No abstract

Uniform-sized monodisperse cerium oxide nanoparticles were prepared in a one-step reaction. A ceriumoleate complex was heated in an organic solvent with high boiling point to decompose and form nanocrystals. The products were characterized by Raman spectroscopy, XRD, UV-visible spectroscopy, room-temperature photoluminescence spectroscopy, and TEM. The TEM images and UV-visible spectra show that the CeO 2 particles prepared are uniform nanosized and absorb UV light in the range of 250-400 nm. The size of the nanoparticles prepared can be controlled from 5 to 20 nm by choice of solvent, reaction time, and reactant concentration without any size sorting. The nanoparticles show a strong violet/blue emission at 400 nm in photoluminescence spectrum (PL). The PL emission was found to be sensitive to the particle size.

No abstract

No abstract

New epoxynorbornane linseed oils (ENLOs) were prepared as a function of the norbornene content. The cationic photopolymerization of ENLOs was investigated with real‐time infrared spectroscopy and photo‐differential scanning calorimetry. The effects of reactive and nonreactive diluents on the polymerization rate were also studied. The diluents reduced the viscosity of the formulations, markedly accelerated the rate of polymerization of ENLOs, and increased their final conversions. The effects of the reactive diluent were compared for ENLOs and epoxidized linseed oil. The relative reactivity of the oxiranes was not as important as the viscosity of the reacting system, and it was proposed that the cationic photopolymerization of ENLOs was controlled by diffusion. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3440–3456, 2003

No abstract

2-Hydroxyethyl methacrylate (HEMA)-rich latex is synthesized via a semibatch monomer-starved emulsion polymerization process. Six emulsion polymerizations, containing 0-40 mol% HEMA in monomer composition, are synthesized and compared. Calculations of mass balances are made in order to predict fi nal particle size and particle size development during the course of polymerization. Average particle sizes obtained by dynamic light scattering (DLS) are compared to ultrasound acoustic attenuation spectroscopy (UAAS) and transmission electron microscopy (TEM). The infl uence of HEMA on polymerization on the onset of secondary nucleation is evaluated using each technique. The DLS, TEM, and UAAS secondary nucleation data are compared to physical latex blends of small and large particles. The blend data are consistent with the secondary nucleation data. Additionally, conductivity and surface tension are monitored. TEM, atomic force microscope (AFM), and UAAS are found to be more appropriate methods than the widely used DLS for particle size and particle size distribution characterization in this system. Increasing HEMA content to 20 mol% results in formation of signifi cant amount of secondary particles via proposed homogeneous nucleation of HEMA-rich oligomers.

New inorganic/organic hybrid coatings containing epoxidized soybean oil were prepared. Three sol-gel precursors [titanium (IV) i-propoxide, titanium (IV) di-i-propoxide bis-acetoacetonate, and zirconium n-propoxide] were utilized as the inorganic phase. Various coating properties, including adhesion, hardness, impact resistance, flexibility and tensile properties, were investigated as a function of sol-gel precursor type and concentration. All ceramer coatings exhibited excellent flexibility and hardness. Tensile strength and hardness increased with sol-gel precursor concentration. A slight decrease in adhesion and impact resistance was observed with increasing precursor content.