Preparation and characterization of polymethacrylimide/silicate foam

Abstract

The polymethacrylimide/silicate (PMI/silicate) composites were successfully prepared from the monomers of acrylonitrile (AN) and methacrylic acid (MAA) via the monomer in situ intercalation polymerization and free foaming. The formation of imide groups was monitored by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results of FTIR and XPS indicated that the imide groups were gradually formed and cyano groups were dwindling but still existed during foaming and thermal treatment. The thermogravimetric analysis results revealed that the thermal stability of the PMI/silicate composites was improved, the rate of thermal degradation was reduced, and the residue was increased because of the addition of silicates. The results of dynamic mechanical analysis revealed that the rigidity and the glass transition temperature of the composites were improved.The limit oxygen index (LOI) and cone calorimeter (CONE) test showed that the fire-retardant properties were improved because of the barrier effect of silicates.The cell morphologies of the PMI/silicate composites were characterized by scanning electron microscopy (SEM), and the results showed that the silicate particles were distributed on the cell walls, but the cells slightly cracked. The mechanical properties were measured by tensile, flexural, and compressive strength. The mechanical strength, especially flexural strength, was significantly improved. The flexural strength of PMI/MMT, PMI/kaolin, and PMI/talc containing 8 wt% silicates was improved to 172%, 240%, and 233%.

Synthesis and Nitrite/Sulfite Electrochemical Response Investigation of Fluorene‐Based, Cross‐Linked Polyisocyanide

“…The signals at 284.7, 285.5, and 291.0 eV in the high‐resolution C1s XPS spectrum of PBIF (Figure 3b) correspond to the segments of C─C/C═C, C═N/C─N, and C≡N/C═O, respectively. [ 28 ] The signals at 399.4 and 400.7 eV in the high‐resolution N1s curve (Figure 3c) could be assigned to the signals of N═C and N≡C, [ 50 ] respectively. On the other hand, the appearance of O1s signal (at ≈533.3) might be attributed to the slight hydrolysis of imine groups in PBIF during the preparation and preservation to afford ketone‐containing segments.…”

Achievements and prospects for the synthesis of poly(meth)acrylimide foams. Stage of the thermal imidisation of polymer precursors

“…Numerous studies have been published on the optimisation of the physico-mechanical properties of PMI foams containing simultaneously acrylic and methacrylic units. 22,23,98,99,109,110 Based on such PMIs, materials with reduced combustibility, 111 -114 promising composite materials such as silicate-containing composites, 115,116 composites with carbon nanotubes 117 have been developed. The development of sandwich materials and various products based on PMI of this type has been started (including those for use in aviation and astronautics).…”

Production and properties of composites based on polymethacrylimides and carbon nanotubes

“…Одновременно происходит разложение вспенивающих агентов, в результате формируются сшитые мелкоячеистые полимерные структуры закрытого типа с требуемой плотностью и характеристиками. Известно, что для улучшения механической прочности и снижения горючести целевых продуктов в исходные мономерные смеси вводят нерастворимые добавки, входящие затем в состав композитного ПМИ -сульфид цинка [11], пористый графит [12], графен [13], наноразмерный оксид кремния или карбонат кальция [14], полые стеклянные шарики [15], различные силикаты -каолин, тальк, наноразмерный диоксид кремния [16]. Силикатсодержащие композиции на основе ПМИ с повышенной звукоизоляцией получены в работе [17].…”