Toward flame-retardant and toughened poly(lactic acid)/cross-linked polyurethane blends via the interfacial reaction with the modified bio-based flame retardants

Zhaoliang Jiang; Meng Ma; Xinpeng Wang; Si Chen; Yanqin Shi; Huiwen He; Xu Wang

doi:10.1016/j.ijbiomac.2023.126206

Toward flame-retardant and toughened poly(lactic acid)/cross-linked polyurethane blends via the interfacial reaction with the modified bio-based flame retardants

Int J Biol Macromol. 2023 Aug 9:251:126206. doi: 10.1016/j.ijbiomac.2023.126206. Online ahead of print.

Authors

Zhaoliang Jiang¹, Meng Ma², Xinpeng Wang¹, Si Chen³, Yanqin Shi³, Huiwen He³, Xu Wang⁴

Affiliations

¹ College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, PR China.
² College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, PR China; Zhejiang Key Laboratory of Plastic Modification and Processing Technology, Zhejiang University of Technology, Hangzhou 310014, PR China. Electronic address: mameng@zjut.edu.cn.
³ College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, PR China; Zhejiang Key Laboratory of Plastic Modification and Processing Technology, Zhejiang University of Technology, Hangzhou 310014, PR China.
⁴ College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, PR China; Zhejiang Key Laboratory of Plastic Modification and Processing Technology, Zhejiang University of Technology, Hangzhou 310014, PR China. Electronic address: wangxu@zjut.edu.cn.

PMID: 37562482
DOI: 10.1016/j.ijbiomac.2023.126206

Abstract

Incorporating bio-based flame retardants into polylactic acid (PLLA) to improve flame retardancy has always been the focus of research, but the improvement of flame retardancy is usually at the expense of mechanical properties. How to successfully balanced the material's mechanical and combustion properties has puzzled many scholars. Herein, ammonium polyphosphate (APP) and chitosan (CS) were used as acid source and carbon source respectively. Biological flame retardant APP@CS was designed and synthesized by electrostatic self-assembly method. In addition, toughened PLLA composites were prepared by reactive blending with the in-situ formed polyurethane (PU) as toughening phase. The results show that the CS shell not only reduces the hydrophilicity of the flame retardant, but also has good flame retardant property because of its excellent char forming property. The addition of 10 phr APP@CS can endow PLLA/crosslinked PU (CPU) with UL-94 V-2 rating and a LOI value of 24.9 %. Interestingly, CS shell participates in the in-situ reaction, which improves the mechanical properties of the composite with elongation at break of 74 %, which is higher than that of sample doped with the same amount of APP. This work provides guidance for the high performance modification of PLLA and is expected to expand the practical application range.

Keywords: Flame retardant; Poly(lactic acid); Reactive blending.