Synergistic effect of poly(ionic liquid) and phosphoramide on flame retardancy and crystallization of poly(lactic acid)

Caixia Li; Bingtao Wang; Yong Yang; Juan Chai; Zhenghong Guo; Zhengping Fang; Peng Chen; Juan Li

doi:10.1016/j.ijbiomac.2022.11.053

Synergistic effect of poly(ionic liquid) and phosphoramide on flame retardancy and crystallization of poly(lactic acid)

Int J Biol Macromol. 2022 Dec 31;223(Pt A):1344-1355. doi: 10.1016/j.ijbiomac.2022.11.053. Epub 2022 Nov 9.

Authors

Caixia Li¹, Bingtao Wang², Yong Yang², Juan Chai², Zhenghong Guo², Zhengping Fang², Peng Chen³, Juan Li⁴

Affiliations

¹ Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
² School of Materials Science and Engineering, NingboTech University, Ningbo 315100, China.
³ Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: pchen@nimte.ac.cn.
⁴ School of Materials Science and Engineering, NingboTech University, Ningbo 315100, China; Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: lijuan@nbt.edu.cn.

PMID: 36370854
DOI: 10.1016/j.ijbiomac.2022.11.053

Abstract

Crystallinity and flame retardancy are two key properties for poly(lactic acid)(PLA) in applications. In this paper, a quaternary phosphonium salt poly(ionic liquid) (PIL) and a phosphamide (POFA) were prepared. The PIL, POFA and their blend were used to regulate the flame retardancy and crystallization behaviors of PLA using the limiting oxygen index, UL-94 vertical burning, and thermogravimetric analysis, and differential scanning calorimetry etc. The results showed that a synergistic effect exists between PIL and POFA on flame retardancy. When 6 wt% PIL/POFA (2/1) was added into PLA, its LOI value is 28.0 vol%, and achieves the UL-94 V-0 rating while the PLA composites containing 6 wt% PIL or POFA just achieve the UL-94 V2. The PIL/POFA improves the flame retardancy of PLA by melting-away mode. In addition, the crystallization rate of PLA containing PIL/POFA is faster than that of PLA/PIL and PLA/POFA. The degradation of PLA induced by PIL/POFA produces some small molecular oligomers, which enhances the molecular chain mobility and rearrangement, thus contributes to better flame retardancy and faster crystallization.

Keywords: Crystallization; Flame retardancy; Phosphoramide; Poly(ionic liquid); Poly(lactic acid).

MeSH terms

Crystallization
Dimethoate
Ionic Liquids*
Poly A
Polyesters

Substances

Ionic Liquids
poly(lactide)
Polyesters
phosphoramide
Dimethoate
Poly A