Preparation,molecular weight determination and structure elucidation of melamine-urea-formaldehyde,melamine-methylurea-formaldehyde and melamine-dimethylurea-formaldehyde polymer resins with IR spectroscopy

摘要

Melamine-urea-formaldehyde (MUF),melamine-methylurea-formaldehyde (MMUF) and melamine-dimethylurea-formal-dehyde (MDUF) resins/polymers have been prepared by condensation polymerization.Average molecular weights (M_w) have been determined with intrinsic viscosity and gel permeation chromatography (GPC) with known molecular weights of polyvi-nyl alcohol as standard marker for calibration.Hydrogen atom substitution by methyl group in urea increases M_w and IR spectra mark the presence of several oligomer units with methylene and ether linkages.Disappearance of 3734 cm~(-1) band from spectra of uncured MUF on curing from 140 to 200degC has been noticed with narrowness in bands and multiple splits between 3451 and 3296 at 140deg,3453 and 3328 at 160deg and 3341 and 3234 cm~(-1) doublet at 200degC.