Change of glass transition temperature of polymers containing gas

Yoon, Jae D.; Sung, W.

doi:10.1016/s0142-9418(00)00034-9

Cited by 37 publications

(26 citation statements)

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“…Dong Hwang and Woon Cha [56] made the same observation for ABS/CO 2 systems. They used a second model, the Cha-Yoon model [57], that takes into account the polymer density:…”

Section: Effect Of Co 2 Solubility On Polymer/gas System T Gmentioning

confidence: 99%

Polymer nano-foams for insulating applications prepared from CO2 foaming

Forest

Chaumont

Cassagnau

et al. 2015

Progress in Polymer Science

254

166

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“…Dong Hwang and Woon Cha [56] made the same observation for ABS/CO 2 systems. They used a second model, the Cha-Yoon model [57], that takes into account the polymer density:…”

Section: Effect Of Co 2 Solubility On Polymer/gas System T Gmentioning

confidence: 99%

Polymer nano-foams for insulating applications prepared from CO2 foaming

Forest

Chaumont

Cassagnau

et al. 2015

Progress in Polymer Science

254

166

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“…The glass transition temperature for polymers in equilibrium with supercritical carbon dioxide can be fitted to the Cha-Yoon equation 20 :…”

Section: Theoretical Estimation Of the T G Of Co 2 -Plasticized Pcmentioning

confidence: 99%

“…The Cha-Yoon equation, together with experimental data for the solubility of CO 2 in polycarbonate, 20 makes it possible to obtain a correlation between pressure used in the reactor and the T g of the sample at equilibrium. This equation predicts, for instance, that for treatments at 80…”

Section: Theoretical Estimation Of the T G Of Co 2 -Plasticized Pcmentioning

confidence: 99%

Crystallization effects on autoclave foaming of polycarbonate using supercritical carbon dioxide

Mascia

Ponti

et al. 2006

Adv Polym Technol

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In this study, the conditions leading to the formation of cells and to the onset of crystallization of polycarbonate were examined with the use of supercritical carbon dioxide for the production of foams from preforms. Small plaques cut from extruded sheets were treated with supercritical carbon dioxide in an autoclave at temperatures varying from 60 to 200°C and from 4.5 to 30 MPa pressure. Visual observations and stereoscan electron microscopy examination revealed that penetration of supercritical carbon dioxide takes place via the advancing layer mechanism and that, for the particular grade of polycarbonate used in this study, the nucleation of the cells can take place at temperatures as low as 60°C. It requires, however, long treatment times and high pressures, and the growth of foam cells is severely restricted. Nucleation and growth of cells occurred much more readily at somewhat higher temperatures. With treatments at around 80°C, the onset of crystallization started to impose considerable hindrance to the formation of uniform and evenly distributed cells. This becomes increasingly evident at higher temperatures, between 100 and 180°C, owing to the formation of large spherulitic crystalline domains. A very effective nucleation and growth mechanism for the formation of cells was obtained, on the other hand, with treatments at 200°C due to the absence of crystallization phenomena. The degree of crystallinity increased with increasing treatment temperature, and the resulting morphology gave rise to two broad melting peaks. These are displaced to higher temperatures and become closer, merging into one peak with a low‐temperature shoulder. These events were monitored by thermal analysis and wide‐angle X‐ray diffraction examinations. © 2007 Wiley Periodicals, Inc. Adv Polym Techn 25:225–235, 2006; Published online in Wiley InterScience (http://www.interscience.wiley.com). DOI 10.1002/adv.20075

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“…According to Yoon and Cha's research [10] , the glass transition temperature decreased because the dissolved gas lowers the viscosity of the polymer. It explained why the swirl disappear temperature decreased.…”

Section: Fig4 Mechanizon For Swirl Markmentioning

confidence: 98%

“…Cha analyzed the cause of surface swirl marks as a function of mold temperature [10] . A model was used to explain how swirl marks appear.…”

Section: Active Temperature Controlmentioning

confidence: 99%