Dynamic mechanical properties of poly(vinyl chloride) and polyurethane carboxylate blends

The miscibility of thermoplastic polyurethane elastomers (TPUs) with poly(vinyl chloride) (PVC) was studied. PVC blends with TPUs, prepared from 4,4‐diphenylmethane diisocyanate as diisocyanate, hydroxy‐terminated poly(butylene adipate) (PBA) as the soft segment, and dimethylolpropionic acid as the chain extender carrying a latent anionic site for neutralization by triethylamine, showed a single glass transition temperature (Tg), irrespective of neutralization of latent anionic sites of TPU. But in neutralized TPU/PVC blends, limited intimate segmental mixing was perceived from the mechanical properties observed. When hydroxy‐terminated poly(propylene glycol) was used as the soft segment instead of hydroxy‐terminated PBA, PVC/TPU blends showed two separate Tg's of PVC and TPU, irrespective of neutralization.