Artificial Membranes from Multiblock Copolymer IV. Four-Component Pentablock Copolymers of the DSD′AD Type Usable to Fabricate a Charge-Mosaic Membrane

Abstract

ABSTRACT:Four-component pen tab lock copolymers of the DSD 'AD type, poly(isoprene-bstyrene-b-bu tadiene-b-( 4-vin y I benzy I )dimeth y Jamine-b-isoprene) and poI y(bu tadiene-b-st yrene-bisoprene-b-(4-vinylbenzyl)dimethylamine-b-butadiene), were prepared by a sequential anionic polymerization and the morphologies of the films cast from benzene, dioxane, and cyclohexane solutions of the samples were studied by electron microscopy and viscoelastic spectrometry. Threelayer lamellar structures were observed for the benzene-and dioxane-cast films just like as the case for ISIAI pentablock copolymers. Charge-mosaic membranes prepared by quaternizing, crosslinking, and sulfonating the films exhibited better refined microstructures and better performance than those prepared from ISIAI block copolymers.KEY

Anionic living polymerization of an α-methylstyrene derivative containing the bis(diethylamino)phosphino group

“…shown in Figure 10, where a good linear relationship is observed. The relationship between [M]e and thermodynamic parameters can be expressed by ln[M] e = AHJRT-ASJR (5) where is the heat of polymerization, ASae the corresponding entropy for a 1 mol L™1 solution, and R the gas constant. Hence, and 5 in THF-dg are estimated to be -6.5i kcal mol™1 and -2.3 X 10 cal mol™1 K™1, respectively.…”

“…Figure5. Example of the variation of the meniscus height ht with time t in the dilatometric measurement at -50 °C.…”

Artificial membranes from multiblock copolymers. 6. Water and salt transports through a charge-mosaic membrane

“…The membrane used in this work was fabricated from a four-component pentablock copolymer of the ISBAI type, poly(isoprene-6-styrene-5-butadiene-6-(4-vinylbenzyl)dimethylamine-b-isoprene) (TUN 1013), which was synthesized by a sequential anionic polymerization. The molecular characteristics of the pentablock copolymer were shown in the preceding paper (Takahashi et al, 1986).…”

“…The charge-mosaic membrane finally obtained had regularly repeated lamellae in the order, -S~-Dc-A+-Dc-, where S~is the sulfonated S (cation-exchange) layer, A+ the quaternized A (anion-exchange) layer, and Dc the cross-linked I and B (neutral) layer (Takahashi et al, 1986). Each of the lamellae was about 20 nm in thickness.…”

“…Recently, we fabricated a charge-mosaic membrane made of a very fine domain structure from pentablock copolymers of the ZXZ'YZ type and have already published the detailed fabrication method (Matsushita et al, 1980;Funabashi et al, 1983; Miyaki et al, 1984a,b;Miyaki and Fujimoto, 1983; Takahashi et al, 1986), brief transport behaviors of salt and water (Fujimoto et al, 1984a,b;Miyaki et al, 1984b), and transport behaviors of various organic and inorganic substances (Hirahara et al, 1986). These reports suggest that our membrane can be made to be of practical use in the field of desalination or separation of organic species even if their molecular weights are low. In this work, in order to reveal the basic characteristics of this charge-mosaic membrane, we study experimentally the salt and water transports for KC1 solutions in detail under the condition where concentration polarization near the membrane surfaces is suppressed as far as possible.…”