Matrimid membranes

Gas Transport Properties of Cross-Linked Matrimid Membranes.377... 

The Gel Contents of Cross-Linked Matrimid Membrane at Various Cross-Linker Concentrations... 

Structure of the polymer matrix and the nodules cannot return to their original positions. The same phenomenon was reported by Aziz and Ismail (2010) and Tin et al. (2003). Lastly, the insertion of pPD cross-linking agents into the membranes, which may increase the space between the chains, could increase the tf-space of the cross-linked Matrimid membranes. The same results were obtained as discussed by Aziz and Ismail (2010) when they varied the immersion time. This reflects that both the parameters that affect the cross-linking reactions, immersion time and cross-linker concentrations, had changed the ordered dimensions and the interchain spacing of cross-linked PI membranes. 

FIGURE 11.3 Phenomenological models of Matrimid membranes (a) without cross-linking after cross-linking with (b) 5% PD, (c) 10% pPD, and (d) 15% /tPD. 

Aziz, F. and Ismail, A.F. 2010. Preparation and characterization of cross-linked Matrimid membranes using para-phenylenediamine for Oj/Nj separation. Sep. Purif. Technol. 73 421 28. 

Figure 5.11 AFM pictures of active and support layer of a Matrimid membrane 14/10 (14% of Matrimid, 10% of n-BuOH, in a 50 50 mixture ofTHF/CBL) evaporated during 10s.

Figure 5.13 Thickness of the active layer of Matrimid membranes 14/10 and 14/12 as a function of the evaporation time obtained by different methods.

Figure 5.14 Active layer thickness obtained by taking into account the silicone layers as a function of the corresponding thickness as measured by AFM for the 14/10 Matrimid membrane.

The authors would like to thank CICYT Plan National de I-tD-tl (projects MAT2005-04976, MAT2004-01946, CTQ2006-01685). We also would like to thank V. Peinemann (in whose laboratory in the GKSS in Geestaacht, Germany, the asymmetric Matrimid membranes were made) and J. Marchese (who manufactured the MMCM studied here). 

The results of the investigation are reported in Table II. The CMS-Matrimid and Zeolite 4A-Matrimid membranes give selectivities approaching those of the native polymer at best. Also, much higher permeabilities were observed than predicted by the model for both carbons molecular sieves and zeolites. These results suggest that there was improper contact between the two phases, probably due to dewetting of... 

Besides zeolites and traditional silica, carbon molecular sieves have been investigated as dispersed phases. Mixed-matrix membranes have been created using carbon molecular sieves dispersed in polyetherimide (Ultem) and Matrimid, separately. These mixed-matrix membranes displayed an increase in both permeability and selectivity over their neat polymer counterparts." The effect of trace amounts of toluene impurity in the feed stream of these carbon-polymer membranes was tested, and the membranes showed promising stability over time against the impurity. Zeolite-carbon mixed-matrix membranes have recently been developed where the carbonized polymer matrix is derived from a pure Matrimid membrane." These mixed-matrix membranes double the CO2/CH4 selectivity of the pure carbonized Matrimid membranes tested but lose over half of their productivity in the process. While these properties are well above Robeson s upper bound, other researchers have achieved better separation properties using only pure carbonized Matrimid membranes. ... 

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