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Abstract
Two models of lignin structure are compared and discussed with respect to experimentally measured molecular weight data. The model of polycondensation of f-functional monomers appears to give incorrect results. A generalized model is presented based upon the concept of a crosslinked polymer formed with randomly distributed pre-polymers. Molecular weight data support a tetrafunctional branch point in the lignin preparation studied. However, viscometry data do not support a tetrafunctional or trifunctional functionality. Number- and weight-average DP measurements give important information concerning the characteristics of degraded lignin fractions.