Search

Composite from recycled newsprint would result in the effective use of a waste product which is currently burned or land-filled, as well as potential reduction in the cost of manufactured composite. In this work, old newsprint (ONP) together with waste polyurethane foam from packaging were used to produce composite. The physical and mechanical properties, polymer concentration, volume resistivity as well as pressure were studied. The increase of pressure from 25 to 50 KN was found to improve the mechanical properties more than twice the polymer concentration. This may be attributed to the higher ability of polyurethane foam to make crosslinks with the free OH groups of cellulose and hemicellulose when the pressure is increased. Also, it may be attributed to the lignin of the ONP, which, under heat above 160°C and higher pressure flow, acts as a thermosetting adhesive, enhancing the naturally occurring hydrogen bonds. Waste sawdust of particleboard and palm leaves, pulped mechanically at 120°C, was blended individually to the ONP at a certain percentage. The mechanical properties and water resistance were improved by approximately 10%. The volume resistivity of the produced composites was measured. It was found that it had increased, as had the pressure, polymer concentration, and mechanical properties. [ABSTRACT FROM AUTHOR]

Paper for special applications was produced using transition metals, cellulose derivatives, and fillers in the presence of fluorescent dye. Sheets were prepared from bleached wood pulp after fluorescein sodium was added along with solutions of transition metals as well as methyl cellulose, cellulose sulfate, starch, and kaolin. The papers produced were identified with UV light and/or alkaline and acidic solutions. The appearance of the papers was changed under the UV light when the fluorescein sodium was used at pH 4.0. The solution of the transition metal of Ni2+ led to slightly yellow fluorescent spots as a result of the ground-state configuration of the transition metal. Moreover, a fluorescent yellow-green color was observed when methyl cellulose, cellulose sulfate, kaolin, and starch were added as fillers in the presence of sodium fluorescent dye. The color appears because the fiber network is disrupted by the inclusion of the filler particles with the fluorescent dye. Application: Made with transition metals or cellulose derivatives as additives along with fluorescent dye, security papers show identifiable fluorescent spots under ultraviolet light. [ABSTRACT FROM AUTHOR]