Browsing by Author "Abd El-Ghaffar, M. A."
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Item Biodegradable polymeric microcapsules for sustained release of riboflavin(ELSEVIER SCIENCE BV, 2016) Abd El-Hay, A. M.; Naser, A. M.; Badawi, A.; Abd El-Ghaffar, M. A.; Abd El-Wahab, H.; Helal, Doaa A.In the current study, a series of polylactic acid and polylactic-co-glycolic acid were prepared in an easy, simple, safe and economically feasible way with yield% greater than 90%. Studying the effect of a catalyst on polymerization process was performed. Riboflavin (RF) was chosen as a model drug and microencapsulated in different (drug: polymer) ratios to modify its performance via o/w emulsion solvent evaporation technique and characterized in terms of the morphology and entrapment efficiency (E.E.) and evaluated via in vitro RF release studies. It has been found that, the release rate consists a burst release at the first 12 h, followed by a gradual release over 3 days. The cumulative riboflavin release from these microcapsules formulations at the end of 3 days was 70% and 80% for PDLA and PDLAGA respectively. The kinetics of release profiles were zero order. The highest (E.E.) of RF obtained among all formulations was 85%. (C) 2016 Elsevier B.V. All rights reserved.Item Micro-emulsion co-polymerisation of butyl acrylate with acrylic acid as binder for textile pigment printing(EMERALD GROUP PUBLISHING LIMITED, 2014) Abd El-Ghaffar, M. A.; Kantouch, Fayza A.; Mahmoud, Zainn M.; Haggag, Karima; Hashem, Ahmed I.; Ramadan, Abdelrahim A.Purpose - The purpose of this paper is to prepare nano size micro-emulsion co-polymer particles based on butyl acrylate (BA)/acrylic acid (AAc) with high monomer/surfactant ratio. The study involved the application of the prepared micro-emulsions co-polymers as textile pigment printing binders. Design/methodology/approach - The micro-emulsion co-polymerisations processes were carried out with different mixtures of BA and Mc using modified process. Sodium dodecyl sulphate (SDS) and potassium peroxy disulphate/glucose were used as emulsifier and redox initiator, respectively. The prepared emulsion co-polymer was characterized via spectroscopic measurements, FT-IR, H-1-NMR and transmission electron microscope (TEM), in addition to thermal analysis. The prepared micro-emulsion co-polymers were applied as binders for pigment printing process onto cotton fabric, polyester and cotton/polyester blend by using flat screen technique. The optimum curing conditions were determined, colour strength and fastness properties of pigment printed areas to light, washing, perspiration and rubbing were evaluated. In addition, stiffness of the prints was studied. Findings - The achieved results indicated that particle size and homogeneity of the prepared micro-emulsions depend on monomers weight ratio, initiator and emulsifier concentrations. On the other hand, the prints obtained using the prepared binders with optimum conditions have satisfactory fastness, good handle and high colour yield. Research limitations/implications - Monomers were continuously and slowly added into the polymerising system with mild stirring to avoid disturbing the stability of the micro-emulsion. Also, emulsifier and initiator concentrations should be controlled to avoid coagulation. Practical implications - The research provides textile pigment printing binder with nano particle size within the range of 24-48 nm. Using the prepared nano binders in pigment printing enhances the stiffness, handle, and fastnesses properties of the prints. Originality/value - The prepared co-polymer binders showed high-performance physico-mechanical properties; in addition, the ultimate goal of this study is to prepare a nano size binder with high monomer/surfactant ratio using a modified micro-emulsion process.