Orientation of precrystallized poly(ethylene terephthalate)

Abstract

The orientation characteristics of crystalline poly(ethylene terephthalate), PET, were studied as a function of degree of crystallinity, orientation temperature, and stretch ratio. Oriented samples were analyzed with respect to mechanical, shrinkage, and barrier properties. The results show that (a) significant impact property improvement can be achieved by orienting crystallized PET, (b) the modulus, ultimate strength, and yield stress increase with orientation of precrystallized PET, (c) the initial degree of crystallinity can affect the strain‐hardening properties of PET, and (d) the total amounts of shrinkage and shrinkage stress of stretched PET increase with increasing amounts of crystallinity before orientation.

Influence of biaxial stretching mode on the crystalline texture in polylactic acid films

“…5) as a result of the chain alignment in the film plane during the increase of l TD . Similar behaviors were observed in other polymers [11][12][13][14][15][16][17][18][20][21][22][45][46][47][48][49][50][51][52].…”

“…Transverse stretching is found to induce strain hardening even at the start of extension in TD. Similar behaviors have been reported in stress vs. strain behavior of PET [48][49][50].…”

“…15 illustrates that the poles of these planes are primarily oriented in the ND. This is typical of SB stretching of many polymers [23][24][25][26]38,[48][49][50][51][52]57,58].…”

Mechanical properties of SiOx gas barrier coatings on polyester films

“…This is most likely a result of the high degree of crystallisation detected at the surface by AFM phase and forcedistance measurements, but which may not be present throughout the bulk. A high degree of crystallisation is known to increase the tensile yield stress (hence shear yield stress) of PET [33] and may also encourage strain hardening of the polymer. No elevated yield stress or strain hardening in the saturation regime (10-15% tensile strain) is observed for the HS PET film during tensile testing but this is probably due to the localisation of the increased crystallinity at the surface of the film, as reported in the literature [31,32].…”

Roll-drawing and die-drawing of toughened poly(ethylene terephthalate). Part 1. Structure and mechanical characterization

“…They co-extruded pre-crystallized PET in the solid state at temperatures between the glass transition and the melting temperature. Another systematic study on the orientation of semicrystalline PET was by Jabarin [24]. In this work, we report two solid-state orientation processes that have been successfully used in the past to produce highly oriented polymer products that have both commercial and technological interests.…”