A high temperature resistant polymer foam and a method of making the same

Abstract

The present application relates to a kind of high-temperature-resistant polymer foam material and its preparation method, belong to polymer processing technical field.The present application is by BMI resin (bismaleimide resin) and polyaryletherketone resin are compounded, after foaming, heat treatment is carried out, BMI resin is completed solidification, crosslinking structure is formed, to form semi-interpenetrating network, so, compared with the mechanical properties and heat resistance of polyaryletherketone foam of thermoplasticity, material can be obviously improved, in addition, the cold-pressing foaming mode used in the present application has the characteristics of short heat preservation time, foaming efficiency is high, can effectively control the solidification degree of BMI resin in foaming process, avoid BMI resin excessive crosslinking, so that composite material has good foaming performance.

Description

Technical Field

[0001] This invention relates to a high-temperature resistant polymer foam material and its preparation method, belonging to the field of polymer processing technology. Background Technology

[0002] Currently, with the development of high technology, fields such as national defense, military industry, and aerospace, which operate in harsh environments, require foam materials with properties such as high temperature resistance, corrosion resistance, and high mechanical strength. Therefore, the development of high-performance foam materials has become an important research direction. Polyaryletherketone (PLEK) foam is a type of high-performance foam prepared using high-performance PLEK resin as raw material and supercritical carbon dioxide foaming technology. It has advantages such as high temperature resistance, self-flame retardancy, recyclability, and radiation resistance, and the foaming process is green and environmentally friendly, showing broad application prospects. However, the mechanical properties of PLEK thermoplastic foams still lag behind other thermosetting foams, such as PMI foam. For example, the literature (Polymer, 2019, 165: 124-132) reports that the compressive strength of PLEK is about 60-70% of that of commercial PMI foam of the same density. This limits the application and promotion of PLEK foam, so the reinforcement and modification of PLEK foam is of great significance.

[0003] In view of the above-mentioned shortcomings, the present invention aims to create a high-temperature resistant polymer foam material and its preparation method, so as to make it more valuable for industrial use. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a high-temperature resistant polymer foam material and its preparation method.

[0005] The present invention discloses a high-temperature resistant polymer foam material, wherein the matrix resin of the foam material comprises polyaryletherketone resin, BMI resin, and curing agent, and is composed of them in a certain proportion.

[0006] Furthermore, the polyaryletherketone resin mentioned refers to phenolphthalein-based polyaryletherketone with an intrinsic viscosity of 0.5–0.8 dl / g.

[0007] Furthermore, the BMI resin powder is one of the BMI resins with the following structural formula:

[0008]

[0009] This invention involves compounding BMI resin (bismaleimide resin) with polyaryletherketone resin, followed by heat treatment after foaming to cure the BMI resin and form a cross-linked structure, thereby creating a semi-interpenetrating network. This significantly improves the mechanical properties and heat resistance of the material compared to thermoplastic polyaryletherketone foam.

[0010] Furthermore, the curing agent is one of diallyl bisphenol A, 4,4-diaminodiphenyl sulfone, and 4,4-diaminodiphenylmethane.

[0011] Furthermore, the mass ratio of BMI resin to PEK-C is 3:100 to 20:100.

[0012] Furthermore, the molar ratio of the curing agent to the BMI resin is 0.8 to 1.1.

[0013] A method for preparing a high-temperature resistant polymer foam material, the specific preparation steps are as follows:

[0014] First, the polyaryletherketone resin, BMI powder, and curing agent are mixed evenly in a high-speed mixer. The resulting mixture powder is then pressed into a pre-foamed board by cold pressing. The pre-foamed board is then placed in a foaming machine for supercritical carbon dioxide foaming. Finally, the resulting foam is heat-treated to complete the curing process.

[0015] Furthermore, the cold pressing molding refers to molding at room temperature with a molding pressure of 40–100 MPa. The cold pressing foaming method used in this invention has the characteristics of short heat preservation time and high foaming efficiency, which can effectively control the curing degree of BMI resin during the foaming process and avoid excessive cross-linking of BMI resin, thereby enabling the composite material to have good foaming properties.

[0016] Furthermore, the supercritical carbon dioxide foaming temperature is 200–250°C, the pressure is 8–15 MPa, and the time is 10–30 min.

[0017] Furthermore, the heat treatment temperature is 230–250°C, and the time is 30–90 minutes.

[0018] By means of the above-described solution, the present invention has at least the following advantages:

[0019] This invention combines BMI resin (bismaleimide resin) with polyaryletherketone resin, followed by heat treatment after foaming to cure the BMI resin and form a cross-linked structure, thereby creating a semi-interpenetrating network. Compared to thermoplastic polyaryletherketone foam, this significantly improves the mechanical properties and heat resistance of the material. In addition, the cold-press foaming method used in this invention features short heat preservation time and high foaming efficiency, which can effectively control the degree of curing of BMI resin during the foaming process and avoid excessive cross-linking of BMI resin, thus giving the composite material excellent foaming performance.

[0020] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show a certain embodiment of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The image shown is a SEM image of the foam material obtained in Example 1. Detailed Implementation

[0023] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0024] (1) Mix polyaryletherketone resin powder with a fineness of 200-400 mesh and an intrinsic viscosity of 0.5-0.8 dl / g, BMI resin powder with a fineness of 200-400 mesh, and curing agent in a high-speed mixer to obtain a mixture powder.

[0025] The polyaryletherketone resin powder is phenolphthalein polyaryletherketone (PEK-C);

[0026] The BMI resin powder is one of the BMI resins with the following structural formula:

[0027]

[0028] The curing agent is one of diallylbisphenol A, 4,4-diaminodiphenyl sulfone, and 4,4-diaminodiphenylmethane;

[0029] The mass ratio of BMI resin powder to polyaryletherketone resin powder is 3% to 20%.

[0030] The molar ratio of the curing agent to the BMI resin powder is 0.8 to 1.1.

[0031] (2) The obtained mixture powder is pressed into a pre-foamed board by cold pressing. The molding pressure is 40-100 MPa. Then the pre-foamed board is placed in a foaming machine for supercritical carbon dioxide foaming. The foaming temperature is 200-250℃, the foaming pressure is 8-15 MPa, the holding time is 10-30 min, and the pressure is quickly released to obtain the foam material. Finally, the obtained foam is heat-treated in an oven at 230-250℃ for 30-90 min to complete the curing and obtain the high-temperature resistant polymer foam material.

[0032] Example 1

[0033] 100g of PEK-C powder (250 mesh) with an intrinsic viscosity of 0.68 dl / g, 15g of BMI powder (300 mesh) with the structure of formula (I), and 10g of 4,4-diaminodiphenyl sulfone were mixed evenly in a high-speed mixer. The resulting powder mixture was then pressed into a pre-foamed board by cold pressing at a molding pressure of 60 MPa. The pre-foamed board was then placed in a foaming machine for supercritical carbon dioxide foaming at a foaming temperature of 220℃, a foaming pressure of 10 MPa, and a holding time of 20 min. The pressure was then rapidly released to obtain the foam material. Finally, the obtained foam was heat-treated in an oven at 230℃ for 2 h to complete the curing process. The resulting foam density was 95 kg / cm³. 3 It has a compressive strength of 2.3 MPa and a heat distortion temperature of 199℃.

[0034] Example 2

[0035] 100g of PEK-C powder (250 mesh) with an intrinsic viscosity of 0.68 dl / g, 13g of BMI powder (300 mesh) with the structure of formula (II), and 9.1g of 4,4-diaminodiphenylmethane were mixed evenly in a high-speed mixer. The resulting powder mixture was then pressed into a pre-foamed board by cold pressing at a molding pressure of 70 MPa. The pre-foamed board was then placed in a foaming machine for supercritical carbon dioxide foaming at a foaming temperature of 240℃, a foaming pressure of 10 MPa, and a holding time of 20 min. The pressure was then rapidly released to obtain the foam material. Finally, the obtained foam was heat-treated in an oven at 230℃ for 2 h to complete the curing process. The resulting foam had a density of 83 kg / cm3, a compressive strength of 1.5 MPa, and a heat distortion temperature of 194℃.

[0036] Example 3

[0037] 100g of PEK-C powder (250 mesh) with an intrinsic viscosity of 0.68 dl / g, 20g of BMI powder (300 mesh) with structure (III), and 12g of allyl bisphenol A were mixed evenly in a high-speed mixer. The resulting mixture was then pressed into a pre-foamed board by cold pressing at a molding pressure of 70 MPa. The pre-foamed board was then placed in a foaming machine for supercritical carbon dioxide foaming at a foaming temperature of 220℃, a foaming pressure of 10 MPa, and a holding time of 20 min. The pressure was then rapidly released to obtain the foam material. Finally, the obtained foam was heat-treated in an oven at 230℃ for 2 h to complete the curing process. The resulting foam density was 150 kg / cm³. 3 It has a compressive strength of 2.9 MPa and a heat distortion temperature of 206℃.

[0038] Comparative Example

[0039] Comparative Example 1

[0040] 100g of PEK-C powder (250 mesh) with an intrinsic viscosity of 0.68 dl / g, 15g of BMI powder (300 mesh) with the structure of formula (I), and 10g of 4,4-diaminodiphenyl sulfone were mixed evenly in a high-speed mixer, and then hot-pressed at a molding temperature of 310℃, a pressure of 6MPa, and a time of 30min to obtain a pre-foamed board. The pre-foamed board was then placed in a foaming machine for supercritical carbon dioxide foaming, with the foaming temperature adjusted to 220-270℃, the foaming pressure to 10MPa, and the holding time to 60min. The pressure was then rapidly released to obtain a foam material with a density greater than 500kg / m³. 3 Low-density foam cannot be obtained.

[0041] Because Comparative Example 1 did not use cold-press foaming but instead used traditional hot-press supercritical carbon dioxide foaming, the BMI resin was prematurely over-crosslinked, resulting in a higher foam density and a significant decrease in foaming performance. This confirms that the cold-press foaming method used in this invention has the characteristics of short heat preservation time and high foaming efficiency, which can effectively control the curing degree of BMI resin during the foaming process and avoid excessive crosslinking of BMI resin, thereby enabling the composite material to have good foaming performance.

[0042] Comparative Example 2

[0043] Pre-foamed boards were cold-pressed using pure PEK-C resin (intrinsic viscosity 0.68 dl / g) at a molding pressure of 60 MPa. The pre-foamed boards were then placed in a foaming machine for supercritical carbon dioxide foaming at a foaming temperature of 220℃, a foaming pressure of 10 MPa, and a holding time of 20 min. The pressure was then rapidly released to obtain the foam material. Finally, the obtained foam was heat-treated in an oven at 230℃ for 2 h to complete curing, resulting in a foam density of 85 kg / m³. 3 At that time, the compressive strength of the foam was 1.1 MPa, and the density was 98 kg / m³. 3 At that time, the compressive strength of the foam was 1.5 MPa and the heat distortion temperature was 183℃.

[0044] Since Comparative Example 2 did not use BMI resin to modify PEK-C resin and directly carried out foaming, the mechanical properties and heat resistance of the final foamed material were significantly reduced. This proves that the present invention, by compounding BMI resin with polyaryletherketone resin and performing heat treatment after foaming, allows the BMI resin to complete curing and form a cross-linked structure, thereby forming a semi-interpenetrating network. In this way, compared with thermoplastic polyaryletherketone foam, the mechanical properties and heat resistance of the material can be significantly improved.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a high-temperature resistant polymer foam material, characterized in that: The foam material matrix resin includes polyaryletherketone resin, BMI resin, and curing agent, and is composed of them in a certain proportion; The polyaryletherketone resin mentioned refers to phenolphthalein-based polyaryletherketone, with an intrinsic viscosity of 0.5–0.8 dl / g; The BMI resin powder is one of the BMI resins with the following structural formula: The mass ratio of BMI resin to phenolphthalein polyaryletherketone is 3:100 to 20:100; The molar ratio of the curing agent to BMI resin is 0.8 to 1.1; The preparation steps of the high-temperature resistant polymer foam material are as follows: First, the polyaryletherketone resin, BMI powder, and curing agent are mixed evenly in a high-speed mixer. The resulting mixture powder is then pressed into a pre-foamed board by cold pressing. The pre-foamed board is then placed in a foaming machine for supercritical carbon dioxide foaming. Finally, the resulting foam is heat-treated to complete the curing process. The cold pressing refers to molding at room temperature with a molding pressure of 40-100 MPa. The supercritical carbon dioxide foaming temperature is 200–250℃, the pressure is 8–15 MPa, and the time is 10–30 min; The heat treatment temperature is 230–250°C, and the time is 30–90 min.

2. The method for preparing a high-temperature resistant polymer foam material according to claim 1, characterized in that: The curing agent is one of diallyl bisphenol A, 4,4-diaminodiphenyl sulfone, and 4,4-diaminodiphenylmethane.

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