▎ 摘　　要

NOVELTY - Ultra-hick high temperature-resistant light broadband frequency-absorbing polymethacrylimide (PMI) foam, comprises 50-120 pts. wt. methacrylic acid, 40-100 pts. wt. methyl acrylonitrile or acrylonitrile, 0.1-1 pts. wt. initiator, 2-10 pts. wt. foaming agent, 0.5-5 pts. wt. crosslinking agent, 0.1-2 pts. wt. heat-resistant additive, 0.1-1.5 pts. wt. antioxidant, 1-20 pts. wt. thickening agent, 5-30 pts. wt. wave-absorbing agent and other auxiliary agent. USE - Used as ultra-hick high temperature-resistant light broadband frequency-absorbing PMI foam. ADVANTAGE - The polymethacrylimide foam improve the mechanical property and heat resistance, and avoids the thick mold heat dissipation is slow and explosion. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a preparation method of ultra-thick high temperature-resistant light-frequency-absorbing PMI foam comprising (i) uniformly mixing methacrylic acid, methyl acrylonitrile (or acrylonitrile) and thickening agent to obtain a thickened monomer solution; firstly adding heavy metal micro-powder absorbing agent into the thickened monomer solution, after mixing uniformly, adding other wave absorbing agent with light specific gravity to obtain thickened wave absorbing monomer solution; uniformly mixing a certain amount of reaction monomer and initiator, foaming agent, crosslinking agent, heat-resistant additive and antioxidant to obtain transparent reaction solution; adding a certain amount of the transparent reaction solution into the dense wave absorbing monomer solution, stirring and mixing uniformly to obtain a reaction liquid to be aggregate; and injecting the reaction liquid into a stainless steel square reaction device for spraying fluorine, (ii) pressing the elastic sealing strip into the edge groove of stainless steel square mold of the fluorine spraying, fixing the clean glass with both sides by a clamp, pouring the reaction liquid into the mold from the screw hole above the mold, and sealing the screw hole by the screw wrapped with the raw material belt to obtain a reaction device, (iii) placing the reaction device into the water area for aggregate to obtain a non-foaming pre-polymer, the temperature of the water aggregate is 16-50°C, and the aggregate reaction time is 336-720 hours, aggregate reaction with a mold thickness is less than 50 mm, and heating at 30-40°C for 300-600 hours, and 40-50°C for 80-120 hours, the thickness of the mold is greater than 50 mm of aggregate reaction at constant temperature and cooling and constant temperature heat preservation and final step heating control and the constant temperature is 30-35°C for 48-96 hours, cooling at 30-35°C for every 10-12 hours, reducing at 2-3°C to 16-18°C, and keeping the temperature for 100-30 hours, raising the temperature from 16-18°C for every 10-12 hours to 45-50°C, (iv) placing the obtained non-foaming pre-polymer into an oven for high temperature pre-treatment at 60-120°C for 40-72 hours, and (v) placing the high temperature processed pre-polymer into an oven for foaming at 120-230°C for 724 hours to obtain a foam, and the foam is 130-210°C for 12-48 hours of secondary tempering post-treatment to obtain a new-resistant ultra-thick high temperature resistant light broadband frequency-absorbing PMI foam . DESCRIPTION OF DRAWING(S) - The drawing shows a flow chart of ultra-hick high temperature-resistant light broadband frequency-absorbing PMI foam (Drawing includes non-English language text).