scholarly journals Hollow Fiber Porous Nanocomposite Membranes Produced via Continuous Extrusion: Morphology and Gas Transport Properties

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2311 ◽  
Author(s):  
Zahir Razzaz ◽  
Denis Rodrigue

In this work, hollow fiber porous nanocomposite membranes were successfully prepared by the incorporation of a porous nanoparticle (zeolite 5A) into a blend of linear low-density polyethylene (LLDPE)/low-density polyethylene (LDPE) combined with azodicarbonamide as a chemical blowing agent (CBA). Processing was performed via continuous extrusion using a twin-screw extruder coupled with a calendaring system. The process was firstly optimized in terms of extrusion and post-extrusion conditions, as well as formulation to obtain a good cellular structure (uniform cell size distribution and high cell density). Scanning electron microscopy (SEM) was used to determine the cellular structure as well as nanoparticle dispersion. Then, the samples were characterized in terms of mechanical and thermal stability via tensile tests and thermogravimetric analysis (TGA), as well as differential scanning calorimetry (DSC). The results showed that the zeolite nanoparticles were able to act as effective nucleating agents during the foaming process. However, the optimum nanoparticle content was strongly related to the foaming conditions. Finally, the membrane separation performances were investigated for different gases (CO2, CH4, N2, O2, and H2) showing that the incorporation of porous zeolite significantly improved the gas transport properties of semi-crystalline polyolefin membranes due to lower cell wall thickness (controlling permeability) and improved separation properties (controlling selectivity). These results show that mixed matrix membranes (MMMs) can be cost-effective, easy to process, and efficient in terms of processing rate, especially for the petroleum industry where H2/CH4 and H2/N2 separation/purification are important for hydrogen recovery.

2020 ◽  
pp. 026248932092930
Author(s):  
Zahir Razzaz ◽  
Abolfazl Mohebbi ◽  
Denis Rodrigue

The production of foamed hollow fiber membranes (HFMs) is presented based on polymer blends using various concentrations of linear low-density polyethylene (LLDPE) and low-density polyethylene (LPDE) combined with azodicarbonamide (chemical blowing agent) to prepare samples via twin-screw extrusion. In particular, the blowing agent concentration as well as the stretching speed were found to be the most important parameters to achieve a good cellular structure for membrane application. From the samples obtained, a complete set of morphological, thermal, and gas transport characterization was performed. The results show that LLDPE/LDPE blends compared to neat LLDPE lead to higher cell density at high stretching speed, which is appropriate for membranes having higher gas permeability and selectivity due to lower cell wall thickness. The results also show that the developed cellular structure has high potential for the continuous production of HFMs for different gas separation, especially for hydrogen recovery.


RSC Advances ◽  
2015 ◽  
Vol 5 (15) ◽  
pp. 11272-11283 ◽  
Author(s):  
Dhorali Gnanasekaran ◽  
A. Shanavas ◽  
Walter W. Focke ◽  
Rotimi Sadiku

Prepared cost-effective and environmentally-friendly POSS/PA by facile synthesis via solvent casting method. Conspectus study and morphology correlation with gas-transport properties. Effective H-bonds of POSS and PA facilitate separation properties.


2011 ◽  
Vol 375 (1-2) ◽  
pp. 150-156 ◽  
Author(s):  
Anil Surapathi ◽  
Jose Herrera-Alonso ◽  
Feras Rabie ◽  
Steve Martin ◽  
Eva Marand

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