Manipulation of polymer foam structure based on CO2-induced changes in polymer fundamental properties

Foaming of polymers with CO2 has attracted increasing attention in polymer processing studies. Some of the fundamental properties of polymer/CO2 systems is discussed in this short review, including solubility and diffusivity of CO2 in the polymer, polymer crystallization, interfacial tension between the polymer and the gas, and rheology of the CO2/polymers melt. These properties understandably affect the foaming process, and the structures of the foam products. Meanwhile, these properties can be changed via manipulation of CO2 in polymer. The proposed idea is to manipulate the foaming process and the foam structure by CO2-induced changes in these properties. Two cases from the authors' laboratory are presented for elucidating how to use the changes to manipulate the foaming process. (C) 2010 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.