Study On Curing Reaction Mechanism Of Water-soluble SMF Resins

For sucrose copolymer of modified melamine formaldehyde resin curing reaction mechanism research,it is of great significance to further explore the carbohydrates in the application of modified thermosetting resin,and to meet the requirements of energy conservation,environmental protection and economic sustainable development.This thesis mainly discussed the effect of different sucrose contents on the curing properties and curing reaction mechanism of Sucrose-Melamine-Formaldehyde(SMF)resins.The curing properties of SMF resins were analyzed by methods of FT-IR and TG.The curing reaction mechanisms of SMF resins was discussed by FT-IR,13C CP/MAS NMR and DSC.And the curing kinetics of SMF resins were researched by non-isothermal DSC.The main contents and results of this thesis are listed as follows:(1)The results of FT-IR and TG showed that the sucrose was involved in the curing SMF resin,and the number of hydroxymethyl groups significantly decreased but the number of hydroxyl groups and ether bonds increased,which made SMF resin reduce the cross-linking density on the basis of reached the national requirement of "A class plywood" and "E1 class of limit of formaldehyde emission",and prolong the pot life of SMF resin.(2)The analysis shows that there are two types of curing reaction mechanism of SMF resins according to the results of FT-IR?13C CP/MAS NMR and DSC.The one was that the hydroxymethyl condensation reaction between resin and methylol melamine molecules in the monomer molecules respectively,the other one was that the reaction between the hydroxyl groups in the monomer molecules of the resin and the hydroxyl groups in the sucrose molecules.(3)According to the SMF resin curing parameters and Kissinger-Crane-Arrhenius equation shows that the curing reaction of SMF resins are complex reaction,which was not related to the concentration of the reactant.With the increased of the number of sucrose,the curing reaction activation energy of SMF resin showed an increased after an initial decrease,which showed that the energy barrier of SMF resin curing system was affected by the addition of sucrose.