The phase separation and the effect of composition on phase inversion

phase structure and dynamic mechanical properties of PMMA/PEA LIPN have been investigated. A comparison of the structure and damping properties between LIPN and mixture system has also been done. The results suggest that the segregation degree of components is lower and the density is higher in LIPN than that in mixture system due to the interpenetration of one network into the other. A refined structure is revealed in LIPN

but not in mixture system. At low EA content the PEA with cell structure dispersed in the PMMA continuous phase

while as EA content continuously increases

the phase inversion will occur and over the range of EA volu-me fraction from 48% to 86% the PMMA and PEA both form co-cotinuous phase where se-veral properties change very rapidly

the higher damping property appears. The calculated curve by using a combination of upper and lower bounds of Halpin-Tsai-Nielsen equation and logarithmic rule of mixtures fits the eperimental data very well.