Diffusion of stabilizers in polymers. III. 2,4‐dihydroxybenzophenone and 2‐hydroxy‐4‐octoxybenzophenone in polyurethanes

摘要

AbstractThe diffusion of the radioactively labeled ultraviolet stabilizers 2,4‐dihydroxybenzophenone and 2‐hydroxy‐4‐octoxybenzophenone in two linear poly(ester‐urethanes) was studied over the temperature range 36–75°C. Within this temperature range, both stabilizers diffused faster in the polyurethane which had a polyester of molecular weight 2000 in its chain rather than in the polyurethane with a polyester of molecular weight 1000 in its chain. 2,4‐Dihydroxybenzophenone diffused slightly faster than 2‐hydroxy‐4‐octoxybenzophenone in both polyurethanes. In each case, the results can be represented by an Arrhenius expressionD=D0exp (−E/RT). The values ofD0andEare discussed in terms of the size of the stabilizer molecular and the st