Phosphonitrilic chloride: 37. Reaction of 1,1-diamino-3,3,5,5-tetrakis (2,2,2-trifluoroethoxy) cyclotriphosphazene with organosilanes

The Spiro compound N₃P₃(OCH₂CF₃)₄(NH)₂Si(CH₃)₂ formed by reaction of 1,1-diamino-3,3,5,5-tetrakis(2,2,2-trifluoroethoxy)cyclotriphosphazene N₃P₃(OCH₂CF₃)₄(NH₂)₂ and dimethyldichlorosilane Cl₂Si(CH₃)₂ is a yellow or orange coloured oil soluble in organic solvents, vapourized at 160°C without decomposition, and not hydrolysed appreciably in boiling water. Linear compounds are formed by reaction of N₃P₃(OCH₂CF₃)₄(NH₂)₂ with diphenyldichlorosilane or phenyltrichlorosilane owing to hindrance of the phenyl radical. These compounds are amorphous or tacky solids, soluble in organic solvents and stable to water.     

Synthesis and properties of poly (organophosphazenes) ionomers [NP(HNC6H5)2−(x+y)(HNC6H4SO3H) x (HNC6H4SO3Li) y ] n

Poly(anilino sulphamicphosphazenes) such as [NP(HNC₆H₅)_2–x (HNC₆H₄SO₃H) _x ] _n for polymer (I) x=0.3 and for polymer (II) x=0.8 were prepared by the reaction of poly(anilinophosphazene) [NP(HNC₆H₅)₂] _n and sulphonic chloride HSO₃Cl in tetrachloroethane solvent several timeS. Also, H protons in the polymer (I) and (II) were prepared from lithum hydroxide in aqueous solution. It was found, by chemical analysis, that the product prepared with (I) and (II) had compositions such as [NP(HNC₆H₅)_1.7 (HNC₆H₄SO₃H)_0.1(HNC₆H₄SO₃Li)_0.2] _n (III) and [NP(HNC₆H₅)_1.2(HN-C₆H₄SO₃Li)_0.8] _n (IV). Also, the resistivity of products (III) and (IV) were determined and found to be 3.3×10⁷ and 1.5×10⁷ cm^–1, respectively.     

Nanocrystallization of Pd74Si18Au8 metallic glass

The crystallization process of Pd₇₄Si₁₈Au₈ amorphous alloy has been investigated by transmission electron microscopy, small angle X-ray scattering and three-dimensional atom probe techniques. Although literature suggests that the alloy decomposes into two glassy phases prior to the crystallization, we found that the crystallization occurs directly from a single amorphous phase by the primary crystallization of fcc Pd–Au solid solution, followed by the polymorphous crystallization of the remaining amorphous phase to a Pd₃Si phase.     

Multicomponent diffusion in phase-separating polymer blends with different frictional interactions: a mean-friction model

We present a compact formula for describing the mean frictional forces acting on a molecule in multicomponent systems. The friction-based diffusion theory of Zielinski and Hanley was extended to newly include the friction-average molar velocity as a reference frame. The results showed that the previous diffusion theories are unified by the friction-average concept by properly choosing the average velocity. The present model based on the diffusivity-related molar average velocity provides better predictions for the diffusive flux in a ternary miscible liquid compared to the other existing theories. The application of the model in phase-separating ternary systems revealed that the introduction of a highly diffusive third component into demixing polymer blends promotes a particular enhancement of the spinodal decomposition due to the difference in the frictional interactions between polymers.     

Design and testing of ITER ECH & CD transmission line components

Initial testing on the Japan Atomic Energy Agency Gyrotron Test Stand of ITER-relevant TL components, has shown reasonable efficiencies, but identified that trapped modes between closely located miter bends, as well as mode conversion at miter bends can lead to excessive heating of the connecting waveguides. General Atomics has designed, built, and will test components to address this issue as well as ITER relevant components that have not been tested at the levels of 1 MW, 170 GHz, for extended pulse lengths. Some of the components that will be tested are ultra low loss miter bends, dc breaks, polarizers, power monitors, bellows, waveguide switches, waveguide cooling clamps, etc. Details of the components and test results will be presented.     

EFFECT OF STEPWISE CHANGE OF DRYING RATE ON MICROSTRUCTURE EVOLUTION IN POLYMER FILMS

The effect of the drying rate of the solvent on microstructure evolution in thin films of immiscible polystyrene/polycarbonate blends was investigated by applying a stepwise change in air velocity. The polymer blend was dissolved in tetrahydrofuran and cast on a glass substrate to form a thin liquid film. The drying rate of the solvent was measured by a gravimetric technique, and the phase-separated structure in the film was observed by optical microscopy. The results indicated that cellular structures of droplet arrays were formed in the phases evolved primarily during the early stage of drying, and the droplets then coalesced in the intermediate stage to form bigger droplets. The size of the first evolved phase decreased with increasing time at a high drying rate, whereas larger droplets were obtained with longer high drying rate regimes. These results suggested that the droplets were induced by secondary phase separation which was strongly affected by the drying rate of the solvent.     

Mechanical fibre optic switching using p.v.d.f. bimorph

An optical fibre switching element has been constructed, based on the electromechanical deformation of a bimorph of piezoclectric polymer, p.v.d.f. (polyvinylidene fluoride). Light transmitted through a fibre was switched between two other fibres situated next to each other by the application of the voltage of 3.5 V r.m.s. at 10 Hz. The insertion loss of this element was 0.7 dB.     

Effect of stress wave shape on the crack propagation velocity in cyclic delayed failure

Crack propagation velocity in delayed failure under superposed repeating load, ($\text{d}\text{a/}\text{d}\text{t)}{}_{\mathrm{R}}$, was compared with that under static load, ($\text{d}\text{a/}\text{d}\text{t)}{}_{\mathrm{S}}$Two peaks appear on the relation between decreasing rate of crack propagation velocity, $\text{1-β = 1 ? (}\text{d}\text{a/}\text{d}\text{t))}{}_{\mathrm{R}}\text{/(}\text{d}\text{a/}\text{d}\text{t)}{}_{\mathrm{S}}$ and frequency, ?, both under sinusoidal and square load. By changing the ratio of holding time at maximum stress intensity factor to that at minimum stress intensity factor in square load, it was deduced that the existence of two peaks on the 1 ? β vs $\text{f}$ curve was caused by an asymmetric interaction between hydrogen atoms and cyclic moving of the position with triaxial tensile stress at crack tip. Moreover, the relation between 1 ? β and $\text{f}$ under the positive or negative saw tooth load could be well explained by the interaction model.