Synthesis and characterization of novel graft copolymers by radiation‐induced grafting

Abstract

The radiation-induced graft copolymerization of N-vinyl-2-pyrrolidone (NVP), 4-vinyl pyridine (4VP), and 2-vinyl pyridine (2VP) monomers onto poly (ethylene-alt-tetrafluoroethylene) (ETFE) was investigated. The influence of synthesis conditions particularly the solvent was studied. Various solvents, such as n-propanol, isoproponol, benzyl alcohol, methanol, ethanol, cyclohexanone, tetrahydrofuran (THF), nitromethane, 1,4-dioxane, and n-heptane were examined for this purpose. Graft copolymers were characterized by Fourier transform infrared (FTIR) spectroscopy, dynamic mechanical analysis (DMA), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDAX). It was found that the nature of the solvent had profound influence over the grafting reaction. Cyclohexanone, n-propanol, and isoproponol for 4VP/ETFE grafting, THF and 1,4-dioxane for NVP/ETFE grafting, and benzyl alcohol and methanol for 2VP/ETFE grafting were found to be the suitable solvents yielding highest graft levels. Isoproponol and n-propanol are promising in terms of both graft level and mechanical properties for 4VP/ETFE. Grafting of NVP, 4VP, and 2VP onto ETFE were verified through FTIR spectroscopy. Storage modulus and glass transition temperature of the copolymers were found to increase as graft level increased. Surface profile of representative films was also investigated by viewing the distribution of elemental nitrogen using SEM-EDAX. Results indicated that copolymers of 4VP, NVP, and 2VP are considerably different from each other. 4VP-based copolymers exhibited relatively more homogenous grafting over the surface compared with NVP-and 2VPbased copolymers.

Metal-Salt Enhanced Grafting of Vinylpyridine and Vinylimidazole Monomer Combinations in Radiation Grafted Membranes for High-Temperature PEM Fuel Cells

“…As depicted in Figure 9 and Figure 10, maximum achieved power density of 237 mW•cm −2 is provided by salt-added membrane with 36% GL at 110 °C and 60% RH that can be considered as comparable performance with 150, 75, and 220 mW•cm −2 at 120 °C for ETFE/P1-VIm/PA, ETFE/PVAm/PA, and PA/ PBI membranes, respectively, which have been reported previously. 30,35 Despite some differences compared to the literature, obtained polarization curves show a similar increasing trend for the maximum power density with the enhancement of the temperature and relative humidity for both membranes (Figure 9). The aforementioned behavior confirms the previous conductivity results for the same samples, which indicates the drastic reliability of the proton conduction to the mobility of charge carriers as the function of temperature as well as to the ease of their diffusion in humidified condition.…”

“…However, Isikel Sanlı and Alkan Gursel observed no improvement in grafting 4VP onto ETFE based on the fact that addition of water increases the difference in solubility parameters of the monomer and the solvents. 35 In this work, first, water was used as solvent for the grafting of the 1-VIm/4-VP mixture. However, a graft level of 17%, the same as water/ethanol mixture, was observed.…”

Radiation-Grafted Membranes for Polymer Electrolyte Fuel Cells: Current Trends and Future Directions

“…Other heterocyclic monomers such as NVP and 2-VP were also used for the preparation of PEM precursors by using RIG onto ETFE films. 232 However, the acid doping of these precursors and the properties of the resulting PEMs are not reported.…”

One-step synthesis of nitrogen-grafted copper-gallic acid for enhanced methylene blue removal

“…Nitrogen-grafting (N g ) is one of the surface functionalization techniques and had been acknowledged to promote the adsorption capacity of adsorbents 23 – 26 . Due to this advantage, various N g methods have been extensively developed via plasma, pyrolysis, radiation, hydrothermal, or basic hydrolysis reaction 27 – 31 . This study utilizes the possible binding interaction of copper (Cu 2+ ), GA, and amino acids through the metal–ligand complexation principle as the foundation for the N g -CuGA synthesis 32 – 34 .…”