Chemical recycling of polyurethane foams (PUFs) leads
to partially
aromatic, amino-functionalized polyol chains when the urethane groups
in the PUF structure are incompletely degraded. Since the reactivity
of amino and hydroxyl groups with isocyanate groups is significantly
different, information on the type of the end-group functionality
of recycled polyols is important to adjust the catalyst system accordingly
to produce PUFs from recycled polyols of suitable quality. Therefore,
we present here a liquid adsorption chromatography (LAC) method using
a SHARC 1 column that separates polyol chains according to their end-group
functionality based on their ability to form hydrogen bonds with the
stationary phase. To correlate end-group functionality of recycled
polyol with chain size, LAC was coupled with size-exclusion chromatography
(SEC) to form a two-dimensional liquid chromatography system. For
accurate identification of peaks in LAC chromatograms, the results
were correlated with those obtained by characterization of recycled
polyols using nuclear magnetic resonance, matrix-assisted laser desorption/ionization
time-of-flight mass spectrometry, and SEC coupled with a multi-detection
system. The developed method allows the quantification of fully hydroxyl-functionalized
chains in recycled polyols using an evaporative light scattering detector
and appropriate calibration curve.