Synthesis and properties of 4‐vinyl pyridine grafted SBS used as charged mosaic membrane

Abstract

The grafting of 4-vinyl pyridine onto styrene-butadiene-styrene triblock copolymer by irradiation was studied. Cationic and anionic groups were introduced by sulfonation and methylation to obtain a charged mosaic membrane.The experiments showed an increased rate of grafting with the increase of irradation dose. The best concentration of monomer was at 20%.After grafting, the contact angle and the water content were tested and morphology studies were performed.Furthermore, the tensile strength of this membrane increased with increased percentage of grafting. After testing, the charged mosaic membrane had a reduced potential. Its anionic and cationic exchange capacitites were between 0.12 to 0.13 meqlg, and 0.24 to 0.343 meqlg, respectively. The ratio of exchanged capacity was up to 0.509. KCl and urea can be separated by dialysis. In the determination of a piezodialysis, the salt enrichment reached a percentage of 10.3. ZUSAMMENFASSUNG:4-Vinylpyridin wurde durch Bestrahlung auf ein Styrol-Butadien-Styrol-Blockcopolymeres aufgepfropft. Kationische und anionische Gruppen wurden durch Sulfonierung und Methylierung eingefiihrt, wobei eine Membran mit Ladungsmosaik entstand.Die Experimente zeigten, dal3 die Pfropfgeschwindigkeit mit der Strahlendosis anstieg. Die giinstigste Monomerkonzentration lag bei 20%.Nach der Pfropfung wurden der Kontaktwinkel und der Wassergehalt bestimmt sowie Morphologiestudien unternommen. Ferner wurden Zug-Dehnungsuntersuchungen durchgefiihrt sowie das Potential, die Ionenaustauschkapazitlten und das Austauschkapazitltsverhiiltnis der Membranen untersucht. KCl und Harnstoff kdnnen mittels solcher Membranen getrennt, und eine Salzanreicherung in einer Druckdialyse kann erreicht werden. 0 1987 Huthig & Wepf Verlag, Basel OOO3-3146/87/$03.00 4-Vinyl Pyridine Grafted SBS ReagentsMethanol, toluene, nitromethane, methyl iodide, and methylene blue were all Merck reagents. Sulfur monochloride, chlorosulfonic acid, silver nitrate, and urea were all reagent grade. Heptane and 1, I ,2,2-tetrachloroethane were practical grade. All reagents were used without purification.The procedure for preparation of a charged mosaic membrane and details of the description of the experiments were given in Scheme I .

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

“…Therefore the solubility of oxygen in epoxidized SBS membrane decreases with the increasing of epoxidation and this is the same for nitrogen. ( 2 ) From the values of cohesive energies, Mc, and glass transition temperature in Table 111, we see that the epoxidation of SBS increases the crosslinking density and enhances the polymer molecular chain interaction by the polar oxirane ring, which results in the increase of cohesive energy and the glass transition shifted to higher temperature. Thus, the chain mobility of epoxidized SBS is lower than that of untreated SBS, which will reduce the diffusivity of gas through epoxidized SBS.…”