Soluble Polyimides Bearing (cis, trans)-Hydrogenated Bisphenol A and (trans, trans)-Hydrogenated Bisphenol A Moieties: Synthesis, Properties and the Conformational Effect

Autor: Hou Ziwen, Sizhuo Jin, Yumin Zhang, Chunhai Chen, Xiaowen Wang, Hongwei Zhou, Zhiming Mi, Zhixiao Liu, Daming Wang, Wang Shuai, Xiaogang Zhao
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Polymers, Vol 11, Iss 5, p 854 (2019)
Polymers
Volume 11
Issue 5
ISSN: 2073-4360
Popis: In this work, hydrogenated bisphenol A (HBPA) based dinitro mixed isomers (1a&prime
and 1a) were synthesized and separated via vacuum distillation under the monitor of DSC and 1H NMR. Corresponding diamines (2a&prime
and 2a) were separately polycondensed with five commercial dianhydrides via a two-step thermal imidization to obtain PI-(1&prime
5&prime
) and PI-(1-5). All the polyimides could afford flexible, tough, and transparent films, and most of them were readily soluble not only in common polar solvents like DMAc, but also in low boiling point solvents such as chloroform. 1H NMR spectra of the polyimides demonstrated that HBPA moiety showed no conformation changes during the preparation of polymers. For a given dianhydride, PI-(1-5) exhibited better thermal stability than that of PI-(1&prime
), this can be attributed that the equatorial, equatorial C&ndash
O in PI-(1-5) promoted denser and more regular molecular chain stacking, as can be evidenced by the WAXD and geometric optimization results. Additionally, when the dianhydride was ODPA, BPADA or 6FDA, no apparent difference was found in either the transmittance or solubility between two series of polyimides, which could be attributed that twisted and flexible ether linkages, as well as bulky substituents, led to the &ldquo
already weakened&rdquo
inter- and intramolecular CT interaction and cohesive force. However, when it came to rigid and stiff dianhydride, e.g., BPDA, PI-3&prime
took an obvious advantage over PI-3 in transmittance and solubility, which was possibly owed to the larger molecular chain d-spacing imparted by equatorial, axial C&ndash
O. An overall investigation of PI-(1&prime
) and PI-(1-5) on aspects of thermal, mechanical, morphological, soluble and optical performance values was carried out, and the conformation effects of HBPA isomers on the properties of two series of polyimides were discussed in detail.
Databáze: OpenAIRE
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