Hydrolysis-resistant and size-stable modified polyphenyl ether composition for vehicles

Abstract

The invention relates to the technical field of high-molecular compound compositions, and discloses a hydrolysis-resistant size-stable automotive modified polyphenyl ether composition which comprises polyphenyl ether resin, polyamide 66 resin, glass fibers, a compatilizer and an interface modification component, the interface modification component is liquid polybutadiene of which the tail end is functionalized by siloxy, and the molecular weight distribution index of the liquid polybutadiene is in a range of 1.2 to 1.6; the viscosity ratio of an interface modification component to polyamide 66 resin in a molten state is limited to be within the range of 80-200, the interface modification component is driven by the viscosity gradient to preferentially migrate to the surface of the glass fiber and generate chemical bonding, and a nanoscale hydrophobic coating layer is constructed on the peripheral side of a reinforced phase. A moisture capillary permeation path is blocked, the problems of interface debonding and size fluctuation of the material under damp and hot working conditions are solved, and the long-acting assembly precision of a precise structural part is guaranteed.

Description

Technical Field

[0001] This invention relates to a hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications, belonging to the technical field of polymer compound compositions. Background Technology

[0002] Currently, polyphenylene ether and polyamide compositions are used in automotive cooling circulation systems and lightweight structural components. Glass fiber reinforcement improves the mechanical strength and creep resistance of the composition. Automotive thermal management systems are in a long-term humid-heat coupled condition. There are water-conducting channels at the interface between the polar resin and glass fiber. Moisture penetrates along the interface capillary, inducing hydrolysis of polyamide segments, which causes interface debonding and material dimensional fluctuations.

[0003] The industry uses chemical scavengers such as carbodiimide to slow down performance degradation. However, these scavengers are passive consumables and tend to become saturated and fail as the frequency of wet and hot cycling increases. In addition to adding scavengers, reducing the water absorption rate of the matrix by screening specific resin monomer structures is a common improvement path. For example, Chinese invention patent CN101679744B discloses a polyamide-polyphenylene ether resin composition and film, which utilizes alicyclic polyamide to optimize the heat resistance and water absorption properties of the composition. Such solutions focus on modifying the static properties of the matrix resin. In the melt processing shear flow field, there is a lack of kinetic control to drive the directional enrichment of functional components. The hydrophobic components are randomly and disorderedly distributed, making it difficult to build a dense hydrophobic barrier on the periphery of the reinforcing phase. The enhanced interfacial bonding strength is accompanied by the enrichment of polar groups, which exacerbates the water penetration rate. The introduction of hydrophobic components generates diffusion resistance, and the entanglement of macromolecular chains hinders the modifier from reaching the interface and completing its occupation within the melt processing time. Existing technologies face physical constraints in maintaining mechanical strength and improving hydrolysis resistance.

[0004] Therefore, how to improve the mechanical erosion of the pretreated layer during shear extrusion, and how excessive introduction of low molecular weight components can lead to over-plasticization of the matrix and reduced mechanical strength, are the technical problems that this invention aims to solve. This is because the industry needs to utilize a phase reconstruction scheme that uses interface blocking in processing kinetics. Summary of the Invention

[0005] To address the problems mentioned in the background art, the technical solution of the present invention is as follows: A hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications, comprising the following components by weight: Polyphenylene ether resin to Parts, polyphenylene ether resin is poly -dimethyl- -Phenyl ether; polyamide resin to 15 to 30 parts glass fiber; maleic anhydride grafted elastomer compatibilizer to Parts; Interface-modifying components to share; The interface-modifying component is terminally silanoxy-functionalized liquid polybutadiene, and the number-average molecular weight of the interface-modifying component is [missing information]. to And its molecular weight distribution index for to ; exist And the shear rate is Under these conditions, polyamide The melt viscosity of the resin is to The apparent viscosity of the interface-modifying component is to Polyamide The ratio of the melt viscosity of the resin to the apparent viscosity of the interface-modifying component is: to ; The weight ratio of the interface-modifying component to the glass fiber is: to The interface-modifying component chemically bonds with the hydroxyl groups on the glass fiber surface through its terminal silanoxy groups, forming a layer with a thickness of [thickness value missing] on the periphery of the glass fiber. to A continuous hydrophobic coating layer.

[0006] Preferably, polyphenylene ether resin and polyamide The weight ratio of the resin is to Interface modification components in The dynamic viscosity is to The maleic anhydride-grafted elastomer compatibilizer is a maleic anhydride-grafted styrene-ethylene / butene-styrene copolymer, and the maleic anhydride grafting rate of the maleic anhydride-grafted elastomer compatibilizer is... to The weight ratio of the interface-modifying component to the maleic anhydride-grafted elastomer compatibilizer is: to .

[0007] Preferred, polyamide resin in And the load is The melt index under the given conditions is to Polyphenylene ether resin in chloroform solvent and in The intrinsic viscosity under the given conditions is to The average fiber diameter of the glass fiber is to Furthermore, the surface of the glass fiber contains silanol groups.

[0008] Preferably, the molecular chain of the interface-modifying component consists of a nonpolar polybutadiene backbone and polar silanoxy functional groups located at the ends of the polybutadiene backbone; the interface-modifying component is enriched on the glass fiber surface by utilizing the difference in apparent viscosity in a shear field.

[0009] Preferably, a continuous hydrophobic coating is used to block polyamide. Moisture permeation at the resin-glass fiber interface; composition in And the relative humidity is Processing in an environment After hours, its tensile strength retention rate is not less than And the rate of change of macroscopic size is lower than .

[0010] Preferably, the terminal silaneoxy functional group is selected from at least one of trimethoxysilyl, triethoxysilyl and methyldimethoxysilyl.

[0011] Preferably, the maleic anhydride-grafted elastomer compatibilizer binds to the polyamide through its maleic anhydride groups. The terminal amino groups of the resin undergo a condensation reaction; the interface-modifying components are simultaneously distributed in both the polyphenylene ether resin and the polyamide. At the phase interface formed by the resin.

[0012] Preferably, the initial length of the glass fiber is to The composition also includes one or more of antioxidants, lubricants, and colorants; the antioxidants include hindered phenolic antioxidants and phosphite antioxidants.

[0013] Preferably, the thickness of the continuous hydrophobic coating layer Satisfy the following formula: ,in, Indicates the thickness of the continuous hydrophobic coating, in units of ; Indicates the weight parts of the interface-modifying component in the composition; It is a constant, and its range is [value range missing]. to , representing the deposition coefficient of the interface-modifying component on the glass fiber surface; This represents the total specific surface area of ​​the glass fibers; This represents the apparent density of the interface-modifying component.

[0014] Preferably, the composition is extruded using a co-rotating twin-screw extruder. to Obtained by melt blending within a temperature range; the length-to-diameter ratio of the co-rotating twin-screw extruder is... to The interface-modifying components are coated around the glass fiber during melt extrusion to give the composition a microstructure that enhances the hydrophobicity of the phase interface.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In automotive modified polyphenylene ether, the interface is transformed from a water-conducting channel to a hydrophobic barrier. The interface reconstruction agent is liquid polybutadiene modified with terminal silane groups. Utilizing the polar end groups and non-polar main chain structure, they are oriented during melt processing. The silane groups are chemically anchored to the hydroxyl groups on the glass fiber surface and the polar groups of the polyamide matrix, driving the non-polar polybutadiene segments to extend to the outside of the interface. A continuous nanoscale hydrophobic layer is constructed around the reinforcing phase. This cuts off the capillary path for water molecules to penetrate along the glass fiber and resin interface, transforming the interface from a vulnerable point to a physical barrier that blocks moisture, thus ensuring the structural integrity of the composition in humid and hot environments.

[0016] 2. By utilizing the kinetic viscosity gradient to achieve transient preoccupation of functional components, and by limiting the melt viscosity difference between the interface remodeling agent and the polyamide matrix to more than two orders of magnitude, a phase migration driving force is formed in the high shear field of the twin-screw extruder. The diffusion rate of the low-viscosity interface remodeling agent is higher than that of the macromolecular chain. Within microseconds before the matrix resin completely encapsulates the glass fiber, it preferentially reaches the surface of the reinforcing phase to complete chemical bonding. By utilizing the kinetic diffusion mechanism, the resistance of polymer entanglement to the migration of the interface modifier is overcome, ensuring the enrichment density and encapsulation continuity of the hydrophobic component at the interface.

[0017] 3. Achieving synergistic decoupling between interfacial adhesion strength and dimensional stability, the hydrophobic interfacial layer blocks water penetration without weakening the mechanical transfer efficiency between the reinforcing phase and the matrix. By controlling the weight ratio of the interfacial remodeling agent to glass fiber, the thickness of the hydrophobic sheath layer is kept at the nanometer level. The material maintains an extremely high interfacial bonding area retention rate after long-term hygrothermal cycling, limiting the interfacial stress caused by moisture-induced matrix expansion, and solving the problem of precision assembly failure of automotive cooling system brackets under complex working conditions. It also has the advantages of optimizing processing energy efficiency and providing long-term material protection. The interfacial remodeling agent exhibits lubricating properties in the early stage of extrusion molding, reducing the current load of the extruder's main motor and improving the energy utilization rate of the processing process. As the processing progresses to the middle stage of extrusion, this component is transformed into a permanent structural component that is firmly bonded to the interface, completing the transformation of the processing aid into a long-term protective function, achieving improved hydrolysis resistance and reduced production energy consumption, reflecting the coupling of material formulation design and manufacturing process. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the microscopic mechanism of the viscosity gradient-driven interface hydrophobicity reconstruction of the present invention; Figure 2 This is a trend diagram showing the correlation between the amount of interface-modifying components used in this invention and the thickness of the coating layer and the properties of the composition. Figure 3 This is a schematic diagram of the process flow for preparing the composition of the present invention and the control logic of key parameters for each step. Detailed Implementation

[0019] The following disclosure is for illustrative purposes only and is not intended to limit the scope of protection of the present invention.

[0020] This invention provides a hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications, comprising polyphenylene ether resin, polyamide 66 resin, glass fiber, maleic anhydride-grafted elastomer compatibilizer, and interface modifiers. During melt blending, the kinetic viscosity gradient between components drives the interface modifiers to migrate to the glass fiber surface and chemically bond, constructing a nanoscale hydrophobic coating layer around the reinforcing phase. This achieves hydrophobic reconstruction of the interface phase, blocking moisture penetration pathways. Addressing the interface debonding problem of precision structural components in automotive cooling systems under humid and hot conditions, this invention uses polyphenylene ether resin as one of the matrix components, with an amount of 40 to 55 parts by weight. The polyphenylene ether resin is poly2,6-dimethyl-1,4-phenylene ether. To ensure the material's mechanical strength and creep resistance at high temperatures, the polyphenylene ether resin is dissolved in chloroform solvent at 25°C. The intrinsic viscosity under the given conditions is 0.35 to 0.50 dL / g; the dimensional accuracy, which is constrained by the water absorption and swelling of the polyamide component, is adjusted by introducing 25 to 35 parts of polyamide 66 resin. The polyamide 66 resin at 260°C... Furthermore, the melt index under a load of 2.16 kg is 15 to 35 g / 10 min, at 260 °C. And the shear rate is 1000s. Under these conditions, the melt viscosity of polyamide 66 resin is 130 to 190 Pa·s. This viscosity parameter ensures that the matrix generates sufficient shear field strength during extrusion, providing impetus for the directional migration of interface-modified components.

[0021] To construct an interfacial physical barrier, the composition comprises 2 to 7 parts of an interfacial modifying component, which is terminally silanoxy-functionalized liquid polybutadiene. The number-average molecular weight of the interfacial modifying component is 2000 to 4500 g / mol, and its molecular weight distribution index is [not specified]. The value ranges from 1.2 to 1.6, and is in the range of 260. And the shear rate is 1000s. Under these conditions, the apparent viscosity of the interface-modifying component is 0.8 to 1.8 Pa·s, and the ratio of the melt viscosity of polyamide 66 resin to the apparent viscosity of the interface-modifying component is set to 80 to 200. Within this viscosity ratio range, the diffusion rate of the low-viscosity interface-modifying component is higher than that of the polyamide macromolecular chain, thus preferentially reaching the surface of the glass fiber and chemically bonding with its surface hydroxyl groups before the melt completely coats the glass fiber. To address the capillary effect at the interface between the glass fiber and the polar resin, this invention adds 15 to 30 parts of glass fiber as a reinforcing phase, with an average fiber diameter of 10 to 13 mm. m, whose surface contains silanol groups, the weight ratio of the interface modification component to the glass fiber is set to 0.12 to 0.25. The interface modification component bonds to the hydroxyl groups on the glass fiber surface through its terminal silanoxy groups, forming a continuous hydrophobic coating layer with a thickness of 80 to 150 nm on the periphery of the glass fiber. Satisfy the following formula: ,in, This indicates the thickness of the continuous hydrophobic coating layer, in nm. This refers to the weight parts of the interface-modifying component in the composition; The deposition coefficient ranges from 0.85 to 0.95. This represents the total specific surface area of ​​the glass fibers. The apparent density of the interface-modifying component is such that this thickness range achieves full surface coverage of the glass fiber, cutting off the penetration path of water molecules.

[0022] To improve the compatibility between components, the composition further includes 5 to 12 parts of maleic anhydride-grafted elastomer compatibilizer, which is a maleic anhydride-grafted styrene-ethylene / butene-styrene copolymer with a maleic anhydride grafting rate of 0.8% to 1.2%. The weight ratio of the interface-modifying component to the maleic anhydride-grafted elastomer compatibilizer is 0.3 to 0.8. The composition is produced in the high-shear section of a co-rotating twin-screw extruder, with a polyamide 66 resin melt viscosity... Apparent viscosity of interface-modified components viscosity ratio Maintain the temperature in the range of 80 to 200, and set the fourth to sixth kneading zones of the extruder to 270. Up to 285 Coupled with a screw speed of 350 to 420 rpm, the shear flow field induces kinetic diffusion pressure, driving the interface-modified components to migrate directionally to the glass fiber surface. This speed is higher than the rearrangement speed of the polyamide 66 macromolecular chain segments. Within a microsecond-level time window before the polyamide 66 resin completely coats the glass fiber, the terminal silane oxygen groups of the interface-modified components undergo a de-alcoholization condensation reaction with the silanol groups on the glass fiber surface. The nonpolar polybutadiene backbone directionally aligns outward to complete interface occupation, resulting in a continuous hydrophobic coating thickness. Satisfy the formula ,in, The weight parts of the interface-modifying components. This represents the total specific surface area of ​​the glass fiber. The apparent density of the interface-modified component is given.

[0023] Sedimentation coefficient The mass fraction was determined using the solvent extraction method. The extruded granules were then subjected to liquid nitrogen cooling and brittle crushing to a particle size of less than 0.5 mm before being placed in a Soxhlet extractor. Hexane was used as the extraction solvent at 70°C. Continuous reflux extraction for 24 h was used to remove unanchored free polybutadiene, and the mass of the interface-modified component in the residual solid was determined. Compared with the initial total mass The ratio is obtained The thickness is between 0.85 and 0.95. The wavelength of the glass fiber stabilizes in the 80-150 nm range. Transmission electron microscopy observation of ultrathin sections reveals a continuous electron cloud density lower than that of the hydrophobic halo around the glass fiber than that of the resin matrix. The interface-modified components are preferentially distributed on the surface of the glass fiber rather than at the interface between polyphenylene ether and polyamide 66. This hydrophobic layer blocks the capillary permeation path of water, solving the problems of interface debonding and dimensional fluctuation under humid and hot conditions, and ensuring the assembly accuracy of precision structural parts. The preparation process of the composition of this invention is as follows: Weighed polyphenylene ether resin, polyamide 66 resin, maleic anhydride grafted elastomer compatibilizer, and antioxidants are added to a high-speed mixer and mixed at room temperature for 3 to 5 minutes. The premix is ​​then added to the main feed inlet of a co-rotating twin-screw extruder, and the glass fiber is added through the side feed inlet. The length-to-diameter ratio of the co-rotating twin-screw extruder is 40 to 48, and the processing temperature range is 250°C. Up to 280 During the melt extrusion process, the interface-modifying components are enriched on the glass fiber surface and react with the difference in viscosity gradient to form a microstructure that enhances the hydrophobicity of the phase interface.

[0024] Example 1: When the vehicle cooling system bracket is at 85 degrees... Under humid and hot conditions with 85% relative humidity and subjected to mechanical vibration and impact, polar groups accumulate at the interface between the glass fiber and the polar resin matrix, creating microscopic capillary channels for water molecules. This causes water to penetrate along the interface and induces hydrolysis of the polyamide segments, resulting in interfacial debonding and a decrease in dimensional accuracy. The composition used in this embodiment includes, by weight, 48 parts of polyphenylene ether resin with an intrinsic viscosity of 0.42 dL / g, 32 parts of polyamide 66 resin, and 20 parts of fiber with an average diameter of 11 mm. The composition includes m parts of glass fiber, 8 parts of maleic anhydride-grafted elastomer compatibilizer with a maleic anhydride grafting rate of 1.0%, and 4 parts of interface modification component, which is terminal silanoxy-functionalized liquid polybutadiene with a number average molecular weight of m. It is 3200 g / mol, and the molecular weight distribution index is... It is 1.4, in 260 And the shear rate is 1000s. Under the conditions, the melt viscosity of polyamide 66 resin The apparent viscosity of the interface-modified component is 155 Pa·s. The Pa·s is 1.2; the co-rotating twin-screw extruder at 250°C Up to 280 The above components are melt-blended within a temperature range. Since the ratio of the melt viscosity of polyamide 66 resin to the apparent viscosity of the interface-modified component is 129.17, which is within the preset range of 80 to 200, the interface-modified component generates a phase migration driving force in the shear flow field. Its diffusion rate is greater than that of the macromolecular chain of polyamide 66 resin. Within microseconds before the polyamide 66 resin completely coats the glass fiber, the interface-modified component reaches the surface of the glass fiber. Its terminal silaneoxy groups undergo a de-alcoholization condensation reaction with the hydroxyl groups on the surface of the glass fiber, causing the non-polar polybutadiene backbone to be oriented outward towards the interface.

[0025] The interface-modifying components construct a continuous hydrophobic coating layer around the glass fiber, with a thickness of [missing information]. Satisfy the following formula: ,in, This indicates the thickness of the continuous hydrophobic coating layer, in nm. This indicates the weight percentage of the interface-modifying component in the composition, which is 4 in this case. is a constant representing the deposition coefficient of the interface modification component on the glass fiber surface, with a value of 0.90; This represents the total specific surface area of ​​the glass fibers; The apparent density of the interface-modified component is indicated. In this embodiment, the thickness of the continuous hydrophobic coating layer is 115 nm, which is within the technical requirement range of 80 to 150 nm. Traditional methods to improve interfacial bonding strength are usually accompanied by the enrichment of polar groups, which intensifies the water penetration rate. The interface preemption mechanism achieved by using the kinetic viscosity gradient, without reducing the interfacial mechanical transfer efficiency, uses non-polar polybutadiene segments to construct a physical shielding layer to block the penetration path of water molecules. This hydrophobic reconstruction of the interfacial phase enables the composition to maintain a tensile strength retention rate of 92.4% and a macroscopic dimensional change rate of 0.038% after 1000 hours of double 85 environmental treatment, thus maintaining the assembly stability of precision structural parts under complex working conditions.

[0026] Example 2: To verify the effect of interface modification components on the hydrolysis resistance of the glass fiber reinforced polyphenylene ether and polyamide 66 composition, the experimental group collected data on a platform simulating the cyclic conditions of an automotive cooling system. This experimental platform included a co-rotating twin-screw extruder with an aspect ratio of 44 and a temperature control accuracy of [missing information]. 1 A constant temperature and humidity aging test chamber with humidity fluctuations of less than 2% was used to evaluate the effectiveness of the technical solution by measuring the dimensional change rate and tensile strength retention rate of the specimens before and after hygrothermal aging. The original input parameters used in the test involved component ratios and melt processing kinetics, among which the key parameter was viscosity ratio. The setting follows this logic: The core factors affecting the interfacial coating quality are identified as the migration rate of the low-viscosity phase in the shear field and the coating speed of the matrix melt on the reinforcing phase. The viscosity ratio is set to achieve an optimal balance between ensuring that the interfacial modification component can reach the glass fiber surface before the matrix resin and maintaining the macroscopic mechanical strength of the system. When the melt viscosity of polyamide 66 resin... The apparent viscosity of the interface-modified component is maintained between 130 and 190 Pa·s. When maintained at 0.8 to 1.8 Pa·s, if the viscosity ratio Increased viscosity enhances the fluid lubricity of low-viscosity components under shear force, accelerating their migration to the flow field edge and facilitating the formation of a dense hydrophobic coating layer. The sample used in this invention has a viscosity ratio of 129, determined by selecting polyamide 66 resin with a melt index of 25 g / 10 min and a number-average molecular weight ratio of... Liquid polybutadiene with terminal silanoxy functionalization of 3200 g / mol was obtained.

[0027] In the preparation procedure of the test samples, 48 ​​parts of poly2,6-dimethyl-1,4-phenyl ether, 32 parts of polyamide 66 resin, and 8 parts of maleic anhydride grafted elastomer compatibilizer with a maleic anhydride grafting rate of 1.0% were weighed and mixed in a high-speed mixer for 4 minutes. The mixture was then added to the main feed inlet of a co-rotating twin-screw extruder, and 20 parts of fiber with an average diameter of 11 mm were added through the side feed inlet. For glass fiber of m, the temperature of the melt kneading section of the extruder is set to 275. To simulate real-world environmental noise, random mechanical vibration disturbances with an amplitude of 0.005 mm were actively introduced during dimensional measurements. In addition to the sample group of this invention, control groups A, B, C, and D were also set up. Control group A lacked the interface modification component; control group B had 1 part of the interface modification component; control group C had 9 parts; and control group D had its resin specifications adjusted to lower the viscosity ratio to 75. The sample group's viscosity was recorded at 85. The actual test results after 1000 hours of treatment in an environment with a relative humidity of 85% are shown in Table 1.

[0028] Table 1: Summary of test data for each sample group after 1000 hours of aging in a dual 85 environment.

[0029] Analysis of the data in Table 1 shows that when the interface modification component is missing or the amount is less than the lower limit of 2 parts, a continuous hydrophobic layer with a thickness of more than 80 nm cannot be formed on the periphery of the glass fiber, which leads to water molecule penetration and induces size fluctuations. Control group C shows that when the amount added is higher than the upper limit of 7 parts, the excessive accumulation of components causes matrix plasticization, resulting in a decrease in tensile strength retention. Control group D confirms that when the viscosity ratio is less than 80, the migration driving force is insufficient, and the coating layer thickness cannot reach the design threshold. In the gradient verification with relative humidity increasing from 60% to 95%, the size change rate of the sample group of the present invention increased slightly from 0.021% to 0.044%.

[0030] Example 3: This example combines Figures 1 to 3 This describes a hydrolysis-resistant, dimensionally stable modified polyphenylene ether composition for automotive applications, such as... Figure 1 As shown, the microscopic mechanism originates from the differences and interactions of the raw materials. Polyamide 66 resin serves as a high-viscosity matrix with a viscosity range of 130 to 190 Pa·s, while the interface modification component, composed of terminally silane-oxygenated polybutadiene, is a low-viscosity component with a viscosity range of 0.8 to 1.8 Pa·s. During the mixing process, both components function through a viscosity gradient-driven mechanism, with the specific viscosity ratio (PA66 / modification component) controlled between 80 and 200. Simultaneously, the polyphenylene ether resin (poly2,6-dimethyl-1,4-phenylene ether), serving as the matrix skeleton, participates in the system construction. Driven by the aforementioned viscosity gradient, the modification component preferentially migrates and accumulates directionally towards the glass fiber surface. Upon reaching the glass fiber surface, which serves as a reinforcing phase and contains hydroxyl groups, the terminally silane-oxygenated groups chemically bond with the hydroxyl groups on the glass fiber surface, thereby forming a continuous hydrophobic coating layer with a thickness of 80 to 150 nm around the glass fiber as a continuous hydrophobic barrier. Ultimately, this results in a hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications.

[0031] like Figure 2 As shown in the figure, the horizontal axis represents the amount of interface modifier in parts, the left vertical axis represents the thickness of the hydrophobic coating in nm, and the right vertical axis represents the dimensional change rate (%) and tensile strength retention rate (%), respectively. The figure contains three curves. The dashed line, representing the thickness of the hydrophobic coating, shows an approximately linear upward trend with the increase of the amount of interface modifier, gradually increasing from 0 nm at 0 parts to over 200 nm at 9 parts. The solid line, representing the dimensional change rate, decreases sharply as the amount increases from 0 to 4 parts, and remains at a low level in the range of 4 to 9 parts. The dotted line, representing the tensile strength retention rate, shows a trend of first increasing and then decreasing, reaching a peak at around 4 parts of interface modifier. This indicates that both excessive and insufficient addition will affect the mechanical retention rate of the material. The data in the figure reveals the optimal balance point of material performance at a specific dosage.

[0032] like Figure 3As shown, the process mainly consists of three nodes. Node one is the raw material pretreatment unit, which uses a high-speed mixer and involves the feeding of matrix resins (polyphenylene ether resin, polyamide 66 resin) and functional additives (interface modifiers, maleic anhydride graft compatibilizers). The mixture is then conveyed to node two, the co-rotating twin-screw extrusion line, with an aspect ratio of 40 to 48. This line includes a main feed and conveying zone with a temperature of 245 to 255°C. Under these conditions, the modifiers form a lubricating film, and silanol-containing components with a diameter of [missing information] are added through the side feed inlet. It is a glass fiber reinforced material with a thickness of 10 to 13 micrometers. The material enters the strong shear kneading zone with a temperature of 270 to 285°C. This is a key reaction site. Following the kinetic control logic, the viscosity ratio is controlled at 80 to 200, which drives the modifier to migrate preferentially to the glass fiber surface. After granulation and molding, it enters node three, namely the finished product characteristics and working environment. It is used in precision structural parts. Its microstructure presents a nanoscale continuous hydrophobic coating layer with a thickness of 80 to 150 nanometers and can withstand working environment with a temperature of 85°C and a relative humidity of 85%.

[0033] Example 4: In the large-scale automated production of automotive cooling fan brackets, the fluctuation of the main motor current load during melt blending is directly related to the dimensional stability of the product. Due to the enrichment of polar groups at the interface between glass fiber and resin matrix in the reinforced modified polyphenylene ether composition, microscopic capillary channels of water molecules are easily formed, leading to excessive shear heat generated when the extrusion rate is increased and inducing degradation of polyamide 66 resin, thereby generating interfacial microvoids. To solve the above engineering challenges, the sample group of this invention uses 45 parts of polyphenylene ether resin with an intrinsic viscosity of 0.45 dL / g, 30 parts of polyamide 66 resin, and 20 parts of fiber with an average diameter of 11 mm. The composition includes m parts of glass fiber, 5 parts of maleic anhydride-grafted elastomer compatibilizer, and 5 parts of interface modifying component, wherein the interface modifying component is terminally trimethoxysilyl-functionalized liquid polybutadiene with a number average molecular weight of m. It is 3800 g / mol, and the molecular weight distribution index is... The value is 1.35. During melt extrusion, the screw assembly of the co-rotating twin-screw extruder is divided into three dynamic functional zones, of which zones one to three are weak shear conveying zones, with the temperature set at 245°C. Up to 255 At this point, the silanoxy condensation reaction is in the induction phase. The low-viscosity interface-modifying component forms a lubricating film on the melt surface to reduce the frictional resistance between the material and the screw. Zones four to six are strong shear kneading zones, and the temperature rises to 270°C. Up to 285 Utilizing the melt viscosity of polyamide 66 resin Apparent viscosity of the interface-modified component The 140-fold difference in the level drives the interface-modified components to migrate to the glass fiber surface within microseconds.

[0034] Sedimentation coefficient The calibration was performed using the solvent extraction mass spectrometry method. The procedure included taking 10g of the extruded granules and subjecting them to liquid nitrogen cooling and brittle crushing until the particle size was less than 0.5mm. The powder was then placed in a Soxhlet extractor, and n-hexane was used as the extraction solvent. The extraction was carried out at 70°C. Continuous reflux extraction for 24 h was performed to remove unanchored free polybutadiene at the interface. The residual solids were collected and then subjected to 80°C. Dry to constant weight in a vacuum oven, deposition coefficient Calculate according to the following formula: ,in, The deposition coefficient of the interface-modifying component on the glass fiber surface; The mass of the interface-modified component remaining in the solid after extraction; This represents the initial total mass of the interface-modifying components in this sample group. Measurements were taken at a screw speed of 350 rpm. The value is 0.92, representing the total specific surface area of ​​the combined glass fibers. Apparent density of interface-modified components The thickness of the continuous hydrophobic coating was calculated. The thickness was 132 nm. Ultrathin sections of the material observed by transmission electron microscopy revealed a continuous halo with low electron cloud density in the transition region between the glass fiber and the matrix resin. The measured radial thickness ranged from 125 nm to 140 nm, confirming the existence of a nanoscale hydrophobic coating. Because this hydrophobic coating is instantaneously anchored to the hydroxyl groups on the glass fiber surface via terminal silanoxy groups during the later stages of extrusion, the main motor current load decreased by 15.5% while maintaining a high extrusion rate. After 1000 hours of aging in a dual 85 environment, the capillary penetration pathway of water molecules was blocked, and the fluctuation range of the assembly gap was controlled within the molecular-level creep range.

[0035] Example 5: When switching the composition production for different batches of raw materials, the grafting rate of terminal silaneoxy functional groups in the interface-modified component fluctuated, and the current system was measured at 260°C. And the shear rate is 1000s. Viscosity ratio under certain conditions ,like If the value deviates from the 80-200 range, the amount of interface-modified component fed can be corrected by adjusting the feeding system. To maintain a higher migration rate of the interface-modified components to the glass fiber surface than the polyamide 66 resin molecular chain rearrangement rate, this procedure ensures that the terminal silaneoxy groups and the hydroxyl groups on the glass fiber surface complete the de-alcoholization condensation reaction in the melt kneading section and construct a continuous hydrophobic coating layer around the reinforcing phase. When the kneading elements of the co-rotating twin-screw extruder experience shear stress attenuation due to wear, the deposition coefficient of the finished pellets is monitored. Process compensation was performed, and the finished granules under operating conditions were analyzed using the solvent extraction mass spectrometry method. If the detected value approaches the lower limit of 0.85, the strong shear kneading temperature range in zones four to six should be maintained at 270°C. Up to 285 Under this premise, the screw speed was increased from 350 rpm to 420 rpm to enhance the shear-induced viscosity gradient over-diffusion effect. This parameter fine-tuning resulted in a continuous hydrophobic coating thickness formed around the glass fiber. The obtained composition remained stable at around 115 nm for 1000 hours at 85 nm. The dimensional change rate after treatment in an environment with 85% relative humidity is no higher than 0.05%.

[0036] In the case of expanding the production capacity of a co-rotating twin-screw extruder for composite materials, the uneven distribution of the shear energy field caused by differences in equipment specifications is addressed by calibrating the total specific surface area of ​​the glass fibers. To determine the baseline parameters in the thickness calculation formula, based on the average fiber diameter. 10 to 13 m and density 2540 to 2580 kg / m The total specific surface area of ​​glass fibers is determined using their geometric morphology parameters. The calculation formula is: ,in Total specific surface area, in m² / kg, The average fiber diameter is expressed in meters (m). This refers to the density of glass fiber, expressed in kg / m³. When the average fiber diameter is selected for this sample group 11 m and density 2550kg / m When using glass fibers, the total specific surface area is calculated. It is 142.60m / kg, this quantification parameter is used as an input to calculate the thickness of the continuous hydrophobic coating. To ensure that a continuous hydrophobic coating layer with a thickness of 80 to 150 nm can be formed on the surface of glass fibers with different diameter distributions; when the system faces shear heat accumulation deviation caused by the power fluctuation of the extruder main motor, the specific mechanical energy is monitored. The screw speed is adjusted in conjunction with the reaction to control the reaction sequence of the interface-modified components, thereby reducing specific mechanical energy. Satisfy the formula ,in Specific mechanical energy, expressed in kWh / kg. The actual output power of the main motor, in kW. This is the mass flow rate of the composition, expressed in kg / h, when the sensor detects... When deviating from the technical range of 0.18 to 0.25 kWh / kg, the screw speed is adjusted by the controller to maintain the shear field output within the dynamic range for inducing interfacial reactions. This prevents the interfacial modified components from failing to self-assemble into a continuous hydrophobic coating layer around the glass fiber due to insufficient diffusion rate. The measured values ​​for this sample group... At a value of 0.21 kWh / kg, the thickness of the continuous hydrophobic coating layer formed around the glass fiber is... The composition is 118nm, and at 85 Furthermore, the tensile strength retention rate was 91.5% after 1000 hours of environmental treatment at a relative humidity of 85%.

[0037] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. 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 be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications, characterized in that, By weight, it consists of the following components: Polyphenylene ether resin to Parts, polyphenylene ether resin is poly -dimethyl- -Phenyl ether; polyamide resin to 15 to 30 parts glass fiber; maleic anhydride grafted elastomer compatibilizer to Parts; Interface-modifying components to share; The interface-modifying component is terminally silanoxy-functionalized liquid polybutadiene, and the number-average molecular weight of the interface-modifying component is [missing information]. to And its molecular weight distribution index for to ; exist And the shear rate is Under these conditions, polyamide The melt viscosity of the resin is to The apparent viscosity of the interface-modifying component is to Polyamide The ratio of the melt viscosity of the resin to the apparent viscosity of the interface-modifying component is: to ; The weight ratio of the interface-modifying component to the glass fiber is: to The interface-modifying component chemically bonds with the hydroxyl groups on the glass fiber surface through its terminal silanoxy groups, forming a layer with a thickness of [thickness value missing] on the periphery of the glass fiber. to A continuous hydrophobic coating layer.

2. The hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications according to claim 1, characterized in that, Polyphenylene ether resin and polyamide The weight ratio of the resin is to Interface modification components in The dynamic viscosity is to The maleic anhydride-grafted elastomer compatibilizer is a maleic anhydride-grafted styrene-ethylene / butene-styrene copolymer, and the maleic anhydride grafting rate of the maleic anhydride-grafted elastomer compatibilizer is... to The weight ratio of the interface-modifying component to the maleic anhydride-grafted elastomer compatibilizer is: to .

3. The hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications according to claim 1, characterized in that, polyamide resin in And the load is The melt index under the given conditions is to Polyphenylene ether resin in chloroform solvent and in The intrinsic viscosity under the given conditions is to The average fiber diameter of the glass fiber is to Furthermore, the surface of the glass fiber contains silanol groups.

4. The hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications according to claim 1, characterized in that, The molecular chain of the interface-modifying component consists of a nonpolar polybutadiene backbone and polar silanoxy functional groups located at the ends of the polybutadiene backbone; the interface-modifying component is enriched on the glass fiber surface by utilizing the difference in apparent viscosity in a shear field.

5. The hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications according to claim 1, characterized in that, Continuous hydrophobic coating for barrier polyamide Moisture permeation at the resin-glass fiber interface; composition in And the relative humidity is Processing in an environment After hours, its tensile strength retention rate is not less than And the rate of change of macroscopic size is lower than .

6. The hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications according to claim 1, characterized in that, The terminal silaneoxy functional group is selected from at least one of trimethoxysilyl, triethoxysilyl, and methyldimethoxysilyl.

7. The hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications according to claim 1, characterized in that, Maleic anhydride-grafted elastomer compatibilizers bind to polyamides via their maleic anhydride groups. The terminal amino groups of the resin undergo a condensation reaction; The interface-modifying components are simultaneously distributed in both polyphenylene ether resin and polyamide. At the phase interface formed by the resin.

8. The hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications according to claim 1, characterized in that, The initial length of the glass fiber is to The composition also includes one or more of antioxidants, lubricants, and colorants; the antioxidants include hindered phenolic antioxidants and phosphite antioxidants.

9. The hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications according to claim 1, characterized in that, Thickness of continuous hydrophobic coating Satisfy the following formula: ,in, Indicates the thickness of the continuous hydrophobic coating, in units of ; Indicates the weight parts of the interface-modifying component in the composition; It is a constant, and its range is [value range missing]. to , representing the deposition coefficient of the interface-modifying component on the glass fiber surface; This represents the total specific surface area of ​​the glass fibers; This represents the apparent density of the interface-modifying component.

10. A hydrolysis-resistant and dimensionally stable modified polyphenylene ether composition for automotive applications according to claim 1, characterized in that, The composition was extruded by a co-rotating twin-screw extruder in to Obtained by melt blending within a temperature range; the length-to-diameter ratio of the co-rotating twin-screw extruder is... to ; The interface-modifying component is coated around the glass fiber during melt extrusion to give the composition a microstructure that enhances the hydrophobicity of the phase interface.

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