Nanoporous–Crystalline Poly(2,6-dimethyl-1,4-phenylene)oxide Aerogels with Selectively Sulfonated Amorphous Phase for Fast VOC Sorption from Water

Abstract

This paper describes the preparation and characterization of poly(2,6-dimethyl-1,4-phenylene)oxide (PPO) highly porous monolithic aerogels with a hydrophobic nanoporous–crystalline phase and a hydrophilic sulfonated amorphous phase. The sulfonated aerogels were obtained by the sulfonation of PPO physical gels, followed by the supercritical CO2 extraction of solvents. WAXD and FTIR analysis showed that the nanoporous–crystalline phase was preserved for a degree of sulfonation up to c.a. 35%, allowing a highly volatile organic compound (VOC) sorption capacity. The sulfonated PPO aerogels exhibited a high water sorption capacity, with a water uptake of up to 500 wt%, and faster VOC sorption kinetics from water with respect to unsulfonated aerogels.

Poly(phenylene oxide) Films with Hydrophilic Sulfonated Amorphous Phase and Physically Cross-Linking Hydrophobic Crystalline Phase

“…Sulfonation of polymers in solution leads to randomly sulfonated chains, which maintain their possible ability to crystallize only for low degrees of sulfonation. − To achieve hydrophilic sulfonated polymer chains, which are physically cross-linked by hydrophobic crystalline domains, sulfonation procedures on semicrystalline polymer samples can be used, as already known for sPS films, sPS gels as well as for sPS and PPO aerogels.…”

“…The sulfonating reagent was prepared by mixing dodecanoic acid and ClSO 3 H with a molar ratio of 1.6, at room temperature for 24 h. The obtained solution was diluted in cyclohexane (3–20 vol %) and directly used for sulfonation of PPO films (Scheme ). A similar sulfonation reaction was used for NC aerogels of PPO and of sPS, as well as for NC films of sPS …”

“…The aim of this study is to prepare PPO films exhibiting hydrophilic sulfonated amorphous phase with the maintenance of an unsulfonated hydrophobic crystalline α phase. The presence of the α phase assures, besides typical functionalities of the NC phase, higher thermal and hydrolytic film stability as well as physical cross-linking between the polymer chains. , In this paper, we also study the dependence of sulfonation kinetics on the kind of planar orientation of the NC phase.…”

“…The presence of the α phase assures, besides typical functionalities of the NC phase, higher thermal and hydrolytic film stability as well as physical cross-linking between the polymer chains. 50,51 In this paper, we also study the dependence of sulfonation kinetics on the kind of planar orientation of the NC phase.…”

“…The sulfonating reagent was prepared by mixing dodecanoic acid and ClSO 3 H with a molar ratio of 1.6, at room temperature for 24 h. The obtained solution was diluted in cyclohexane (3−20 vol %) and directly used for sulfonation of PPO films (Scheme 1). A similar sulfonation reaction was used for NC aerogels of PPO 51 and of sPS, 52 as well as for NC films of sPS. 53 Before sulfonation, PPO films were pretreated in pure cyclohexane at room temperature for 24 h. The cyclohexane uptake of the PPO films was in the 12−20 wt % range.…”