In fact, polystyrene functionalized into polystyrene sulfonate is a solid strongly acidic plastic that is filterable.
ɪn fˈækt, pˌɑːlɪstˈaɪɹɛn fˈʌŋkʃənəlˌaɪzd ˌɪntʊ pˌɑːlɪstˈaɪɹɛn sˈʌlfənˌeɪt ɪz ɐ sˈɑːlɪd stɹˈɔŋli ɐsˈɪdɪk plˈæstɪk ðæt ɪz fˈɪltɚɹəbəl.