Structure development in reactive polycarbonate-Poly(ethylene terephthalate) melt blends

A. N. Wilkinson, E. M I Nita, M. L. Clemens, E. Jöbstl, J. P A Fairclough

    Research output: Contribution to journalArticlepeer-review

    Abstract

    A series of 50:50 polycarbonatepoly(ethylene terephthalate) (PCPET) blends were formed via reactive melt blending in a torque rheometer at 270°C. The degree of interfacial transesterification between the two homopolymers was promoted by the incorporation of an alkyl titanium catalyst during melt blending. The resultant materials were characterized using differential scanning calorimetry (DSC), smallangle light scattering (SALS), Fouriertransform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Multicycle DSC showed the uncatalyzed (0 T) blend to exhibit significant reactivity after four consecutive heatcoolheat cycles between 50 and 280°C. The effect of interfacial transesterification on the melt morphology of the 0 T blend was studied using SALS. As transesterification proceeded, the domain size within the blend melt was observed to drop from 50 m to 35 m over a period of 120 s. The range of domain sizes measured by SALS after 120 s showed good agreement with values of domain thicknesses measured for cocontinuous PCrich and PETrich phases from SEM and TEM micrographs. The DSC, FTIR, and dynamic mechanical thermal analysis (DMTA) studies of 0 T and blends containing up to 150 ppm added alkyltitanium catalyst indicated that only relatively low levels of interfacial transesterification occurred during melt blending, although the level did increase with catalyst addition. The SALS, SEM, and TEM showed that the increased level of interfacial reaction changed the distribution of domain sizes in the blends and that a cocontinuous morphology persisted. In contrast, addition of 200 ppm catalyst resulted in a significant increase in the degree of transesterification and the formation of an amorphous, singlephase material.
    Original languageEnglish
    Pages (from-to)1087-1102
    Number of pages15
    JournalJournal of Macromolecular Science - Physics
    Volume44
    Issue number6
    DOIs
    Publication statusPublished - Nov 2005

    Keywords

    • Blends
    • Poly(ethylene terephthalate)
    • Polycarbonate
    • Transesterification interfacial reaction

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