Surface Modification of Acrylonitrile Copolymer Membranes by Grafting Acrylamide. II. Initiation by Fe2+/H2O2

Abstract

Surface modification of membranes of an acrylonitrile copolymer (PAN) containing 5.5% methyl methacrylate and 4.0% sodium methylpropylenesulfonate by grafting acrylamide (AAm) with ferrous ammonium sulfate/H 2 O 2 as an initiator in aqueous medium was studied. The grafted copolymer was verified by infrared spectra, X-ray photoelectron spectroscopy, and a scanning electron microscope (SEM). From the SEM photos, we know that the AAm homopolymer branches were grafted onto the surface of the membrane and the morphology of the PAN membrane did not change. The results showed that the extent of grafting was varied with some parameters, such as the pH value of the medium, reaction time and temperature, and concentration of AAm and H 2 O 2 . The results of the water-absorption percent of the membrane showed that the wettability of the modified PAN membrane was improved.

Modification ofHibiscus cannabinusfiber by graft copolymerization: application for dye removal

“…The kinetic energy of free radicals increases due to rise in temperature. This enhances the probability of self-coupling of free radicals or growing chains of monomers with each other leading to termination [35]. With the initial increase in time, graft yield increased and reached up to the optimum value at 120 min and decreased with further increase in reaction time ( Fig.…”

“…The effect of reaction temperature on percent grafting of AAc onto H. cannabinus fiber was observed. The behavior of variation of percent grafting with temperature could be attributed to the fact that with the initial rise in temperature, the kinetic energy of the molecules increased and more radicals drifted at faster rate onto the backbone of fibers, resulted in the increase in grafting yield [21,35]. Thus, with the initial increase in temperature, graft yield increased which reached up to the optimum value at 60˚C and started to decrease when further reaction temperature increased ( Fig.…”

Effect of reaction conditions on the thermal stability of polystyrene grafted oil palm empty fruit bunch (OPEFB) fiber

“…In addition, the reactivity of the monomer was also increased, thus producing more grafted product. The percentage grafting decreased at 70°C due to the increase of free radicals leading to termination [29]. The decrease in percentage grafting was also due to the increase of homopolymerization normally favored at high temperatures [30].…”

Functionalizing of polyurethane surfaces by photografting with hydrophilic monomers

“…The wettability of the membrane was determined by using the water-absorption method. 8 The membrane was soaked in deionized water in a beaker at room temperature for at least 24 h. It was then removed, blotted dry, and weighed immediately. The water absorption percent was defined as the difference of the wet mass (w 3 ) and dry mass of the membrane (w 1 ): water absorption percent (%) ϭ (w 3 Ϫ w 2 )/w 2 ϫ 100%.…”