Graft copolymerization of methyl methacrylate upon gelatin initiated by benzoyl peroxide in aqueous medium

Abstract

The graft copolymerization of methyl methacrylate upon gelatin was studied using benzoyl peroxide as an organic initiator in aqueous medium. The grafting reactions were carried out within the 65–90°C temperature range, and the effect of monomer and initiator concentrations on the graft yield were also investigated. The maximum graft yield was obtained at a benzoyl peroxide concentration of 0.20 × 10−2 mol/L and the optimum temperature was 80°C. Thermogravimetric analysis showed that the thermal stability of gelatin increased as a result of grafting. Further, such changes in the properties of methyl methacrylate‐grafted gelatin as density, moisture regain, and water uptake were also determined. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1547–1556, 1999

Polymer gel dosimetry

“…Although no hard evidence has been published for methacrylic acid based polymer gel dosimeters to date, it is assumed that in these polymer gel dosimeters the methacrylic acid polymer chains react with the gelatin in a process called ‘graft polymerization’ (Stejskal et al 1988, Keles et al 1999). This assumption is based on the observation of physical properties of polymer gel dosimeters irradiated to different doses such as the completely different characteristics of ultrasonic speed and elasticity modulus (Mather et al 2002a), the different characteristics of restricted molecular self-diffusion of the water molecules, the melting temperature of both gels, the chemical stability of the gels (De Deene et al 2002b) and the dose– R 2 response curves obtained for different irradiation temperatures.…”

Radiation Dosimetry by Use of Radiosensitive Hydrogels and Polymers: Mechanisms, State-of-the-Art and Perspective from 3D to 4D

“…It is believed that as a result of the change in relative monomer/cross-linker ratio during the radiation and the varying size of polymer aggregates, the intertwined polyacrylamide network is not uniform on the microscopic level. Other studies on PAG gels have also shown large heterogeneities with different gel densities [ 32 , 33 , 228 , 231 ].…”

“…Another source of non-linearity of the radiation dose response is attributed to a different reaction rate of the two comonomers. The different reaction rates of the co-monomers lead to a shift in the instantaneous relative co-monomer concentration [ 227 , 228 ]. Baselga et al distinguish three different reaction steps in the cross-linking co-polymerization of an AAm/Bis aqueous solution: a pre-gel step, gelation and post-gel reactions [ 229 ].…”

Electroresponsive Polyacrylamide-grafted-xanthan Hydrogels for Drug Delivery

“…Another advantage of this grafted copolymer is the easy conversion into an ionic form by the hydrolysis of the amide groups [26][27][28][29]. Xanthan gum (XG) is a high-molecular weight anionic extracellular polysaccharide that is produced by Gram-negative bacterium, Electroresponsive PAAm-g-XG Hydrogel Xanthamonas campestris.…”