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Multiblock ethylene-1-butene copolymers (PEB-n) with graded ethylene content (where n is the number of ethyl branches per 100 backbone carbons) represent efficient cold filter plugging point (CFPP) depressants for crude oils and middle distillates. The aggregation behavior and the interaction with wax molecules of a tetrablock PEB-2.6/PEB-6.0/PEB-10.9/ PEB-13.2 and triblock PEB-6.5/PEB-8.9/PEB-10.1 copolymers in decane solutions were investigated over a wide temperature range by combining different small-angle neutron scattering techniques and optical microscopy. The experimental results revealed in the decrease of temperature formation and evolution of multisized structural levels showing a hierarchical organization on the length scale from 1 nm up to 10 μm. One-dimensional polymer aggregates arising as initial structures associate and branch that lead to the occurrence of complex macroaggregates with diffusive interfaces and sizes of several microns. The one-dimensional copolymer structure shows longitudinal density modulation and micellar-like substructures in neat polymer solutions. When wax is added, this structure becomes more homogeneous in decrease of temperature as a consequence of the cocrystallization of wax and copolymer. The wax crystallization in board-like objects of much smaller size than required by the CFPP criterion of oil and refinery industry (filter mesh size of 45 μm) is templated and controlled by the assembling features of the crystalline-amorphous PEB-n multiblock copolymers.

The structures of a range of PSS combs in aqueous solutions were characterized using SLS, DLS, SANS and SAXS. Combined SLS and SANS data indicated that the comb polyelectrolytes adopted extended cylindrical structures in dilute solutions. The degree of extension of the side-chains was analyzed by fitting the data with a novel cylindrical form factor using a variable number density of monomers. The results were in agreement with hydrodynamic radii from DLS measurements. Addition of salt to the samples caused a contraction of the cylindrical morphology, but the chains continued to adopt relatively extended conformations. In semi-dilute solutions a universal behaviour, indepedent of the comb topology, was found for the screening length in SAXS measurements.

Random crystalline–amorphous copolymers containing ethylene and butene segments, yielded from dilute-solution, and self-assembled to one-dimensional, needle-shaped aggregates, can modify wax crystal structures through the cocrystallization of the copolymer and wax molecules into hairy platelets. These copolymers show selectivity in their wax crystal modification capacities that depends on the ethylene content of the backbone. Thus, it has been qualitatively established that a copolymer containing larger crystallizable polyethylene sections [poly(ethylene butene) with 7.5 ethyl branches per 100 backbone carbons (PEB-7.5)] is very efficient for longer wax molecules (C36), whereas for shorter waxes (C24), its efficacy diminishes. Here we present a quantitative evaluation of the small-angle neutron scattering results obtained in a complex study of the self-assembling behavior of PEB-7.5 and paraffin waxes (C24 and C36) in decane and of cocrystallization for different polymer–paraffin combinations and solution conditions. The richness of the morphologies was evaluated with a contrast variation technique and the application of structural models. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3113–3132, 2004

In the present work, a quaternary CoCrFeNi high entropy alloy (HEA) is investigated by means of high energy synchrotron X-ray diffraction (SYXRD) and small angle neutron scattering (SANS). At the as-forged state, the microstructure of CoCrFeNi HEA is pure austenite. The as-cast dendritic structure has been eliminated by the hot forging at about 1100 °C and the average grain size obtained is approximately 11.6 μm. The result shows pronounced lattice distortion phenomenon in CoCrFeNi HEA, which supposedly contributes to the solid solution strengthening of the alloy. The CoCrFeNi HEA exhibits good yield strength (Rp0.2 = 710 MPa at room temperature and Rp0.2 = 660 MPa at 500 °C). The small angle neutron scattering results further indicate the local ordering effect in the fcc solid solution of CoCrFeNi HEA at both room temperature and at 500 °C after tensile deformation.

Inelastic neutron scattering (INS) measurements of the vibrational frequencies in δ-Zr hydride containing uranium, ZrH 1.6 U 0.32 , have been performed in the range of high temperatures (between 293 and 973 K) at the DIN-2PI time-of-flight spectrometer at the IBR-2 pulsed reactor of JINR, Dubna. From the temperature dependence of the generalized vibrational density of states (GVDS), information on the H potential has been obtained. Also the high frequency limit of lattice vibrations as well as the frequency of optical vibrations have been studied as functions of temperature. Starting from basic properties, the main thermodynamic functions, the characteristic Debye and Einstein temperatures and the total specific heat have been derived.

The vibrational frequencies of D in δ and e deuterides of Zr have been measured by inelastic neutron scattering. From the experimental data analyzed in terms of the generalized vibrational density of states new information on the H(D) potential in Zr have been obtained. Performing an accurate analysis of the high energy range of scattering spectra, the distribution of D atoms on the available interstitial sites in fcc and fct Zr lattices has been studied.

The changes of the dynamic properties of the zirconium lattice at transition from pure metal to different hydride and deuteride phases have been studied by investigating the generalized vibrational density of states (GVDS) or Zr, ZrH 1.6 , ZrD 1.6 , ZrH 2 , ZrD 2 and ZrH 1.6 U 0.32 in the region of the host lattice modes. The spectra obtained from inelastic neutron scattering (INS) measurements have been analysed in terms of the classical Debye model. The dependence of the high-frequency limit of lattice vibrations to different regular structures of zirconium atoms and its correlation with the main thermodynamic quantities, lattice specific heat C V and Debye temperature θ D have been reported.