Linear polyphosphazene halogen-containing flame-retardant toughening modified glass fiber reinforced polyamide 6 / polyamide 66 composite

Abstract

The application provides a linear polyphosphazene halogen-containing flame-retardant toughening modified glass fiber reinforced polyamide 6 / polyamide 66 composite material.The linear polyphosphazene used in the composite material has a structure shown in formula 1: wherein, in the formula 1, R1 and R2 can be the same or different substituent groups in a single chain segment, R1 and R2 are not completely the same in the whole molecular chain structure of the linear polyphosphazene, and the proportion of a single kind of substituent group in all substituent groups is not more than 90 mol%; the linear polyphosphazene contains halogen.The linear polyphosphazene halogen-containing flame-retardant toughening modified glass fiber reinforced polyamide 6 / polyamide 66 composite material provided by the application has good flame retardancy, heat resistance and mechanical properties.

Description

Technical Field

[0001] This invention relates to a linear polyphosphazene halogenated flame-retardant toughened modified glass fiber reinforced polyamide 6 / polyamide 66 composite material, belonging to the field of polymer composite material technology. Background Technology

[0002] Polyamide 6 (PA6) and polyamide 66 (PA66), due to their excellent mechanical properties, wear resistance, and good chemical stability, have become one of the most widely used engineering plastics. However, polyamide materials still have many problems such as high water absorption, high molding shrinkage, low modulus, and flammability. To address these issues, composite PA6 / PA66 with glass fiber (GF) is currently the most common modification method. Compared to the pure matrix, PA6 and / or PA66 / GF composites show significantly enhanced dimensional stability, material modulus, and tensile strength. However, the flammability and dripping properties of PA6 cannot be improved by this method; in fact, the "wick effect" caused by the addition of GF makes these composites more prone to continuous combustion. Furthermore, the addition of high GF content increases the brittleness of PA6 / PA66, significantly reducing the elongation at break, while the addition of high flame retardant content further deteriorates the mechanical properties of PA6 and / or PA66 / GF composites. Therefore, developing a highly efficient flame retardant and toughening agent for PA6 and / or PA66 / GF composites and preparing a flame retardant and toughening modified glass fiber reinforced PA6 / PA66 composite material is of great significance for improving the reliability of PA6 / PA66 and expanding its application fields.

[0003] Phosphazene elastomers possess strong toughness due to the good flexibility of their molecular chains, and based on their high phosphorus and nitrogen content, they have been applied in fire-retardant materials. Some phosphazene materials have been studied in the field of flame retardants. For example, Chinese patent application CN201810939424 discloses a method for preparing polyphosphazene microspheres as a highly efficient flame-retardant additive for polymers. However, the polyphosphazene microspheres described in this patent are hypercrosslinked polymers, which have limited toughening effect on the material, and the mechanical properties of the material have not received much attention. Chinese patent application CN201711430401 discloses a halogen-free flame-retardant polyamide 6 polymer and its composite material and preparation method, which involves the application of linear polyphosphazene flame retardants, but the related polyphosphazene structure is relatively simple, and the mechanical properties of the material have not been considered. CN201610632613 involves grafting small cyclophosphonitrile molecules or linear polyphosphonitrile into amide structures. This process improves the compatibility between flame retardants and polyamide matrices while limiting the phosphorus and nitrogen content. Furthermore, the local cross-linking structure caused by small cyclophosphonitrile molecules is not conducive to their dispersion in the polymer matrix. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a glass fiber reinforced polyamide 6 / polyamide 66 composite material and its preparation method.

[0005] To achieve the above objectives, the present invention provides a linear polyphosphazene halogenated flame-retardant toughened modified glass fiber reinforced polyamide 6 / polyamide 66 composite material, wherein the structure of the linear polyphosphazene is shown in Formula 1:

[0006]

[0007] In Formula 1, R1 and R2 may be the same or different substituent groups in a single repeating unit. In the entire molecular chain structure of the linear polyphosphazene, R1 and R2 are not completely the same. Furthermore, the proportion of a single type of substituent group in all substituent groups does not exceed 90 mol%. The linear polyphosphazene contains halogens.

[0008] Linear polyphosphazene materials are a class of polymeric materials with a linear backbone structure composed of phosphorus and nitrogen atoms linked by alternating single and double bonds, exhibiting extremely high phosphorus and nitrogen content. The composite material provided by this invention uses linear polyphosphazene as a halogenated flame-retardant and toughening modifier. By selecting and controlling the structure of the substituents, the polyphosphazene molecular chain can achieve good flexibility while maintaining good compatibility with the polyamide molecular chain. R1 and R2 can be substituent groups with the same or different chemical structures in a single chain segment, but the entire molecular chain structure must include two or more different substituent structures, and the proportion of a single type of substituent group in the total number of substituent groups must not exceed 90% (molar percentage) to prevent a decrease in toughness caused by molecular chain crystallization.

[0009] According to a specific embodiment of the present invention, preferably, R1 and R2 are selected from two substituent groups, and the molar ratio between the two substituent groups is 1:1-1:9, more preferably 1:1-1:2 or 1:2-1:9, specifically for example 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9.

[0010] According to a specific embodiment of the present invention, preferably, R1 and R2 are selected from one or more combinations of fluoroalkoxy, fluorophenoxy, bromophenoxy, 2-fluoroaniline, 4-fluoroaniline, 2-bromoaniline, 2,4,6-tribromoaniline and phenoxy; and the phenoxy group is not used alone, that is, the phenoxy group needs to be used in combination with one or more other substituent structures.

[0011] According to a specific embodiment of the present invention, preferably, the structure of the fluoroalkoxy group is as shown in Formula 2 or Formula 3:

[0012]

[0013] In Equation 3, m takes the value of an integer from 1 to 5.

[0014] According to a specific embodiment of the present invention, preferably, the fluorophenoxy group includes one or more of pentafluorophenoxy, 2,3,5,6-tetrafluorophenoxy, and 4-fluorophenoxy.

[0015] According to a specific embodiment of the present invention, preferably, the bromophenoxy group includes one or more combinations of pentabromophenoxy, 2,3,4,6-tetrabromophenoxy, 2,4,5-tribromophenoxy, 2-bromophenoxy, 3-bromophenoxy, and 4-bromophenoxy.

[0016] According to a specific embodiment of the present invention, preferably, the number-average molecular weight of the linear polyphosphazene is (3 × 10⁻⁶). 6 )-(9×10 6 ).

[0017] According to a specific embodiment of the present invention, preferably, the raw material composition of the composite material, by mass percentage, includes: 40-85 wt% polyamide 6 / polyamide 66, 10-40 wt% modified glass fiber, 5-30 wt% linear polyphosphazene, 0.1-5 wt% antioxidant, and 0.1-1 wt% lubricant.

[0018] According to a specific embodiment of the present invention, preferably, the raw material composition of the composite material, by mass percentage, includes: 48.5-67.5 wt% polyamide 6 / polyamide 66, 10-30 wt% modified glass fiber, 5-20 wt% linear polyphosphazene, 0.5-1 wt% antioxidant, and 0.5-1 wt% lubricant.

[0019] According to a specific embodiment of the present invention, the polyamide 6 / polyamide 66 can be polyamide 6 alone or polyamide 66 alone, or it can be a mixture of the two in a certain molar ratio (e.g., 1:1).

[0020] According to a specific embodiment of the present invention, preferably, the antioxidant is one or a combination of two or more of the following: bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphate, tetra-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester, (2,4,6-tri-tert-butylphenyl-2-butyl-2-ethyl)-1,3-propanediol phosphite, 2,2'-ethylidene bis(4,6-di-tert-butylphenyl)fluorophosphite, or bis(2,4-di-p-isopropylphenyl)pentaerythritol diphosphate.

[0021] According to a specific embodiment of the present invention, preferably, the lubricant is one of di(2-ethylhexyl) phthalate, dioctyl phthalate, or dimethyl phthalate.

[0022] According to a specific embodiment of the present invention, preferably, the linear polyphosphazene halogenated flame-retardant toughened modified glass fiber reinforced polyamide 6 / polyamide 66 composite material has an oxygen index of 21-37%, a tensile strength of 110-150 MPa, an elongation at break of 10-30%, and an impact strength of 10-40 kJ / m. 2 The flame retardant performance in the vertical burning test (UL-94) reaches V-2 to V-0 levels.

[0023] This invention also provides a method for preparing the above-mentioned linear polyphosphazene halogenated flame-retardant toughened modified glass fiber reinforced polyamide 6 / polyamide 66 composite material, comprising the following steps:

[0024] Polyamide 6 / polyamide 66, linear polyphosphazene, lubricant and antioxidant are blended with glass fibers modified with coupling agent through a twin-screw extruder and then extruded and granulated to obtain the linear polyphosphazene halogenated flame retardant toughening modified glass fiber reinforced polyamide 6 / polyamide 66 composite material.

[0025] According to a specific embodiment of the present invention, preferably, the temperature of the twin-screw extrusion is controlled at 230-290°C.

[0026] According to a specific embodiment of the present invention, preferably, when the glass fiber is modified with a coupling agent, the amount of the coupling agent added accounts for 0.1-2% of the mass of the glass fiber.

[0027] According to a specific embodiment of the present invention, preferably, the coupling agent is one or a combination of two or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane or γ-methacryloyloxypropyltrimethoxysilane.

[0028] The linear polyphosphazene halogenated flame-retardant toughened modified glass fiber reinforced polyamide 6 / polyamide 66 composite material provided by the present invention has good flame retardancy, heat resistance and mechanical properties. Detailed Implementation

[0029] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0030] All polyamide 6, linear polyphosphazene flame retardant toughening agent, and glass fiber involved in the embodiments were dried at 90°C for 6 hours under vacuum before use.

[0031] Example 1

[0032] In this embodiment, the linear polyphosphazene flame retardant toughening agent has the following structure:

[0033]

[0034] In this structure, the molar ratio of trifluoroethoxy to octafluoropentoxy is 1:1, and the number-average molecular weight of this linear polyphosphazene is 9 × 10⁻⁶. 6 .

[0035] According to the mass fraction, 20 wt% of the above-mentioned linear polyphosphazene flame retardant toughening agent, 48.5 wt% of polyamide 6 / polyamide 66 (the mass ratio of polyamide 6 to polyamide 66 is 1:1), 1 wt% of pentaerythritol tetrakis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.5 wt% of dioctyl phthalate, and 30 wt% of modified glass fiber (modified with γ-aminopropyltriethoxysilane at 1 wt% of the glass fiber mass) are blended in a twin-screw extruder (extruder temperature setting range is 220-290℃) and then extruded and granulated to obtain the product composite material.

[0036] The limiting oxygen index, tensile properties, impact strength, and vertical burning performance of the material were tested according to standards ISO4859-2:2006, GB1040-1992, GB1843-1993, and GB4609-84, respectively (the test methods for the following examples and comparative examples are the same). The oxygen index of the above composite material was 28.1%, the tensile strength was 135 MPa, the elongation at break was 17%, and the impact strength was 32 kJ / m. 2 The flame retardant performance (UL-94) of the vertical burning test reached V-0 level.

[0037] Example 2

[0038] In this embodiment, the linear polyphosphazene flame retardant toughening agent has the following structure:

[0039]

[0040] In this structure, the molar ratio of phenoxy to trifluoroethoxy is 1:1, and the number-average molecular weight of this linear polyphosphazene is 7 × 10⁻⁶. 6 .

[0041] According to the mass fraction, 15 wt% of the above-mentioned linear polyphosphazene flame retardant toughening agent, 53.5 wt% of polyamide 6, 1 wt% of bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphate, 0.5 wt% of dimethyl phthalate and 30 wt% of modified glass fiber (modified with γ-aminopropyltriethoxysilane at 1 wt% of the glass fiber mass) are blended in a twin-screw extruder (extruder temperature setting range is 220-240℃) and then extruded and granulated to obtain the product composite material.

[0042] The composite material tested showed an oxygen index of 30.8%, a tensile strength of 127 MPa, an elongation at break of 16.5%, and an impact strength of 25 kJ / m². 2 The flame retardant performance (UL-94) of the vertical burning test reached V-0 level.

[0043] Example 3

[0044] In this embodiment, the linear polyphosphazene flame retardant toughening agent has the following structure:

[0045]

[0046] In this structure, the molar ratio of phenoxy to octafluoropentoxy is 2:1, and the number-average molecular weight of this linear polyphosphazene is 5 × 10⁻⁶. 6 .

[0047] According to the mass fraction, 20 wt% of the above-mentioned linear polyphosphazene flame retardant toughening agent, 48.5 wt% of polyamide 66, 1 wt% of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester, 0.5 wt% of dimethyl phthalate and 30 wt% of modified glass fiber (modified with γ-aminopropyltriethoxysilane at 0.1 wt% of the glass fiber mass) are blended in a twin-screw extruder (extruder temperature setting range is 240-290℃) and then extruded and granulated to obtain the product composite material.

[0048] The composite material tested showed an oxygen index of 31.9%, a tensile strength of 140 MPa, an elongation at break of 23.5%, and an impact strength of 34 kJ / m². 2 The flame retardant performance (UL-94) of the vertical burning test reached V-0 level.

[0049] Example 4

[0050] In this embodiment, the linear polyphosphazene flame retardant toughening agent has the following structure:

[0051]

[0052] In this structure, the molar ratio of pentafluorophenoxy to 4-fluorophenoxy is 1:1, and the number-average molecular weight of this linear polyphosphazene is 3 × 10⁻⁶.6 .

[0053] According to the mass fraction, 15 wt% of the above-mentioned linear polyphosphazene flame retardant toughening agent, 63.5 wt% of polyamide 6, 1 wt% of (2,4,6-tri-tert-butylphenyl-2-butyl-2-ethyl)-1,3-propanediol phosphite, 0.5 wt% of di(2-ethylhexyl) phthalate and 20 wt% of modified glass fiber (modified with γ-aminopropyltriethoxysilane at 1 wt% of the glass fiber mass) were blended in a twin-screw extruder (extruder temperature setting range of 220-240℃) and extruded and granulated to obtain the product composite material.

[0054] The composite material tested showed an oxygen index of 36.5%, a tensile strength of 129 MPa, an elongation at break of 23.1%, and an impact strength of 36 kJ / m². 2 The flame retardant performance (UL-94) of the vertical burning test reached V-0 level.

[0055] Example 5

[0056] In this embodiment, the linear polyphosphazene flame retardant toughening agent has the following structure:

[0057]

[0058] In this structure, the molar ratio of pentafluorophenoxy to 2,3,5,6-tetrafluorophenoxy is 1:1, and the number-average molecular weight of this linear polyphosphazene is 4 × 10⁻⁶. 6 .

[0059] According to the mass fraction, 10 wt% of the above-mentioned linear polyphosphazene flame retardant toughening agent, 58.5 wt% of polyamide 6, 1 wt% of (2,4,6-tri-tert-butylphenyl-2-butyl-2-ethyl)-1,3-propanediol phosphite, 0.5 wt% of di(2-ethylhexyl) phthalate and 30 wt% of modified glass fiber (modified with γ-aminopropyltriethoxysilane at 1 wt% of the glass fiber mass) are blended in a twin-screw extruder (extruder temperature setting range is 220-240℃) and then extruded and granulated to obtain the product composite material.

[0060] The composite material tested showed an oxygen index of 31.2%, a tensile strength of 139 MPa, an elongation at break of 16%, and an impact strength of 20 kJ / m². 2 The flame retardant performance (UL-94) of the vertical burning test reached V-0 level.

[0061] Example 6

[0062] In this embodiment, the linear polyphosphazene flame retardant toughening agent has the following structure:

[0063]

[0064] In this structure, the molar ratio of 2-fluoroaniline groups to 4-fluoroaniline groups is 1:1, and the number-average molecular weight of this linear polyphosphazene is 3 × 10⁻⁶. 6 .

[0065] According to the mass fraction, 15 wt% of the above-mentioned linear polyphosphazene flame retardant toughening agent, 53.5 wt% of polyamide 6, 1 wt% of 2,2'-ethylene bis(4,6-di-tert-butylphenyl) fluorophosphite, 0.5 wt% of di(2-ethylhexyl) phthalate and 30 wt% of modified glass fiber (modified with γ-aminopropyltriethoxysilane at 1 wt% of the glass fiber mass) are blended in a twin-screw extruder (extruder temperature setting range is 220-240℃) and then extruded and granulated to obtain the product composite material.

[0066] The composite material tested showed an oxygen index of 31.3%, a tensile strength of 132 MPa, an elongation at break of 13.6%, and an impact strength of 20 kJ / m². 2 The flame retardant performance (UL-94) of the vertical burning test reached V-0 level.

[0067] Example 7

[0068] In this embodiment, the linear polyphosphazene flame retardant toughening agent has the following structure:

[0069]

[0070] In this structure, the molar ratio of pentabromophenoxy to 2,3,4,6-tetrabromophenoxy is 9:1, and the number-average molecular weight of this linear polyphosphazene is 3 × 10⁻⁶. 6 .

[0071] According to the mass fraction, 10 wt% of the above-mentioned linear polyphosphazene flame retardant toughening agent, 58.5 wt% of polyamide 6, 1 wt% of di(2,4-di-p-isopropylphenyl) pentaerythritol diphosphite, 0.5 wt% of di(2-ethylhexyl) phthalate and 30 wt% of modified glass fiber (modified with γ-aminopropyltriethoxysilane at 1 wt% of the glass fiber mass) are blended in a twin-screw extruder (extruder temperature setting range is 220-240℃) and then extruded and granulated to obtain the product composite material.

[0072] The composite material tested showed an oxygen index of 30.3%, a tensile strength of 130 MPa, an elongation at break of 13.1%, and an impact strength of 14 kJ / m². 2 The flame retardant performance (UL-94) of the vertical burning test reached V-0 level.

[0073] Example 8

[0074] In this embodiment, the linear polyphosphazene flame retardant toughening agent has the following structure:

[0075]

[0076] In this structure, the molar ratio of phenoxy to 4-bromophenoxy is 1:1, and the number-average molecular weight of this linear polyphosphazene is 7 × 10⁻⁶. 6 .

[0077] According to the mass fraction, 15 wt% of the above-mentioned linear polyphosphazene flame retardant toughening agent, 53.5 wt% of polyamide 6, 0.5 wt% of 2,2'-ethylene bis(4,6-di-tert-butylphenyl) fluorophosphite, 1 wt% of di(2-ethylhexyl) phthalate and 30 wt% of modified glass fiber (modified with γ-aminopropyltriethoxysilane at 2 wt% of the glass fiber mass) are blended in a twin-screw extruder (extruder temperature setting range is 220-240℃) and then extruded and granulated to obtain the product composite material.

[0078] The composite material tested showed an oxygen index of 30.1%, a tensile strength of 126 MPa, an elongation at break of 23.9%, and an impact strength of 24.5 kJ / m². 2 The flame retardant performance (UL-94) of the vertical burning test reached V-0 level.

[0079] Example 9

[0080] In this embodiment, the linear polyphosphazene flame retardant toughening agent has the following structure:

[0081]

[0082] In this structure, the molar ratio of 2-bromoaniline to 2,4,6-tribromoaniline is 1:1, and the number-average molecular weight of this linear polyphosphazene is 3 × 10⁻⁶. 6 .

[0083] According to the mass fraction, 5 wt% of the above-mentioned linear polyphosphazene flame retardant toughening agent, 63.5 wt% of polyamide 6, 0.5 wt% of 2,2'-ethylene bis(4,6-di-tert-butylphenyl) fluorophosphite, 1 wt% of di(2-ethylhexyl) phthalate and 30 wt% of modified glass fiber (modified with γ-aminopropyltriethoxysilane at 2 wt% of the glass fiber mass) are blended in a twin-screw extruder (extruder temperature setting range is 220-240℃) and then extruded and granulated to obtain the product composite material.

[0084] The composite material tested showed an oxygen index of 34.1%, a tensile strength of 132 MPa, an elongation at break of 12.7%, and an impact strength of 14.8 kJ / m². 2The flame retardant performance (UL-94) of the vertical burning test reached V-0 level.

[0085] Example 10

[0086] In this embodiment, the linear polyphosphazene flame retardant toughening agent has the following structure:

[0087]

[0088] In this structure, the molar ratio of pentabromophenoxy to 2,4,5-tribromophenoxy is 1:1, and the number-average molecular weight of this linear polyphosphazene is 3 × 10⁻⁶. 6 .

[0089] According to the mass fraction, 20 wt% of the above-mentioned linear polyphosphazene flame retardant toughening agent, 68.5 wt% of polyamide 6, 0.5 wt% of 2,2'-ethylene bis(4,6-di-tert-butylphenyl) fluorophosphite, 1 wt% of di(2-ethylhexyl) phthalate and 10 wt% of modified glass fiber (modified with γ-aminopropyltriethoxysilane at 0.1 wt% of the glass fiber mass) are blended in a twin-screw extruder (extruder temperature setting range is 220-240℃) and then extruded and granulated to obtain the product composite material.

[0090] The composite material tested showed an oxygen index of 36.9%, a tensile strength of 122 MPa, an elongation at break of 19.1%, and an impact strength of 34.7 kJ / m². 2 The flame retardant performance (UL-94) of the vertical burning test reached V-0 level.

[0091] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and / or characteristics in the technical solutions is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed by the present invention should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A linear polyphosphazene halogenated flame-retardant toughened modified glass fiber reinforced polyamide 6 / polyamide 66 composite material, wherein, The composite material was obtained by blending 15 wt% linear polyphosphazene flame retardant and toughening agent, 63.5 wt% polyamide 6, 1 wt% (2,4,6-tri-tert-butylphenyl-2-butyl-2-ethyl)-1,3-propanediol phosphite, 0.5 wt% di(2-ethylhexyl) phthalate, and 20 wt% modified glass fiber in a twin-screw extruder and then extruding and granulating. The linear polyphosphazene flame retardant and toughening agent has the following structure: In this structure, the molar ratio of pentafluorophenoxy to 4-fluorophenoxy is 1:1, and the number-average molecular weight of this linear polyphosphazene is 3 × 10⁻⁶. 6 Modified glass fibers are obtained by modifying glass fibers with γ-aminopropyltriethoxysilane at 1 wt% of their mass; the extruder temperature setting range is 220-240℃; or, The composite material was obtained by blending 20 wt% linear polyphosphazene flame retardant toughening agent, 48.5 wt% polyamide 66, 1 wt% β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 0.5 wt% dimethyl phthalate, and 30 wt% modified glass fiber in a twin-screw extruder and then extruding and granulating the mixture. The linear polyphosphazene flame retardant toughening agent has the following structure: In this structure, the molar ratio of phenoxy to octafluoropentoxy is 2:1, and the number-average molecular weight of this linear polyphosphazene is 5 × 10⁻⁶. 6 Modified glass fibers were obtained by modifying glass fibers with 0.1 wt% γ-aminopropyltriethoxysilane; the extruder temperature setting range was 240-290 ℃; or, The composite material was obtained by blending 15 wt% linear polyphosphazene flame retardant and toughening agent, 53.5 wt% polyamide 6, 0.5 wt% 2,2'-ethylene bis(4,6-di-tert-butylphenyl) fluorophosphite, 1 wt% di(2-ethylhexyl) phthalate, and 30 wt% modified glass fiber in a twin-screw extruder and then extruding and granulating the mixture. The linear polyphosphazene flame retardant and toughening agent has the following structure: In this structure, the molar ratio of phenoxy to 4-bromophenoxy is 1:1, and the number-average molecular weight of this linear polyphosphazene is 7 × 10⁻⁶. 6 The glass fiber was modified by adding 2 wt% γ-aminopropyltriethoxysilane to obtain the modified glass fiber; the extruder temperature setting range was 220-240 ℃.

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