Limitation and potential of lignin-assisted stabilisation of oriented liquid crystalline cellulosic mesophase
F. Robert Gleuwitz,
Gopakumar Sivasankarapillai,
Ahmed Bentaleb,
Nadine Kohlhuber,
Marie-Pierre G. Laborie
Affiliations
F. Robert Gleuwitz
Institute of Earth and Environmental Science, Chair of Forest Biomaterials, University of Freiburg, 79085 Freiburg, Germany; Freiburg Materials Research Centre (FMF), University of Freiburg, 79104 Freiburg, Germany; Department of Nanotubes and Graphene, Centre de Recherche Paul Pascal, University of Bordeaux, 33600 Pessac, France
Gopakumar Sivasankarapillai
Institute of Earth and Environmental Science, Chair of Forest Biomaterials, University of Freiburg, 79085 Freiburg, Germany; Freiburg Materials Research Centre (FMF), University of Freiburg, 79104 Freiburg, Germany
Ahmed Bentaleb
Department of Nanotubes and Graphene, Centre de Recherche Paul Pascal, University of Bordeaux, 33600 Pessac, France
Nadine Kohlhuber
Department of Chemistry, Institute of Chemistry of Renewable Resources, University of Natural Resources and Life Sciences Vienna (BOKU), 3430 Tulln, Austria
Marie-Pierre G. Laborie
Institute of Earth and Environmental Science, Chair of Forest Biomaterials, University of Freiburg, 79085 Freiburg, Germany; Freiburg Materials Research Centre (FMF), University of Freiburg, 79104 Freiburg, Germany; Corresponding author.
This study aimed at progressing in the fundamental understanding of the lignin-assisted microstructural stabilisation observed in solution-processed materials based on the polymer blend of hydroxypropyl cellulose and hardwood organosolv lignin. Mechanical analysis, polarised infrared spectroscopy and wide-angle X-ray scattering of shear cast blend films revealed that the effect of lignin on the flow-oriented cellulosic mesophase is also valid for blends composed of ethyl cellulose as liquid crystalline matrix polymer and lignin derived oligomers from base-catalysed depolymerisation as dispersed “microstructural cementing agent”. The results underline the significant role of the solvent diffusion between the continuous cellulosic and the dispersed lignin phase, which is ascribed to polymer-/oligomer-solvent interactions. An abundance of the solvent within the lignin phase caused the disruption of the microstructural stabilisation effect. The concept of a balanced proton-donor activity was introduced linking the solvent diffusion with the lyotropic liquid crystalline phase formation, the macro- and microstructural blend morphology and aspects regarding the solution processing.
