The solution behavior and molecular conformation of sodium lignosulfonates (NaLS) in saline solution has been studied by means of static and dynamic light scattering (LS stat and LS dyn ). Results show that the salt content must be larger to eliminate the slow mode in LS dyn analysis of NaLS than that of the theory, and this discrepancy can only be explained by a modified microgel model. The higher salt amount is needed for the formation of a strong ionic gradient field between surface and the inner part of NaLS, which forces counter ions to penetrate into the inner part of NaLS to screen the small amount of charges. The NaLS single molecular shape can be described by an oblate spheroid based on the absolute molecular weight M w and diffusion coefficients D. The best fitting result is semiaxis a = 1.6 nm and axial ratio r = 3.5, D = 5.73 × 10 -7 cm 2 s -1 , and the corresponding M w = 1.7 × 10 5 g mol -1 .

The problems related to the determination of the absolute molecular weight (Mw) of sodium lignosulfonate (NaLS) are the focus of the present work. Four narrow-dispersed NaLS fractions were collected by filtration, ultrafiltration, and gel permeation chromatography (GPC), and their Mw measured by laser light scattering (LLSMw) was compared with that obtained by GPC (GPCMw). The LLSMw values were much larger than GPCMw, and this Mw difference increased with increasing Mw of NaLS. This finding confirms the known polyelectrolyte and aggregation effects of NaLS. The deviation is also partly due to the conformation differences between the GPC standard (sodium polystyrene sulfonate) and the NaLS molecules. The effects of polyelectrolytes and NaLS aggregates could be inhibited by adding enough NaCl salt in the NaLS solution and filtering the NaLS/NaCl solution through a syringe filter. As a result, the slow mode in dynamic LLS measurement disappeared. By this approach, the absolute LLSMw values were only slightly larger than that determined by GPC due to the conformation differences between the GPC standard and the NaLS molecules.

A new type of layer-by-layer (LBL) self-assembled films of a lignin-based polymer (GCL1-JB) with Poly(4-vinylpyridine) (P4VP) has been obtained via hydrogen bonding interaction. Fourier-transform infrared spectroscopy results confirmed a strong hydrogen bonding between GCL1-JB and P4VP. And the hydrodynamic radius of the GCL1-JB/P4VP mixture was larger than individual polymer due to the hydrogen bonding. The adsorption characteristics of GCL1-JB self-assembled films based on hydrogen bonding or electrostatic interaction were investigated by UV−vis spectrophotometry and atomic force microscopy, respectively. Compared to the GCL1-JB self-assembled films based on electrostatic interaction, that based on hydrogen bonding has a larger adsorbed amount, a faster adsorption transfer rate from dipping solution to the substrate surface and a larger surface roughness. This study gives significant information to understand the adsorption characteristics of lignin-based polymers on the solid surface via different driving forces.

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The bioeconomy era will rely on efficient fractionation of renewable resources via integrated biorefineries. The food supply chain waste, despite its inherent variability, could evolve into an important industrial feedstock on account of its availability, versatility, and sustainability, for the production of bio-based products. Waste streams generated from all stages of the life cycle of food products could be refined into different fractions, which will be either purified to high-value molecules or converted via green chemical and/or biotechnological routes for the production of biobased products. A working group of the EUBis COST Action TD1203 is taking steps to gather a critical mass of knowledge and expertise to create innovation and technological breakthroughs.