EFFECT OF THE ACIDIC TREATMENT OF DOMESTIC WOOD RESIDUE ON BIOCOMPOSITE WETTABILITY AND MOISTURE SORPTION PROPERTIES

The aim of the work was to evaluate the effect of the acidic treatment temperature of aspen sawdust as a filler on the moisture sorption, wetting and mechanical properties of wood-polymer composites. Aspen wood sawdust was treated with the dilute hydrochloric acid solution at 60oC and 90oC during 5 h. Both the treated particles and the filled composites were studied in terms of moisture sorption and wettability; their surface free energy was calculated using the Owens-Wendt-Rabel-Kaelble (OWRK) approach. The obtained results have shown that the acidic treatment of aspen wood sawdust at 90oC leads to an increase in its hydrophobicity that decreases the wettability and moisture sorption of the obtained composite and increases its mechanical properties

VALORIZED SODA LIGNIN AND ITS POSSIBLE APPLICATION

The aim was to obtain a valorized soda lignin and to study its properties for the followed treatment of hardwood sawdust as a filler for obtaining a wood-polymer composite. It was shown that the treatment of aspen sawdust microparticles by their immersion into a water solution of the valorized soda lignin, that is a water-soluble soda lignin/polyethylenimine polyelectrolyte complex, leads to hydrophobisation of the sawdust particles, which in turn positively affects the mechanical performance of the obtained wood-polymer composite

Characteristics of the Waste Wood Biomass and Its Effect on the Properties of Wood Sanding Dust/Recycled PP Composite

To decrease climate changes, more research focuses on decreasing waste wood biomass (WWB) burning and increasing its conversion into value-added products. The WWB was isolated from model wood processing wastewater with a new hybrid coagulant by the coagulation/flocculation method. This study is aimed to characterize the WWB and to investigate its effect in the composition of a hybrid lignocellulosic filler on the properties of recycled polypropylene (rPP)-based wood–plastic composites (WPCs). The waste biomass contained high-molecular lignin and hemicelluloses substances and represented a finely dispersed powder. It was hydrophobic and was characterized by enhanced thermal stability. To minimize the negative effect of polymer wastes on the environment, recycled polypropylene as a polymer matrix was used with the hybrid filler in fabricating WPC samples. The presence of the coagulated WWB in the hybrid filler composition positively affects the mechanical properties, water uptake and dimensional stability of the composite samples. Such a behavior of the waste biomass showed its function as a compatibilizer, which promoted the interfacial adhesion in the composite system

Wettability of Modified Lignocelluloses as a Filler for Polymer Composites

The contact angle (CA) of lignocellulosic powder allows predicting important properties of a filled polymer composite material such as its wettability, adhesion, adsorption, etc. The contact angle and the surface free energy can be measured by the Washburn method, which is used to determine the capillary constant calculated from the penetration rate of a liquid into the compacted lignocellulosic powder, and by the Wilhelmy method based on measuring interface surface tension of the filled polymer composites. The aim of the work was to evaluate the wettability of the initial and the modified wood microparticles as well as the composite samples consisting of recycled polypropylene and the lignocellulosic microparticles, using contact angle, water sorption and Zeta potential (ζ) measurements. The contact angle was determined with a tensiometer Kruss 100M. The capillary constant (K) for each lignocellulosic powder was determined in n-heptane. The surface free energy was calculated using the approach suggested by Owens-Wendt-Kaeble. The Zeta potential of the microparticles was measured with a dynamic light scattering device Zetasizer Nano SZ. For the modification, at first, the hardwood lignocelluloses were treated with low temperature acid hydrolysis under mild conditions [1]. Then, the fractionated hydrolysed microparticles were modified to introduce the new functional groups at their surface. It was found that the hydrolysis and the modification of the lignocellulosic particles differently effect on their water wettability. While the hydrolysis of the lignocelluloses led to the increase in the negative Z potential values of the particles and the decrease in their contact angles, the modification essentially decreased the negative charge of the lignocellulosic microparticles and remarkably enhanced their contact angles in water

Obtaining Lignocellulosic Microparticles Using Energy Saving Pre-treatment Method

In this work, aspen sawdust, a by-product of the mechanical processing of aspen wood, was studied as a feedstock for obtaining microparticles as a filler for polymeric composites. It is know that, due to enhanced energy requirements, milling of untreated wood is not economically beneficial. With the aim to partially destruct and activate the lignocellulosic matrix for the following modification, low temperature acid hydrolysis of aspen sawdust under mild condition was carried out. The effect of the acid conentration, the hydrolysis duration and the hydromodulus on the components and fractional composition of milled hydrolysed aspen sawdust was inwestigated