Materials Literature
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Abstract In a previous article, 1 we reported on the interaction of cellulose with NH 3 /NH 4 SCN by using solid state CP / MAS 13 C‐NMR, wide‐angle X‐ray and other techniques. It appears that during an imposed temperature cycling sequence, specific cellulosic inter‐ and intramolecular hydrogen bonds are broken as pol…
Abstract Ammonia/ammonium thiocyanate (NH 3 /NH 4 SCN) is an excellent swelling agent and solvent for cellulose, even at a high degree of polymerization. Because polymorphic conversion in cellulose has been a long‐standing, perplexing, troublesome problem, we have undertaken to study that mechanism. Solid state CP/MAS…
Abstract An improved technique for casting highly oriented films of block copolymers from solutions subjected to flow is presented. Polymer solutions were rolled between two counter‐rotating adjacent cylinders while at the same time the solvent was allowed to evaporate. As the solvent evaporated, the block copolymers…
Abstract Bilayer film Fourier transform infrared (FTIR) model experiments are designed to provide a well‐defined interface for study which can be probed by infrared spectroscopy during the interdiffusion and reaction of two reactive polymers. This provides a model experiment to determine the kinetics and extent of rea…
Abstract Gel spinning of poly(vinyl alcohol) (PVA) was attempted from the PVA dope prepared from the mixture of dimethyl sulfoxide (DMSO) and water. The DMSO/H 2 O = 80/20 (w/w) mixture and methanol were found to be the best solvent for the spinning dope and the coagulant, respectively, to give PVA fiber with the high…
Abstract Nylon‐11 polymorphs have been studied by x‐ray diffraction and by infrared spectroscopy. A γ or γ‐like phase of Nylon‐11 was produced by treating the metastable δ' phase with gaseous HCl or DCl and then exposing the resulting complex (amidonium salt) to 100% RH H 2 O or D 2 O vapor. An oriented form of the γ…
Abstract The structure and compatibility of poly(vinyl alcohol)‐silk fibroin (PVA/SF) blend films were analyzed by differential scanning calorimetry (DSC), thermomechanical (TMA) and thermogravimetric (TGA) analysis, x‐ray diffractometry, and scanning (SEM) and transmission (TEM) electron microscopy. DSC curves of PVA…
Conjugated organic compounds with 3-phenyl-5-isoxazolone or N,N'-diethylthiobarbituric acid acceptors have large first molecular hyperpolarizabilities (beta) in comparison with compounds with 4-nitrophenyl acceptors. For example, julolidinyl-(CH=CH)(3)-CH=N,N'- diethylthiobarbituric acid, which has 12 atoms between th…
Instron Residual Seal Force (IRSF) of glass vial/rubber closure systems was determined using an Instron 4501 Materials Testing System. Computer programs were written to process raw data and calculate IRSF values. Preliminary experiments indicated both the appearance of the stress-deformation curves and precision of th…
An experimental study of the interaction of weak shock waves in a liquid with bubbles and solid particles has been conducted. Cavities were punched, and solid particles were cast, into a thin sheet of gelatine clamped between two transparent blocks. A shock of pressure 0.3 GPa was introduced by impacting the gelatine…
Abstract The blending effect of poly(vinyl chloride) (PVC) with relatively higher molecular weight (HMW‐PVC) and relatively lower molecular weight (LMW‐PVC) has been investigated by measuring various thermal stability and fusion times. The thermal stability of the blended PVC is improved when the small amount of LMW‐P…
Abstract The intrinsic viscosities of blends of poly(vinyl chloride)/poly(ethylene‐ co ‐vinyl acetate) (PVC/EVA), poly(vinyl chloride)/poly(styrene‐ co ‐acrylonitrile) (PVC/SAN), and poly(ethylene‐ co ‐vinyl acetate)/poly(styrene‐ co ‐acrylonitrile) (EVA/SAN) have been studied in cyclohexanone as a function of blend c…
Abstract Nylon 6–clay hybrid (NCH) is a molecular composite of nylon 6 and uniformly dispersed silicate layers of montmorillonite. We found that the phase with the high melting temperature (HMT phase) in the NCH annealed under elevated pressure. The melting temperature of the HMT phase was 240°C. Nylon 6 annealed unde…
We show that thin films 3000 Å in thickness of the icosahedral AlCuFe phase can be formed by solid state diffusion of sputtered Al, Cu, and Fe layers. As for bulk materials, we propose that the icosahedral phase grows by diffusion of the Cu in the Al3Fe layer previously formed by interdiffusion of the Al and Fe layers…
Properties of molecular transport in nanometer channels where the molecules move all or most of the time in interaction with the surface are shown to differ significantly from those in macroscopic structures. Apart from strong deviations from ordinary flow in its dependence on channel dimensions and temperature, under…
Powder and foils containing up to 40% alpha"Fe 16 N 2 have been prepared by annealing nitrogen-martensite. The magnetization of the alpha" phase is deduced from magnetization measurements, coupled with a quantitative phase analysis based on Mossbauer spectra. At room temperature the values are 225-270 J T -1 kg -1 cor…
We describe the fabrication and characterization of self-assembled gold island arrays on diblock-copolymer thin films. The natural tendency of these polymers to form ordered phases is used to induce selective aggregation of evaporated gold metal during an annealing process. We obtain well-defined, nanoscale island arr…
Abstract Methylene diphenyl isocyanate (MDI)‐based polyurethane flexible foams were decomposed by alkanolamines without a catalyst at 150°C. The decomposition products were completely separated into two layers. The upper liquid layer was a polyether polyol, and the lower liquid layer was methylene diphenyl amine (MDA)…
Porous silicon (p type) has been exposed to several chemical vapors at various partial pressures. The quenching of the photoluminescence by the adsorbates has been quantified and correlation to the electrical conductivity of the porous silicon sample has been studied. Some gases, e.g., water and benzene, have a small…
We investigate the phase diagram of mixtures of charge stabilized polystyrene spheres of two different sizes in the hard-sphere limit. We observe bulk phase separation into two disordered phases and find a new ordered phase located on the cell walls. The ordered phase occurs at volume fractions as low as 0.2, much les…