Open AccessFouling Resistance and Physicochemical Properties of Polyamide Thin‐Film Composite Membranes Modified with Functionalized Cyclodextrins
Author(s) -
Mbuli Bhekani S.,
Mhlanga Sabelo D.,
Mamba Bhekie B.,
Nxumalo Edward N.
Publication year - 2016
Publication title -
advances in polymer technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 44
eISSN - 1098-2329
pISSN - 0730-6679
DOI - 10.1002/adv.21720
Subject(s) - membrane , materials science , thin film composite membrane , differential scanning calorimetry , polyamide , chemical engineering , crystallinity , fouling , polymer chemistry , permeation , crystallization , composite material , reverse osmosis , chemistry , biochemistry , physics , thermodynamics , engineering
Thermal and mechanical properties and fouling resistance of polyamide thin‐film composite ( PA ‐ TFC ) membranes modified with amino‐cyclodextrins and diethylamino‐cyclodextrins are investigated. It was found that the decomposition temperatures of the modified membranes were 500°C and were not significantly different with those of the unmodified membranes. Differential scanning calorimetry ( DSC ) studies showed that the modified membranes with heating melting temperatures in the range 112.5–113.8°C were more crystalline than the unmodified membranes due to the presence of cyclodextrin derivatives on the interfacial layer. The crystallization temperatures ( T c ) were found to range between 128.75 and 129.03°C and the glass transition temperatures ( T g ) ranged between 78.67 and 79.33°C. The modified PA ‐ TFC membranes were found to have comparable ultimate tensile strengths ( UTS ) to the unmodified membranes, except for the membranes modified with amino‐ β ‐ CD s, with a UTS of 20.00 ± 0.50 MP a. The PA ‐ TFC membranes had a lower water uptake percentage due to their enhanced crystallinity. However, these materials had a higher water permeate flux due to the hydrophilic nature of the modified membranes enhanced by the rich hydroxyl groups on the CD s. The modified PA ‐ TFC membranes also exhibited high Mg SO 4 salt rejection and fouling resistance capacities compared to unmodified membranes. Different pH levels resulted in different fouling resistance patterns of the membranes. Therefore, the membranes modified with functionalized CD s were thermally and mechanically stable, had enhanced crystallinity, high divalent salt rejection and fouling resistance under different pH conditions.