Isothermal decomposition behavior and dynamic mechanical properties ofin situ-reinforcing elastomer composites based on thermoplastic elastomers and thermotropic liquid crystalline polymer

2006 ◽  
Vol 103 (2) ◽  
pp. 917-927 ◽  
Author(s):  
Sunan Saikrasun ◽  
Taweechai Amornsakchai
Keyword(s):  
Mechanical Properties ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Dynamic Mechanical Properties ◽  
Thermoplastic Elastomers ◽  
Isothermal Decomposition ◽  
Dynamic Mechanical ◽  
Elastomer Composites ◽  
Decomposition Behavior

Self-Reinforcing Composites of Polyacrylic Elastomers and Liquid Crystalline Polymer: Mechanical, Thermal, and Dynamic Mechanical Properties

2005 ◽  
Vol 13 (7) ◽  
pp. 687-695
Author(s):  
E. Shivakumar ◽  
C.K. Das
Keyword(s):  
Interfacial Adhesion ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Nucleating Agent ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Substantial Improvement ◽  
Crystalline Polymers ◽  
Dynamic Mechanical

In order to study the effect of liquid crystalline polymers (LCP) as reinforcing agents for polyacrylic elastomer (ACM), blends of ACM and a liquid crystalline polymer were prepared. These blends were cured with ammonium benzoate and Diak-4, 4,4'-methylen ebis(cyclohexylamine) carbamate in order to understand the curing behaviour of ACM in presence of LCP. A rheometric study of the blends indicated an improved state of cure in presence of Diak-4, but a deteriorated state of cure in presence of ammonium benzoate. All the blends showed substantial improvement in modulus and tear strength with the increasing amounts of LCP however; this improvement was predominant when Diak-4 was used as a curing agent. The tensile strength of the blends decreased with increasing LCP content, attributed to lack of interfacial adhesion between ACM and LCP, which was confirmed by scanning electron microscopy (SEM). It was found from the X-rd measurements that LCP acts as a nucleating agent by increasing the crystallinity of the blend. The degradation temperatures and heats of degradation deduced from the thermal analysis suggested that ACM had reduced thermal stability when in presence of LCP. A dynamic mechanical analysis (DMA) study revealed the improved storage modulus of the blends with increasing LCP content.

scholarly journals Fiber Formation and Structural Development of HBA/HNA Thermotropic Liquid Crystalline Polymer in High-Speed Melt Spinning

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1134
Author(s):  
Bo Seok Song ◽  
Jun Young Lee ◽  
Sun Hwa Jang ◽  
Wan-Gyu Hahm
Keyword(s):  
Mechanical Properties ◽  
Shear Rate ◽  
High Speed ◽  
Melt Spinning ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Fiber Formation ◽  
Structural Development ◽  
Thermotropic Liquid Crystalline Polymer

High-speed melt spinning of thermotropic liquid crystalline polymer (TLCP) resin composed of 4-hydroxybenzoic acid (HBA) and 2-hydroxy-6-napthoic acid (HNA) monomers in a molar ratio of 73/27 was conducted to investigate the characteristic structure development of the fibers under industrial spinning conditions, and the obtained as-spun TLCP fibers were analyzed in detail. The tensile strength and modulus of the fibers increased with shear rate in nozzle hole, draft in spin-line and spinning temperature and exhibited the high values of approximately 1.1 and 63 GPa, respectively, comparable to those of industrial as-spun TLCP fibers, at a shear rate of 70,000 s−1 and a draft of 25. X-ray diffraction demonstrated that the mechanical properties of the fibers increased with the crystalline orientation factor (fc) and the fractions of highly oriented crystalline and non-crystalline anisotropic phases. The results of structure analysis indicated that a characteristic skin–core structure developed at high drafts (i.e., spinning velocity) and low spinning temperatures, which contributed to weakening the mechanical properties of the TLCP fibers. It is supposed that this heterogeneous structure in the cross-section of the fibers was induced by differences in the cooling rates of the skin and core of the fiber in the spin-line.

Morphology of Polyamideliquid Crystalline Polymer Blend

1990 ◽  
Vol 215 ◽  
Author(s):  
K. Nishii ◽  
M. Usui ◽  
T. Muraya ◽  
K. Kimura
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Polymer Blend ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Polymer Structure ◽  
High Mechanical Strength ◽  
Blend Morphology ◽  
The Relationship

Polymer blend technology is attractive from the standpoint of both science and industry, and many combinations have been studied. Recently, the polymer blends, including liquid crystalline polymer, have been especially worthy of notice, [1,2,3]. In order to obtain materials with a high mechanical strength and moldability for use in thin molded items, we chose polyamide (PA)-liquid crystalline polymer (LCP) blends. In this study, we first measured the mechanical properties, then studied the features of the polymer structure. We also examined the relationship between morphology and mechanical properties. As a result, we found that the mechanical properties of the blends depended largely on blend morphology, and that mechanical strength increased as blend compatibility increased. On the other hand, we also found that the blends showed compatible and microheterogeneous dispersion at less than 25 wt% LCP, while at more than 30 wt% LCP, blends tended to show twophase separation.

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