Water-vapor Permeability of Hydrophilic Polyurethanes Studied by Positron Annihilation

Abstract

Abstract: Positron annihilation lifetime spectroscopy was used to study the effect of temperature and content of PEG on the free volume size, distribution and water-vapor permeability(WVP) for a series of polyester-based polyurethane films based on poly(butylene adipate)(PBA) as soft segments. The PALS results indicated that the mean volume of free-volume increased and the distribution of free-volume broadened with the temperature increased. The variation rate of free-volume hole size as a function of temperature has an abrupt increase, which is attributed to the crystalline region melting. In all membranes, water-vapor permeability coefficient increased with the increase of temperature. PBA-20 has almost the same values of WVP as PBA-10 and PBA-15. More PEG groups added exert no significant effects on the water-vapor permeability, because there are two opposite effects of PEG groups on WVP. The experimental results indicated that WVP could be controlled by not only free volume, but also hydrophilicity of polymer.

Key words: Water-vapor permeability, Free volume, Hydrophilicity

CLC Number:

O631.2

TrendMD:

WANG Zhi-Fen, QI Ning, WANG Bo, DING Xue-Mei, HU Jin-Lian . Water-vapor Permeability of Hydrophilic Polyurethanes Studied by Positron Annihilation[J]. Chem. J. Chinese Universities, 2004, 25(10): 1953.

References

[1] 　V anb ogart J.W.C.,Gibs on P.E.,Cooper S.L..J.Pol ym.S ci.,Pol ym.Ph ys.[J],1983,21:65—95 [2] 　Y en M.S.,Cheng K.L..J.A ppl.Pol m.S ci.[J],1994,52:1707—1717 [3] 　Cohen M.H.,Tu rnbull D..J.C hem.Phys.[J],1959,31:1164 [4] 　Jean Y.C.,Y uan J.P.,Liu J.et al..J.Polym.Sci.,Par t B:Pol ym.Phys.[J],1995,33:2365—2371 [5] 　Eas t mond G.C.,Daly J.H.,M cK innon A.S.et al..Pol ymer[J],1999,40:3605—3610 [6] 　M cG onigl e E.A.,Liggat J.J.,Pet h rick R.A.et al..Polymer[J],2001,42:2413—2426 [7] 　K ob ayashi Y.,Haraya K.,Hat t ori S.et al..Pol ymer[J],1994,35:925—928 [8] 　Wang B.,W ang Z.F.,Zh ang M.et al..M acrom olecules[J],2002,35:3993—3996 [9] 　Beck er O.,Ch eng Y.B.,V arley R.J.et al..M acromolecules[J],2003,36:1616—1625 [10] 　Cangial osi D.,Schut H.,V an V een A.et al..M acrom ol ecules[J],2003,36:142—147 [11] 　ZHU J un(朱俊),W A N G S hao-J ie(王少阶),LU O Xi-Hui(罗锡辉).Chem.J.C hinese U n iversit ies(高等学校化学学报)[J],2002,23(11):2159—2162 [12] 　K el kar A.J.,Paul J.K..J.M emb r.S ci.[J],2001,181:199—212 [13] 　Schult K.A.,Paul D.R..J.Pol ym.S ci.,Part B:Polym.Phys.[J],1996,34:2805—2817 [14] 　Jean Y.C..M ir ochem.J.[J],1990,42:72—102 [15] 　Wu Q.X.,Zh ang L.N..Ind.Eng.Ch em.Res.[J]2001,40:558—564 [16] 　Y ou ng R.J.,Lovell P.A..Int roducti on t o Pol ymers,2n d Edit ion[M],London:Ch apman an d Hall,1991 [17] 　Lin D.,Wang S.J..J.Ph ys.Conden s.M att er.[J],1992,4:3331—3336 [18] 　Porto A.O.,Sil va G.G.e t al..J.Pol ym.S ci.,Part B:Polym.Phys.[J],1998,37:219—226 [19] 　M eares P..J.A m.Chem.Sci.[J],1954,76:3415—3422 [20] 　Coleman M.R.,K oros W.J..J.M embr.Sci.[J],1990,50:285—297 [21] 　Wang Z.G.,Ch en T.L.,Xu J.P..M acromolecul es[J],2001,34:9015—9022 [22] 　V iet h W.R..D iff us ion in and T hrough Polymers:Principl es and A ppl icat ions[M],N ew Y ork:Hanser Publ ishers,2002:73—110 [23] 　St er n S.A..G as permeat ion processes,Indus tr ial Process ing wit h M embranes[M],N ew Y or k:W iley,1972:279—299