In this study, effects of mixed hardeners (ammonium chloride mixed with ammonium persulfate, oxalate and phosphoric acid) on the properties of 2,4,6-trimethylolphenate modified UF resin (TMPUF) were studied, and the potlife, gel time and curing temperature of TMPUF/hardeners were characterized. The results indicated that the hardeners used have critical influence on the pH value of TMPUF and some proton donor can be used to lower the pH value of TMPUF with low formaldehyde content. Besides, bamboo particleboards were made with TMPUF/hardeners, and tensile properties, water absorption ratio and the swelling ratio of bamboo particleboards were characterized. The study demonstrated that the tensile strength of bamboo particleboards increased when partial ammonium chloride was replaced by ammonium persulfate to cure the TMPUF adhesives in our experiment.

Keywords: mixed hardener; UF resin; bamboo particleboard; tensile strength