SYNOPSISThe grafting of acrylic acid onto poly(ethy1ene terephthalate) fibers subjected to a noswelling treatment using benzoyl peroxide was investigated. The temperature was found to increase the graft yield. The grafting yield increased up to a benzoyl peroxide concentration of 4.0 X M and slightly decreased at higher initiator concentrations. The effects of solvents such as dimethylformamide, dimethylsulfoxide, pyridine, and some alcohols upon the grafting were examined by carrying out the graft copolymerization at various water/ solvent ratios. Pyridine was found to inhibit the grafting totally. The properties of the grafted fibers such as density, diameter, dyeability, and moisture regain were also investigated. It was concluded due to the observations made in these properties that the grafting took place mainly in the subsurface regions of the fibers and there occurred a diffusion barrier after the grafting value of 8-9%. The overall activation energy for grafting was calculated to be 9.9 kcal/mol.
SYNOPSISThe grafting of acrylic acid onto poly(ethy1ene terephthalate) fibers subjected to a noswelling treatment using benzoyl peroxide was investigated. The temperature was found to increase the graft yield. The grafting yield increased up to a benzoyl peroxide concentration of 4.0 X M and slightly decreased at higher initiator concentrations. The effects of solvents such as dimethylformamide, dimethylsulfoxide, pyridine, and some alcohols upon the grafting were examined by carrying out the graft copolymerization at various water/ solvent ratios. Pyridine was found to inhibit the grafting totally. The properties of the grafted fibers such as density, diameter, dyeability, and moisture regain were also investigated. It was concluded due to the observations made in these properties that the grafting took place mainly in the subsurface regions of the fibers and there occurred a diffusion barrier after the grafting value of 8-9%. The overall activation energy for grafting was calculated to be 9.9 kcal/mol.
The modification of biomaterials by radiation induced grafting is a promising method to improve their bioactivity. Successful introduction of carboxyl and amine functional groups on the surface of a polytetrafluoroethylene membrane was achieved by grafting of acrylic acid (AA) and 2-aminoethyl methacrylate hydrochloride (AEMA) using simultaneous gamma irradiation grafting. Chemical characterization by attenuated total reflectance Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy confirmed the presence of amine and carboxylate functionalities and indicated that all protonated amines formed ion pairs with carboxyl groups, but not all carboxyl are involved in ion pairing. It was found that the irradiation doses (2, 5, or 10 kGy) affected the grafting outcome only when sulfuric acid (0.5 or 0.9 M) was added as a polymerization enhancer. The use of the inorganic acid successfully enhanced the total graft yield (GY), but the changes in the graft extent (GE) were not conclusive. Dual functional films were produced by either a one- or a two-step process. Generally, higher GY and GE values were observed for the samples produced by the two-step grafting of AA and AEMA. The in vitro mineralization in 1.5× simulated body fluid (SBF) induced the formation of carbonated hydroxyapatite as verified by FITR. All samples showed an increase in weight after mineralization with significantly larger increases observed for the samples which had the 1.5× SBF changed every third day compared to every seventh. For the dual functional samples, it was found that the sample grafted by the one-step method shows a significantly higher increase in weight despite a much lower GY compared to the sample prepared by the two-step method and this was attributed to the different architecture of grafted chains.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.