Melting and Recrystallization of PA-6/PA-66 Blends

摘要

The morphology of a number of polyamides (P A) of current andpotential use for mobile air conditioning and refrigerant tubing, namelyPA-6, PA-66, PA-6/PA-66 blends and PA-6/PA-66 copolymers, asprepared from the melt and from HCOOH solution and the effect ofannealing thereof has been examined. In tpe blends the P A -6 crystallizeswithin the P A -66 spherulites, the P A -66 crystallizing first in a looselamellar framework. The copolymers also crystallize as large spherulites.When prepared from HCOOH solution at 25??C (77??F) the PA-66 containingsamples show a large exothermic peak before the sample melting peak isobserved by DSC. This exothermic peak, which cannot be fully explainedby either previously known observations, P A recrystallization and/or themorphology changes we describe here, is not seen for PA-6 or for PA-66prepared from HCOOH solution at 100??C (212??F).