Vladimir Jambreković

Chemical and Thermal Properties of Cellulose Acetate Prepared from White Willow (Salix alba) and Black Alder (Alnus glutinosa) as a Potential Polymeric Base of Biocomposite Materials

Natural polymeric materials are an interesting alternative to petrochemical products with potential application in almost all areas of human activity. Wishing to expand the field of cellulose acetate application to the biocomposite wood materials, the possibilities of cellulose isolation and its acetylation from two domestic, commercially meagrely used, wood species was investigated in this paper. Cellulose isolated from white willow (Salix alba) and black alder (Alnus glutinosa) was acetylated using acetic anhydride and perchloric acid catalyst, by treatment at room temperature for 45 minutes. Analysis of the laboratory acetylation process, beside chemical analysis of the gained product by infrared spectroscopy (FT-IR), indicated the impact of hemicelluloses, present both in cellulose and cellulose acetate structure, on values of mass increase, number of acetyl groups and the degree of substitution. Results of thermogravimetric analysis (TGA) later confirmed the statement that thermal properties of cellulose acetate were also dependant on hemicelluloses.

The theory and mathematical model underlying the radial sawing simulator - RadSawSim.

Gaining additional knowledge of sawing methods that produce sawn boards with a radial grain is a significant problem today because such methods are rarely used. The current technology in Croatian sawmills is adapted to the standard live and cant sawing methods. Experimental in-mill sawing studies designed to monitor yield are subject to financial and technological restrictions. Therefore, simulated sawing is often required. This research presents the calculation method used to formulate a mathematical model that simulates sawing. The objective was to produce as many radial sawn boards as possible.