Preparation of liquid crystalline polymers with ester terminal

Lim, Hui Sing (2007) Preparation of liquid crystalline polymers with ester terminal. Universiti Malaysia Sabah. (Unpublished)


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The objective of this study was to prepare liquid crystalline polymers with ester terminal and determined the functional groups, chemical structure, phase transition and melting point of the product with Fourier Transform lnfared Spectroscopy (FT -IR); Nuclear Magnetic Resonance Spectroscopy (NMR); Differential Scanning Calorimetry (DSC) and capillarial melting point apparatus. The experiments involved three main steps and ethyl- 4-aminobenzoate was used as a starting material. The initial step was diazonium salt coupling reaction with phenol at pH 10 to obtain 4-(4-Hydroxyphenylazo) ethyl benzoate, which have a melting point in the range 125°C to 144 DC. The next reaction was Williamson ether reaction with bromopropene to obtain 4-(4-Alloyloxy-phenylazo) ethyl benzoate with a melting point in the range 85°C to 105°C. Subsequently, this compound was undergone additional polymerization reaction where the compound is dissolved into dry Tetrahydroferam (THF) and degassed using Nitrogen with catalytic Azobisisobutyronitrile (AIBN) under 60°C to yield the desired liquid crystalline polymer with ester terminal. The final products have a melting point in the range 125°C to 135°C. All compounds synthesized in each steps shown C-H in alkyl, carbonyl group (C=O), C=C in aromatic, C-O. The chemical structure of the final products was confirmed by NMR. Besides that, two obvious peak of Tm (melting temperature) and Tc (crystallization temperature) was obtained through the DSC thermogram of final products.

Item Type: Academic Exercise
Uncontrolled Keywords: liquid crystalline polymer, ester terminal, chemical structure, phase transition, reaction, melting temperature
Subjects: Q Science > QD Chemistry
Divisions: SCHOOL > School of Science and Technology
Date Deposited: 19 Jul 2013 02:33
Last Modified: 23 Oct 2017 07:12

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