High-performance flame-retardant aliphatic polyamide via enhanced chain entanglement

Although conventional chemical copolymerization method has shown favorable results in improving certain performance of polymers, simultaneous improvement of overall properties is hardly achieved. Here, we reported a feasible method to fabricate high-performance polymers with great overall properties by simultaneously tailoring their chemical constitution and topological conformation. We designed and synthesized a novel functional monomer with a sidechain caged structure based on phosphorus chemistry, and prepared the corresponding aliphatic polyamide as a typical representative of thermoplastic synthetic polymers. The incorporation of a sidechain caged structure enhanced the chain entanglement of the resultant polyamide, thus improved the mechanical strength by 39% and largely enhanced the heat resistance. The great processability was basically uninfluenced due to the easy dissociation of the entanglement during processing, enabling the potentially wide application fields as both fibers and engineering plastics. Furthermore, based on the free radical scavenging effect of the phosphorus-based monomer, the flame retardancy of the resultant polyamide was significantly improved. In sight of these findings, this work provides a novel method for fabricating high-performance polymers for various applications.