Study on cellular structure of acrylonitrile/methacylic acid copolymer foam plastic

Acrylonitrile (AN)/methacylic acid (MAA) copolymer foam plastic was prepared by free foaming. The change trend of average cellular diameter with the apparent density was discussed. The influence of nucleate agent and stress whitening on average cellular diameter was studied. The macroscopic and microscopic foam structure were observed by optical microscope and scanning electronic microscope. The results indicate that the average cellular diameter of AN/MAA copolymer foam plastic decreases with the increase of the density. Carbamide can be used as nucleate agent and minish the cellular dimension evidently. Stress whitening of foamable copolymer can increase the nucleation process during foaming and decrease the cellular diameter greatly. AN/MAA copolymer foam plastic has high obturator foramen ratio and isotropic. The side number of cell wall is between three and seven, and three cell walls intersected as cell arris. The volume occupied ratio of cell walls decreases with the increase of the density.