The synthesis and characterization of different series of methyl methacrylate/hydroxyethyl methacrylate (MMA/HEMA) copolymeric nanoparticles with different monomer feed compositions and utilization of them in entrapment and controlling the release of hydrophilic drug (sodium warfarin) and hydrophobic drugs (ibuprofen and praziquantel) were investigated. The polymeric nanoparticles and their entrapment with drugs were prepared using oil‐in‐water (O/W) differential microemulsion polymerization technique in the presence of polyvinyl pyrrolidone and polyethylene glycol as biocompatible emulsifiers as well as ammonium persulfate as an initiator. The effect of HEMA content in the monomer feed composition on the colloidal properties was studied, and it is found that the particle size Dv, turbidity, and the negative charge increase with increasing of HEMA content but the surface tension decrease. Moreover, the entrapment efficiency (EE) is affected by the content of HEMA in the monomer feed composition, the drug hydrophobicity, and the monomer to drug ratio. It is concluded that, EE into MMA/HEMA in monomer feed composition as 90/10, 70/30, and 50/50 is found to be (95.3–98)%, (84–96.9)%, and (69.5–94.6)% for sodium warfarin (with high hydrophilicity) as well as, ibuprofen and praziquantel (with high hydrophobicity), respectively. The entrapment of drugs in polymeric nanoparticles is confirmed by IR‐spectroscopy and transmission electronic microscopy. In vitro drug release experiments show that controlled release of drugs from copolymeric nanoparticles depend on HEMA content, the monomer to drug ratio, and the physiological pH. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

No abstract

No abstract

SYNOPSISComposites of styrene-butadiene rubber were prepared with three different types of lead oxide, namely, monolead oxide ( PbO) , lead dioxide ( PbOz), and red lead oxide ( Pb304).Concentrations of PbsO, ranging between 17 and 88 wt % were utilized, whereas 87 wt 7% was used for PbO and Pb02. The prepared composites were investigated for their gamma radiation shielding properties. Moreover, physical and mechanical properties, and electrical conductivity were measured for both the unirradiated and irradiated composites. The highest value obtained for the linear absorption coefficient was 0.424 cm-' for 88% Pb304.

The kinetics of emulsion polymerization of vinyl acetate using the redox system potassium persulfate – acetone sodium bisulfite as initiator is studied. The effect of the reaction conditions on the rate of polymerization and on the number and size of the formed particles is established. The polymerization proceeded smoothly till high conversion and yielded stable emulsions. The apparent activation energy for the polymerization system has been calculated.

Nanosized particles derived from poly(methyl methacrylate) as well as copolymer of methyl methacrylate (MMA) and 2hydroxyethyl methacrylate (HEMA) were synthesized by differential microemulsion technique in the presence of ammonium persulfate as water-soluble initiator. The polymerization was stabilized by adding biologically safe emulsifiers namely the sodium dodecyl sulfate (SDS) or polyvinyl pyrrolidone (PVP) either alone or in conjunction with polyethylene glycol. The turbidity measurements, surface tension, f potential, and morphological characterizations of the obtained nanosized poly MMA and its copolymer with HEMA in different monomer feed compositions were investigated. It is found that increasing HEMA content leads to increase in the particle size, turbidity measurements but the negatively charged f potential decreased. However, when SDS is used, the surface tension of the prepared lattices increased, whereas it is decreased by using PVP. Kinetic studies of (MMA/HEMA) in ratio of 95/5 wt % in the presence of SDS or PVP revealed that the emulsifier concentration has a considerable effect on the rate of polymerization and the power of the emulsifier. The entrapment of drug was investigated using two active molecules different in water solubility (sodium warfarin and ibuprofen). It is noted that entrapment efficiency is independent of HEMA content in the monomer feed composition but dependent on type of drug and the amount of drug introduced. Hence, higher entrapment efficiency was attained for sodium warfarin (more hydrophilic) than that of ibuprofen (more hydrophobic) and they were 95.5 and 85%, respectively.

No abstract

Porous polymethacrylic acid-co-triethylene glycol dimethacrylate (MAA-co-3G) and polyacrylic acid-co-triethylene glycol dimethacrylate (AA-co-3G) were prepared by four different polymerization techniques, namely, suspension, dispersion, seed, and microemulsion polymerization using an inert diluent (n-hexane and polystyrene). The morphology and porosity of the obtained polymers were examined by means of a scanning electron microscope. The surface areas of the obtained polymers were determined colorimetrically. The copolymers were modified by hydroximation and chlorination using hydroxyl amine and thionyl chloride, respectively. The effect of polymerization type, surface area, modification, and pH on the protease enzyme immobilization over poly(MAA-co-3G) and poly(AA-co-3G) was examined. The enzyme activity was measured by means of a spectrophotometer. The reactivity ratios of the two monomers MAA and 3G were determined by means of the elemental analysis method.