Study On Synthesis And Properties Of Co-condensated PUF Resin

Phenolic resin has excellent bond strength, water resistance, durability, acid-resistant and drug-resistant features, excellent performance,which is an excellent adhesive. Urea-formaldehyde resin adhesive has the advantages of the low production costs, adequate sources of raw materials, simple production technology, colorless layer after curing and so on. But because of the bad durability and water resistance, the Urea-formaldehyde resin adhesive needed to be improved. In order to develop low-cost and high-performance new wood adhesive, the Synthesis and Properties of phenol-urea-formaldehyde resin polycondensation was studied, which showed the great significance of developing this new type of adhesive.The following conclusions arrived from studying the synthesis and properties of co-condensation of PUF resin:(1) PUF resin through the Fourier transform infrared spectroscopy and nuclear magnetic resonance spectrum(H) analysis showed that of the PUF synthetic resin under the weak-base alkaline conditions was mainly obtained by Methylol urea and Methylol phenol condensation. The Hydroxymethyl-urea and Phenol ring were mainly linked by Methylene bond structure.(2) By comparative analysis of the Fourier transform infrared spectra before and after the curing of PUF resins and PUF resins of different molar ratio,through non-isothermalDSC curve showed that the PUF resin was mainly cross-linking curing through the phenolic hydroxyl group and methylol; the curing temperature of PUF resin as the rate of the heating increases, the peak curing temperature (Tp) also increases. With the increase of F / (P+U) molar ratio, PUF copolymer resin curing process of the apparent activation energy reduces gradually. And four different kinds of the copolymer resin cure kinetics model with different molar ratios were obtained.(3) The studies through using the gel permeation chromatography to measure the molecular weight of PUF resin have shown that the number-average molecular weight increases with the increase of the molar ratio F/ (P+U), the molecular weight of the PUF of the three molar ratio were close and the dispersion coefficients were all less than 2.0, which showed that the molecular weight and molecular weight distribution of PUF resins were accurately feasible, simple and good precision.(4) The result was found that the modulus of elasticity and the hot-pressing temperature(110~150℃)and the combination of strength of the molding bamboo with PUF resin both increased and the water swelling gradually reduced by measuring mechanical properties of the molding bamboo with PUF resin. The poplar plywood bonding strength with PUF resin increased as the hot-pressing temperature increased.