Migratory behaviour of a phosphite process stabilizer in polyolefins

Abstract

The migration of a phosphite process stabilizer tris (2,4-di t-butyl phenol) phosphite from polypropylene and a linear low density polyethylene is examined. At the 0.2% and 0.5% levels, no migration from polypropylene takes place, confirming earlier measurements made at the 10% level of phosphite. In the LLDPE, a slow migration takes place with a diffusion constant of approximately 2x10^-16 m²s^-1, which is slower than would be expected from single molecules. Migration of aggregates of phosphite molecules through the polymer matrix is suggested as a likely mechanism for this effect.