Preparation and Characterization of Modified PVDF-g-PSSA Membrane

Abstract

A new method based on a solution graft technique was used to prepare poly (vinylidene fluoride) grafted polystyrene sulfonated acid (PVDF-g-PSSA) proton exchange membrane. Polystyrene is grafted into PVDF modified by plain sodium silicate (Na4SiO4). There is a linear relationship between the degree of grafting and the content of Na4SiO4. Fourier transform infrared spectroscopy is used to characterize changes of the membrane's microstructures after grafting and sulfonation. The morphology of the membrane's microstructures after grafting and sulfonation is studied by scanning electrolytic microscope (SEM). The effect of plain sodium silicate (Na4SiO4) concentration and relative humidity on the conductivity of the electrolyte was investigated by the impedance at room temperature. The results show that the styrene has been grafted into PVDF. The conductivity of PVDF-g-PSSA electrolyte doped 10% plain sodium silicate (Na4SiO4) is 0.016 S/cm at room temperature. The conductivity of the electrolyte changes slightly at a relative humidity range of 20%-70%. The weightlessness of PVDF-g-PSSA electrolyte heated to 40°C was less than 2%, which indicated that water capacity was good.

English Language Education and Assessment

“…Dong and Ma 2011 ;Zhou et al 2010 ). Fairness is undermined in writing assessment when raters' scoring decisions are infl uenced by factors such as different interpretations of scoring rubrics between raters and between regions, raters' levels of expertise and workplace environment (Guo 2010 ;Ma 2009 ;Wang 2011 ) or test-takers' appearance and personalities in teacher-based classroom writing assessment (Yang 2001 ). Scoring fairness is also considered an interchangeable term with rater bias and an integral part of test validation (Lu 2011 ).…”

Preparation of PVDF anionic exchange membrane by chemical grafting of GMA onto PVDF macromolecule

“…The arborescent samples exhibit comparable selectivity and low IEC values compared to Nafion 117. Guibao Guo et al [4][5][6][7] had also investigated PVDF-g-PSSA membrane and poly (vinylidene fluoride)-graft-poly (2-acrylamido-2-methylpropane sulfonic acid) (PVDF-g-PAMPS) membrane prepared by the method of chemically induced radical grafting polymerization. In our previous work [10], OMMT/PVDF-based cationic exchange membranes were prepared by two-step chemically induced grafting method.…”

“…In our previous work [10], OMMT/PVDF-based cationic exchange membranes were prepared by two-step chemically induced grafting method. However, for the chemically induced grafting methods reported in references [4][5][6][7][8][9][10], the grafting reaction is usually used to introduce cation-exchange groups and almost conducted on the surface of the treated PVDF membrane. The internal grafting reaction is limited and the cation-exchange groups are mainly grafted on the surface of the membranes, which limits the physical and chemical properties of the obtained PVDF cationexchange membranes.…”

“…One effective method to introduce ionic conducting groups to PVDF membranes and prepare PVDF ion-exchange membranes is chemically induced radical grafting polymerization [4][5][6][7][8][9][10]. The PVDF membranes are treated in oxidant or alkaline solutions with introduction of active sites to proceed radical grafting polymerization.…”

Preparation of cationic exchange membranes based on organo‐montmorillonite/poly(vinylidene fluoride) by two‐step chemically induced grafting method

“…Poly(vinylidene fluoride) (PVDF) is convincing a base material for preparation of ion‐exchange membranes because of its sufficient thermal, mechanical, and chemical stability . One effective method to introduce cationic conducting groups to PVDF membranes is chemically induced radical grafting polymerization . The PVDF membranes were treated in alkaline solutions with introduction of CC bonds to proceed radical grafting polymerization.…”