Evaluation of liquid crystal polymers for high performance SOP application

2003 ◽  
Author(s):  
K. Brownlee ◽  
P.M. Raj ◽  
S.K. Bhattacharya ◽  
K. Shinotani ◽  
C.P. Wong ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
High Performance ◽  
Liquid Crystal Polymers

The Influence of Thermal Annealing on Microstructure and Mechanical Properties in High Performance Liquid Crystal Copolyesters

2012 ◽  
Vol 1373 ◽  
Author(s):  
Adriana Reyes-Mayer ◽  
Amaury Constant ◽  
Angel Romo-Uribe ◽  
Michael Jaffe
Keyword(s):  
Mechanical Properties ◽  
Liquid Crystal ◽  
Thermal Treatment ◽  
Thermal Annealing ◽  
High Performance ◽  
Molecular Conformation ◽  
Liquid Crystal Polymers ◽  
Thermal And Mechanical Properties ◽  
Monomer Composition ◽  
Extruded Films

ABSTRACTIn this research we have focused on the influence of thermal treatment for periods of time on the thermal and mechanical properties of extruded films of a series of high-performance thermotropic liquid crystal polymers (LCPs). The dependence of microstructure, thermal and mechanical properties on the extent of thermal treatment is investigated. Especially synthesized wholly aromatic LCPs based on hydroxybenzoic acid (B), hydroxynaphthoic acid (N), terephthalic acid (TA) and biphenol (BP) are kindly supplied by Hoechst Celanese Research Corp in the form of 50 μm thick extruded films. Thus, the influence of monomer composition is also studied in order to contrast the influence of molecular conformation. Thermal treatments are carried out at temperatures close to the solid-to-nematic transition (Ts→n) for up to several hours under dry air conditions. The results show a profound influence of thermal annealing on morphology and mechanical modulus when annealing is carried out c.a. 40ºC below Ts→n, where solid-to-nematic transition and Young’s modulus are significantly increased.

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.

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