New performance of a modified poly(amide-12-b-ethyleneoxide) A. Gugliuzza a, * , E. Drioli a,b a Research Institute on Membrane Technology, ITM-CNR, Via Pietro Bucci 17/C, I-87030 Rende, Italy b Department of Chemical Engineering and Materials, University of Calabria, Via Pietro Bucci 17/C, I-87030 Rende, Italy Accepted 10 January 2003 Abstract The purpose of this work was the investigation of the water vapour transport through thermoplastic dense films of a poly(am ethylenoxide) such as Pebax w 2533. Similar polymers have gained a unique position in many technologies for different reasons, such good physical properties, high processability, notable strength and transport properties to gases and vapours. Moreover, a ris materials with specific characteristics in terms of water vapour transport comes from various market niches (i.e. textiles, building trade, packaging). For these reasons in this work particular attention has been paid to an elastomeric polymer such as the Pebax w 2533, an easily processable material with good transport properties. Previous studies have pointed out that Pebax w copolymers can be used as precursors of membranes for separation processes of condensable vapours and gases. In this work a further investigation of the water trans through Pebax w 2533 and derivative films allowed an understanding of their potential applications. The efficiency of these films h tested by means of vapour permeability, solubility, diffusivity, and hydrophobicity/hydrophilicity measurements. q 2003 Elsevier Science Ltd. All rights reserved. Keywords: Water vapour; Pebax; Membrane 1. Introduction The watervapourtransport through porous and dense films is of great interest for different industrial fields ranging from textile [1 – 3] to pharmaceutical [4,5],building trade [6] and dehydration process of gas streams [7,8]. In the last decades a lot of attention has been paid to the influence of chemicalstructure on gas [9 – 12] and vapour [13 – 15] transport through dense polymer films. The attempt to find a relationship between the polymer structure and the water vapourtransport through polymeric membranes has been the goal of many works [14 – 17] in order to understand and plan the influence of chemical functionality and structure flexibility on thepermeant speciestransport. Previous studies [18 – 20] have been focused on the use of additives in order to modify the physico-chemical properties of trade polymers. In this work the main interests were the attempt to improve,by meansof additionof differentorganic compounds, the performance of a trade polymer such as the Pebax w 2533,and theunderstanding of the vapour permeation mechanism, influenceof temperature, com- ponenthydrophilicity and additive concentration in this system. Pebax w 2533 shows the typical characteristics of an elastomeric polymer. It consists of a regular linear chain of rigid polyamide(Nylon 12, 20 wt%)interspaced with flexiblepolyether(PTMO). The amideblocksproduce hard segments and the polyether blocksbehave assoft segments. The main contribution to crystallinity of the copolymer comes from the amide block in which the less permeable phase resides, whereas the ether block acts as permeable phase for its high chain mobility. The vapour transport through dense Pebax w 2533 filmsobeysto the solution-diffusionmechanism. The solubilityinto the polymermatrixdependson the favourablechemical interactions between permeant and polar chemical groups of the polymer, whereas the diffusivity is strictly connected to the mobility of the polymer chain, low packing density and hence the presence of microcavities with sufficient dimension to allow the passage of the vapour molecules. When adding organic molecules with different chemical structure to a polymer matrix, the system morphology, the chemicalcompositionand eventhe physico-chemical properties change, influencing the transport through the 0032-3861/03/$ - see front matter q 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0032-3861(03)00037-5 Polymer 44 (2003) 2149–2157 www.elsevier.com/locate/polymer * Corresponding author. Tel.: þ 39-984-492014; fax: þ 39-984-402103. E-mail address: a.gugliuzza@itm.cnr.it (A. Gugliuzza). Abbreviations: TEC, triethylcitrate;KET, N-ethyl-o,p-toluene- sulphonamide; SB, sucrose benzoate.