Synthesis and Structure Characterization of Phenol-Urea-Formaldehyde Resins in the Presence of Magnesium Oxide as Catalyst

Polymers

Dong-Bin Fan²  Gai-Yun Li¹  Te-Fu Qin² 

[1] Research Institute of Wood Industry, Chinese Academy of Forestry, Xiangshan Road, Beijing 100091, China;

关键词: phenol-urea-formaldehyde resin;    catalyst;    synthesis;    chemical structure;    high-content reactive group;    fast cure;   

DOI  :  10.3390/polym6082221

来源: mdpi

【 摘 要 】

The objective of this research was to provide a useful approach of polymer synthesis for accelerating the fast cure of phenol-urea-formaldehyde (PUF) resin as wood adhesive by optimizing its structure and composition. The PUF resins containing high contents of very reactive groups such as para-methylol groups were synthesized by reacting methylolurea, phenol, and formaldehyde in the presence of magnesium oxide (MgO) as catalyst. The effects of synthesis parameters including F/(P + U), OH/P, and MgO/P mole ratios on the structure, composition, curing characteristics, and their relationships of PUF resins were investigated. The results indicated that MgO seemed to be an efficacious catalyst for PUF resin synthesis and promote its faster cure. The increase in the F/(P + U) mole ratio or/and OH/P mole ratio appeared to be beneficial for the formation of para-methylol groups and cocondensed methylene linkages between phenolic methylol groups and urea units, and for the removal of unreacted urea. In case of Catalyst/P mole ratio, an appropriate dosage of added metal-ion was very important for synthesizing the high-content reactive groups of PUF resins, otherwise leading to the reverse effects.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.