The influence of the modification of the montmorillonite KSF and K10 on the hydrolytic stability of UF composites

Abstract

In this work, the hydrolytic stability of composites based on the urea-formaldehyde resin (UF) and montmorillonite-MMT (K1 0 and KSF) as a formaldehyde (FA) scavenger was investigated. K10 and KSF were activated by sodium chloride (NaCl) for the purpose of modified Na-MMT. The degree of activation was determined using specific surface measurement by Sir's method. Evaluation of MMT activation was performed by determining free and liberated FA after acid hydrolysis of synthesized crosslinked UF/MMT composites. The specific surface area (SSA) of montmorillonite KSF and KlO calculated by the Sear's method are 270 m2/g and 119 m2/g, respectively. After modification of MMT, the SSA ofNa-KSF is 48.6 m2/g and 71 m2/g for Na-K10. The amount of free formaldehyde is 0.6% for both UF/KlO and UF/Na-KlO and 0.4% and 0.12% for UF/KSF and UF/Na-KSF composites. The content of liberated FA are 2.1% and 2.2% for UF/K10 and UF/Na-K10 composites and 1.2% and 2.3% for UF/KSF and UF/Na-KSF composites, respectively. It was concluded that the UF composite with modified KSF has a smaller content of free formaldehyde (0.2%) compared to UF composites with pure and modified K10. The UF composite with pure KSF has the highest resistance to acid hydrolysis and the lowest released FA percent.