The effect of amine substituent chain length on POSS/Polysulfone mixed matrix membrane

Abstract

The main obstacle encountered during the development of polyhedral oligomeric silsesquioxane (POSS) mixed matrix membrane (MMM) via physical blending is the combination of compatible inorganic filler and polymeric matrix. In this work, mono-functional POSS of different amine functionalised substituent chain lengths namely aminopropylisobutyl POSS (AMPOSS-a) and aminoethylaminopropylisobutyl POSS (AMPOSS-b) were incorporated into Polysulfone (PSf) membrane at 1wt%, 2wt% and 3wt% loadings. The effect of amine substituent chain lengths on its compatibility and dispersion properties as well as the glass transition temperature of the MMMs were studied using scanning electron microscope (SEM), energy dispersive X-ray (EDX) and differential scanning calorimeter (DSC). Particle agglomerations were observed to increase with the loadings of both fillers although more prominent in AMPOSS-b/PSf membranes. This was attributed to the interparticle forces such as van der Waals and electrostatic forces. Distribution of both fillers were concentrated at the upper region of the membranes at 1wt% and 2wt% as a consequence of their density difference. The glass transition temperature (T g ) for pristine PSf at 197ºC showed an overall decrement between 40.3ºC to 47.1ºC when AMPOSS-a and AMPOSS-b were incorporated. The decrement was due to AMPOSS particle loadings, surface chemistry and particle-polymer chain topology. Hence, mono-substituted POSS with varying amine substituent chain lengths did not improve the glass transition temperature nor contribute to homogeneous MMM morphology. This had been identified to be the consequence of POSS surface energy, which might be caused by the association of hydrocarbon chains saturated on the particle surface due to the presence of isobutyl group.

Obtainment and Characterization of Hydrophilic Polysulfone Membranes by N-Vinylimidazole Grafting Induced by Gamma Irradiation

“…Furthermore, glass transition temperatures (Tg) for PSU film were found at 189.15 °C. This value was in concordance with those reported elsewhere (190–200 °C) [ 66 , 67 , 68 ]. Sequentially, PSU-VIM membranes displayed a Tg range of 185.40 to 186.58 °C.…”

Modification and acidification of polysulfone as effective strategies to enhance adsorptive ability of chromium (VI) and separation properties of ultrafiltration membrane

“…Figure 5a indicates that glass transition temperature ( T g ) of the PSF membrane was 182.71°C. This value was close to that (190–200°C) of most literatures 29,32,33 . The literature reported that the T g value of the PSF membrane was 142°C 34 .…”

“…close to that (190-200 C) of most literatures. 29,32,33 The literature reported that the T g value of the PSF membrane was 142 C. 34 The T g value of the CM-PSF membrane decreased to 173 C, and the T g value of the T-PSF membrane further decreased to 158.24 C. This phenomenon was reported in literature 27 : The T g value of CM-PSF decreased from 183 to 158 C, which depended on the grafting degree. Higher grafting degree resulted in lower glass transition temperature.…”

Enhanced permeation performance with incorporation of silver nitrate onto polymeric membrane

“…The few factors that define a membrane's effectiveness are permeability, pore structure, selectivity, hydrophilicity, and mechanical stability As for permeability which mostly affected by fouling can be control by introducing nanoparticles to altered the membrane structure [58]. Besides that, polymeric membranes are favored for their ease of fabrication and their low cost [59], however, their disadvantages are that the polymers most commonly used, namely polysulfone (PSU) which are semi-hydrophobic which can lead to reduced flux and increased fouling [60] but the polyethyleneimine had been used in this study to increase the hydrophilicity with the adding of silver nanoparticles. Silver is another commonly used nanoparticle for nanocomposite membranes: silver nanoparticles are widely known to be antimicrobial, and there are commercial home water systems currently available which use membranes or filters coated with silver nanoparticles, and these are reported to remove 99.99% of pathogens [47].…”

“…As stabilizing agent, PEI will provide increase in hydrophilicity, lowering non-intended adsorption and increase water solubility of the membrane. [60,61]. Despite the ability to increase membrane permeability, PEI also consist of cationic charge that can react with heavy metal ion either in basic or acidic environment to form a complex coordination [66].…”