Development of a new type lacquer based on Rhus vernicifera sap with chitosan

• The lacquer has a remarkable kinetic stability blended with 3 wt% LMW chitosan.
• The blended lacquer dried quickly and had 2H hardness higher than the blank lacquer.
• The blended lacquer film has more slight color.
• Found out the directly evidence of the reaction occurred between urushiol and amine.

A new type lacquer coating was developed by adding certain molecular weight of chitosan to the Rhus vernicifera lacquer sap. The optimum range of chitosan molecular weight and adding quantity were investigated, and the blended lacquer coating was prepared based on these results. The properties, such as molecular weight distribution, particle size distribution, drying times, and gel fraction were examined. In addition, the reaction between urushiol and chitosan is discussed based on the results of nuclear magnetic resonance (NMR) and infrared (IR) measurements. A blended lacquer coating with 3% chitosan dissolve in 5% of citric acid showed almost the same drying time and film hardness as 100% R. vernicifera lacquer sap as examined in an automatic drying time recorder, but had lighter surface color. Furthermore, the UV resistance and viscoelastic property also were investigated in detail.

Signals at δH3.32 in sample II are the signals of secondary amine reacted with urushiol.Figure optionsDownload as PowerPoint slide