ABSTRACT:Styrene and methacrylate type monomers having oligoorganosiloxane substituents were synthesized, and the properties of the polymers therefrom as material for oxygen permeable membranes were evaluated by gas chromatographic method. Homopolymers with short siloxane chains were found to be better than those with long branches in selectivity in permeation and mechanical strength. Introduction of fluorine atoms into polymer structure did not improve the selectivity in permeation.KEY WORDS Oligosiloxane I Ultrasonic Irradiation I Macromer I Fluoro Si1oxane I Ring-Opening Polymerization I Vinyl Polymerization I Comb Polymer I Graft Copolymer I Oxygen Permeation I Permselective Membrane I Recently, much attention has been paid to the selective gas permeable membranes. As material for oxygen permselective membrane, at least three basic requirements must be satisfied: 1) high permeability coefficientand 3) self-supporting property. We have reported poly(p-disiloxane substituted styrene)s as good self-supporting material for oxygen permeable membranes of considerably high separation factor [a=2.8 for poly(p-pentamethyldisiloxanylstyrene )]. 1 We have been also interested in polydimethylsiloxane (PDMS) graft copolymers as surface modifying material of hydrophilic polymers. 2 -5 Such polymers might be also of interest as oxygen permeable membrane material, because PDMS has high P 02 although the selectivity in permeation and mechanical strength are low. The disadvantage about the mechanical strength has been overcome by putting the PDMS chain into block 6 or crosslinked7 copolymers; however, the selectivity a remained still low. Since the reason for the low selectivity was suspected to be because of the inherent nature of the rather long PDMS chains in these copolymers, experiments were carried out to study the effects of the length of oligoorganosiloxane side chains on back bone polymers on the film forming property, and permeability and selectivity m oxygen permeation.Up till now, many perfiuorinated compounds have been known to show high solubility of oxygen, and some of them are used as artificial blood substitutes. 8 In designing oxygen permeable membranes, the modification of polymer structure by fluorine atoms seems quite interesting.In this article, the syntheses of oligoorganosiloxanes having various vinyl-polymerizable groups (including macromers) and the properties of the polymers therefrom as material for oxygen permselective membranes are reported. 1159

ABSTRACT:Selective oxygen permeation through the films of p-(oligosiloxanylstyrene)s was investigated, and the role of the oligosiloxane substituents is discussed based on a dissolutiondiffusion mechanism. The oligosiloxane side chains were found to play an important role to enhance the diffusion of oxygen.KEY WORDS Oligosiloxane I Macromer I Film I Oxygen Permeation I Mechanism I Dissolution-Diffusion I Activation Energy I Free Volume I Poly(p-oligosiloxanylstyrene)s were reported to be good self-supporting oxygen permeable membrane materials.1,2 In that report, an imaginative structure of polymer film was postulated/ in which oxygen permeation is influenced by both polymer back bones and oligosiloxane side chains. In order to obtain more understanding of the permeation, the permeation behavior of air through the films of )s were analyzed based on dissolution-diffusion mechanism. EXPERIMENTALMonomer 1-(p-Bromopheny{)-1-butanone. This compound was synthesized similarly to the reported method, 3 and the solid product was recrystallized from petroleum ether. 90% Yield. mp 37-39°C.4-n-Butyl-1-bromobenzene 1-( 4-Bromophenyl)-1-butanone was reduced by hydrazine to give the product. 4 · 5 4-n-ButylstyreneVinylchloride (248 mmol) and Nickel chloride-his( diphenylphosphinopropane) complex [Ni( dppp )Cl 2 ] ( 40 mg) were added in ether (1 00 ml), and small amounts of methylmagnesium bromide were slowly added until all Ni(dppp)Cl 2 completely dissolved. To this reaction mixture, 4-n-butylphenylmagnesium bromide prepared from activated Mg turnings (250 mmol) by dibromoethane (0.6 ml) and 4-n-butyl-1-bromobenzene (200 mmol) in ether (1 00 ml) was added drop wise during 1 h. 6 After the addition, the mixture was stirred overnight, decomposed with aq NH 4 Cl, and extracted with ether. Distillation gave the product in 75% yield. The compound was further purified by silica gel column chromatography in order to remove the uncoupled product, butyl benzene. 1 H NMR (CDC1 3 ) b 0.92 (t, 3H, 1=7.0Hz, Cl;:h), 0.9-2.07 (m, 6H, (Ctl 2 ) 3 ), 2.57 (t, 2H, 1= 7.0Hz, QCtl2), 5.07 (q, lH, 11 =1.0Hz, 1 2 =7.0Hz, 237