this paper reports on formaldehyde exposure and its health hazards in a melamine manufacturing industry. the mean of workers' exposure was measured according to 3500 njosh and was found to be 1.44±o.2l, and 2. 17±o.24 ppm in morning and evening shifts, respectively. for stationary ones it was 1.37±o.20, and 2.06±o.25ppm, respectively. the results show that formaldehyde concentration at the...

Poly urea-formaldehyde was synthesized simply and rapidly from urea and formaldehyde by condensation polymerization and studied for the sorption of trace acid blue from aqueous solution. The optimum pH value for sorption of the acid blue was 4. Experimental results showed that the sorption capacity of poly urea-formaldehyde for acid blue was determined. The synthetic polymer can be reused for 5...

This work deals with the influence of specific pressure during the press process on the radial and tangential penetration of urea-formaldehyde (UF) adhesive into poplar, as well as on the shear strength of lap joints prepared at these different pressures. An epi-fluorescence microscope was used for measuring the adhesive penetration when investigating microtome slides (20-μm thick) cut from the...

poly urea-formaldehyde was synthesized simply and rapidly from urea and formaldehyde by condensation polymerization and studied for the sorption of trace acid blue from aqueous solution. the optimum ph value for sorption of the acid blue was 4. experimental results showed that the sorption capacity of poly urea-formaldehyde for acid blue was determined. the synthetic polymer can be reused for 5...

Poly urea-formaldehyde was synthesized simply and rapidly from urea and formaldehyde by condensation polymerization and studied for the sorption of trace acid blue from aqueous solution. The optimum pH value for sorption of the acid blue was 4. Experimental results showed that the sorption capacity of poly urea-formaldehyde for acid blue was determined. The synthetic polymer can be reused for 5...

The objective is to evaluate the primary mechanical and physical properties of particleboard made from hammer-milled rice straw particles of six different categories and two types of resins. The results show the performance of straw particleboards is highly dependent upon the straw particle size controlled by the opening size of the perforated plate inside the hammer-mill. The static bending an...

Descriptions of methods and results experiments on the preservation geometry dimensional parameters compressed wood using chemical physical are given. Wide ranges substances were used as stabilizers in urea aqueous solution (plasticizer during pressing). Wood treatment with ultrasound, liquid nitrogen pulsed magnetic field was methods. Urotropine, urea-formaldehyde oligomer, phenol-formaldehyde...

When applying an adhesive to wood, the chemical heterogeneity of wood cell walls makes it difficult understand contribution they make interfacial adhesion between and as is a very complex physical phenomenon. This study, for first time, directly measured surface cellulose, major component urea–formaldehyde (UF) resin adhesives. The thin, smooth nanocellulose films, such cellulose nanofibrils (C...