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Keywords:

  • composites;
  • extrusion;
  • rheology;
  • structure–property relations;
  • mechanical properties

ABSTRACT

Highly filled poly(vinyl alcohol) (PVA) composites, PVA/talc and PVA/CaCO3, were successfully prepared through melt-processing technology without use of coupling agents or compatibilizers. Morphology analysis showed that both of the two fillers well dispersed in PVA matrix. Differently, the flaky talc obviously oriented, while the particulate CaCO3 was randomly scattered in PVA matrix. Rheological analysis showed that the two filled systems exhibited a common shear-thinning phenomenon, confirming their pseudoplastic nature. Compared with the particulate CaCO3, the flaky talc exhibited a closer arrangement in the composite, resulting in a lower threshold filler content to form the network structure. Therefore, PVA/talc composite showed higher melt viscosity and lower extrudate-swell ratio. The orientation of the flaky talc particles in the system also resulted in the higher melting and heat-deflection temperatures, as well as a greater reinforcement effect on the composite, but a lower elongation at break. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3050–3057, 2013