Polymers of styrene, in primary forms

390311 Styrene polymers; expansible polystyrene, in primary forms 390319 Styrene polymers; (other than expansible polystyrene), in primary forms 390320 Styrene polymers; styrene-acrylonitrile (SAN) copolymers, in primary forms 390330 Styrene polymers; acrylonitrile-butadiene-styrene (ABS) copolymers, in primary forms 390390 Styrene polymers; in primary forms, n.e.c. in heading no. 3903