Mutual influence of the morphology and capillary rheological properties in nylon/glass‐fiber/liquid‐crystalline‐polymer blends

Abstract

Nylon‐6/glass‐fiber (GF)/liquid‐crystalline‐polymer (LCP) ternary blends with different viscosity ratios were prepared with three kinds of nylon‐6 with different viscosities as matrices. The rheological behaviors of these blends were characterized with capillary rheometry. The morphology was observed with scanning electron microscopy and polarizing optical microscopy. This study showed that although LCP did not fibrillate in binary nylon‐6/LCP blends, LCP fibrillated to a large aspect ratio in some ternary blends after GF was added. The addition of 5 wt % LCP significantly reduced the melt viscosity of nylon‐6/GF blends to such an extent that some nylon‐6/GF/LCP blends had quite low viscosities, not only lower than those of neat resins and nylon‐6/GF blends but also lower than those of corresponding nylon‐6/LCP blends. The mutual influence of the morphology and rheological properties was examined. The great reduction of the melt viscosity was considered the result of LCP fibrillation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1619–1627, 2004

Rheological hybrid effect in nylon 6/liquid crystalline polymer blends caused by added glass beads

“…In comparison to the phenomenon described before [20], the bigger the initial size of LCP droplets, the easier the fibrillation of LCP was.…”

“…The most substantial decrease in viscosity does not correlate directly with the onset of fibrillation, because the latter also depends on the LCP concentration and the deformation of LCP droplets from spheres to fibrils. Due to this competition, the viscosity decrease of highly-filled ternary blends is mainly resulted from the lubrication of LCP droplets [20]. The viscosity of N/GB1/LCP 34/55/11 lower than that of N/GB/LCP 84/5/11 (Fig.…”

“…For ternary N/GB/LCP hybrid blends, the N/GB was taken as the matrix, as done in the literature [3,4,[14][15][16][17][18]20]. Then the initial size of LCP droplets in ternary N/GB/LCP hybrid blends was estimated according to Eq.…”

Rheological Hybrid Effect and its Conditions in Filled Polymer Melts

“…[9] Surprisingly, it was found that the addition of glass fiber significantly reduced the melt viscosity of PA6/LCP blends. This effect was so marked that some PA6/GF/LCP composites had a quite low viscosity, not only lower than neat PA6, Morphology of ternary N/GB/LCP composites with different GB contents at shear rate of 115 s À1 (LCP content is 11 wt %).…”

“…Except for the abovediscussed factors, the geometrical factor in these multi-phase systems also had its influence. It included the size of temporarily formed capillaries in fiber-filled melts [8,9] and the size of gaps between nearby rotating spheres. [14,15] It was the prerequisite for the hydrodynamic driving force to act.…”