Novel semi-aromatic polyamides containing ether bond and pendant methyl group: synthesis and properties

• Published in: Polymer bulletin (Berlin, Germany) Vol. 79; no. 11; pp. 9629 - 9642
• Main Authors: Ren, Haohao, Fan, Xiaoxia, Li, Pengcheng, Ji, Mizhi, Zhang, Gang, Yan, Yonggang
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.11.2022; Springer Nature B.V
• Subjects: Aramid fibers; Bisphenols; Characterization and Evaluation of Materials; Chemical industry; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Glass transition temperature; Hydroquinone; Mechanical properties; Melting points; Monomers; Organic Chemistry; Original Paper; Physical Chemistry; Polyamide resins; Polymer Sciences; Polymers; Potash; Potassium; Rheology; Soft and Granular Matter; Storage modulus; Synthesis; Temperature; Thermodynamic properties; Thin films; Viscosity; Weight loss; Structures; Synthesis; Semi-aromatic polyamides; Pendant methyl
• ISSN: 0170-0839; 1436-2449
• DOI: 10.1007/s00289-021-03951-z

Through synthesizing novel difluoro-monomer (1,6-N,N’-bis(4-fuorobenzamide) trimethylhexane (BFBT)) and adjusting the structure of bisphenol monomer (hydroquinone (HQ) or 4,4’-biphenol (BH)), two kinds of novel semi-aromatic polyamides (HQ-BBT and BH-BBT) containing ether bond and pendant methyl were synthesized in this work. The inherent viscosities of these obtained polymers were in the range of 0.921–1.151 dLg −1 . The polyamides HQ-BBT and BH-BBT exhibited high glass transition temperatures (T g ) of 144–160 °C and weight loss temperature (T 5% ) of 401–406 °C. The resultant polyamides HQ-BBT and BH-BBT showed good melting flowability with complex viscosities of 1931–252 Pa s and 3829–376 Pa s, respectively, and they can be hot-pressed into thin films, which showed tensile strengths of 64.4–64.6 MPa and storage modulus over 1.28 GPa at about 150 °C, indicating their good thermal and mechanical properties. Interestingly, we found that the aggregation structures of these two kinds of polymers were quite different with the addition of different bisphenol. HQ-BBT with HQ as monomer was amorphous and can be dissolved in polar solvents such as NMP, DMF and so on, while BH-BBT with BH as monomer was found to be crystalline polymer with moderate melting point of 245 °C and much higher glass transition temperature of 160 °C. These moderate T m and T g were very beneficial for the melting processing of the high-performance polymers.