Measurement of gas solubility in linear/branched PP melts

Abstract

A magnetic suspension balance was employed in experiments to measure gas solubility in the polymer melts. The gas solubilities of CO 2 and N 2 in both linear and branched Polypropylene (PP) were investigated. The swollen volumes predicted by the Sanchez-Lacombe equation of state (EOS) and Simha-Somcynsky EOS were applied to incorporate the buoyancy effect, which is essential for the accurate measurement of solubility data. The effects of the branched structure on the swollen volume and gas solubility were discussed. It was observed that the long chain branched PP exhibited less expandability than the linear PP, due to the entangled molecular chain structure. Therefore, the total amount of gas that was able to dissolve into the long chain branched PP turned out to be less.

Maximal cell density predictions for compressible polymer foams

“…These χ parameters correspond to a blowing agent of a "nitrogen" type, since we get higher solubilities at higher temperatures [14]. Other choices of χ parameters can give lower solubilities at higher temperatures which would correspond to "carbon dioxide" type blowing agents [15,16,17,18,19]. Figure 2 shows cell densities as a function of sample volume for the above choices of parameters corresponding to T = 1.5 and T = 2.0.…”

Measurement of the PVT property of PP/CO2 solution

“…Theoretical work using equations of state (EOS), such as the Sanchez and Lacombe (SL) EOS [24][25][26], the Simha and Somocynsky (SS) EOS [27,28], and SAFT [29,30] all based on the statistical thermodynamic theory, have been developed and used intensively to predict the volume swelling of polymers due to gas dissolution.…”

“…Eq. (19) is the Tait equation in the Moldflow PVT model for the specific grade of PP used in this study where the specific volume pp is measured in units of m 3 /kg; the pressure, P, is in Pa; and the temperature, T, is in • C [28]:…”

Effect of pressure and temperature on interfacial tension of poly lactic acid melt in supercritical carbon dioxide

“…The term is the swollen volume of the polymer melt due to gas dissolution. [21] If the volume of swollen polymer ( ) is not considered, the apparent solubility is as follows:…”