TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The composition comprises: either 27 wt.% of PVC, 10 wt.% of polyacrylonitrile, 40 wt.% of poly(methyl acrylate), 8 wt.% of poly(amide-imide) and 15 wt.% of poly(butyl acrylate); or 10 wt.% of PVC, 20 wt.% of polyacrylonitrile, 40 wt.% of poly(methyl acrylate), 10 wt.% of poly(amide-imide) and 20 wt.% of poly(butyl acrylate); or 35 wt.% of PVC, 7 wt.% of polyacrylonitrile, 50 wt.% of poly(methyl acrylate), 7 wt.% of poly(amide-imide) and 10 wt.% of poly(butyl acrylate); or 25 wt.% of PVC, 8 wt.% of polyacrylonitrile, 50 wt.% of poly(methyl acrylate), 7 wt.% of poly(amide-imide) and 10 wt.% of poly(butyl acrylate). The composition further comprises 15-35 wt.% of polystyrene and 20-40 wt.% of polybutadiene. The composition comprises: either 10 wt.% of PVC, 7 wt.% of polyacrylonitrile, 11 wt.% of poly(methyl acrylate), 13 wt.% of poly(amide-imide), 9 wt.% of poly(butyl acrylate), 24 wt.% of polystyrene and 26 wt.% of polybutadiene; or 10 wt.% of PVC, 5 wt.% of polyacrylonitrile, 10 wt.% of poly(methyl acrylate), 10 wt.% of poly(amide-imide), 10 wt.% of poly(butyl acrylate), 25 wt.% of polystyrene and 30 wt.% of polybutadiene; or 5 wt.% of PVC, 2 wt.% of polyacrylonitrile, 15 wt.% of poly(methyl acrylate), 6 wt.% of poly(amide-imide), 14 wt.% of poly(butyl acrylate), 22 wt.% of polystyrene and 26 wt.% of polybutadiene; or 15 wt.% of PVC, 2 wt.% of polyacrylonitrile, 15 wt.% of poly(methyl acrylate), 5 wt.% of poly(amide-imide), 15 wt.% of poly(butyl acrylate), 20 wt.% of polystyrene and 28 wt.% of polybutadiene; or 8 wt.% of PVC, 2 wt.% of polyacrylonitrile, 15 wt.% of poly(methyl acrylate), 8 wt.% of poly(amide-imide), 15 wt.% of poly(butyl acrylate), 22 wt.% of polystyrene and 30 wt.% of polybutadiene; or 9 wt.% of PVC, 3 wt.% of polyacrylonitrile, 7 wt.% of poly(methyl acrylate), 8 wt.% of poly(amide-imide), 9 wt.% of poly(butyl acrylate), 27 wt.% of polystyrene and 37 wt.% of polybutadiene; or 8 wt.% of PVC, 2 wt.% of polyacrylonitrile, 15 wt.% of poly(methyl acrylate), 5 wt.% of poly(amide-imide), 15 wt.% of poly(butyl acrylate), 20 wt.% of polystyrene and 35 wt.% of polybutadiene; or 8 wt.% of PVC, 2 wt.% of polyacrylonitrile, 10 wt.% of poly(methyl acrylate), 3 wt.% of poly(amide-imide), 10 wt.% of poly(butyl acrylate), 30 wt.% of polystyrene and 37 wt.% of polybutadiene; or 5 wt.% of PVC, 8 wt.% of polyacrylonitrile, 5 wt.% of poly(methyl acrylate), 15 wt.% of poly(amide-imide), 5 wt.% of poly(butyl acrylate), 30 wt.% of polystyrene and 32 wt.% of polybutadiene. The composition comprises: either 7 wt.% of polyacrylonitrile, 13 wt.% of poly(methyl acrylate), 8 wt.% of poly(amide-imide), 18 wt.% of poly(butyl acrylate), 32 wt.% of polystyrene and 22 wt.% of polybutadiene; or 4 wt.% of polyacrylonitrile, 10 wt.% of poly(methyl acrylate), 5 wt.% of poly(amide-imide), 20 wt.% of poly(butyl acrylate), 36 wt.% of polystyrene and 25 wt.% of polybutadiene; or 3 wt.% of polyacrylonitrile, 4 wt.% of poly(methyl acrylate), 3 wt.% of poly(amide-imide), 8 wt.% of poly(butyl acrylate), 55 wt.% of polystyrene and 27 wt.% of polybutadiene; or 1 wt.% of polyacrylonitrile, 6 wt.% of poly(methyl acrylate), 3 wt.% of poly(amide-imide), 12 wt.% of poly(butyl acrylate), 47 wt.% of polystyrene and 31 wt.% of polybutadiene. EXAMPLE - Typical contact medium comprised of: 90% of poly(amide-imide); and 10% of polystyrene.