The amorphous copolyester PETG was recognized to mix with semicrystalline PEN molecules homogeneously above melting temperature over an entire range of blending composition. After being through uniaxial stretching at 120 oC, oriented mixtures further crystallized in a continuous manner via local cooperative segmental sliding, which is similar to the mechanism accounting for lamellar reorganization. This crystallization mechanism prevailingly induced missed transverse registries of packing stems as lattice defects, indicating that sufficient motions of joining segments are frequently not available. Nevertheless, the relaxation of stretched PETG has emerged helpful for avoiding lattice defect via yielding free volume and thus lessening encountered friction during segmental sliding.  Longer stacking periods were recognized with increasing PETG fraction also, indicating the inclusion of amorphous PETG within lamellar stacking scheme. This inclusion of PETG was found capable of enhancing lamellar thickening during heating, manifesting the impact of free volume within amorphous region. Furthermore, the PETG fraction was recognized able to enhance self-organization of crystalline lamellae into a regular stacking pattern during heating. In summary, this research has associated diluent effects to the establishment of regular lattice packing, and corresponding enhancement to lamellar association and reorganization within stretched blends.

Novel diluent effect on crystallization of poly(ethylene naphthalate)(PEN) within uniaxially stretched blends

243rd National Meeting (2012)

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