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Its multi- walled carbon nanotubes functionalized nano- composites LCD

Author: ZouJiaGui
Tutor: ChenXianHong
School: Hunan University
Course: Materials Science
Keywords: Multi-walled carbon nanotubes Liquid crystal Functional Composites
CLC: TB383.1
Type: Master's thesis
Year: 2009
Downloads: 161
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Abstract

Carbon nanotubes (CNTs) have excellent mechanical properties, the unique microstructure, great aspect ratio and specific surface area, has aroused great interest. In composite materials, add a small amount of CNTs on the overall performance of the system can have a significant impact. About CNTs / liquid crystal (LC) composite materials research in recent years has become a hot research CNTs composites. Currently used in the dispersion method, although to some extent, improve the CNTs in the LC matrix dispersion, it is still difficult to reach the nano-dispersion, and because the surface of CNTs chemical inertness makes them the base material is difficult to form a strong interface bonding . Therefore, to play the CNTs in the CNTs / LC The advantage of the composite material must be kept their original superior performance based on the effective modification of CNTs, the LC increase their compatibility with the matrix. For this purpose, the paper made the following aspects: (1) using the phosphorylating reaction, a method of synthesis of LC amide compound 2 - methyl-N, N'-bis (4 - substituted benzoic acyl)-p-phenylenediamine (LC-A), and using bromosuccinimide (NBS) on the LC-A bromination, synthesis of intermediate 2 modified LC - (bromomethyl)-N, N'- bis (4 - substituted benzoyl)-p-phenylenediamine (LC-B). FT-IR and 1HNMR that the LC-A and LC-B molecular structure. DTA-TG results show that the LC-A and LC-B into the Tm of 269 ℃ and 229 ℃, and their thermal decomposition starting temperature is not very different; POM proved LC-A and LC-B are nearly thermotropic crystal LC, LC they exhibit a fan texture smectic A phase is (SmA) type LC. (2) multi-walled carbon nanotubes using metal reduction (MWNTs) method, through step will LC-B molecules waist sidewall received MWNTs were prepared LC functionalized MWNTs (LC-MWNTs). Raman and FT-IR spectrum shows that the LC molecules covalently grafted to the sidewall of MWNTs; HRTEM shows 3-5 nm coated MWNTs LC molecules; TGA results show LC-MWNTs on the mass fraction of the LC molecules grafted about 23%; Solubility Test Description LC-MWNTs in DMF exhibits good dispersion stability. (3) were prepared by solution blending MWNTs / LC-A LC-MWNTs/LC-A composite materials and composite materials. SEM showed that the composite LC-MWNTs/LC-A LC-MWNTs the LC matrix good dispersion, the composite material was purified MWNTs agglomeration appeared, indicating by LC modified MWNTs (LC-MWNTs) and LC -A matrix has good compatibility. (4) TGA results show that the thermal stability of the LC order: LC-A lt; MWNTs / LC-A composite lt; LC-MWNTs/LC-A composite materials. The DSC results show that the LC-MWNTs with increasing content of LC-MWNTs nanocomposites down then up Tm emergence of the phenomenon; when content is 0.5 wt%, the composite material Tm reduced by nearly 18 ℃, to 247 ℃ . POM LC-MWNTs test results show that not only did not destroy the original LC-A smectic A phase of the LC texture, but there is a smectic C phase of the LC texture; while LC-MWNTs induced effects by the LC effect, the LC matrix There are arranged in the direction of alignment with the LC trend, as the increase of the anisotropic LC LC-MWNTs alignment occurs more obvious trend.

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