Study On Synthesis And Properties Of Co-condensated MPF Resin

Phenolic resin(PF) is a kind of widely used adhesive in plywood industry, but the use of which is most in building formwork, carriage board and container board because of high cost and dark colour and high curing temperature(140-150℃). Melamine-formaldehyde (MF) resin has advantage of high bonding strength, high water resistance, a large supply of raw materials, clear and colourless liquid and law curing temperature, but it also has disadvantage of great brittleness, short storage life and low aging resistance. In the recent years, people like green and high properties bamboo-wood products more and more. The cost of phenol is higher, and the supply of wood resources comes to be insufficient. It is necessary to study and develop a new kind of adhesive which is low formaldehyde emission, green, aging resistance, high bonding strength, long storage life and modest price. MPF resin which has advantage of green, fire resistance, high bonding strength, high durability, no pollution to bamboo-wood products, easy to use and modest price can have the good properties of PF reisn and MF resin. And it can be used in fireproof board, plywood, parquet, bamboo strand forming board(BSFB) and other bamboo-wood products. Therefore, the MPF resin will have a great market prospect and potential.According to the study on the synthesis and properties of co-condensated MPF resin, the results are as follow:â‘ In accordance with the FTIR analysis and 1H-NMR analysis of MPF resin, the cocondensation of phenol-formaldehyde-melamine was achieved by reacting methylolphenols with methylolmelamines at weak alkali condition, and the phenol ring and triazine ring were mainly joined by the methylene linkage(Ph-CH2-N<).â‘¡In accordance with the DSC analysis of MPF resin, with the molar ratio of F/(M+P) increasing, the characteristic curing temperatures all decreased, and the activation energy also decreased in the curing process of MPF resin; The kinetics model of three kinds of MPF resin(molar ratio of F / (M+P)=1.3,1.6,1.8 ) were da/dt=1.04×10¹⁵e^-116140/RTp(1-a)^0.9291 and da/dt=8.45×10¹³e^-107230/RTp(1-a)^0.9407 and da/dt=2.40×10¹¹e^-87030/RTp(1-a)^0.9448 respectively; With the molar ratio of F/ (M+P) increasing, the characteristic curing temperatures Ti,Tp and Tf (β= 0℃/min ) all decreased. And the sequence of activation energy was consistent with that of curing reaction of MPF resin; With the pH value decreasing, the activation energy of curing reaction of MPF resin system increased.â‘¢In accordance with the studying on buring kinetics and buring behavious of Bamboo Strand Forming Material(BSFM) with MPF resin by using a cone calorimeter at different heat radiations, the results showed that the average activation energy Eaes of four kinds of BSFM calculated by the chemical equation were: 29.89KJ.mol^-1(BSFM with MPF resin and phosphorus fire retardant), 13.54KJ.mol^-1(BSFM with MPF resin), 13.93KJ.mol^-1 (BSFM with PF resin and phosphorus fire retardant and 12.26KJ.mol^-1 (BSFM with PF resin) respectively; The fire resistance of BSFM with MPF resin before and after treated by phosphorus fire retardant are all better than that of PF resin; And according to the studying on fireproof board with MPF and PF resin, the fire reistance of MPF resin was better than that of PF resin.â‘£In accordance with the mechanical properties analysis of BSFB and plywood with MPF resin at different hot-processing temperatures, the results showed that with the hot-processing temperature improving, the bonding strength of MPF resin improved. In accordance with the mechanical properties analysis of BSFB and plywood with MPF resin at different pH value, the results showed that the changing of pH in the range of alkali condition did not have obvious effect on the bonding strength of MPF resin.