Solid-phase polymerizations at high pressures

1970 ◽  
Vol 23 (3) ◽  
pp. 511 ◽  
Author(s):  
MG Bradbury ◽  
SD Hamann ◽  
M Linton
Keyword(s):  
High Pressure ◽  
Spectral Analysis ◽  
Solid State ◽  
High Pressures ◽  
Solid Phase ◽  
Crystal Form ◽  
Optical Cell ◽  
Itaconic Anhydride ◽  
Temperature Requirements ◽  
Infrared Spectral

The following compounds have been found to polymerize spontaneously in the solid state at pressures in the range 10-50 kbar, at temperatures between 20 and 200�C: acrylamide, p-phenylstyrene, potassium p-styrenesulphonate, itaconic anhydride, maleic anhydride, maleimide, 1,2,3,6-tetrahydrophthalic acid, 1,2,3,6-tetrahydrophthalic anhydride, acenaphthylene, p-benzoquinone, N,N'-p-phenylene-dimaleimide, sulpholene, diphenylacetylene, 8-trioxan. The pressure-temperature requirements for polymerization have been determined in a high-pressure "squeezer" apparatus and in a diamond optical cell which permits infrared spectral analysis of a specimen while it is under compression. Apart from diphenylacetylene and trioxan, the compounds that polymerized were either monosubstituted ethylenes or cyclic 1,2-disubstituted ethylenes. Non-cyclic 1,2-disubstituted ethylenes and tri-substituted and tetra-substituted ethylenes failed to polymerize. There is evidence that shearing stresses played a part in some of the reactions. 1-Allyl-2-thiourea did not polymerize, but transformed from its stable crystal form I to the unstable modification 11.

scholarly journals High-pressure diffraction studies of molecular organic solids. A personal view

2007 ◽  
Vol 64 (1) ◽  
pp. 218-231 ◽  
Author(s):  
Elena V. Boldyreva
Keyword(s):  
High Pressure ◽  
Solid State ◽  
High Pressures ◽  
Experimental Studies ◽  
Personal View ◽  
Organic Solids ◽  
High Pressure Studies

This paper discusses the trends in the experimental studies of molecular organic solids at high pressures by diffraction techniques. Crystallization of liquids, crystallization from solutions and solid-state transformations are considered. Special attention is paid to the high-pressure studies of pharmaceuticals and of biomimetics.

The Possible Importance of Pressure in Metastable Precipitate Formation in Ion Implanted Metals

1988 ◽  
Vol 100 ◽  
Author(s):  
John H. Evans
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Solid Phase ◽  
Inert Gas ◽  
Fine Scale ◽  
Host Matrix ◽  
Driven Cavity ◽  
Precipitate Formation ◽  
Very High ◽  
Metastable Precipitate

ABSTRACTPrompted by the recent discovery that the heavier inert gas atoms implanted into metals precipitate in the solid phase, indicative of very high pressures (,>,1 GPa), the present paper discusses the conditions under which such pressures might be expected. The metal/inert gas results are briefly described and then used as a model to show that the two essential features apart from low or moderate metal temperatures, are the insolubility of the implanted species in the host matrix and its precipitation on a very fine scale. This combination suppresses the bias-driven cavity swelling that would otherwise control vacancy acquisition in an irradiation environment.The extrapolation to other combinations of implanted ion and metal will be discussed. Where the implanted ion is insoluble and precipitates on a scale similar to the inert gas atoms, exact analogy suggests that the precipitates will again be under high pressure. The formation of high pressure phases might not be unexpected and could be a factor in explaining the presence of phases previously thought to be metastable.

scholarly journals High-pressure Seebeck coefficients and thermoelectric behaviors of Bi and PbTe measured using a Paris-Edinburgh cell

2016 ◽  
Vol 23 (6) ◽  
pp. 1368-1378 ◽  
Author(s):  
Jason Baker ◽  
Ravhi Kumar ◽  
Changyong Park ◽  
Curtis Kenney-Benson ◽  
Andrew Cornelius ◽  
...  
Keyword(s):  
High Pressure ◽  
Seebeck Coefficient ◽  
Structural Changes ◽  
High Pressures ◽  
Solid Phase ◽  
Thermal Conductance ◽  
X Ray Diffraction ◽  
Seebeck Coefficients ◽  
Assembly Design ◽  
Relative Change

A new sample cell assembly design for the Paris-Edinburgh type large-volume press for simultaneous measurements of X-ray diffraction, electrical resistance, Seebeck coefficient and relative changes in the thermal conductance at high pressures has been developed. The feasibility of performingin situmeasurements of the Seebeck coefficient and thermal measurements is demonstrated by observing well known solid–solid phase transitions of bismuth (Bi) up to 3 GPa and 450 K. A reversible polarity flip has been observed in the Seebeck coefficient across the Bi-I to Bi-II phase boundary. Also, successful Seebeck coefficient measurements have been performed for the classical high-temperature thermoelectric material PbTe under high pressure and temperature conditions. In addition, the relative change in the thermal conductivity was measured and a relative change in ZT, the dimensionless figure of merit, is described. This new capability enables pressure-induced structural changes to be directly correlated to electrical and thermal properties.

scholarly journals Low Temperature and High-Pressure Study of Bending L-Leucinium Hydrogen Maleate Crystals

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1575
Author(s):  
Kseniya D. Skakunova ◽  
Denis A. Rychkov
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Low Temperatures ◽  
High Pressures ◽  
Solid Phase ◽  
Extreme Conditions ◽  
Pressure Impact ◽  
Solid Phase Transition ◽  
High Pressure Study ◽  
Crystal Fracture

The polymorphism of molecular crystals is a well-known phenomenon, resulting in modifications of physicochemical properties of solid phases. Low temperatures and high pressures are widely used to find phase transitions and quench new solid forms. In this study, L-Leucinium hydrogen maleate (LLHM), the first molecular crystal that preserves its anomalous plasticity at cryogenic temperatures, is studied at extreme conditions using Raman spectroscopy and optical microscopy. LLHM was cooled down to 11 K without any phase transition, while high pressure impact leads to perceptible changes in crystal structure in the interval of 0.0–1.35 GPa using pentane-isopentane media. Surprisingly, pressure transmitting media (PTM) play a significant role in the behavior of the LLHM system at extreme conditions—we did not find any phase change up to 3.05 GPa using paraffin as PTM. A phase transition of LLHM to amorphous form or solid–solid phase transition(s) that results in crystal fracture is reported at high pressures. LLHM stability at low temperatures suggests an alluring idea to prove LLHM preserves plasticity below 77 K.

High-pressure phase stability and elasticity of ammonia hydrate

2019 ◽  
Vol 104 (9) ◽  
pp. 1307-1314 ◽  
Author(s):  
Xinyang Li ◽  
Weigang Shi ◽  
Xiaodi Liu ◽  
Zhu Mao
Keyword(s):  
Phase Diagram ◽  
High Pressure ◽  
Single Crystal ◽  
Phase Stability ◽  
High Pressures ◽  
Solid Phase ◽  
High Pressure Phase ◽  
Residual Liquid ◽  
Dominant Form ◽  
Pressure Phase

Abstract Phase stability and elasticity of ammonia hydrate have been studied using Raman spectroscopy and Brillion scattering in diamond-anvil cells up to 53 GPa at 300 K. Here we have established the high-pressure phase diagram of ammonia hydrate in three different compositions, including ammonia monohydrate (AMH, NH3·H2O), dihydrate (ADH, NH3·2H2O), and trihydrate (ATH, NH3·3H2O). In contrast to previous experimental results, our Raman and Brillouin measurements at 300 K have shown that all three ammonia hydrates start to dehydrate at 2.1–2.2 GPa. Dehydration of the ammonia hydrate leads to the formation of single-crystal ice-VII and an increase in the concentration of NH3 in the residual liquid. The residual liquid finally turns into solid ammonia hemihydrate phase II (AHH-II) at 4–4.6 GPa, leading to a 28% jump in the compressional-wave velocity (VP). Considering a 10–15 vol% NH3 in the mantle of ice giants, AHH should thus be the dominant form of NH3 coexisting with H2O-ice in the ice giants. Further Brillouin measurements provide crucial constraints on the VP of AHH and the single-crystal elasticity of ice-VII at high pressures and 300 K. VP of AHH increases smoothly with pressure. No anomalous change in VP of AHH was identified up to 39 GPa, although a solid to solid phase transition was noted to occur at ~18 GPa by Raman measurements. In addition, the elasticity of single-crystal ice-VII, which was the dehydration product of ammonia hydrate, has been determined up to 53 GPa at 300 K. The deviation of C12 from C44 observed at 11.4 and 14.6 GPa could be caused by the hydrogen bond symmetrizations or the ordering of dipole of single-crystal ice-VII. An abnormal softening in the elastic moduli C11, C12, and the adiabatic moduli KS together with stiffening in C44 was observed between 42 and 53 GPa, which should be caused by the transition from ice-VII to its pre-transitional state. Of particular interest is the dramatic increase in the anisotropy of ice-VII with increasing pressure. Combining the sound velocity of AHH and ice-VII, we have modeled the VP of ice giants with a volume ratio of 20% AHH and 80% ice-VII in the mantle. The obtained high-pressure phase diagram and elastic properties of ammonia hydrate could contribute to understanding the structure of the mantle in the ice giants and satellites.

Lateral Solid Phase Crystallization of Amorphous Silicon Under High Pressure

1999 ◽  
Vol 557 ◽  
Author(s):  
Seung-Mahn Lee ◽  
Rajiv K. Singh
Keyword(s):  
Thin Films ◽  
High Pressure ◽  
Amorphous Silicon ◽  
High Pressures ◽  
Solid Phase ◽  
Applied Pressure ◽  
Polycrystalline Diamond ◽  
Silicon Thin Films ◽  
Amorphous Substrates ◽  
Seeded Crystallization

AbstractWe have investigated a novel surface-seeded crystallization technique at low processing temperatures (≤ 550°C) and high pressures (10MPa~25MPa) using polished polycrystalline diamond seeds. By controlling the high pressure, the nucleation and growth of silicon can be controlled to obtain improved quality silicon films on amorphous substrates at low temperatures. Depending on the annealing temperature and applied pressure, the orientation of crystallized silicon thin films varies as seen by x-ray diffraction and transmission electron microscopy results. In addition, crystallization of amorphous silicon thin films has effect on their roughness.

scholarly journals More superior pyroelectric performance of synthesized dravite by high-pressure solid-state method

AIP Advances ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 035304
Author(s):  
You Shan ◽  
Guojun Zhou ◽  
Kairen Chen ◽  
Changchun Zhao ◽  
Kun Shen ◽  
...  
Keyword(s):  
High Pressure ◽  
Solid State ◽  
Solid State Method ◽  
State Method
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