High pressure jump apparatus for measuring Grűneisen parameter of NaCl and studying metastable amorphous phase of poly (ethylene terephthalate)

Abstract

A rapid-compression apparatus with a large pressure jump is described. The pressure jump was performed principally by using a large volume bladder-type power accumulator that contains compressed nitrogen and the connected electromagnetic valves. Maximum force induced by the press is 1.1 MN. Within 20 ms the pressure of the sample could be increased from 0.1 to 2.0 GPa in piston-cylinder modules of 26 mm diameter and to 5.8 GPa in Bridgman-type anvils of 26 mm top diameter. The apparatus has been used successfull in determining the Grűneisen parameter of NaCl at high pressures. Furthermore a metastable amorphous phase of poly (ethylene terephthalate) was solidified from its melt in a rapid compressing process; this phase could not be obtained by slow compressing to high pressure or by naturally cooling at ambient pressure.

Chain Breakage in the Supercooled Liquid - Liquid Transition and Re-entry of the λ-transition in Sulfur

“…Sulfur’s extremely high crystallization tendency limits these explorations of phase transitions, especially the direct transition from amorphous sulfur to liquid sulfur. Pressure-induced rapid solidification from liquid provides an alternative way of preparing amorphous materials 13 . The amorphous sulfur thus obtained exhibited relatively high thermal stability 14 , 15 .…”

Cold crystallization behavior of glassy poly(lactic acid) prepared by rapid compression

“…The problem of temperature quenching is that there is a temperature and even a cooling rate gradient distribution in the samples, which could induce structure defect of the products . Recently using a high‐pressure jump apparatus, Hong et al have prepared many glassy polymers under a dynamic pressurization process—rapid compressing (RC). Different from the most widely used quench cooling techniques, in RC process the melts are solidified by high pressure jump (pressure of the melt can increase from atmospheric pressure to 2.5 GPa in only 20 ms) rather than temperature drop, so it can get rid of the thermal conductivity limitation of polymer materials and proves effective to prepare amorphous polymer materials in large bulk.…”

“…It is obvious that melts have experienced different physical process during RC and quench cooling preparations, so the as‐obtained glassy samples might present different microstructures and performances. For instance, Hong et al found that RC process could induce two amorphous phases of poly (ethylene terephthalate) (PET) which were different from that in quenched samples. Yu et al reported that the glassy sulfur obtained by RC process exhibited an exceptional thermodynamic and kinetic stability, and Yuan et al reported that the glassy polyether‐ether‐ketone samples prepared by RC exhibited high thermodynamic stability, excellent friction, and considerable stiffness in contrast to that prepared by quench cooling.…”

Pressure Dependence of the Electrical Resistivity in Polymer Polyaniline

“…The schematic sample PAN assembly is shown in Figure 1. A set of Bridgman anvils [21] was used to produce high pressure. The anvil is made of tungsten carbide, and the top diameter is 26 mm.…”

“…The conductivity of PAN is not high enough [1,4]. To overcome this problem is to use the doping process [6,9] or to apply the high pressure, while PAN under high pressure will show different electrical properties in contrast to the atmospheric pressure, which can be widely applied in fields such as new pressure calibration materials, buffer electrode materials, recharge batteries, and solar cells [13][14][15][16][17][18][19][20][21][22][23][24].…”