Poly(ethylene terephthalate)–poly(caprolactone) block copolymer. I. Synthesis,reactive extrusion,and fiber morphology |
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Authors: | Weiming Tang N. Sanjeeva Murthy Frank Mares Milton E. Mcdonnell Sean A. Curran |
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Abstract: | A novel poly(ethylene terephthalate)–poly(caprolactone) block copolymer (PET–PCL) is synthesized in a reactive twin‐screw extrusion process. In the presence of stannous octoate, ring‐opening polymerization of ϵ‐caprolactone is initiated by the hydroxyl end groups of molten PET to form polycaprolactone blocks. A block copolymer with minimal transesterification is obtained in a twin‐screw extruder as a consequence of the fast distributive mixing of ϵ‐caprolactone into high melt viscosity PET and the short reaction time. The PET–PCL structure is characterized by IV, GPC, 1H‐NMR, and DSC. Fully drawn and partially relaxed fibers spun from PET–PCL are characterized by WAXD and SAXS. A substantial decrease in the oriented amorphous fraction appears to be the major structural change in the relaxed fiber that provides the fiber with the desired stress–strain characteristics. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1858–1867, 1999 |
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Keywords: | PET– PCL block copolymers twin‐screw extrusion ring‐opening polymerization ϵ ‐caprolactone |
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