Materials Literature
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Abstract A regenerated cellulose film (RC) was coated with a graft‐IPNs coating, which was composed of castor oil‐based polyurethane and 2.8 wt % nitrolignin (NL), to obtain water‐resistant films. The effects of NCO/OH molar ratio and different polyols, such as 1,4‐butanediol (BDO) and trimethanol propane (TMP), on th…
Magnetization of Mn 1−x Zn x PS 3 in fields up to 35 T is presented. Small amounts of weakly bound moments have been observed for the more diluted compounds with a preferential orientation equal to that of the long-range antiferromagnetic order. The width of the spin-flop transition can be described by static domain w…
We calculate the short-time translational and rotational self-diffusion coefficients of mixtures of colloidal hard spheres. The influence of hydrodynamic interactions is accounted for by a series expansion of the two-body mobility tensors, and by considering the leading hydrodynamic three-body term. Explicit results a…
Abstract A series of chitosans with various molecular weights from 1.2 × 10 3 to 30.0 × 10 4 were prepared by oxidative degradation with H 2 O 2 and characterized by IR, 13 C‐NMR, and gel permeation chromatography. Their carboxylic contents increased with a decrease in molecular weight ( M w ). The moisture‐absorption…
CuCN has been found to be polymorphic. The structure of one form, which is isomorphous with AgCN, has been determined using the information provided by Bragg and diffuse neutron scattering. The polymorph of CuCN formed has been found to depend on the Cu/CN ratio used in its preparation.
Abstract Regenerated cellulose/chitin blend films (RCCH) were satisfactorily prepared in 6 wt % NaOH/4 wt % urea aqueous solution by coagulating with 5 wt % CaCl 2 aqueous solution then treating with 1 wt % HCl. The structure, miscibility, and mechanical properties of the RCCH films were investigated by infrared, scan…
As a result of inflammatory processes, plaque formation on dental titanium implants often leads to clinically pathogenic situations. This special biofilm formation on (bio)materials in contact with saliva is initiated by ionic and protein interactions. In this interfacial process, albumin becomes a main constituent of…
Benzylic, allylic, and aliphatic alcohols are oxidized to aldehydes and ketones in a reaction catalyzed by Keggin-type polyoxomolybdates, PV(x)Mo(12-x)O(40)(-(3+x)) (x = 0, 2), with DMSO as a solvent. The oxidation of benzylic alcohols is quantitative within hours and selective, whereas that of allylic alcohols is les…
Comparative studies on the four ATiO 3 compounds are carried out to investigate the different ferroelectric behaviors of ATiO 3 on the basis of the experimental and theoretically optimized lattice structures. The stability predicted from the calculated total energies is in agreement with experimental observation. The…
Diamond is in many ways the perfect semiconductor material for high power electronic applications. But difficulties with making diamond films with the required purity and structural integrity has prevented widespread application. In his Perspective, [Amaratunga][1] highlights the report by [ Isberg et al .][2], who ha…
RESS experiments were performed on the semicrystalline fluoropolymer poly(heptadecafluorodecyl acrylate) [poly(HDFDA); M w = 254 000, M w / M n = 2.95] from solutions in carbon dioxide, with both concentration and degree of saturation being varied in a systematic manner. Phase-behavior measurements were carried out be…
Molecular structure and fundamental vibrational frequencies of benzimidazole (BZI) are reported using ab initio-Hartree−Fock (HF) and density functional theory (DFT) methods at different levels of calculation. Observed polarized IR and Raman fundamentals of polycrystalline, single crystal, KBr−BZI disks, and gaslike s…
Abstract Several polymers were evaluated as candidates for the production of high‐performance microcellular closed‐cell foams. The polymers involved were a polysulfone, a polyethersulfone, a polyphenylsulfone, a polyetherimide, and a poly(ether ketone ketone), and their suitability was gauged by measuring rates at whi…
A fine Au powder, with a mean particle diameter of 4 nm, has been successfully fabricated. The crystalline structure of the 4 nm Au nanoparticles remains in fcc symmetry. No structural changes were found between 15 and 450 K. A crossover from a positive thermal expansion at low temperatures to a negative thermal expan…
A propanesulfonic acid-derivatized mesoporous SBA-15 catalyst was synthesized, characterized in terms of surface properties, and shown to have high selectivities for alcohol coupling to form ethers, specifically from methanol and isobutanol coupling to form methyl isobutyl ether with no detectable formation of butenes…
Micro-Raman scattering was used to characterize spinel CoFe 2 O 4 at high temperature up to 870 K and under an external magnetic field up to 6.0 kOe. It was found that the rapid increase in the linewidth of the Raman modes was related to the inter-site cation migration starting at ∼390 K. A red-shift of the Raman peak…
Abstract The glass transition temperature of the hard‐segment phase and the storage modulus of segmented polyurethane increased substantially in the presence of a small amount of tethered nano‐sized layered silicates from montmorillonite compared with their pristine state (by 44°C and by 2.8‐fold, respectively). Furth…
Ozonation of single-walled carbon nanotubes (O 3 -SWNTs) produces oxygenated functional groups, e.g., carboxylic acid, ester, and quinone moieties, which can be removed from the SWNT surface by heating at 600−800 °C. The annealed SWNTs appear to be pristine. The electrical resistance of the O 3 -SWNTs depends on the d…
Abstract During mechanical loading–unloading cycles shape‐memory alloys (SMA) are able to undergo large deformations without showing residual strains ( pseudoelasticity ) or recovering them through thermal cycles ( shape memory effect ). Motivated by stress‐induced solid phase transformations, these unique behaviours…
A recent theory that determines the properties of disordered solids as the solid accumulates damage is applied to the special case of fiber bundles with global load sharing and is shown to be exact in this case. The theory postulates that the probability of observing a given emergent damage state is obtained by maximi…