The purpose of this study was to compare two different acetylation mechanisms using acetic anhydride (AA) or vinyl acetate (VA) modification with using various catalysts. Acetylation of Scots pine wood flour with acetic anhydride could be significantly improved in the presence of potassium acetate, potassium carbonate, and sodium carbonate at 100°C. Sodium carbonate had low effect on VA acetylation, potassium acetate was found to be more effective, and potassium carbonate was better for vinyl acetate modification of wood flour. The two modification methods and the effect of different catalysts on AA or VA modification were characterized by infrared and NMR spectra and analyzed in detail. The acetylation of Scots pine flour with VA and AA showed almost the same WPG values for catalysts when based on long reaction times.

Effects of heat treatment parameters on the physical properties, mechanical properties, and crystallinity index of Scots pine and beech wood were investigated. Scots pine (Pinus sylvestris L.) and beech (Fagus orientalis Lipsky) sapwood samples were prepared in 2 cm × 2 cm × 36 cm dimensions by considering the physical and mechanical tests. The samples were heat-treated for 2 h and 4 h at 150 °C, 180 °C, and 210 °C in an atmospheric environment. The shrinking and swelling percentages of all samples were calculated. The compressive strength, bending strength, modulus of elasticity (MOE), and hardness tests were carried out. X-ray diffraction (XRD) was performed to calculate the crystallinity index values. As a result of the study, it was determined that heat treatment generally had a positive effect on the physical properties of Scots pine and beech samples. It was observed that the bending strength of the wood samples decreased up to 180 °C as the temperature increased and then increased. It was determined that the MOE of the Scots pine and beech wood decreased with the heat treatment. As the heat treatment temperature and time were increased, the crystallinity index values initially increased partially and then decreased.

Propolis is an important antifungal agent found naturally in beehives and used as a food supplement for many purposes. This study aimed to use methanolic propolis extract (MPE) as a treatment material as an antifungal agent for wood preservation. Scots pine and paulownia woods were exposed to Trametes versicolor and Neolentinus lepideus fungi for 12 weeks, and untreated woods were used as the controls. Compared with the control, paulownia wood exposed to N. lepideus had a 47.2% mean mass loss, while the treated wood with 7% MPE had an 11.6% mean mass loss. In addition, a 27.2% mass loss occurred with the control for Scots pine when exposed to N. lepideus, and a 2.5% mass loss occurred with the 7% propolis-treated specimens. Total phenolic content and the phenolic profile of the raw propolis samples were also analyzed. Scanning electron microscopy images showed that the propolis extracts still remained in the wood cells without being degraded after the fungal destruction and the propolis-treated specimens were more durable against fungal decay compared to the untreated control specimens. The results from this study indicated that propolis could be used as an environmentally compatible and natural wood preservative to protect wood against fungal attack.

Vinyl Acetate Modified Scots Pine Reinforced HDPE Composites: Influence of Various Levels of Modification on Mechanical and Thermal Properties

Effect of Wood Acetylation with Vinyl Acetate and Acetic Anhydride on the Properties of Wood-Plastic Composites

The goal of this study is to find out how some properties of wood–polymer nanocomposites are affected by the processing technology, the nanomaterials, and the ratio of coupling agents. To achieve this objective, the extruded and dry blended samples are made from wood flour with MAPP, ZnO nanoparticles (0, 1, 3, and 5 wt%), and polypropylene. The mechanical properties of the nanocomposites improve significantly with ZnO and MAPP loading. Due to the more homogeneous structure of nanocomposites, better mechanical results are obtained with the extrusion method. With ZnO and MAPP loading, the thermal stability of nanocomposites improves. The storage and loss modulus values indicate that the processing technology of nanocomposites could be a key factor in the resistance of the materials obtained by extrusion. The storage and loss modulus of nanocomposites manufactured by the extrusion technology are determined to be higher than those of the samples produced using the dry blending method.