SYNTHESIS AND CHARACTERIZATION OF MODIFIED LOW CURING PHENOL-FORMALDEHYDE RESIN FOR MANUFACTURE OF WOOD COMPOSITES.
The objective of this study was to develop a modified phenol formaldehyde resin to cure at low curing temperature than the conventional PF resin and its performance study in manufacturing of exterior grade plywood. In this study phenol formaldehyde resin was modified by using a combine catalyst based on propylene carbonate (C4H6O3), sodium carbonate(Na2CO3), Para toluene sulphonic acid (C7H8O3S) and ethyl formate (C3H6O2) at a certain reciprocal proportion .The cure –acceleration effect of resin properties by using catalyst were analyzed .The effect of shortening temperature and adhesion strength were determined by using catalyst concentrations starting from 0.25%, 0.5%, 1.0%, 2.0% and 3% on the basis of the weight of liquid resin. The pot life and adhesion performance of accelerated–Phenol formaldehyde resins (PF) were evaluated by studying variation of viscosity and both dry and wet glue shear strength of the plywood respectively. Results indicates that the modified PF resin after incorporation of catalyst effectively accelerates the curing performance at lower temperature (1200C) than the conventional PF resin used at present in plywood industries. FTIR Spectroscopy to characterize the Structure of resin and differential scanning calorimeter (DSC-TGA) measurement was carried to study the thermal curing behavior of PF resin. The results shows that PF resin synthesized under catalytic system shows that the adhesive can be cured at low curing temperature (1200C) and shorten gel time as compared with control sample. Hence the catalyst accelerated –Phenol formaldehyde resin (PF) can overcome the short coming of high curing temperature and improve the quality of plywood.