Studies on synthesis,characterization and adhesive strength evaluation of KFA substituted resole adhesives

Preliminary investigations revealed the presence of appreciable amount of gum rich in lignin and tannin in kendu fruit (Diospyros Cordifolia Roxb). The kendu fruit adhesive (KFA) was used to substitute phenol in resole formulations to achieve cost effectiveness. Substituted resole formulations with 50 and 100% KFA were prepared in alkaline medium through stepwise addition process. Unsubstituted and KFA substituted resole adhesives were then characterized by FT‐IR, thermogravimetric analysis, differential scanning calorimetry and X‐ray diffraction analysis. The adhesive strength of the above mentioned formulations were evaluated by comparing the results of mechanical tests as per the ASTM specifications using UTM‐LR‐100K LLOYD Instruments, UK. Analytical characterizations revealed the substitutions of phenol by KFA in the substituted resole formulations. The results of adhesive strength test revealed that the 50% KFA substituted PF resin exhibits better adhesive strength than the virgin phenol‐formaldehyde and 100% KFA‐formaldehyde resole formulation. Copyright © 2001 John Wiley & Sons, Ltd.