Transient shear and elongational behavior of blends of PET with a LCP

Blends of polyethylene terephthalate (PET) with a liquid crystalline polymer (LCP) and a compatibilizer were produced by twin screw extrusion and injection molding. Transesterification and compatibilization studies were made in a torque rheometer. The morphology of the injection-molded plaques was s...

Full description

Saved in:
Bibliographic Details
Published in:Rheologica acta 2006, Vol.45 (3), p.268-280
Main Authors: DA SILVA, Lucineide Balbino, MASSAYOSHI UEKI, Marcelo, FARAH, Marcelo, COELHO BARROSO, Vitor Manuel, LOPES MAIA, Joao Manuel, ELIDA SUMAN BRETAS, Rosario
Format: Article
Language:English
Subjects:
Applied sciences
Compatibility
Elongation
Exact sciences and technology
Extrusion molding
Injection molding
Liquid crystal polymers
Liquid crystals
Morphology
Physical properties
Plastic deformation
Polyethylene terephthalate
Polymer blends
Polymer industry, paints, wood
Properties and testing
Rheological properties
Scanning electron microscopy
Shear thinning (liquids)
Shear viscosity
Technology of polymers
Transesterification
Viscosity
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Blends of polyethylene terephthalate (PET) with a liquid crystalline polymer (LCP) and a compatibilizer were produced by twin screw extrusion and injection molding. Transesterification and compatibilization studies were made in a torque rheometer. The morphology of the injection-molded plaques was studied by scanning electron microscopy. The blends shear growth function\[(\eta ^{+}(t,\ifmmode\expandafter\dot\else\expandafter\.\fi{\gamma}))\] was measured in a cone and plate rheometer. The elongational growth function\[(\ifmmode\expandafter\bar\else\expandafter\=\fi{\eta}^{+}(\ifmmode\expandafter\dot\else\expandafter\.\fi{\varepsilon},t))\] was measured in a modified rotational rheometer. Transesterification was observed in the PET/LCP/compatibilizer 95/5/0 blend. The injection-molded plaques displayed the usual “skin-core” morphology. All the blends were highly shear-thinning, even at low shear rates; thus, a zero-shear viscosity could not be calculated. The compatibilized blend had the highest shear viscosity of all the blends, confirming the strong PET/LCP interphase and the effectiveness of the compatibilizing agent. On the other hand, the 90/10/0 blend had the lowest shear viscosity. All the blends showed strain softening behavior, similar to the PET. The 90/10/0 blend had the highest elongational growth function, while the 95/5/0 had the lowest. The compatibilized blend had an intermediate behavior between both blends.
ISSN:0035-4511
1435-1528
DOI:10.1007/s00397-005-0030-x