Sequential IPNs Obtained Using Anionic Polymerization

Sequential IPNs Obtained Using Anionic Polymerization 

IPN-l-MGP is formed, while for IPN-2-MGP they remain practically unchanged. The same dependence was observed for IPNs based on TMA, but Ic values in this case were approximately half as large as those in the former case. The specific surface of the heterogeneities for IPN-l-MGP increases a bit, whereas for IPN-2-MGP it increases sharply. For both IPNs based on TMA, an increase in the specific surface is observed. One must pay attention to the increase of the average square fluctuations of electron density by one or two orders of magnitude when passing from copolymer network to MGP or TMA networks. 

Next we discuss the interrelation between the structme parameters and the conditions of IPN formation, determined by the successive addition of the components forming the second network and the catalyst. During the formation of IPN-l-MGP a living network matrix was obtained at first, after which styrene and DVB were added. During the initial steps of styrene-DVB polymerization, fragments of PS chains were formed due to transition of electrons from the phthalate rings of the first network. Then the fragments of PS chains were cross-Hnked by DVB. Coulomb interactions in the system decrease in this case. The ratio of the network matrix to the second matrix was 0.6 0.4. 

IPN-2-MGP was obtained in a different way, namely, by adding DVB (2 1) simultaneously to the living network matrix along with an additional portion of the catalyst, hi this case the total concentration of the catalyst for the IPN-1 and IPN-2 remained unchanged. The differences in the synthesis conditions caused the difference in the effective density of the penetrating network, and 

These data show again that the special features of the network formation, even not considering the conditions of phase separation in the system, contribute much to the formation of the second network in sequential IPNs. In the present case, this contribution is influenced by the presence of a great number of charges and by different intensities of the Coulomb interactions between the charged fragments in the network matrix and the growing net- 

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Sequential IPNs Obtained Using Anionic Polymerization. 80... 

Nearly all of the materials described in this monograph were prepared by some combination of free-radical and/or condensation reactions. Most recently, however, Lipatova et obtained grafted sequential IPNs on the basis of matrices from living network polymers, using anionic polymerizations for both networks I and II. 

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