Liquid crystal polymers—11. Structure-property relationships in a series of thermotropic poly(2-n-alkyl-1,4-phenylene terephthalates)

1983 ◽  
Vol 19 (10-11) ◽  
pp. 1043-1046 ◽  
Author(s):  
J MAJNUSZ ◽  
J CATALA ◽  
R LENZ
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystal Polymers ◽  
Structure Property ◽  
Structure Property Relationships

scholarly journals Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

2020 ◽  
Vol 16 ◽  
pp. 674-680 ◽  
Author(s):  
Zeguo Fang ◽  
Nawaf Al-Maharik ◽  
Peer Kirsch ◽  
Matthias Bremer ◽  
Alexandra M Z Slawin ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Thermodynamic Properties ◽  
Organic Liquid ◽  
Dielectric Anisotropy ◽  
Structure Property ◽  
Structure Property Relationships

This paper describes the synthesis of a series of organic liquid crystals (LCs) containing selectively fluorinated cyclopropanes at their termini. The syntheses used difluorocarbene additions to olefin precursors, an approach which proved straightforward such that these liquid crystal candidates could be efficiently prepared. Their physical and thermodynamic properties were evaluated and depending on individual structures, they either displayed positive or negative dielectric anisotropy. The study gives some guidance into effective structure–property relationships for the design of LCs containing selectively fluorinated cyclopropane motifs.

Structure-Property Relationships Between Morphological Anisotropy and Mechanical, Thermal, and Dielectric Behavior in Liquid Crystal Polymers

2019 ◽  
Author(s):  
Anthony Sullivan ◽  
Anil Saigal ◽  
Michael A. Zimmerman
Keyword(s):  
Liquid Crystal ◽  
High Performance ◽  
Dielectric Behavior ◽  
Microstructural Development ◽  
Liquid Crystal Polymers ◽  
Structure Property ◽  
Degree Of Orientation ◽  
Injection Molded ◽  
The Individual ◽  
Bulk Behavior

Abstract Liquid crystal polymers (LCPs) form a class of high-performance plastics that exhibit comparable mechanical, chemical, and electrical characteristics to engineering metals and ceramics arising from their mesoscopic ordering. The unique hierarchal LCP microstructure leads to anisotropic bulk behavior and an understanding of the development of this morphology during manufacturing, as well as the subsequent effect on polymer properties, is essential to the design of isotropic material manufacturing processes. In this investigation, the preferred orientation in injection molded LCP plaque samples was measured using wide-angle x-ray scattering (WAXS). The direction of preferred alignment was observed from the WAXS scattering patterns and the degree of orientation in the material was quantified using an anisotropy factor. In addition, the mechanical, thermal, and dielectric bulk behavior was measured with respect to the mold direction (MD) and transverse direction (TD). To investigate the effects of processing geometry on microstructural development, and the resulting macroscopic properties, plaques of three different thicknesses were analyzed. In addition, the influence of melt rheology was probed through the comparison of two different commercial LCP resins. It is shown that a strong correlation exists between material performance and both the bulk polymer texture and the individual regimes of the hierarchal structure. The effects of processing geometry and polymer rheology also demonstrate the structure-property-processing dynamics at work in injection molded LCPs.

The Design, Synthesis and Structure-Property Relationships of Ferroelectric and Antiferroelectric Liquid Crystal Materials

2002 ◽  
Vol 276 (1) ◽  
pp. 219-237 ◽  
Author(s):  
Michael Hird ◽  
John W. Goodby ◽  
Paul Hindmarsh ◽  
Robert A. Lewis ◽  
Kenneth J. Toyne
Keyword(s):  
Liquid Crystal ◽  
Structure Property ◽  
Design Synthesis ◽  
Structure Property Relationships ◽  
Liquid Crystal Materials

Structure-property-processing relationships in extruded liquid crystal polymer film

2021 ◽  
pp. 096739112110070
Author(s):  
Anthony Sullivan ◽  
Anil Saigal ◽  
Michael A Zimmerman
Keyword(s):  
Liquid Crystal ◽  
Industrial Applications ◽  
Practical Implementation ◽  
Liquid Crystal Polymers ◽  
Structure Property ◽  
Bulk Properties ◽  
Industrial Processing ◽  
Film Extrusion ◽  
Modeling Methodology ◽  
Orientation State

Liquid crystal polymers (LCPs) derive favorable mechanical, chemical, and electrical behavior from long-range molecular ordering. The microstructure gives rise to anisotropic bulk properties that are problematic for industrial applications, and thus the ability to model the polymer directionality is essential to the design of isotropic material manufacturing processes. This investigation proposes a modeling methodology to simulate the 3D director field in full-scale film extrusion geometries. Wide-angle x-ray scattering (WAXS) is used to validate the predicted orientation for a standard coat-hanger die, and is compared with macroscopic mechanical, thermal, and dielectric testing of LCP film to illustrate the morphological dependence of the polymer properties. The highly anisotropic orientation state resulting from cast film extrusion is both predicted by the model and confirmed experimentally, and this preferred orientation is shown to correlate with observed anisotropy in the bulk properties. Additionally, a practical implementation of the modeling tool is presented to simulate directionality in two alternative die geometries designed to improve bulk isotropy, and it is demonstrated that the model is capable of simulating the resulting order for large, irregular domains typical of industrial processing.

scholarly journals Synthesis, characterization and structure-property relationships of 1,3-bis(5-substituted-1,3,4-oxadiazol-2-yl)benzenes

2019 ◽  
Author(s):  
Afef Mabrouki ◽  
Malek Fouzai ◽  
Armand Soldera ◽  
Abdelkader Kriaa ◽  
ahmed hedhli
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Dipole Moments ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Rigid Core ◽  
X Ray ◽  
Structure Property Relationships ◽  
Crystal Properties

Two series containing 1,3-bis(1,3,4-oxadiazol-2-yl)benzene as a rigid core (RC) and alkyl or perfluoroalkyl as terminal chains were synthesized and characterized. Liquid Crystal properties of the synthesized compounds have been investigated by Polarizing Optical Microscopy, Differential Scanning Calorimetry and X-ray Diffraction techniques. Conformation effects of the synthesized products on the dipole moments were also investigated.

Structure-property relationships of PE/PP sandwiched films

1987 ◽  
Vol 45 ◽  
pp. 454-455
Author(s):  
J. Petermann ◽  
G. Broza ◽  
U. Rieck ◽  
A. Jaballah ◽  
A. Kawaguchi
Keyword(s):  
Mechanical Tests ◽  
Polymer Materials ◽  
Ionic Crystals ◽  
Structure Property ◽  
Polymer Systems ◽  
Structure Property Relationships ◽  
Oriented Films ◽  
Materials Used ◽  
Polymer Laminates ◽  
Heated Glass

Oriented overgrowth of polymer materials onto ionic crystals is well known and recently it was demonstrated that this epitaxial crystallisation can also occur in polymer/polymer systems, under certain conditions. The morphologies and the resulting physical properties of such systems will be presented, especially the influence of epitaxial interfaces on the adhesion of polymer laminates and the mechanical properties of epitaxially crystallized sandwiched layers.Materials used were polyethylene, PE, Lupolen 6021 DX (HDPE) and 1810 D (LDPE) from BASF AG; polypropylene, PP, (PPN) provided by Höchst AG and polybutene-1, PB-1, Vestolen BT from Chemische Werke Hüls. Thin oriented films were prepared according to the method of Petermann and Gohil, by winding up two different polymer films from two separately heated glass-plates simultaneously with the help of a motor driven cylinder. One double layer was used for TEM investigations, while about 1000 sandwiched layers were taken for mechanical tests.

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