نتایج جستجو برای: urea formaldehyde

تعداد نتایج: 48106  

2004
Charles R. Frihart

9.1 General..................................................................................................................................216 9.2 Wood Adhesive Uses............................................................................................................217 9.3 Terminology..........................................................................................................

2013
An Mao El Barbary Hassan Moon G. Kim

Urea-melamine-formaldehyde (UMF) resins with 2.5% and 5.0% melamine levels added at the beginning of the third step of the typical urea-formaldehyde (UF) synthesis procedure were synthesized with an F/(U+M) mole ratio of 1.05 and evaluated as particleboard binders to investigate the positive effects of melamine on the formaldehyde content and physical performance of boards. Resins were tested f...

Journal: :Environmental Health Perspectives 1976
M Spassovski

Results of the toxicological studies of working conditions, general and professional morbidity, and complex examinations carried out on workers engaged in the production of polyamides, polyacrylonitrile fibers, polyester fibers and poly (vinyl chloride) resin, urea-formaldehyde glue, glass fibre materials and polyurethane resins are given. An extremely high occupational hazard for workers in th...

2012
F. Qaderi B. Ayati H. Ganjidoust

Nowadays formaldehyde is used as raw material in many industries. It has also disinfection applications in some public places. Due to its toxicity for microorganisms, chemical or anaerobic biological methods are applied for treating wastewater containing formaldehyde.In this research, formaldehyde removal efficiencies of aerobic biological treatment systems including moving bed biofilm (MMBR) a...

Journal: :Indoor air 2010
D E Hun R L Corsi M T Morandi J A Siegel

UNLABELLED Chronic human exposure to formaldehyde is significantly increased by indoor sources. However, information is lacking on why these exposures appear to persist in older homes with aging sources. We use data from the Relationships of Indoor, Outdoor, and Personal Air study to evaluate 179 residences, most of which were older than 5 years. We assess the dependence of indoor formaldehyde ...

2006
Peep Christjanson Tõnis Pehk Kadri Siimer

The structure formation in acid promoted polycondensation and particularly in alkaline post-treatment with urea was studied by 13C NMR spectroscopy in the three-step synthesis of ureaformaldehyde resins. Trishydroxymethyl urea was identified as the constituent of the mixture of hydroxylmethylated urea derivatives obtained in alkaline conditions. The formation of methylenes linked to secondary o...

Journal: :Journal of Renewable Materials 2022

The reinforcing impact of Lignocellulosic micro and nanofibrillated cellulose (L-MNFCs) obtained from Eucalyptus Globulus bark in Urea-Formaldehyde UF adhesive was tested. L-MNFCs were prepared by an environmentally friendly, low-cost process using a combination involving steam explosion followed refining ultra-fine grinding. Obtained showed web-like morphology with some aggregates lignin nanod...

Journal: :Bioresources 2023

Urea-formaldehyde is one of the commonly used resin types in particleboard industry. In this study, effect nanofibrillated cellulose (NFC) and titanium dioxide (TiO2) addition formulation urea formaldehyde on physical, mechanical, morphological properties samples was investigated. The NFC (0.5% 1%) TiO2 (0.5%, 1%, 2%) were added to 10% adhesive formulation. Two different pressure times, 4 8 min...

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