Structural development and mechanical properties of polyethylene naphthalate/polyethylene terephthalate blends during uniaxial drawing

摘要

The blends of poly(ethylene naphthalate)(PEN) and poly(ethylene terephthalate)(PET) were obtained by melt blending at 310 deg C for 2 min and quenching into an ice water. Mechanical properties and structural formation of unoriented amorphous PEN/PET bend films during drawing at 85, 100 and 130 deg C were studied by tensile tests and in situ X-ray measurements. The results obtained were compared with the pure PEN and PET.The PET film could not be drawn due to partial melt at above 100 deg C and a lower drawing rate but the film blended with PEN was possible to be drawn. The crystallization of PEN/PET blend during drawing proceeded gradually due to the effect of PET at 100 deg C though the crystalline reflections in the crystallization of pure PEN appeared suddenly by necking. This was evidenced by the formation of #alpha#-form crystalline reflections of PEN as detected by in situ X-ray measurements.