Influence of Polystyrene on PDMS IPNs Blend Membrane Performance

Abstract

In this work, a series of pervaporation blend membranes with polydimethylsiloxane (PDMS)/polystyrene (PS) were prepared by using the sequential interpenetrating polymer network (IPNs) technique with various amount of PS (10-70 wt.%). The blend IPN membranes were supported by Teflon (polytetrafluoroethylene) ultrafiltration membrane. Effect of PS contents in PDMS IPNs on crosslinked density, molecular weight, network-chain segment concentration, water swelling properties, and tensile properties were investigated. Results revealed that the degree of crosslink density and tensile strength of the PDMS IPNs blend membrane depending on wt.% of PS added and scan electron microscope image confirmed that the PDMS/PSt IPN membranes have continuous microphase structures. The synthesized IPNs blend membrane was used for ethanol recovery from aqueous solution by pervaporation, and exhibited enhanced separation performance compared with PDMS membranes. The maximum separation factor of IPNs blend membrane were obtained at 50 C, and the total flux increased exponentially along with the increase of temperature. The PDMS/PS membrane synthesized by 50 wt.% PS gave the best pervaporation performance with a selectivity (a) of 7.6, permeation rate of 214 g/m 2 h with a 10 wt.% ethanol (EtOH) concentration at 60 C.

Structuring and characterization of a novel microporous PVDF membrane with semi‐interpenetrating polymer networks for vacuum membrane distillation

“…After the application of crosslinking agent TEOS, from M2 to M5, the pore size distribution of the membranes narrowed, and were 37.2–183 nm, 29.71–156.00 nm, 17.98–124.80 nm and 26.00–124.80 nm, respectively. This is because the crosslinking reaction in the semi‐IPNs system caused a close structure . In addition, with the gradually adding of TEOS, from M1 to M5, the total porosity value increased linearly from 73.65% to79.05%, and the mean pore radius declined as shown in Table , which was in agreement with the analysis of membrane morphology in the Membrane morphologies section.…”

“…The peak at 1,404 cm −1 was assigned to dissymmetry deformation vibration of the two methyls which linked with Si. The characteristic absorption peak at about 1,066 cm −1 was corresponded to the Si–OH stretching , which means that PDMS had been incorporated and presented in PVDF matrix during the process of semi‐IPN synthesis. Furthermore, with the keep adding of TEOS, the absorption peaks of SiOH at about 1,066 cm −1 became weakened for the reason that SiOH had been consumed by the crosslinking reaction, which also means that the crosslinking reaction had been occurred.…”

Easy-Processable and Aging-Free All-Polymer Polysiloxane Composites

“…In addition, the immiscibility between PDMS and PS heavily destabilizes the morphology and precludes strong interfacial adhesion, − limiting the improvement of mechanical properties. The modifications can be also achieved via interpenetrating polymer networks. − Adding block copolymers (BCPs) is a classical solution to reduce the interfacial energy among otherwise incompatible polymers. The well-known thermoplastic elastomers, such as poly­(styrene-butadiene-styrene) or PS-PDMS-PS, are block copolymers composed of hard and soft polymer blocks. − Self-assembly yields microphase-separated structures with plastically deformable microdomains that serve as physical cross-links; a careful design of the composition and molecular weight allows tailored mechanical properties.…”