Morphology development and crystallization behavior of poly(ethylene terephthalate)/phenoxy blend

• Published in: Journal of polymer science. Part B, Polymer physics Vol. 46; no. 3; pp. 223 - 232
• Main Authors: Kim, Geon Seok, Lee, Jong Kwan, Choi, Mi Ju, Lee, Kwang Hee
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.02.2008; Wiley
• Subjects: Applied sciences; Crystallization; Exact sciences and technology; morphology; Organic polymers; phase separation; phenoxy; Physicochemistry of polymers; poly(ethylene terephthalate); Properties and characterization; Ethylene terephthalate polymer; Polymer blends; morphology; Spinodal decomposition; Ether polymer; Experimental study; Alcohol polymer; Melt crystallization; Supramolecular structure; Phase separation; crystallization; Kinetics; phenoxy; Isothermal crystallization; poly(ethylene terephthalate)
• ISSN: 0887-6266; 1099-0488
• DOI: 10.1002/polb.21359

The morphological development and crystallization behavior of a poly(ethylene terephthalate)/poly(hydroxyl ether of bisphenol A) (phenoxy) blend were studied with time-resolved light scattering, optical microscopy, differential scanning calorimetry, and small-angle X-ray scattering (SAXS). During annealing at 280 °C, liquid-liquid phase separation via spinodal decomposition proceeded in the melt-extruded specimen. After the formation of a domain structure, the blend slowly underwent phase homogenization by the interchange reactions between the two polymers. Specimens annealed for various times (ts) at 280 °C were subjected to a temperature drop and the effects of liquid-phase changes on crystallization were then investigated. The shifts in the position of the cold-crystallization peaks indicated that the crystallization rate is associated with the composition change of the separated phases as well as the change of the sequence distribution in polymer chains during annealing. The morphological parameters at the lamellar level were determined by a correlation function analysis on the SAXS data. The crystal thickness (lc) increased with ts, whereas the amorphous layer thickness (la) showed little dependence on ts. Observation of a constant la value revealed that a large number of noncrystallizable species formed by the interchange reactions between the two polymers were excluded from the lamellar stacks and resided in the interfibrillar regions, interspherulitic regions, or both. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 223-232, 2008