A Comparative Study of Crystallization of iPP and PA6 under Pressure
Experimental data for two semicrystalline polymers (iPP and PA6) crystallized
under pressure are supplied. The effect of two typical process operating conditions
(solidification pressure and cooling rate) on the final properties of the obtained product is
quantified. The influence of processing conditions on some macroscopically relevant
properties, such as density and micro hardness is discussed, together with the influence of
processing conditions on the product morphology, investigated by means of Wide Angle X-Ray
Scattering (WAXS). Results on the iPP samples display a lower density and a lower
density dependence on cooling rate for increasing solidification pressure. Micro Hardness
confirms the same behavior. PA6 samples exhibit an opposite behavior with density and
Micro Hardness increasing with solidification pressure. A deconvolution technique was
applied to iPP and PA6 WAXS patterns to evaluate the final phase content and to assess a
crystallization kinetics behavior. A “negative” influence of solidification pressure on the
crystallization behavior of the alpha phase might be assessed in the case of iPP, while a
slightly “positive” influence of the pressure applied on the crystallization behavior of PA6
has been found.
Vicenzo LA CARRUBBA, Valerio BRUCATO, S. PICCAROLO
Reçu le 19 juillet 2001.
Accepté le 29 octobre 2001.
Semicrystalline polymers, pressure, cooling rate, crystallization kinetics.