Epoxidation of styrene–butadiene–styrene block copolymer and use for gas permeation

Abstract

The epoxidation of styrene–butadiene–styrene triblock copolymer (SBS) by an in situ generated peracid method is discussed. The presence of an acid acting as catalyst led to side reaction. The reactivities of internal double bonds (the 1, 4‐structure) were higher than those of the vinyl bonds (the 1, 2‐structure). In the 1, 4‐structure, the reactivities of cis‐structure were higher than those of trans‐structure. The oxirane weight content and total oxygen weight content were determined by titration and element analysis, respectively. The cohesive energy, solubility parameter, and the glass transition temperature of epoxidized SBS increased with increasing total oxygen weight content. But the molecular weight between crosslinking points decreased resulting in an increase of crosslinking density with increasing total oxygen weight content. The changes of properties of epoxidized SBS reduced the gas permeability of oxygen and nitrogen through epoxidized SBS membrane, but increased the gas selectivity between oxygen and nitrogen. When the operating temperature of gas permeation was increased, the permeability of oxygen and nitrogen increased but the selectivity decreased. For epoxidized SBS containing 7.35 wt % oxygen content, the activation energy was 9 and 12.2 kcal/mol for oxygen and nitrogen, respectively.

Synthesis and Characterization of Nanostructured Blends of Epoxy Resin and Block Copolymers

“…The peaks centered around 810 cm -1 , 889 cm -1 as well as 1215 cm -1 and 1265 cm -1 can be assigned to half epoxy group stretching and whole epoxy ring stretching, respectively. According to some literature works (Hsiue & Yang 1990), the peaks due to epoxy absorption were found at 810 cm -1 , 880 cm . In addition, the absorption of carbonyl (C=O) group at about 1700 -1740 cm 1 and hydroxyl (OH) group at about 3200 -3700 cm -1 were found.…”

“…Polystyrene-block-polybutadiene-block-polystyrene (SBS) triblock copolymer is one of the thermoplastic elastomers which act as the vulcanized rubber at ambient temperature (Hsiue & Yang 1990). Polystyrene (PS) block is immiscible with epoxy resin system whereas the polybutadiene (PB) block is chemically modified to turn it miscible with the epoxy resin system at hand (Grubbs et al 2000b).…”

Investigations into Morphology and Mechanical Properties of Epoxidized Polystyrene/Polybutadiene/Polystyrene (SBS) Triblock Copolymer

“…The SBS block copolymer was epoxidized to different degrees following the standard procedures discussed in literature [11][12][13]21 . In a typical experiment, 5 g of the SBS sample was dissolved in 50 ml of toluene in 250 ml three necked round bottom flask equipped with a magnetic stirrer, thermometer and reflux condenser.…”

Synthesis of acrylated styrene-isoprene-styrene copolymer

“…To prepare ultraviolet-sensitive polymer, reactions are separated into two parts: epoxidation and acrylation. SIS contains a phase structure similar to styrenebutadiene-styrene block copolymer (SBS); the epoxidation reaction was investigated by Hsiue and Yang [1], Jian and Hay [2], and Margaritis et al [3]. In addition, SIS molecules consist of isoprene units similar to the natural rubber; the epoxidized natural rubber was studied by Nakason et al [4] and Saito et al [5] while the acrylated natural rubber was studied by Phinyocheep and Duangthong [6], and Xuan and Decker [7].…”