Antioxidant toughened polyphenylene sulfide composite material and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to an antioxidant toughened polyphenylene sulfide composite material and a preparation method thereof. According to the specific technical scheme, the preparation method of the antioxidant toughened polyphenylene sulfide composite material comprises the following steps: adding a nano composite antioxidant compounded by quercetin and a multi-walled carbon nanotube into polyphenylene sulfide resin, uniformly mixing, carrying out melt blending extrusion on the mixture at 250-320 DEG C, and carrying out strip drawing, cooling and pelletizing to prepare the polyphenylene sulfide composite material. Compared with pure polyphenylene sulfide, the polyphenylene sulfide composite material prepared by the invention has higher crystallinity, thermal stability, oxidation resistance and mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to an antioxidant toughened polyphenylene sulfide composite material and a preparation method thereof. Background Art

[0002] With the rapid development of industrialization, exhaust emissions from industrial production processes are becoming increasingly severe, especially in high-temperature, highly corrosive environments where dust filtration is in high demand. Polyphenylene sulfide (PPS) fiber, due to its excellent heat resistance, chemical corrosion resistance, and mechanical properties, has become a key material for industrial exhaust dust removal. PPS bag filter fabrics, with their heat resistance, corrosion resistance, and high filtration efficiency, are widely used in industries such as coal-fired power plants, waste incineration, cement production, and the chemical industry. They are an ideal choice for dust removal equipment in high-temperature, corrosive environments.

[0003] However, ordinary PPS fibers still face problems such as insufficient oxidation resistance and poor toughness during long-term use. PPS bag filter cloths are prone to oxidative degradation in high-temperature and highly oxidizing environments, resulting in reduced fiber strength and shortened service life. Oxidation problems mainly manifest as yellowing, brittleness, and even damage to the filter bags. In severe cases, this can lead to reduced dust removal efficiency and equipment failure. To address this issue, antioxidant modification treatment (addition of antioxidants or surface modification of the fibers) or blending with other oxidation-resistant fibers is commonly used to improve the durability of PPS filter bags in harsh environments.

[0004] However, blending or compounding with other fibers (such as blending with PI and PTFE) is costly and complex. The process of directly adding antioxidants is simple and generally divided into three types: organic antioxidants (hindered phenol type, aromatic amine tertiary amine type, chain termination type, phosphite type, etc.), inorganic nanomaterials (montmorillonite, silicon carbide, silicon dioxide, carbon black and other nanoparticles), and nanocomposites. However, directly adding organic antioxidants has problems such as high temperature resistance, easy decomposition, migration and dispersion, and poor compatibility; directly adding inorganic nanomaterials has problems such as poor dispersibility, compatibility, and antioxidant effect. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides an antioxidant toughened polyphenylene sulfide composite material and a preparation method thereof. The polyphenylene sulfide composite material can be used to prepare bag-type dust removal cloth for application in the field of industrial exhaust dust removal, thereby improving the dust removal efficiency and service life of polyphenylene sulfide filter bags in harsh environments.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] The invention discloses a preparation method of an antioxidant toughened polyphenylene sulfide composite material. The method comprises the following steps: adding quercetin and multi-walled carbon nanotubes into a polyphenylene sulfide resin, mixing the mixture, and then melt-blending and extruding the mixture at 250-320°C. The mixture is then drawn into strands, cooled, and pelletized to prepare a polyphenylene sulfide composite masterbatch.

[0008] Preferably, the preparation process of the nanocomposite antioxidant is as follows: quercetin is added to a mixed solvent of phosphate buffer and dimethyl sulfoxide, stirred evenly, multi-walled carbon nanotubes are added, stirred to obtain a suspension, and the suspension is filtered, washed, dried, and ground to obtain the nanocomposite antioxidant.

[0009] Preferably, the mass ratio of the multi-walled carbon nanotubes to quercetin is 1:5-6; and the particle size of the multi-walled carbon nanotubes is 20 nm to 5 μm.

[0010] Preferably, the volume ratio of the phosphate buffer to dimethyl sulfoxide is 20-25:1, and the usage ratio of the phosphate buffer to multi-walled carbon nanotubes is 1:0.9-1.1, v / w.

[0011] Preferably, the particle size of the polyphenylene sulfide resin is ≤1 mm.

[0012] Preferably, the mass ratio of the polyphenylene sulfide resin to the nanocomposite antioxidant is 599-601:19.8-20.0.

[0013] Preferably, the polyphenylene sulfide resin is dried at a temperature of 130° C. and a vacuum degree of ≤-0.1 MPa for 5 hours.

[0014] Preferably, the mixture is blended and extruded through a twin-screw extruder, and the temperatures of each zone of the twin-screw extruder are: zone 1 250℃±5℃; zone 2 290℃±5℃; zone 3 290℃±5℃; zone 4 300℃±5℃; zone 5 295℃±5℃; zone 6 315℃±5℃; zone 7 300℃±5℃; zone 8 300℃±5℃; zone 9 300℃±5℃; the head temperature value is 300℃±5℃; and the main engine speed is 120r / min.

[0015] Preferably, the polyphenylene sulfide composite masterbatch is vacuum dried at 60° C. for 8 hours to obtain a polyphenylene sulfide composite material.

[0016] Correspondingly, the polyphenylene sulfide composite material prepared by the above preparation method.

[0017] The present invention has the following beneficial effects:

[0018] 1. The present invention combines an antioxidant with nanoparticles to protect the nanoparticles, preventing them from decomposing prematurely during processing and improving their antioxidant properties. Quercetin (Q) is a natural, high-temperature-resistant antioxidant. Its molecular structure contains multiple phenolic hydroxyl groups (-OH), which can provide hydrogen atoms to react with free radicals, neutralize the activity of free radicals, and thus block the chain oxidation reaction initiated by free radicals. It can also directly scavenge free radicals through an electron transfer mechanism. During the preparation of PPS masterbatch, it will not decompose and lose its antioxidant properties due to excessive temperatures. It will not release toxic substances during processing, and will not affect the performance of PPS due to side reactions or inactivation, nor will it affect the subsequent spinnability of PPS. WCNTs have good thermal and chemical stability, excellent mechanical properties, and a good toughening effect. Due to their unique structure, they can serve as a carrier for Q, improving its water solubility and stability. The combination of Q and WCNTs facilitates better distribution of the complex in PPS, improving the antioxidant properties of PPS while also achieving a certain toughening effect.

[0019] 2. In view of the shortcomings of PPS fiber such as susceptibility to oxidative degradation, decreased fiber strength, and shortened life in high temperature and strong oxidizing environment, the present invention adopts a melt blending method to add a nano-composite antioxidant (WCNTs-Q) compounded by Q and WCNTs to the PPS matrix, which directly enhances the antioxidant ability of PPS, delays oxidative degradation, and has a simple process. It can better meet the antioxidant and strength requirements of PPS dust removal filter bags in the exhaust gas treatment process of highly polluting enterprises, and effectively improve their dust removal efficiency and service life.

[0020] 3. The present invention first compounded Q and WCNTs in a solvent to form a nanocomposite antioxidant (WCNTs-Q). The nanocomposite antioxidant (WCNTs-Q) was then added to PPS, blended and extruded through a twin-screw extruder. The mixture was then stretched, cooled, and pelletized to produce an antioxidant-toughened PPS composite material. This enhances the PPS material's oxidation resistance and improves its mechanical properties. The resulting modified PPS composite material exhibits enhanced thermal stability, oxidation resistance, and mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 (a) is a scanning electron microscope image of WCNTs; (b) is a scanning electron microscope image of WCNTs-Q;

[0022] Figure 2 is the scanning electron microscope image of the cross section of the PPS / WCNTs-Q composite material;

[0023] Figure 3 DSC curves of pure PPS and PPS / WCNTs-Q composites under nitrogen atmosphere;

[0024] Figure 4TG (a) and DTG (b) curves of pure PPS and PPS / WCNTs-Q composites under nitrogen atmosphere;

[0025] Figure 5 is the oxidation induction temperature (dynamic OIT) curve of pure PPS and PPS / WCNTs-Q composites in air atmosphere;

[0026] Figure 6 Figure 2 shows the fracture strength of pure PPS and PPS / WCNTs-Q composites. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0029] The present invention discloses a method for preparing an antioxidant toughened polyphenylene sulfide composite material, which comprises the following steps:

[0030] (1) Preparation of nanocomposite antioxidant (WCNTs-Q):

[0031] At room temperature, dimethyl sulfoxide (DMSO) was added to phosphate buffered saline (PBS) to prepare a mixed solvent. Quercetin (Q) was added to the mixed solvent and stirred evenly. Multi-walled carbon nanotubes (WCNTs) were added and stirred for 13 h to obtain a suspension. The suspension was filtered and washed, and then dried at 60°C for 12 h to obtain a black powder block. The black powder block was ground into a black powder in a mortar to prepare a nanocomposite antioxidant (WCNTs-Q).

[0032] The ratio of PBS to WCNTs is 1:0.9-1.1 (v / w). For example, if 1 g of WCNTs is added to 1 L of PBS, the mass ratio of WCNTs to Q is 1:5-6. The volume ratio of PBS to DMSO is 20-25:1.

[0033] (2) The process of drying the polyphenylene sulfide resin is as follows: the PPS resin is dried at a temperature of 130° C. and a vacuum degree of ≤-0.1 MPa for 5 hours.

[0034] (3) Preparation of antioxidant toughened polyphenylene sulfide composite materials:

[0035] The dried PPS resin and the nanocomposite antioxidant (WCNTs-Q) are mixed evenly, and then the mixture is subjected to low-temperature heating and melting at 250°C to 320°C using a twin-screw extruder, shear dispersion, mixing, and homogenization extrusion into a melt stream, which is then cooled into strips using deionized water and pelletized by a pelletizer to produce an antioxidant-toughened polyphenylene sulfide composite masterbatch; the polyphenylene sulfide composite masterbatch is vacuum dried at 60°C for 8 hours to produce a polyphenylene sulfide composite material.

[0036] Wherein, the temperature of each zone of the twin-screw extruder is: zone 1 250℃±5℃; zone 2 290℃±5℃; zone 3 290℃±5℃; zone 4 300℃±5℃; zone 5 295℃±5℃; zone 6 315℃±5℃; zone 7 300℃±5℃; zone 8 300℃±5℃; zone 9 300℃±5℃; head temperature value 300℃±5℃; main engine speed 120r / min.

[0037] The PPS resin (C6H6S)n is a solid particle with a melting point of 280°C to 290°C and a particle diameter of 1 mm or less. Multi-walled carbon nanotubes (WCNTs) are a black solid powder with a particle diameter of 20 nm or less and 5 μm or less. Quercetin (Q) is a food-grade yellow solid powder. The mass ratio of PPS resin to WCNTs-Q is 599-601:19.8-20.0.

[0038] The present invention will be further described below with reference to specific embodiments.

[0039] Example 1

[0040] Preparation of antioxidant toughened polyphenylene sulfide composite materials:

[0041] (1) Nanocomposite antioxidant (WCNTs-Q): 250±10 mL of dimethyl sulfoxide (DMSO) was added to 6±0.1 L of phosphate buffered saline (PBS) at room temperature to prepare a mixed solvent. 36±0.1 g of quercetin was added to the mixed solvent and stirred evenly. 6±0.1 g of multi-walled carbon nanotubes was added and stirred for 13 h to obtain a suspension. The suspension was filtered and washed, and then dried at 60°C for 12 h to obtain a black powder block. The black powder block was ground into a black powder in a mortar to obtain WCNTs-Q. The mass of the obtained composite antioxidant was about 19.9±0.1 g, and its SEM image is shown in FIG. Figure 1 (b) shows the SEM image of WCNTs. Figure 1 (a) The results show that the microscopic state of WCNTs is like a ball of wool; in the nanocomposite antioxidant, some Q enters the surface of the WCNTs, which is similar to a ball of wool, while some Q simply adheres to the surface of the WCNTs.

[0042] (2) Drying treatment of polyphenylene sulfide masterbatch: 600±1g of PPS resin particles were placed in a vacuum drum for drying at a drying temperature of 130°C, a vacuum degree of -0.1MPa, and a drying time of 5h.

[0043] (3) Preparation of antioxidant toughened polyphenylene sulfide composite material: 600±1g dried PPS resin and 19.9g±0.1g WCNTs-Q were mixed evenly, and then the mixture was heated and melted at 250-320°C using a twin-screw extruder, sheared and dispersed, mixed, and homogenized to form a melt stream, which was then cooled into strips with deionized water and pelletized by a pelletizer to prepare antioxidant toughened PPS composite masterbatch;

[0044] Among them, the temperatures of each zone of the twin-screw extruder are: zone 1 250℃±5℃; zone 2 290℃±5℃; zone 3 290℃±5℃; zone 4 300℃±5℃; zone 5 295℃±5℃; zone 6 315℃±5℃; zone 7 300℃±5℃; zone 8 300℃±5℃; zone 9 300℃±5℃; head temperature value 300℃±5℃; main engine speed 120r / min.

[0045] (4) Drying the antioxidant toughened polyphenylene sulfide composite masterbatch: The prepared PPS composite masterbatch was dried in a vacuum drying oven at 60°C for 8 h to obtain a PPS composite material.

[0046] (5) Detection, analysis, and characterization: The structure and properties of the prepared WCNTs-Q and dried PPS composite materials were detected, analyzed, and characterized.

[0047] (5.1) The cross-section and longitudinal sections of the PPS composite material were observed using a Hitachi HITACHI cold field emission scanning electron microscope. The results are as follows: Figure 2 As shown, the results show that WCNTs-Q is evenly distributed in the PPS matrix and the WCNTs deagglomeration phenomenon is good, which indicates that the dispersion and compatibility of WCNTs-Q in PPS fibers are good.

[0048] (5.2) The crystallization properties of PPS composites were analyzed using a PerkinElmer DSC-6000 differential scanning calorimeter. The DSC curves of pure PPS and PPS composites under nitrogen atmosphere are shown in Figure 5. Figure 3 As shown, the crystallinity (Xc) of PPS is calculated according to formula (1):

[0049] Xc=(ΔHm-ΔHcc) / ΔHf (1)

[0050] Wherein, Xc is the crystallinity, ΔHm is the melting enthalpy, ΔHcc is the cold crystallization enthalpy, and ΔHf is the melting enthalpy of complete crystallization of PPS, which is 77.5 J / g.

[0051] The results are shown in Table 1 below. The results show that the crystallinity of pure PPS is 31.69% and the supercooling degree is 73.83°C, and the crystallinity of the PPS composite material is 35.01% and the supercooling degree is 54.52°C, indicating that after adding WCNTs-Q, the crystallization rate of the PPS composite material becomes faster and the crystallinity is improved.

[0052] Table 1 DSC data of pure PPS and PPS composites

[0053] sample Tg(℃) △Hcc(J / g) Tm(℃) △Hm(J / g) Tc(℃) △T(℃) Xc(%) PPS 90.87 3.74 281.16 28.30 207.33 73.83 31.69 PPS / WCNTs-Q 92.27 17.54 282.42 44.67 228.00 54.42 35.01

[0054] In the table: Tg: glass transition temperature; Tm: melting point; Tc: crystallization peak temperature; △Hcc: cold crystallization enthalpy; △Hm: melting enthalpy; △T: supercooling; Xc: crystallinity.

[0055] (5.3) The thermal properties of the PPS composites were characterized using a PerkinElmer TGA-4000 thermogravimetric analyzer. The results are shown in Table 2. The TG (a) and DTG (b) curves of pure PPS and PPS composites under nitrogen atmosphere are shown in Table 2. Figure 4 As shown, the results show that the decomposition temperature and the temperature at which the decomposition rate is maximum in each period of the PPS composite material are higher than those of pure PPS, and the heat resistance index of the PPS composite material is improved, indicating that the thermal stability of the PPS composite material is improved after the addition of WCNTs-Q.

[0056] Table 2 Thermal decomposition data of pure PPS and PPS composites

[0057] sample <![CDATA[T 5％ (℃)]]> <![CDATA[T 15％ (℃)]]> <![CDATA[T 30％ (℃)]]> <![CDATA[T MAX (℃)]]> <![CDATA[T HRI (℃)]]> PPS 519.5 540.5 568.67 558.00 269.01 PPS / WCNTs-Q 521.67 549.00 573.00 564.00 270.71

[0058] In the table: T 5％ 、T 15％ and T 30％ are the temperatures when the PPS masterbatch loses 5%, 15% and 30% of its weight; T MAX : The temperature at which the decomposition rate is maximum; T HRI : Polymer heat resistance index temperature.

[0059] (5.4) The oxidation induction temperature (dynamic OIT) of PPS composites was analyzed using a PerkinElmer DSC-6000 differential scanning calorimeter. The dynamic OIT curves of pure PPS and PPS composites in air atmosphere are shown in Figure 5 As shown, the results show that the oxidation induction temperature of pure PPS is 407.89℃, the oxidation induction temperature of PPS composite material is 419.56℃, and the oxidation induction temperature of PPS composite material is 11.67℃ higher than that of pure PPS, indicating that the addition of WCNTs-Q improves the antioxidant properties of PPS composite material.

[0060] (5.5) The PPS composite material was spun using an M12 spinning test machine to prepare PPS composite primary fibers. The fiber samples were placed in a blast drying oven, air was introduced, and the temperature was set at 240°C. The treated fiber samples were placed for 24 hours, 72 hours, and 96 hours, respectively. The mechanical properties of the treated fiber samples were tested using a YG006 single-line electronic strength tester. The results are shown in Figure 5. Figure 6 As shown, the results show that the fracture strength of the PPS composite material is improved to a certain extent compared with that of pure PPS, indicating that the addition of WCNTs-Q improves the mechanical properties of the PPS composite material.

[0061] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing an antioxidant toughened polyphenylene sulfide composite material, characterized in that: A nano-composite antioxidant prepared by adding quercetin and multi-walled carbon nanotubes into polyphenylene sulfide resin is mixed evenly, and the mixture is melt-blended and extruded at 250-320° C. The mixture is then drawn, cooled, and pelletized to prepare a polyphenylene sulfide composite masterbatch.

2. The preparation method according to claim 1, wherein: The preparation process of the nanocomposite antioxidant is as follows: adding quercetin to a mixed solvent of phosphate buffer and dimethyl sulfoxide, stirring evenly, adding multi-walled carbon nanotubes, stirring to obtain a suspension, and filtering, washing, drying, and grinding the suspension to obtain the nanocomposite antioxidant.

3. The preparation method according to claim 2, wherein: The mass ratio of the multi-walled carbon nanotubes to quercetin is 1:5-6; and the particle size of the multi-walled carbon nanotubes is 20 nm to 5 μm.

4. The preparation method according to claim 2 or 3, characterized in that: The volume ratio of the phosphate buffer to dimethyl sulfoxide is 20-25:1, and the usage ratio of the phosphate buffer to multi-walled carbon nanotubes is 1:0.9-1.1, v / w.

5. The preparation method according to claim 1, wherein: The particle size of the polyphenylene sulfide resin is ≤1 mm.

6. The preparation method according to claim 1 or 5, characterized in that: The mass ratio of the polyphenylene sulfide resin to the nano composite antioxidant is 599-601:19.8-20.

0.

7. The preparation method according to claim 1, wherein: The polyphenylene sulfide resin is dried at a temperature of 130° C. and a vacuum degree of ≤-0.1 MPa for 5 hours.

8. The preparation method according to claim 1, wherein: The mixture is blended and extruded through a twin-screw extruder, and the temperatures of each zone of the twin-screw extruder are: zone 1 250℃±5℃; zone 2 290℃±5℃; zone 3 290℃±5℃; zone 4 300℃±5℃; zone 5 295℃±5℃; zone 6 315℃±5℃; zone 7 300℃±5℃; zone 8 300℃±5℃; zone 9 300℃±5℃; the head temperature value is 300℃±5℃; and the main engine speed is 120r / min.

9. The preparation method according to claim 1, wherein: The polyphenylene sulfide composite masterbatch was vacuum dried at 60° C. for 8 hours to obtain a polyphenylene sulfide composite material.

10. The polyphenylene sulfide composite material prepared according to the preparation method according to any one of claims 1 to 9.

Images