Preparation method and product of a density-adjustable flexible polyimide foam

Abstract

The invention discloses a preparation method and product of a density-adjustable flexible polyimide foam. The preparation method includes the following steps: (1) firstly prepare an anhydride group-terminated polyimide precursor solution I; then slowly add polyisocyanate Reaction is complete, cooled to room temperature to obtain polyimide precursor solution II; (2) first remove most of the polar solvent in polyimide precursor solution II, and then solidify in a vacuum oven under vacuum conditions to obtain Partially imidized polyimide precursor foam; finally, the foam in the rotary steamer is taken out, and after being pulverized and ground by a planetary ball mill, a fine and uniform partially imidized polyimide precursor is obtained (3) After pressing the polyimide precursor powder into a foaming master, place it in microwave equipment; set the microwave equipment parameters to complete the foaming molding process; then, adjust the microwave equipment parameters to complete the curing get the product. The invention realizes the effective control of the density and strength of the flexible polyimide foam.

Description

technical field [0001] The invention relates to the technical field of polyimide foam preparation, in particular to a preparation method and product of density-adjustable flexible polyimide foam. Background technique [0002] Polyimide foam material is an organic polymer foam material containing imide structure in the molecular main chain. Polyimide foam has excellent thermal stability, flame retardancy, heat preservation and chemical corrosion resistance. It is an ideal thermal insulation, sound absorption and shockproof material in advanced fields such as aerospace and marine ships. material application field. However, different laying locations have certain requirements for the density and strength of the thermal insulation material, and the special sound absorption frequency band and thermal insulation performance of polyimide foams with different densities are quite different. Therefore, how to prepare polyimide foam materials with different densities and strengths, r...

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Problems solved by technology

Although the above methods can improve the density and mechanical strength of the polyimide foam material, these methods all increase processing steps or adopt special equipment and control molds on the basis of the original polyimide foam preparation technology, which will increase The complexity of the preparation process increases the preparation cycle, which is not conducive to the development of polyimide foam. At the same time, a set of process system may only produce foam materials with one density, which is not conducive to the diversification of polyimide foam with a wide density range. preparation of

[0004] At the same time, in the past polyimide foam preparation process, the curing temperature for the transformation of the precursor to polyimide is generally above 200 ° C, which consumes a lot of energy; and the foam molding process and the imidization process need to be separated It is carried out in different microwave and high-temperature oven equipment, which increases the demand for equipment and increases the entire process flow line; the further problem is that the foam intermediate after foaming is taken out from the microwave equipment and transferred to the oven. During the process, it will be exposed to the lower room temperature outside, and the change of temperature difference often easily causes internal cracking, and the brittle foam intermediate is prone to collapse and other problems during the transfer process, resulting in a large number of unqualified products.

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