High-performance polyvinylidene fluoride/poly(styrene–butadiene–styrene)/functionalized MWCNTs-SCN-Ag nanocomposite membranes

• Published in: Iranian polymer journal 2015-07, Vol.24 (7), p.549-559
• Main Authors: Mehwish, Nabila, Kausar, Ayesha, Siddiq, Muhammad
• Format: Article
• Language: English
• Subjects: Ceramics; Chemistry; Chemistry and Materials Science; Composites; Glass; Natural Materials; Original Paper; Polymer Sciences
• ISSN: 1026-1265; 1735-5265
• DOI: 10.1007/s13726-015-0346-z

In this work, solution blending technique was used to fabricate nano-filtration membranes of polyvinylidene fluoride (PVDF) and poly(styrene–butadiene–styrene) (SBS) blend matrix and modified multi-walled carbon nanotubes (MWCNTs) as filler. In this regard, two types of nanofiller, thiocyanate-modified nanotubes (MWCNTs-SCN) and silver-modified nanotubes (MWCNTs-SCN-Ag), were used as reinforced nanofiller in PVDF/SBS blend to form PVDF/SBS-MWCNTs-SCN 0.01–0.1 and PVDF/SBS-MWCNTs-SCN-Ag 0.01–0.1 membranes. Fourier transform infrared; field emission scanning electron microscopy; transmission electron microscopy; X-ray photoelectron spectroscopy; Brunauer, Emmett and Teller; and tensile tests were used for the exploration of structural and physical properties. Morphology studies showed the dispersion of polymer-coated silver nanoparticles with smooth and homogeneous surface in the spongy matrix. Porous nature of membranes was also observed in high-resolution cross-section micrographs. Tensile strength of PVDF/SBS-MWCNTs-SCN 0.01–1 nanocomposite series increased from 10.2 to 13.9 MPa, while PVDF/SBS-MWCNTs-SCN-Ag 0.01–1 had values in the range of 12.6–20.1 MPa. According to TGA, PVDF/SBS-MWCNTs-SCN revealed maximum decomposition temperature around 550–580 °C, while PVDF/SBS-MWCNTs-SCN-Ag had T max of 567–599 °C. The influence of various filler content on membrane performance and structure was studied using pertinent methods and techniques. Percentage of water content of PVDF/SBS-MWCNTs-SCN 0.01–0.1 was estimated around 1.08–2.80 % and this value was further increased to 1.94–4.65 % in silver nanoparticle-modified system. Moreover, the porosity of silver nanoparticle-modified system was found superior compared with the other composites. Pure water flux, salt rejection, and recovery were also found optimal for 0.05 wt% silver nanoparticle-based modified system. According to the consequences, novel membranes have fine nano-filtration characteristics to be utilized in advance water treatment industrial units.