可发性聚甲基丙烯酰亚胺前驱体珠粒的制备及发泡性能

Using acrylonitrile (AN) and methacrylic acid (MAA) as co monomer, azodiisobutyronitrile (AIBN) as initiator, and tert- butyl methacrylate methacrylate (tBMA) containing double bonds as thermal decomposition foaming agent, the precursor beads of foamable polymethylacrylimide (PMI) were prepared by aqueous suspension polymerization. The effects of dispersant type and dosage, stirring rate, oil- water ratio, monomer ratio, aqueous polymerization inhibitor and other factors on the particle size and distribution of beads in aqueous suspension polymerization were discussed, and the structure and properties of beads before and after foaming were analyzed by Fourier infrared spectroscopy (FT- IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric test (TGA) and universal testing machine. The results show that when the mole ratio of AN/MAA in oil phase is 0.3/0.2, the copolymerizable foaming agent is 7%, the organic dispersant in water phase is 1.4% of the monomer mass, and appropriate NaCl, aqueous phase polymerization inhibitor and inorganic dispersant are added, the oil- water ratio is 1/5, the reaction temperature is 60 ℃, and the stirring rate is 250~275 r/min, the foamable PMI precursor spherical beads with an average particle size of 1~2 mm, narrow distribution and about 80% yield can be prepared. The foamable beads containing 7% foaming agent were foamed into PMI foam with a density of 150 kg/m³ in mold at 230 ℃ . The 10% compressive strength is 2.15 MPa, and the initial temperature of thermal decomposition is 368.2 ℃.