No abstract

Meticulous chemical analysis of decaying xylem and linking it to corresponding anatomical modification at the cellular level can improve our understanding of the decay process. The aim of this study was to monitor the histological, chemical, photochemical, and progression of wood degradation by two white-rot fungi at different intervals. Oriental beech wood (Fagus orientalis) blocks were exposed to Pleurotus ostreatus and Trametes versicolor to investigate the degradation capabilities of these two fungi. Light microscopy was used to study the decay patterns in wood. Decayed wood samples were also analyzed to determine lignin, cellulose and sugar contents and also evaluated at two week intervals by FT-IR spectroscopy to study chemical alterations. According to chemical analyses lignin is the most degraded polymer followed by cellulose and hemicelluloses for both white rot fungi. However, both test fungi tended to consume lignin more than cellulose. FT-IR spectra changes for lignin and carbohydrates in beech wood supported chemical alteration and indicated that both fungi decay wood in a simultaneous pattern.

The objective of this research was to evaluate the influence of acetyl and methyl bonds on the physical, mechanical, photochemical and biological resistance properties of hornbeam wood.Carpinus betulus(hornbeam) wood is considered to be a less valuable species due to poor durability. In order to improve its properties, a novel and simple method was applied to modify wood samples. Hence, wood samples were modified by either acetylation or methylation at four treatment levels. Reactions between hornbeam wood and the formalin and acetic acid treatment system were successful as exemplified by increased mass [weight percent gain (WPG)], slightly better compression strength and considerably improved impact bending strength. Furthermore, the biological decay resistance of the treated wood samples increased for all of the treatments.

The work demonstrates the utilization of fractionalized lignin from the black liquor of soda pulping for the development of starch-lignin biocomposites. The effect of ultrafine friction grinding on lignin particle size and properties of the biocomposites was investigated. Microscopic analysis and membrane filtration confirmed the reduction of lignin particle sizes down to micro and nanoparticles during the grinding process. Field Emission Scanning Electron Microscopy confirmed the compatibility between lignin particles and starch in the composites. The composite films were characterized for chemical structure, ultraviolet blocking, mechanical, and thermal properties. Additional grinding steps led to the reduction of large lignin particles and the produced particles were uniform. The formation of 7.7 to 11.3% lignin nanoparticles was confirmed in the two steps of membrane filtration. The highest tensile strain of the biocomposite films were 5.09 MPa, which displays a 40% improvement compared to starch films. Further, thermal stability of the composite films was better than that of starch films. The results from ultraviolet transmission showed that the composite films could act as an ultraviolet barrier in packaging applications.

Precipitated calcium carbonate (PCC) filler is used in many industrial products like constructions, plastics, pharmaceutics, etc. In this study producing cationic precipitated calcium carbonate filler for paper industry was investigated. Hence, a cationic polyacrylamide and cationic corn starch have been incorporated into the PCC particles to produce a modified filler with cationic structure and improved hydrogen bonding ability with cellulose fibers. According to the FESEM and XRD results, cubic-like fillers with prominently calcite polymorph and a slight amount of aragonite were successfully produced from the industrial burnt lime using carbonation process. The presence of organic substances in the structure of the modified samples was confirmed by FT-IR analysis. Besides, based on the FESEM results, filler morphology and particle size could be affected by the polymer content. In conclusion, introducing cationic groups to mineral fillers could be considered as a possible strategy to overcome some detrimental effects of using mineral fillers in paper products.