Physicochemical and Thermal Properties of Phenol-Formaldehyde-Modified Polyphenol Impregnate

摘要

Tannin, a natural polymer belonging to the polyphenolic group of compounds, is widely used in the leather industry, specifically as a tanning agent for the conversion of putrescible collagen fibers into leather matrix during the leather-manu-facturing process. Unspent tannin poses a serious environmental threat to the public because it has a very high half-life, leading to groundwater pollution when discharged into soil. Attempts have been made to separate tannins through chemical means and recovered tannin needs to be encapsulated for its safe disposal. In the present study the recovered tannin was impregnated in phenol-formaldehyde (PF) resin. Spectroscopic and thermogravimetric (lR, NMR, TGA and DSC) studies revealed that the modified polyphenol was held physically in the impregnate. The impregnated matrix showed resistance to mineral acids, strong alkalis and organic solvents and was tested for its adhesive property on leather sheets. The leather that bonded with PF-modified polyphenol impregnate (PFT) had a 27% increase in peel strength and a 40% increase in lap shear strength as compared to the sample bonded with PF resin. The corrosive resistance result of the PFT resin shows it has potential application as an anticorrosive paint in the paint industry.