High impact strength modified Melamine–Formaldehyde resin with special “building blocks” structure

Abstract

Two kinds of modified melamine–formaldehyde (MF) resin with high impact strength were prepared, especially the modified MF resin with the special “building blocks” structure. First, three copolymers (HMM‐PEGDGE, HMM‐PPGDGE, and HMM‐C12‐14AGE) of glycidyl ether [polyethylene glycol diglycidyl ether (PEGDGE), polypropylene glycol diglycidyl ether (PPGDGE), C12‐14 alkyl glycidyl ether (C12‐14AGE)] and hexahydroxymethyl melamine (HMM) were synthesized and proved by FTIR and 1H NMR. Then, the copolymers were mixed with melamine–formaldehyde resin water solution to prepare samples (EMM1‐PEs, EMM1‐PP, and EMM1‐C12‐14) through drying and hot pressing. The results indicated that the addition of HMM‐PEGDGE could significantly improve the impact strength of EMM1‐PEs, much higher than EMM1‐PP and EMM1‐C12‐14. Meanwhile, PEGDGE was also directly mixed with melamine–formaldehyde resin water solution and made into samples (EMM2‐PEs). The results showed that the impact strength of EMM2‐PEs was also higher than pure MF but lower than EMM1‐PEs. The impact strength of EMM1‐PE‐20 reached 9.46 kJ/m2, about two times that of pure MF. The mechanism of EMM1‐PEs with high impact strength was ascribed to the special “building blocks” structure, which had the flexible HMM‐PEGDGE block, could cause many cracks because of the poor compatibility between HMM‐PEGDGE and melamine–formaldehyde resin.