The Research Of Glass Transition Of Polystyrene And Inhomogenity Of The Blend Systems

The glass transition of PS is studied by DSC and FTIR.In the process of temperature rise,the intensity of three conformation insensitive bands of linear PS increased and the location of bands also changed.During glass transition,the shape of bands assigned to main chain changed more dramatically than that assigned to the side chain.This dramatical change can be regarded as the sign of glass transition.In fact,this phenomenon also indicates that the main chains of PS are more sensitive than the side chains.In order to restrict the activity of main chains,we add the DVB which do not affect the original IR spectrum of PS in the process of synthesis.Based on molo ration of St and DVB,Three crosslinked PS whose Tg are 94.4?,100.6?,l10.5?respectively are synthesized.They are studied by the temperature scanning FTIR.Compared to results of linear PS,There is a great change in the formation of bands assigned to main chain.But changes do not happen on the formation of side chain.That indicates the vibration suppression of crosslinking action to the main chain is greater than the side chain.In addition,we blend OTP into crosslinked PS to get the PS/OTP blend system samples.By using DSC scan this sample twice,two different Tg are shown.The higher one is 30? more than the lower one.Actually,The lower one is just the average of the statistical sense.The higher one shows that OTP do not blend into the crosslinking PS completely,which indicates the inhomogenity of the blend systems.