High performance polydimethylsiloxane pervaporative membranes with hyperbranched polysiloxane as a crosslinker for separation of n-butanol from waterElectronic supplementary information (ESI) available: PV experiments method, SEM, contact angle and GPC values. See DOI: 10.1039/c5ra06886j

• Main Authors: Bai, Yunxiang, Dong, Liangliang, Lin, Jiaqiang, Zhu, Yuanhua, Zhang, Chunfang, Gu, Jin, Sun, Yuping, Xu, Youyi
• Format: Article
• Language: English
• ISSN: 2046-2069
• DOI: 10.1039/c5ra06886j

Hyperbranched polysiloxane (HPSiO) was successfully synthesized by a three-step process. The result of 29 Si Nuclear Magnetic Resonance (NMR) measurement indicates that the degree of branching (DB) of HPSiO is 0.73. Then, novel polysiloxane membranes, HPSiO- c -PDMS, were prepared by the cross-linking reaction between HPSiO and α,ω-dihydroxypolydimethylsiloxane (H-PDMS) with different molecular weights. HPSiO- c -PDMS membranes were first used as membrane materials for recovering n -butanol from an aqueous solution by pervaporation (PV). The HPSiO- c -PDMS membranes demonstrated high n -butanol/water selectivity as well as high permeability. As the molecular weight of H-PDMS increased, the selectivity increased and the n -butanol permeability of HPSiO- c -PDMS-2 (with moderate H-PDMS molecular weight) membrane showed the highest value. The effects of temperature and feed concentration on the PV performances were also investigated. The PV performance, n -butanol permeability and n -butanol/water selectivity of the HPSiO- c -PDMS-2 membrane, reached 4.3 × 10 5 Barrer and 8.75, respectively, with a feed concentration of 1.0 wt% at 30 °C. Novel hyperbranched polysiloxane crosslinkers, HPSiO, were synthesized to prepare high performance polydimethylsiloxane pervaporation membranes HPSiO- c -PDMS membranes for recovering n -butanol from aqueous solution by pervaporation.