Acetaldehyde scavengers and their effects on thermal stability and physical properties of poly(ethylene terephthalate)

Abstract

The acetaldehyde (AA) scavenging abilities of poly(ethylene terephthalate) (PET) blends containing various concentrations of anthranilamide, meta-xylenediamine (MXDA), or alpha-cyclodextrin have been evaluated. It was found that higher AA scavenger concentrations generally resulted in greater reductions in detectable AA in terms of both the AA generation rates and residual AA contents. As little as 100 ppm, by weight, of anthranilamide and MXDA were respectively shown to reduce residual AA detected in PET preforms by 46% and 36%. Melt-blending 500 ppm of alpha-cyclodextrin, into PET, reduced preform residual AA concentration by 42%. The scavengers acted as PET nucleating agents causing more rapid crystallization while heating the blends from the glassy state and when cooling from the melt; however, they caused no changes in the glass transitions, melting characteristics, or oxygen permeation behaviors of the blends. Addition of optimal scavenger concentrations had minimal effects on preform intrinsic viscosity and color changes. © 2012 Wiley Periodicals, Inc.