Nonisothermal elongational behavior of blends with liquid crystalline polymers

Mantia, F. P. La; Valenza, A.; Scargiali, Francesca

doi:10.1002/pen.760341004

Cited by 7 publications

(1 citation statement)

References 26 publications

(7 reference statements)

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“…Most of the studies reported in the literature on the evaluation of the polymer rheological properties in elongational flow have been carried out in isothermal conditions, while less attention has been devoted to the rheological behavior of polymer melts experiencing non-isothermal elongational flow, notwithstanding its technological relevance for the assessment of the processing behavior of polymer melts. Similar to what was observed in the previous section, polyethylene-and polypropylene-based materials are the most investigated materials, given the widely exploitation of these polyolefins in processing operations, in which the non-isothermal elongational flow is prominent [78][79][80][81].…”

Section: Rheological Properties In Non-isothermal Elongational Flowsupporting

confidence: 61%

Effect of the Elongational Flow on the Morphology and Properties of Polymer Systems: A Brief Review

2021

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Polymer-processing operations with dominating elongational flow have a great relevance, especially in several relevant industrial applications. Film blowing, fiber spinning and foaming are some examples in which the polymer melt is subjected to elongational flow during processing. To gain a thorough knowledge of the material-processing behavior, the evaluation of the rheological properties of the polymers experiencing this kind of flow is fundamental. This paper reviews the main achievements regarding the processing-structure-properties relationships of polymer-based materials processed through different operations with dominating elongational flow. In particular, after a brief discussion on the theoretical features associated with the elongational flow and the differences with other flow regimes, the attention is focused on the rheological properties in elongation of the most industrially relevant polymers. Finally, the evolution of the morphology of homogeneous polymers, as well as of multiphase polymer-based systems, such as blends and micro- and nano-composites, subjected to the elongational flow is discussed, highlighting the potential and the unique characteristics of the processing operations based on elongation flow, as compared to their shear-dominated counterparts.

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Section: Rheological Properties In Non-isothermal Elongational Flowsupporting

confidence: 61%

Effect of the Elongational Flow on the Morphology and Properties of Polymer Systems: A Brief Review

2021

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Liquid Crystalline Composite

Isayev

2012

Wiley Encyclopedia of Composites

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A review of novel technologies for manufacturing composites involving liquid crystalline polymers (LCPs) is presented. In particular, this review provides a classification scheme of various types of LCPs, with a special emphasis paid to the history, key approaches, milestones in developments of thermotropic LCPs, and their commercialization. Methods of characterization of LCPs by optical and electron microscopy, X‐ray diffraction, NMR, light scattering, and thermal, rheological, and mechanical techniques are discussed. The development of the concept of self‐reinforced or in situ composites based on blending LCPs with flexible‐chain polymers and LCPs with other LCPs is presented. In these composites, the dispersed fibrous reinforcing LCP species in polymer matrices are not actually present before the processing of the resin, but come into existence during the processing step. Various aspects of manufacturing of these composites are discussed including methods of mixing and compounding, transition temperatures, different factors governing LCP fibrillations, effects of LCP on crystallization of thermoplastic matrices, rheology of composites, and the use of LCP as a processing aid for thermoplastics. Special attention is paid to manufacturing and mechanical properties of the composites based on LCP/thermoplastic, LCP/LCP and ternary blends, and LCP/thermoplastic and LCP/LCP laminates. The effect of compatibilization and anisotropy of composites are also considered along with proposed approaches to reduce their anisotropy. Finally, various existing and future possibilities for industrial applications of self‐reinforced composites are discussed.

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A rheological and morphological model for blends of flexible and rigid macromolecules

Edwards

Williams

2003

Polymer Engineering & Sci

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A model is developed that describes the complicated rheology and morphology of thermoplastic polymers blended with relatively small amounts of liquid‐crystalline polymers (LCPs). Such blends typically display properties superior to, but more complicated than, those of ordinary thermoplastic polymers. Viscosity predictions are obtained with this model that exhibit the wide range of behavior that is observed experimentally in these blended materials for both shear and elongational flows. For example, the viscosity‐composition curve can display a minimum at low compositions of LCP, and the addition of an LCP to a thermoplastic polymer can result in a reduction in the shear viscosity but an increase in the elongational viscosity. Corresponding morphological descriptions are also obtained for the internal microstructure of the blends that provide information about the underlying causes of the complicated rheological behavior.

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Nonisothermal elongational behavior of blends with liquid crystalline polymers

Cited by 7 publications

References 26 publications

Effect of the Elongational Flow on the Morphology and Properties of Polymer Systems: A Brief Review

Effect of the Elongational Flow on the Morphology and Properties of Polymer Systems: A Brief Review

Liquid Crystalline Composite

A rheological and morphological model for blends of flexible and rigid macromolecules

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