There is described a new disordered nanoporous crystalline form of syndiotactic polystyrene, characterized by a specific X-ray diffractrogram, the process for its preparation and various articles comprising this form of s-PS. This disordered nanoporous crystalline form exhibits empty crystalline cavities of nanometric sizes, and in this case performs the function of absorbing molecules with low molecular mass and is useful in particular as functionally active packaging for plant products.