Characterization of polystyrene and polyisoprene by normal-phase temperature gradient interaction chromatography

Area of Science:

• Polymer characterization
• Chromatographic techniques

Background:

• Polyisoprene (PI) and polystyrene (PS) are widely used polymers.
• Characterizing their molecular mass and structure is crucial for understanding material properties.
• Existing chromatographic methods may have limitations in resolution or sensitivity.

Purpose of the Study:

• To apply normal-phase temperature gradient interaction chromatography (NP-TGIC) for characterizing PI and PS.
• To evaluate the resolution and capabilities of NP-TGIC for molecular mass fractionation.
• To investigate the thermodynamic properties of adsorption in the NP-TGIC system.

Main Methods:

• Utilized normal-phase chromatography with bare silica or diol-bonded silica stationary phases.
• Employed tetrahydrofuran-isooctane mixtures as the mobile phase.
• Applied temperature gradient elution to fractionate polymer samples.

Main Results:

• Successfully fractionated PI and linear/star-shaped PS by molecular mass with high resolution.
• Achieved resolution comparable to reversed-phase HPLC.
• Observed exothermic enthalpy of adsorption for PS on the stationary phase.
• Demonstrated high sensitivity to polar end groups.

Conclusions:

• NP-TGIC is a powerful technique for high-resolution molecular mass characterization of PI and PS.
• The method offers advantages over reversed-phase methods, including sensitivity to polar end groups.
• NP-TGIC enables simultaneous size-exclusion and interaction-based characterization.