyamide, and 2 parts polystyrene.

[0033] Example 5 This embodiment is prepared in the same way as Example 1, except that the raw materials are modified as follows: 47.5 parts commercially available PPS, 45 parts glass fiber, 5 parts epoxy silane coupling agent, 5 parts calcium carbonate, 2 parts triphenyl phosphite, 3 parts polyamide, and 2 parts polystyrene.

[0034] Example 6 This embodiment is prepared in the same way as Example 1, except that the raw materials are modified as follows: 50 parts commercially available PPS, 48 parts glass fiber, 8 parts aminosilane coupling agent, 5 parts small molecule PPS, 2 parts triphenyl phosphite, 2 parts polyamide, and 2 parts polystyrene.

[0035] Example 7 The preparation steps in this embodiment are the same as in Example 1, except that the raw materials are modified as follows: 49.5 parts commercially available PPS, 45 parts glass fiber, 9 parts aminosilane coupling agent, 4 parts talc, 2 parts triphenyl phosphite, 3 parts polyamide, and 4 parts polystyrene.

[0036] Example 8 This embodiment is prepared in the same way as Example 1, except that the raw materials are modified as follows: 49.5 parts commercially available PPS, 45 parts glass fiber, 6 parts carboxysilane coupling agent, 5 parts small molecule PPS, 3 parts triphenyl phosphite, 2 parts polyamide, and 3 parts polystyrene.

[0037] Example 9 This embodiment has the same preparation steps as Example 1, except that the raw materials are modified to be: 60 parts commercially available PPS, 40 parts glass fiber, 2 parts carboxysilane coupling agent, 5.5 parts talc, 2 parts triphenyl phosphite, 2 parts polyamide, and 2 parts polystyrene.

[0038] Comparative Example 1 The preparation steps of this comparative example are the same as those of Example 1, except that the raw materials are modified as follows: by weight, 49.5 parts PPS, 50 parts glass fiber, 2 parts aminosilane coupling agent, and 2 parts triphenyl phosphite.

[0039] Comparative Example 2 The preparation steps of this comparative example are the same as those of Example 1, except that the raw materials are modified as follows: by weight, 54.5 parts PPS, 45 parts glass fiber, 2 parts aminosilane coupling agent, and 2 parts triphenyl phosphite.

[0040] Comparative Example 3 The preparation steps of this comparative example are the same as those of Example 1, except that the raw materials are modified as follows: by weight, 52.5 parts PPS, 47 parts glass fiber, 2 parts aminosilane coupling agent, and 2 parts triphenyl phosphite.

[0041] Comparative Example 4 The preparation steps of this comparative example are the same as those of Example 1, except that the raw materials are modified as follows: by weight, 49.5 parts PPS, 45 parts glass fiber, 5 parts aminosilane coupling agent, 5 parts small molecule PPS, and 2 parts triphenyl phosphite.

[0042] Comparative Example 5 The preparation steps of this comparative example are the same as those of Example 1, except that the raw materials are modified as follows: by weight, 49.5 parts PPS, 45 parts glass fiber, 5 parts aminosilane coupling agent, 5 parts talc, and 2 parts triphenyl phosphite.

[0043] Comparative Example 6 The preparation steps of this comparative example are the same as those of Example 1, except that the raw materials are modified as follows: by weight, 49.5 parts PPS, 45 parts glass fiber, 2 parts aminosilane coupling agent, 5 parts aluminum hydroxide, and 2 parts triphenyl phosphite.

[0044] Comparative Example 7 The preparation steps of this comparative example are the same as those of Example 1, except that the raw materials are modified as follows: by weight, 49.5 parts PPS, 45 parts glass fiber, 8 parts aminosilane coupling agent, 5 parts silica, and 2 parts triphenyl phosphite.

[0045] Comparative Example 8 The preparation steps of this comparative example are the same as those of Example 1, except that the raw materials are modified as follows: by weight, 49.5 parts PPS, 45 parts glass fiber, 2 parts aminosilane coupling agent, 5 parts calcium carbonate, and 2 parts triphenyl phosphite.

[0046] Comparative Example 9 The preparation steps of this comparative example are the same as those of Example 1, except that the raw materials are modified as follows: by weight, 49.5 parts PPS, 50 parts glass fiber, 2 parts epoxy silane coupling agent, and 2 parts triphenyl phosphite.

[0047] Comparative Example 10 The preparation steps of this comparative example are the same as those of Example 1, except that the raw materials are modified as follows: by weight, 49.5 parts PPS, 50 parts glass fiber, 5 parts carboxylated silane coupling agent, and 2 parts triphenyl phosphite.

[0048] Comparative Example 11 The preparation steps of this comparative example are the same as those of Example 1, except that the raw materials are modified as follows: by weight, 49.5 parts PPS, 50 parts glass fiber, 5 parts carboxylated silane coupling agent, 2 parts triphenyl phosphite, 2 parts polyamide, and 2 parts polystyrene.

[0049] The performance of the products of Examples 1-9 and Comparative Examples 1-11 after injection molding was compared, as shown in Table 1 below; Table 1 Comparison of Performance Parameters

[0050] As shown in Table 1, the composite material obtained by controlling the crystallization properties of PPS according to the present invention exhibits significantly improved tensile strength, tensile modulus, and heat distortion temperature compared to the comparative example. This demonstrates that the addition of the nucleating agent results in excellent crystallization properties in PPS, leading to higher tensile strength, rigidity, and hardness. The crystalline regions form a more regular structure with tightly packed molecular chains, thus significantly improving mechanical properties. Furthermore, highly crystallized PPS possesses higher thermal stability and heat distortion temperature. The compact crystalline structure and strong intermolecular forces allow the material to maintain its shape and properties at high temperatures, enabling it to withstand higher temperatures without deformation or decomposition. Highly crystallized PPS also exhibits a lower coefficient of thermal expansion, resulting in smaller dimensional changes and better dimensional stability in high-temperature environments.

[0051] Therefore, the present invention provides a network crosslinked elastomer-toughened PPS composite material and its preparation method, which significantly overcomes the defects of the prior art through component design and process optimization. The selected epoxy silane coupling agent reacts with the hydroxyl groups on the filler surface through alkoxy groups to form chemical bonds, thereby enhancing the interfacial bonding between the filler and the PPS matrix and constructing a strong interfacial connection of "filler-coupling agent-matrix". Flexible monomers or alloying additives (such as butadiene and polyamide) form an elastomer dispersion phase during processing, which forms a network cross-linked structure with the PPS matrix through physical entanglement or chemical bonding. This effectively disperses impact energy, significantly improves the impact toughness of the material, and avoids the strength reduction problem caused by the addition of a single elastomer. Nucleating agents such as low molecular weight PPS, talc, and aluminum hydroxide can act as crystallization sites, promoting rapid crystallization of PPS and refining grains, increasing crystallinity by 15%-25%, thereby improving the rigidity and dimensional stability of the material. Organic nucleating agents such as triphenyl phosphate and high molecular weight fatty acid esters can adjust crystal morphology, reduce melt viscosity, and improve processing fluidity, achieving a balance between rigidity, toughness, and processability. At the same time, by adjusting the ratio of PPS to fillers and flexible monomers, high rigidity (filler-dominated) or high toughness (flexible component-dominated) composite materials can be prepared as needed to meet the personalized needs of different fields.

[0052] Subsequently, the nucleating agent, epoxy silane coupling agent, and flexible monomer that play a role are added to the formulation. Through multiple mechanisms of action such as "interface reinforcement-crystallization regulation-network crosslinking", a PPS composite material with high strength, high toughness, excellent processing performance and high temperature resistance is prepared, providing an innovative solution for expanding the application of high-performance engineering plastics.

[0053] 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 them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A network cross-linked elastomer-toughened PPS composite material, characterized in that, The following components are included in parts by weight: 30-90 parts PPS, 10-90 parts filler, 2-15 parts nucleating agent, 2-15 parts coupling agent, 2-15 parts flexible monomer or alloying additive and 0.1-5 parts antioxidant.

2. The network crosslinked elastomer-toughened PPS composite material according to claim 1, characterized in that: The filler is one or a mixture of glass fiber, carbon fiber, and mineral filler.

3. The network crosslinked elastomer-toughened PPS composite material according to claim 1, characterized in that: The nucleating agent is one or a mixture of several of the following: low molecular weight PPS, talc, aluminum hydroxide, silicon dioxide, calcium carbonate, aluminum fluoride, triphenyl phosphate, high molecular weight fatty acid ester, polyester, etc.

4. The network crosslinked elastomer-toughened PPS composite material according to claim 1, characterized in that: The coupling agent is a silane coupling agent or a boric acid-containing organic compound; The silane coupling agent is one or a mixture of several of the following: aminosilane coupling agents, carboxylsilane coupling agents, and epoxysilane coupling agents. The boric acid-containing organic compound is one or more of phenylboronic acid, 1,4-phenyldiboronic acid, 4-vinylphenylboronic acid, tetraphenylboronic acid, etc.

5. The network crosslinked elastomer-toughened PPS composite material according to claim 1, characterized in that: The flexible monomer or alloying additive is one or a mixture of several of the following: alkyl or aryl monomers, butadiene, polyamide, polystyrene, polyethylene, etc.

6. The network crosslinked elastomer-toughened PPS composite material according to claim 1, characterized in that: The antioxidant is a phosphite, thiol, phenolic antioxidant, organic acid oxidant, or metal complex.

7. A method for preparing a network crosslinked elastomer-toughened PPS composite material as described in any one of claims 1-6, characterized in that, Includes the following steps: PPS, fillers, nucleating agents, coupling agents, antioxidants, flexible monomers or alloying additives are mixed in a high-speed mixer with a speed of 3000-6000 rpm according to the specified ratio; after mixing, the mixture is transferred to a twin-screw extruder for extrusion granulation to obtain a network crosslinked elastomer toughened PPS composite material.

8. The method for preparing a network crosslinked elastomer-toughened PPS composite material according to claim 7, characterized in that: The extrusion granulation temperature is 250~350℃.

9. The method for preparing a network crosslinked elastomer-toughened PPS composite material according to claim 7, characterized in that: The crystallization properties of polyphenylene sulfide can be controlled by selecting the types of PPS, fillers, nucleating agents, coupling agents, flexible monomers, or alloying additives.

10. The method for preparing a network crosslinked elastomer-toughened PPS composite material according to claim 7, characterized in that: The zone temperatures of the twin-screw extruder are set to 230℃, 270℃, 300℃, 300℃, 300℃, 290℃, 285℃, 285℃, 285℃, 285℃, 285℃, 285℃, 300℃, and 300℃, respectively. The screw speed is 300 rpm, and the feed rate is 30 kg / h.

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