EFFECT OF COMPOSITION AND PROCESSING CONDITION ON MICROSTRUCTURAL PROPERTIES AND DURABILITY OF FLUOROPOLYMER/ACRYLIC BLENDS

Fluoropolymer blends have been widely used as binders for exterior coatings because of their excellent resistance to ultra-violet (UV) radiation as well as to many corrosive chemical agents.It is known that the fluorinated component usually has a lower glass transition temperature and easily crystallizes in the final structure depending upon the blend composition and sample annealing condition.We investigated the effect of blend composition and annealing process (slow and fast cooling) on the surface mor...     

Decoherence via the dynamical casimir effect

We derive a master equation for a mirror interacting with the vacuum field via radiation pressure. The dynamical Casimir effect leads to decoherence of a superposition state in a time scale that depends on the degree of "macroscopicity" of the state components, and which may be much shorter than the relaxation time scale. Coherent states are selected by the interaction as pointer states.     

Crystal and molecular structure of bis(tropolonato)-dioxo-(ethanol)uranium(vi)

Crystals of bis(tropolonato)-dioxo(ethanol)uranium(VI) are orthorhombic:a = 12·495(8),b = 8·817(7),c = 15·459(9) Å,Z = 4, space groupPnam. The structure was determined with MoK diffractometer data by standard Patterson and Fourier methods, and was refined by full-matrix least-squares methods toR = 0·049 for 1289 observed reflexions.The coordination plane consists of the four tropolonato oxygen atoms and the oxygen from the ethanol ligand; the uranyl group is perpendicular to it. The molecule lies across the mirror plane, consistent with a boat conformation for the tropolone rings; the dihedral angle between the plane of tropolone ring and the coordination plane is 22·5 °. The deviations of the tropolonato oxygen atoms from the tropolonato plane are 0·08 Å (above) and 0·16 Å (below). It is almost certain that the ethyl group of the ethanol ligand does not lie in the symmetry plane; C(8) is about 0·3 Å on one side of this plane and C(9) is about the same distance on the other, within a satisfactory bonding scheme.     

The synthesis and structure of 5-hydroxy-2-methyl-2-(2-pyridinyl)hexahydro-1,3-pyrimidine

The synthesis and the x-ray structure of 5-hydroxy-2-methyl-(2-pyridinyl)hexahydro-1,3-pyrimidine are reported. The compound was prepared by reaction of 2-acetylpyridine and 1,3-diamino-2-hydroxypropane in a 2:1 molar ratio. The colourless crystals are monoclinic, space group P2₁/c with cell parameters, a = 10.385(5), b = 11.171(5), c = 17.415(6)Å, β = 93.05(37)° for Z = 8. The asymmetric unit of the structure is composed of two independent molecules of the compound which are in the chair form and adopt the same conformation with equatorial -OH and -CH₃ groups and axial pyridine substituents. The packing of the molecule seems to be controlled by two independent hydrogen-bonding sequences.