Factors with Influence on Determining IPN Compatibility

The state of IPNs based on PBA or PBMA and a diaUyl network, obtained by stepwise polymerization (at 333 and 398 K) using two initiators [ 18] and by simultaneous polymerization with one initiator, was studied using the DMA method. It was discovered that in the first case compatible IPNs were formed, which were characterized by the presence of one very broad maximum of tan S, typically what is observed for IPNs. It was supposed that in this case gross phase separation is impeded due to the pecuhar synthesis mode. For 

In [90,347], from the investigation of the reaction kinetics and the kinetics of phase separation for IPNs based on PS and PU, the role of gelation in the process was established. The authors conclude that if the reaction system separates into two phases before the gel point of PU, the semi-IPNs are turbid, whereas if the phase separation proceeds after the gel point the IPNs formed are transparent. 

In [350,351], the IPNs were obtained using the method of RIM from PU and unsaturated polyesters. It was shown that by varying the component ratio and reaction rates a compatible systems may be obtained. The kinetic study of the formation of simultaneous and sequential acrylic-polyurea IPNs [298] in the course of RIM allowed us to establish that by variation of the component ratio and of the sequence of the reaction it is possible to achieve various degrees of interpenetration up to the formation of transparent IPNs with small domain sizes. The degree of transparency of the IPN materials 

In some of our works [341,352] we established the effect of various compounds, which could be potentially considered as compatibihzers, on the compatibiUzation of IPNs together with studying the kinetics of IPN formation in the presence of such additives and the viscoelastic properties. We supposed that combination of kinetic data and data on the viscoelastic properties of IPNs can give an approach to understanding the mechanism of compatibiUzation. 

For this study we chose well-investigated semi-IPNs based on cross-linked PU and Unear PBMA with ratios of components (by mass) of 75 25 and 50 50. Semi-IPNs were synthesized by the method of simultaneous reactions of polyaddition to form the cross-Unked PU and radical polymerization of BMA. Components for PU were POPG MM 2000 and the product of interaction of IMP with 2,4-/2,6-TDI in the ratio 1 3. 

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