Properties of Polymethacrylimide Foams with Different Monomer Ratios

Document Type

Article

Publication Date

1-1-2020

Abstract

The polymethacrylimide(PMI) foams with different monomer ratios were prepared from acrylonitrile (AN) and methacrylic acid (MAA) by ultraphonic combined with thermal initiation radical bulk copolymerization and then free heat foaming. The chemical structure, thermal properties, combustion properties, morphologies and mechanical properties of the PMI foams were investigated in details by Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), vertical burning tests, limit oxygen index (LOI), scanning electron microscopy (SEM) and universal testing machine. The FT-IR results show that the cyano groups and the carboxyl groups formed the cyclic imide by rearranging reaction at high temperature. The results of TGA demonstrate the residues of PMI foams are beyond 11% at 600℃ in nitrogen atmosphere, which indicate that the prepared PMI foams possess excellent char forming capability. The results of DMA reveal that the glass transition temperature (Tg) of the PMI foams exceed 155℃. The LOI values of PMI foams are gradually increased with the increase of AN content. The SEM tests indicate that the prepared PMI foams are consisted of honeycomb structure with the diameter of 0.1~0.3 mm. Meanwhile, the obtained PMI foams present superior mechanical properties, for example, the tensile, flexural and compressive strength of the PMI foam with the density of 50.1 kg/m3 are 1.85 MP, 2.71 MP and 3.74 MPa, respectively.

Publication Source (Journal or Book title)

Gaofenzi Cailiao Kexue Yu Gongcheng/Polymeric Materials Science and Engineering

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