Different types of southern European hardwoods and softwoods were subjected to a liquefaction process with glycerol/diethylene glycol. The liquefied spruce wood was reacted with melamine– and melamine–urea–formaldehyde resin precursors and used as adhesives for wood particle boards. The mechanical properties and the determination of formaldehyde release proved that at the addition of 50% of liquefied wood the product meets the European standard quality demands for particle boards. Up to 40% reduction of the formaldehyde emission was achieved.
COBISS.SI-ID: 4298522
The role of p-toluenesulfonic acid (p-TSA) for the formation of ZnO particles with different sizes (20 to 250 nm) and shapes was studied in 1-butanol solutions of zinc acetylacetonate hydrate. The catalytic role of p-TSA was pronounced at low concentrations, while at elevated concentrations the reactivity of the ZnO precursor toward the alcoholysis was inhibited, presumably due to the adhesion of the p-TSA on its surface. The ZnO surface chelation with p-TSA controls the ZnO particle growth and shape as well as the self-assembly of ZnO nanocrystals into complex architectures.
COBISS.SI-ID: 23387175
A blend of spruce and fir sawdust was liquefied in the presence of multifunctional alcohols and p-toluene sulfonic acid as a catalyst. Samples were characterized by quantitative 31P, 13C NMR and by size exclusion chromatography. The final products showed increased molar masses indicating the condensation reactions between the lignin and the multifunctional alcohols. Aliphatic chains were incorporated into the lignin network after liquefaction. The resulting polymer showed an increased content of aliphatic hydroxyl groups with respect to the starting material.
COBISS.SI-ID: 4352282
ZnO nanoparticles of different sizes (20 to 200 nm) and morphologies were synthesized by refluxing an oversaturated solution of zinc acetylacetonate hydrate in 1-butanol and isobutanol. The reactions proceed via the alcoholytic C-C cleavage of the acetylacetonate ligand, followed by the hydrolytic formation of the reactive Zn-OH intermediate. FE-SEM studies showed that in 1-butanol the growth of the rod-shaped particles occurs via the agglomeration of ZnO primary particles that are less than 10 nm in size. The morphology of the particles formed in the isobutanol is time dependent.
COBISS.SI-ID: 23583527
Zinc(II) oxide particles were synthesized by the polyol method and were used for the preparation of ZnO/poly(methyl methacrylate) composites. With 0.1 wt.% nano ZnO they absorbed over 98% of UV light and the initial decomposition temperature of the PMMA matrix increased by 30–40 °C. Nano ZnO also increased the reaction rate and reduced the activation energy. Submicrometer ZnO showed lower UV absorption, thermal stabilization and no influence on the reaction kinetics indicating that particle size is of vital importance for the properties of PMMA nanocomposites and for MMA polymerization.
COBISS.SI-ID: 4388378