Alkylated kraft lignin-based thermoplastic blends with aliphatic polyesters

Polymeric materials solely composed of certain alkylated kraft lignin preparations can be quite similar to polystyrene in tensile behavior. They may be plasticized in forming miscible blends with aliphatic polyesters possessing methylene/carboxylate group ratios (CH₂/COO) of 2.0-4.0. The alkylated kraft lignin species in such materials range from individual molecular components to huge supramacro-molecular associated complexes. The interactions between the alkylated kraft lignin components and polyester chains are most favorable when CH₂/COO fails between 2.5 and 3.0. Under these circumstances a much smaller proportion of alkylated kraft lignin in the blend is required to disrupt the crystalline domains of the polyester than if CH₂/COO were 4.0. Despite this, appreciably more aliphatic polyester is needed to plasticize the alkylated kraft lignin when CH₂/COO lies between 2.5 and 3.0: the supramacro-molecular complexes tend to be dismantled to a greater extent when the plasticizer interacts more favorably with the individual kraft lignin components of which they are composed.