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A method for preparing high-density high-performance PMI foam by suspension polymerization

A suspension polymerization and foam technology, applied in the field of high-performance foam preparation, can solve the problems of low material utilization rate, insufficient mechanical properties, long reaction time, etc., and achieve the effects of low equipment cost, shortened reaction time, and easy operation.

Active Publication Date: 2021-05-04
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to overcome the problems of explosive polymerization, long reaction time, low material utilization rate, low density, and insufficient mechanical properties during the polymerization reaction during the preparation of PMI foam by the bulk polymerization process, the present invention provides a high-density anti-compression foam prepared by the suspension polymerization process. The method of PMI foam composite material, introduces suspending agent into the reaction system, removes the density control agent, and finally prepares a density of 0.2 ~ 0.3g / cm 3 , a high-performance PMI foam with a compressive strength of 9MPa

Method used

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  • A method for preparing high-density high-performance PMI foam by suspension polymerization
  • A method for preparing high-density high-performance PMI foam by suspension polymerization

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Monomer: The molar ratio of acrylonitrile (AN) to methacrylic acid (MAA) is 2.5:1, and the total mass fraction is 100 parts.

[0033] Dispersion medium: 100 parts of deionized water, suspending agent Al(OH) 3 The dosage is 0.5 parts.

[0034] Initiator: azobisisobutyronitrile (AIBN), the dosage is 0.1 part.

[0035] Crosslinking agent: acrylamide (AM), the dosage is 0.5 parts.

[0036] Foaming agent: azodicarbonamide (AC), the dosage is 1 part.

[0037] Steps: first dissolve the suspending agent PVA1788 in deionized water to prepare a suspending agent solution, put the solution into the reaction kettle, and turn on the stirring device at the same time. Add two reaction monomers in sequence, start heating, raise the temperature to 65°C, then add an initiator into the reaction kettle, adjust the rotation speed to 150r / min, and the viscosity of the suspension in the reaction system becomes larger after 5 hours of reaction. Adjust the reaction temperature to 70°C, the sti...

Embodiment 2

[0039] Monomer: the molar ratio of acrylonitrile (AN) to acrylic acid (AA) is 2.5:1, and the total mass fraction is 100 parts.

[0040] Dispersion medium: the amount of deionized water is 150 parts, and the amount of suspending agent PAAS is 1.5 parts.

[0041] Initiator: azobisisoheptanonitrile (ABVN), the dosage is 0.5 parts.

[0042] Crosslinking agent: allyl methacrylate (AMA), the dosage is 1 part.

[0043] Foaming agent: azodicarbonamide (AC), the dosage is 5 parts.

[0044] Steps: first mix the suspending agent PAAS and deionized water, stir to obtain a colloid, and put the colloid into the reaction kettle, and the rest of the implementation process is similar to that of Example 1.

Embodiment 3

[0046] Monomer: The molar ratio of methacrylonitrile (MAN) to acrylic acid (AA) is 2:1, and the total mass fraction is 100 parts.

[0047] Dispersion medium: 150 parts of deionized water, suspending agent MgCO 3 The dosage is 3 servings.

[0048] Initiator: dibenzoyl peroxide (BPO), the dosage is 1.5 parts.

[0049] Cross-linking agent: magnesium oxide (MgO), the dosage is 1.5 parts.

[0050] Foaming agent: expanding microsphere foaming agent, consumption is 10 parts.

[0051] Steps: first add deionized water and suspending agent into the reactor, stir for 0.5h and then add the monomer, and the rest of the implementation process is similar to that of Example 1. However, the subsequent foaming process is 160 ° C for 40 minutes, and the heat treatment process is 200 ° C for 2 hours.

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Abstract

The invention discloses a method for preparing high-density and high-performance PMI foam by suspension polymerization. A free radical suspension polymerization process is adopted, and a suspending agent is introduced into the reaction system. The form is dispersed in the medium water, which is easy to discharge the heat of reaction. No density control agent is introduced into the system, but by controlling the amount of prepolymer flakes, a density as high as 0.2g / cm 3 , High performance PMI foam with compressive strength up to 9MPa. The high-density compression-resistant PMI foam prepared by the invention can be applied to the fields of aerospace, weaponry and the like.

Description

technical field [0001] The invention relates to a method for preparing high-performance foam, in particular to a method for preparing high-density and high-performance PMI foam by suspension polymerization. Background technique [0002] Polymethacrylimide (PMI) foam was first successfully developed by the German Rohm company in 1972. After more than 40 years of development, a variety of products have been developed. At present, there are mainly products produced by Evonik Degussa in the market. Produced by Sekisui Chemical Co., Ltd. series foam plastic. PMI foam is a kind of cross-linked rigid structural foam material prepared by low-temperature prepolymerization and high-temperature cyclization process with acrylic monomer and acrylonitrile monomer as the main monomer raw materials. It has a 100% closed-cell structure, and isotropic. Among many foams, PMI foam has the highest specific strength and specific modulus under the same density. PMI foam also has excellent me...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08J9/10C08J9/32C08J3/24C08L33/02C08L33/20C08K3/22C08F220/48C08F220/46C08F220/06C08F220/40C08F220/56C08F2/18
CPCC08F2/18C08F220/06C08F220/46C08F265/02C08F265/08C08J3/24C08J9/10C08J9/32C08J2203/04C08J2203/22C08J2333/02C08J2333/20C08K2003/222C08F220/56C08F220/40
Inventor 周金堂钱逸姚正军徐体寿
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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