Crystallization studies of polymer blends of nylon-11/poly(vinylidene fluoride)

Abstract

The crystallization of blends of two semi-crystalline polymers nylon-11 and poly(vinylidene fluoride) (PVF2) was studied. The existence of separate melting and crystallization temperatures over the whole composition range showed that these two polymers did not co-crystallize. However, blending affected the crystallization behavior of each component. Adding nylon-11 decreased the crystallization temperature (Tc) of PVF2, but increased its crystallization rate. On the other hand, the Tc of nylon-11 decreased, and its crystallization rate decreased as well when blended with PVF2. The crystallization mechanism of both nylon-11 and PVF2 changed in the blends compared to that in the pure states. The Ozawa index, or Avrami exponent, of PVF2 in the blend decreased from 3 to 1 as the crystallization temperature decreased from 137°C to 131°C, compared with a decrease from 2.5 to 1.3 observed in pure PVF2 at the temperature range from 145°C to 135°C. The Avrami exponent of nylon-11 in the blend decreased from 2 to 1 as the crystallization temperature decreased from 159°C to 153°C, compared with a decrease from 2.5 to 0.75 observed in pure nylon-11 at the same temperature range.