文献类型：期刊文献

英文题名：Correlations between gas permeation and free-volume hole properties of polyurethane membranes

作者：Wang, Zhi Fen[1]; Wang, Bo[1]; Yang, Yu Run[2]; Hu, Chun Pu[2]

机构：[1]Wuhan Univ, Dept Phys, Wuhan 430072, Peoples R China;[2]E China Univ Sci & Technol, Inst Mat Sci & Engn, Shanghai 200237, Peoples R China

年份：2003

卷号：39

期号：12

起止页码：2345

外文期刊名：EUROPEAN POLYMER JOURNAL

收录：;EI(收录号：2003477735366);WOS:【SCI-EXPANDED(收录号:WOS:000187363300013)】；

语种：英文

外文关键词：positron annihilation; free-volume; gas permeability

摘要：A series of polyurethane films based on hard segments consisting of toluene diisocyanate and 1,4-butanediol and different soft segments consisting of hydroxyl terminated polybutadiene, hydroxyl terminated polybutadiene/styrene and hydroxyl terminated polybutadiene/acrylonitrile were synthesized by solution polymerization separately. Positron annihilation lifetimes were measured at room temperature for all samples studied. We found that both the free volume size and fractional free-volume decreased with the increase of hard segment content. On the other hand, direct relationship between the gas permeability and the free-volume has been established based on the free-volume parameters and gas diffusivity measured. Experimental results revealed that the free-volume plays an important role in determining the gas permeability. (C) 2003 Elsevier Ltd. All rights reserved.