Non-fluorinated polymeric substances as follows: (a) Imides as follows: 1. Bismaleimides; 2. Aromatic polyamide-imides (PAI) having a ‘glass transition temperature (Tg)’ exceeding 290 °C; 3. Aromatic polyimides having a ‘glass transition temperature (Tg)’ exceeding 232 °C; 4. Aromatic polyetherimides having a ‘glass transition temperature (Tg)’ exceeding 290°C; (b) Polyarylene ketones; (c) Polyarylene sulphides, where the arylene group is biphenylene, triphenylene or combinations thereof; (d) Polybiphenylenethersulphone having a ‘glass transition temperature (Tg)’ exceeding 290°C. Note : Applies to the substances in liquid or solid ‘fusible’ form, including resin, powder, pellet, film, sheet, tape, or ribbon.