Development of lamellar morphology in poly(ethylene terephthalate)/polycarbonate blends

Abstract

We have studied the lamellar-level morphology of poly(ethylene terephthalate) (PET)/polycarbonate (PC) blends using small-angle X-ray scattering (SAXS). Measurements were made as a function of the holding time in the melt. We determined the morphological parameters at the lamellar level by correlation function analysis of the SAXS data. An increased amorphous layer thickness was identified in the blend, indicating that some PC was incorporated into the interlamellar regions of PET during crystallization. The blend also exhibits a larger lamellar crystalline thickness (l c ) than that of pure PET. A possible reason for the increase in l c is that the inclusion of the PC molecules in the interlamellar regions causes an increase in the surface free energy of folding. At the early stage of isothermal crystallization, we observed a rapid drop in the value of l c in the blend; this finding indicates that a relatively large fraction of secondary crystals form during the primary crystallization. In contrast, the value of l c for the sample that underwent a prolonged holding time increased with time in the secondary crystallization-dominant regime; this observation suggests that the disruption of chain periodicity, which results from transesterification between the two polymers, favors the development of fringed micellar crystals that have larger values of l c , rather than the development of normal chain-folded crystals.

Poly(trimethylene terephthalate‐block‐tetramethylene oxide) elastomer/single‐walled carbon nanotubes nanocomposites: Synthesis, structure, and properties

“…The long period ( L ) was estimated from the position of the first maximum of γ( r ) [see later Fig. 7(b)], and the thickness of the crystalline and amorphous layers in the stacks was calculated as follows: The transition layer ( E ) between the amorphous and crystalline regions was calculated from where R = L φ c ( 1 − φ c ) is the position of the first intercept of the correlation function with the r ‐axis 29…”

Effects of PP-g-MAH on the Mechanical, morphological and rheological properties of polypropylene and poly(acrylonitrile-butadiene-styrene) blends

“…However, most of the polymer blends are found to be incompatible. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] These incompatible polymer blends have poor mechanical and physical properties. In order to improve the mechanical properties of the polymer blends, the compatibilizer has been widely used.…”

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“…Because properties of these phase-separated polymer blends depend on the morphology of the blends, factors which determine phase-separated morphology, such as the interfacial tension, viscosities of constituent polymers, and shear rate should be controlled to produce the optimum size and shape of constituent phases in polymer blends. [1][2][3][4][5][6][7] Thermoplastic polyurethane elastomer (TPU) is a linear, segmented copolymer composed of a rubbery, soft segment and a rigid, polar hard segment. TPU is one of the most versatile engineering thermoplastics with elastomeric properties because a wide range of monomeric materials are commercially available, and tailor-made properties can be obtained from well-designed combinations of monomeric materials.…”