نتایج جستجو برای: urea formaldehyde

تعداد نتایج: 48106  

2013
An Mao

The previous study on low mole ratio urea-formaldehyde (UF) and ureamelamine–formaldehyde (UMF) resins synthesized in the typical way as particleboard binders was repeated with the inclusion of a strong acidic reaction step at a mole ratio of 2.7 in the beginning of the resin synthesis procedure. The resulting UF and UMF resins showed longer storageand pot-lives, longer gel times, and the parti...

2018
Freddy Muñoz Roger Moya

Physical and mechanical properties were evaluated on cross-laminated panels (plywood) fabricated with three plantation species (Cordia alliodora, Gmelina arborea and Vochysia ferruginea) from tropical climates in Costa Rica. The panels were glued with urea-formaldehyde resin modified with nanoclay at four concentrations (0,75; 1,00; 1,50 and 2,00 %) and unmodified resin. It was determined that ...

Journal: :Forests 2022

By focusing on the disadvantages of weak water resistance and high formaldehyde emission urea–formaldehyde resin (UF), this research provides a new method to overcome these shortages UF by using tannin for partial substitution urea. Furthermore, plasma pretreatment wood was introduced strengthen bonding performance plywood. The investigation chemical structure tannin–urea–formaldehyde (TUF) wer...

2014
V. S Kishan Kumar C. M Sharma Sachin Gupta

In this paper, an attempt was made to assess the effectiveness of finger jointing in utilising mango wood sections for various end uses like furniture. The study was based on the estimation of Modulus of elasticity and Modulus of rupture under static bending and Maximum Crushing Stress and Modulus of elasticity under compression parallel to grain of finger jointed sections and comparing them wi...

Journal: :Journal of the Korean wood science and technology 2021

Inherent crystalline domains present in low formaldehyde to urea (F/U) molar ratio urea-formaldehyde (UF) resins are responsible for their poor adhesion wood-based composite panels. To modify the crystallinity of (LMR) UF resins, this study investigates additional effect cellulose nanomaterials (CNMs), such as microfibrils (CMFs), nanofibrils (CNFs), and TEMPO-oxidized CNFs (TEMPO-CNFs) on modi...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشکده علوم پایه 1384

چکیده ندارد.

Journal: :Drvna Industrija 2021

Formaldehyde-based adhesives are used in the forestry industry. This is because formaldehyde inexpensive, easy to use and resistant moisture; it also has particular mechanical effects. Formaldehyde both advantages disadvantages. It known that various diseases such as lung cancer occur humans a result of release into air during after board production. In this study, urea glue mixture was prepare...

2017
Ming Cao Taohong Li Jiankun Liang

1,3-dimethylurea (DMU) was used to mimic urea and to model melamine-urea-formaldehyde (MUF) co-condensation reactions. The products of 1,3-dimethylurea-formaldehyde (DMUF), melamine-formaldehyde (MF), and melamine-1,3-dimethylurea-formaldehyde (MDMUF) reactions under alkaline and weak acidic conditions were compared by performing quantitative carbon-13 nuclear magnetic resonance (13C-NMR) analy...

Journal: :Journal of Physics: Conference Series 2020

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