Synthesis of novel aromatic polyamides containing cardo groups and triphenylphosphine oxide structures by a heterogeneou
- PDF / 1,550,206 Bytes
- 21 Pages / 439.37 x 666.142 pts Page_size
- 69 Downloads / 180 Views
Synthesis of novel aromatic polyamides containing cardo groups and triphenylphosphine oxide structures by a heterogeneous palladium‑catalyzed carbonylation and condensation reaction Li Wei1 · Huali Tang1 · Feihua Zou1 · Mingzhong Cai1 Received: 22 June 2020 / Revised: 30 September 2020 / Accepted: 1 November 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract New aromatic polyamides containing cardo groups and triphenylphosphine oxide structures were synthesized by a heterogeneous palladium-catalyzed carbonylation and condensation of bis(4-(3-iodophenoxy)phenyl)phenylphosphine oxide (BIPPO), aromatic diamines bearing cardo groups, and carbon monoxide. Polycondensations were carried out in N,N-dimethylacetamide under 1 atm of CO at 120 °C in the presence of a magnetically recyclable heterogeneous palladium catalyst and 1,8-diaza-bicyclo[5,4,0]-7-undecene (DBU) and afforded novel aromatic polyamides with inherent viscosities between 0.72 and 0.76 dL/g. All the polyamides were quite soluble in dipolar aprotic solvents and pyridine and could be converted into transparent, flexible, and tough polyamide films by casting from DMAc solutions. These polymers exhibited high thermal and thermooxidative stability with the glass transition temperatures of 237 °C–256 °C, the temperatures at 5% weight loss of 448 °C–465 °C in air. All the phosphorus-containing polyamides self-extinguished as soon as the flame was removed, and the limited oxygen indices (LOIs) of these polymers were in the range of 39%–44%. The polymer films also showed good mechanical properties and high optical transparency. Keywords Aromatic polyamide · Cardo group · Triphenylphosphine oxide · Palladium · Carbonylative polymerization
* Mingzhong Cai [email protected] 1
Key Laboratory of Functional Small Organic Molecule, Ministry of Education and College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022, People’s Republic of China
13
Vol.:(0123456789)
Polymer Bulletin
Introduction Wholly aromatic polyamides, or aramids, are high-performance polymeric materials characterized by their outstanding thermal and mechanical properties, good chemical and flame resistance as well as electrical insulating performance and have been widely utilized in military, transportation, and other high-tech fields [1–7]. However, macromolecular chain stiffness provided by high density of aromatic rings and strong interchain attractive forces due to hydrogen bond lead to high melting temperatures and limited solubility in most organic solvents, which result in their poor processability and restrict their applications to some extent. Therefore, the synthesis of organosoluble high-performance aromatic polyamides is highly desirable, and modifications of aromatic polyamide structures have received much attention. Numerous attempts have been recently made to improve their processability without much impairing their thermal and mechanical properties. The successful methods used for the improvement in solubility includ
Data Loading...
