Structure and properties of AN/MAA/AM copolymer foam plastics

In this article, acrylonitrile (AN)/methacrylic acid (MAA)/acrylamide (AM) copolymer foam was prepared. DSC, TG and FTIR were adopted to analyze the chemical reactions in AN/MAA/AM copolymer foam, and confirm its molecule structure. SEM was employed to observe its cell structure, and the calculational method of resin distribution was founded basing on dodecahedron cell structural model. At last, its mechanical properties and thermal resistance were tested. The results indicate that cyclization reactions occur between adjacent AN/MAA units and MAA/AM units. Six-member imide rings, residuary MAA and AN units exist in main chains, and imide groups crosslink the chains. AN/MAA/AM copolymer foam has flat and closed cell walls with a high cell wall volume ratio. Cell wall volume ratios with the density of 32 kg/m³, 54 kg/m³ and 75 kg/m³ are 76%, 57% and 50% respectively. Because of rigid molecule structure and ideal cell structure, AN/MAA/AM copolymer foam possesses excellent mechanical properties and thermal resistance. As the densities are 32 kg/m³, 54 kg/m³ and 75 kg/m³, tensile strength are 1.00 MPa, 1.85 MPa and 2.30 MPa, compressive strength are 0.40 MPa, 1.00 MPa and 1.72 MPa, and shear strength are 0.45 MPa, 0.86 MPa and 1.29 MPa respectively. Heat distortion temperature of the copolymer foam is higher than 180 °C.