Polyimide foam and preparation method thereof

Abstract

The invention relates to polyimide foam and a preparation method thereof. The raw materials of the polyimide foam include aromatic dianhydride or aromatic tetracid, isocyanate, polar solvent, composite catalyst, surfactant, foaming agent and other assistants. The preparation method comprises: reacting the aromatic dianhydride or aromatic tetracid with the isocyanate to obtain solution of polyimide foam precursor; adding the foaming agent into the solution of the foam precursor to perform a reaction to obtain a foam intermediate by free foaming; and solidifying and setting the foam intermediate by heat treatment. The method is characterized in that: the polyimide foam prepared by the method has uniform cells, hard texture, low density, a glass-transition temperature of 260 to 305 DEG C, a Shore hardness of 40 to 88 HC and a compression strength of 400 to 700kPa; the preparation process is simple; the cost is low; the foaming process is nontoxic and environmentally-friendly; an innovation is made in high-temperature, light, pressure-resistance, sound-absorbing, noise-reducing and heat-insulating polymer foam materials; and an important support is provided for high-temperature advanced composite material technology.

Description

technical field [0001] The invention relates to a polyimide foam plastic and a preparation method thereof. Background technique [0002] Existing polyimide foam materials can be used for a long time at 250°C to 300°C, and can be used at 400°C to 500°C for a short time. It is one of the materials with the best thermal stability among polymer foams. Polyimide foam also has good heat insulation and sound absorption properties, good dielectric properties, good flexibility and elasticity, and good radiation resistance. Therefore, polyimide foam materials are widely used as engineering materials in the fields of aerospace, tactical weapons, electronics, communications and ships. [0003] The research on polyimide foam material began in the 1860s, and DuPont of the United States applied for a patent US3249561 in 1966. This patent discloses a method of first preparing a polyamic acid solution, and then adding a dehydrating agent or a dehydrating agent / tertiary amine mixture. Then ...

AI Technical Summary

Problems solved by technology

[0009] It can be seen from Table 1 that the compressive strength of rigid polyvinyl chloride (PVC) foam, rigid polyurethane (PU) foam and polystyrene (PS) foam is relatively high, but the glass transition temperature is less than 130 °C, and the long-term use temperature is low. At ≤120°C, it cannot be used as a high-temperature sound-absorbing or noise-reducing material, and it is difficult to use as a support for carbon fiber reinforced epoxy resin composite materials, and it is even less likely to be used as a support for high-temperature advanced resin-based composite materials; The long-term service temperature of amine (PMI) foam is as high as 180 °C, and the compressive strength and service temperature are increased. Although it basically meets the requirements of carbon fiber reinforced epoxy resin composite support, it has low thermal deformation or creep resistance during molding, and Its foam closed cell rate is almost 100%, and its sound absorption performance is poor

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