Separation and Characterization of Polymer Blends Using Online Ultra-high Performance Liquid Chromatography-Size Exclusion Chromatography

The characterization of polymer blends is a difficult problem in adhesives and coatings industry???and thestudies on the separation of complex mixtures are always popular.In this paper???an online ultra-high performanceliquid chromatography-size exclusion chromatography???UHPLC-SEC???system was designed and set up.The solventcompatibility and orthogonality of the two-dimensional chromatography system were investigated using the hydroxylpolybutadiene???HTPB???.The applicability of the two-dimensional chromatography was studied in the separation and characterization of each fraction from the styrene-butadiene block copolymer???SBS??????styrene-isoprene block copolymer???SIS???and polymethacrylate???PMMA???blends.The results showed that the molecular weight and distribution ofHTPB were determined by UHPLC-SEC???which were consistent with those determined by SEC.The peak molecularweight???Mp??????the weight average molecular weight???Mw???and the polymer dispersity index???PDI???of HTPB were3407Da???6573Da and2.36???respectively???and the relative standard deviations???RSDs???were less than5.7%.Moreover???the solvent compatibility and orthogonality of the system were good.Compared to the existing SECmethod???the relative errors ofMp???Mwand PDI of PMMA???SBS and SIS fraction measured by UHPLC-SEC were allless than7.1%.The PMMA remained stable after the mixture of PMMA???SBS and SIS was heated at200 degrees C for3h???while SBS and SIS components degraded significantly.Due to the good accuracy and reproducibility of theUHPLC-SEC method in the characterization of the polymer blends???it is suitable for the failure analysis of thepolymer formulations.