Influence of additives on crystallization of poly(ethylene 2,6-naphthalate)

The influences of additives, Ceraflour 991(R) (low molar mass polyethylene) , Ceraflour 993(R) (low molar mass polyamide), and poly (1,4-butylene sebac ate), on the crystallization of poly(ethylene 2,6-naphthalate) (PEN) were i nvestigated by means of differential scanning calorimetry, scanning electro n microscopy, and polarized optical microscopy. It was revealed that these additives could substantially accelerate the crystallization of PEN at low temperature due to an improvement of molecular motion of PEN. They can be a ttributed to a kind of nucleating promoter. They also enhance the crystalli zation rate of PEN at high temperature; this could be caused by phase separ ation between additive and PEN. The separated microdroplets of the additive s serve as heterogeneous nuclei to initiate primary nucleation. In the high temperature region, however, Ceraflour 993 is much more effective to accel erate nucleation than others, and it acts as if it is also a nucleating age nt.