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Fully Aromatic Thermotropic Copolyesters Based on Vanillic, Hydroxybenzoic, and Hydroxybiphenylcarboxylic Acids
Pavel A Mikhaylov1, Kirill V Zuev1, Yaroslav V Golubev1
1A. V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences (TIPS RAS), 29 Leninsky Prospekt, 119991 Moscow, Russia.
Polymers
|June 19, 2024
Summary
New copolyesters synthesized using vanillic acid (VA) exhibit high molecular weights and glass transition temperatures around 130 °C. These thermotropic polymers show potential for applications but require processing below 280 °C.
Area of Science:
- Polymer Chemistry
- Materials Science
- Organic Synthesis
Background:
- Aromatic polyesters are crucial in advanced materials due to their thermal and mechanical properties.
- Exploring novel monomers like vanillic acid (VA) can lead to new polymer architectures with tailored characteristics.
- Liquid crystalline polymers (LCPs) offer unique processing and performance advantages.
Purpose of the Study:
- To synthesize and characterize novel binary and ternary copolyesters incorporating vanillic acid (VA).
- To investigate the thermal stability, liquid crystalline behavior, and mechanical properties of these new polymers.
- To evaluate the suitability of vanillic acid as a mesogenic monomer for thermotropic copolyesters.
Main Methods:
- Synthesis of binary (VA/HBCA) and ternary (VA/HBCA/HBA) copolyesters via solution, melt, and solid-state methods.
- Characterization using intrinsic viscosity, glass transition temperature (Tg) determination, and thermogravimetric analysis (TGA).
- Assessment of liquid crystalline properties and mechanical characteristics.
Main Results:
- High molecular weight copolyesters were successfully synthesized, indicated by high intrinsic viscosities and insolubility.
- Vanillic acid incorporation resulted in a glass transition temperature (Tg) around 130 °C.
- Ternary copolyesters exhibited thermal stability with onset weight loss at 330-350 °C and 5% mass loss at 390-410 °C, with two-stage thermal destruction observed.
- The synthesized copolyesters were thermotropic, displaying nematic liquid crystalline order.
- Mechanical properties were comparable to semi-aromatic copolyesters but lower than fully aromatic ones.
Conclusions:
- Vanillic acid (VA) is a viable mesogenic monomer for synthesizing thermotropic fully aromatic and semi-aromatic copolyesters.
- The resulting copolyesters possess good thermal stability and liquid crystalline properties.
- Processing temperatures should not exceed 280 °C to maintain polymer integrity.
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