Macroporous copolymer networks

Macroporous copolymer networks form as a result of the phase separation dur ing the free-radical crosslinking copolymerization of vinyl and divinyl mon omers in the presence of an inert diluent. In this article, the development s achieved in the field of macroporous networks over the last few years are presented. Special attention is paid to the preparation techniques of macr oporous networks in an effort to highlight the new synthesis strategies dev eloped in the recent years. It has been demonstrated that a variety of poro us structures can be obtained during or after the cross linking process by changing the independent variable of the network synthesis, i.e. the extent of the polymer-(diluent + monomer) interactions, the amount of the crossli nker and the diluent as well as the initiator concentration or the polymeri zation temperature. The reaction system leading to macroporous networks is a (quasi)ternary system composed of a polymer network, soluble polymers, an d low molecular compound (monomers and diluent). All concentrations and pro perties of the components of the system change continuously during the cros slinking process. It will be shown that the theoretical models developed re cently correctly predict the phase separation condition during the crosslin king process as well as the total porosity of the resulting macroporous net works. (C) 2000 Elsevier Science Ltd. All rights reserved.