Characterization of polyisoprene by temperature gradient interaction chromatography

Temperature gradient interaction chromatography (TGIC) analysis of polyisop rene (PI) is reported. PI can be fractionated in terms of molecular weight with high resolution by TGIC using a C18 bonded silica column as the statio nary phase and a mixture of CH2Cl2/CH3CN (80/20, v/v) as the mobile phase. The temperature was increased during the elution from 5 degrees C to 34 deg rees C to optimize the fractionation of high molecular weight PI. The relat ively poor resolution in the low molecular weight range was improved by cha nging the eluent composition. For example, all the oligomeric species from the unimer to the 29mer of a low molecular weight PI (average mol. wt.: -90 0) were fully resolved with the mixed eluent of CH2Cl2/CH3CN (50/50, v/v) a nd a linear temperature program from 5 degrees C to 40 degrees C. In additi on, simultaneous size exclusion chromatography and TGIC fractionation of PI /polystyrene, PI/poly(methylmethacrylate) mixtures are also reported.