Effect of phosphorus–nitrogen compound on flame retardancy and mechanical properties of polylactic acid. Issue 7 (10th September 2020)

• Record Type: Journal Article
• Authors: Hu, Xu; Sun, Jinhao; Li, Xing; Qian, Lijun; Li, Juan
• Is Part Of: Journal of applied polymer science. Volume 138:Issue 7(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-09-10
• Subjects: biopolymers and renewable polymers -- degradation -- thermogravimetric analysis; Polymers -- Periodicals; Polymerization -- Periodicals; 668.9
• DOI: 10.1002/app.49829
• Languages: English
• ISSNs: 0021-8995

Abstract

Abstract: A phosphorus‐nitrogen flame retardant (PN) was synthesized by using cytosine and diphenylphosphinic chloride. The flame retardancy and thermal stability of polylactic acid (PLA)/PN composites were investigated by the UL‐94 vertical burning test, limited oxygen index (LOI), cone calorimeter test, and thermogravimetric analysis. The PN performs efficiently on improving the flame retardancy of PLA. The PLA composite achieves the UL‐94 V‐0 rating and its LOI increases to 30.4 vol% by adding 0.5 wt% PN. The flame retardant mechanism analysis showed that PN catalyzes the degradation of PLA to improve the flame retardancy by melting‐away mode. Meanwhile PN reduces the release of flammable gasses during thermal degradation of PLA by promoting the transesterification of PLA, which is helpful for extinguishing flame. Moreover, triglycidyl isocyanurate (TGIC) was used as a micro‐crosslinking agent to reduce the loss of mechanical properties of PLA/PN composites caused by degradation. Adding 0.1 wt% TGIC and 1.0 wt% PN into PLA, the tensile strength and elongation at break of PLA/PN are increased to the same level as that of PLA. Therefore, PLA with excellent comprehensive performance can be obtained. Abstract : This work synthesized a novel flame retardant of polylactic acid (PLA) by using biobased cytosine (Cy) and diphenylphosphinic chloride (DPPC). Degradation and chain extension synergy improve the fame retardancy and mechanical properties of PLA.