Identifying optimal dispersant aids for flame retardant additives in tetramethyl cyclobutanediol‐based copolyesters

Abstract

Proper dispersion of an additive throughout a polymer matrix is essential to achieving the desired effects of the additive. Typically, this dispersion is difficult due to poor interactions between the polymer and additive. In the case of melamine cyanurate (MC), an extensive hydrogen bonding network among the principal components results in large domains that prevent it from adequately dispersing within many polymer matrices. Adding a hydrogen bonding capable polymer that competes with intramolecular hydrogen bonding of the MC may lead to a reduction in MC domain size. The disruption of intramolecular MC hydrogen bonding was monitored with attenuated total reflection Fourier transform infrared spectroscopy, while crystalline domain size was determined with scanning electron microscopy. Water-soluble polymers are identified as an ideal category of dispersing aids for their hydrogen bonding ability and compatibility with melamine cyanurate. Disrupting the hydrogen bonding network on an atomic level with a water-soluble polymer dispersant led to at least a 50% reduction in measured particle size, as well as in increase in the domain size's homogeneity, as indicated by a 75% reduction in the polydispersity of particle sizes in melt mix samples.