Effects of individual components in a vitamin E formulation on off-odor release, melt flow index, and yellowness index of an HDPE polymer

A three-phase study was conducted to investigate the effects of individual components in a vitamin E formulation (CF-120) on off-odor release, melt fl ow index, and yellowness index of high-density polyethylene (HDPE) resin pe llets. CF-120 consists of vitamin E, glycerol, polyethylene glycol-400 (PEG -400), and glyceryl monocaprylate/caprate (GMC). The resin pellets were ext ruded from HDPE resin powder using a laboratory-scale single-screw extruder . Off-odor release from the resin pellets was evaluated using a sensory pan el and gas chromatography/mass spectrometry (GC/MS) analysis. A Phase I(pre liminary experiment) study showed that GMC greatly contributed to off-odor and melt flow index (MFI) reduction; vitamin E greatly contributed to yello w color formation. A Phase II (factorial experiment) study confirmed that G MC was the major off-odor contributor. A Phase III (response surface experi ment) study showed that yellowness index and odor score reasonably correlat ed to vitamin E and GMC concentrations. In contrast, MFI and nonanal concen tration had no correlation with vitamin E and GMC concentrations. The resul ts are useful for designing a better vitamin E formulation for reducing the off-odor, without significantly enhancing yellow color formation.