An overview of the recent advances in flame retarded poly(lactic acid)

Abstract

Poly(lactic acid) (PLA) is derived from crops, and has a broad application prospect in electronics and electrical, automotive industries due to its biodegradability and good physical and mechanical properties. However, PLA's flammability and serious melt dripping cannot meet the requirements of terminal products, thus limiting its application. Over the past decade, much research on flame retardant PLA has emerged. This paper reviews the development of PLA flame retardants in recent years, focusing on phosphorus-based, phosphorus-nitrogen-based, bio-based, nanoparticles, intumescent flame retardants, and their combinations. Besides that, the efficiency of flame retardant and its loading on the thermal and mechanical properties of PLA is also thoroughly reviewed. Finally, the future development of flame-retardant PLA is briefly summarized and prospected.

Enhanced Flame Retardancy and Mechanical Properties of Polylactic Acid Composites with Phytate-Chelated Nanotitanium Dioxide-Modified Bagasse Cellulose

“…6,27 Generally, the addition of excess flame retardants to PLA improves the flame retardancy but degrades the mechanical properties. 27 Figure 4 demonstrates the effect of various types and amounts of flame retardants on the mechanical characteristics of PLA composites. As shown in Figure 3a,b, with a loading of 10 wt % A-MBC/PA/A-TiO 2 as the flame retardant, the tensile, bending, and impact strengths of PLA/10AM increase, and the same enhancement trend is observed for PLA/10AM with 10 wt % A-MBC and PLA/ 10AT with 10 wt % A-TiO 2 .…”

Functionalized Soybean Oil as a Bio-based Flame Retardant for Poly(lactic acid): Role of Phosphorus Content

“…Over the past few decades, researchers have been actively working on mitigating the flammability of PLA through the development of flame retardants or intrinsically flame-retardant PLA. 5,6 Phosphorus flame retardants (PFR) draw more and more attention to improve the flame retardancy of polymers for their more environmentally friendly and higher efficiency compared to the traditional halogen and inorganic flame retardants. 7,8 According to the different flame-retardant methods, it can be divided into gas phase flame retardant and condensed phase flame retardant.…”

“…However, similar to most of plastics, PLA is intrinsically flammable, which greatly limits its applications. , It has been found that PLA has a limiting oxygen index (LOI) of only 18.0–21.0%, , which is a flammable grade, and has no burn rating in vertical burn tests with a large amount of molten droplet generation. Over the past few decades, researchers have been actively working on mitigating the flammability of PLA through the development of flame retardants or intrinsically flame-retardant PLA. , …”

Effects of ammonium polyphosphate and casein on the properties of poly (lactic acid)

“…Ammonium polyphosphate (APP) is widely used because of its good thermal stability, low price, low toxicity, and high flame-retardant performance. [21][22][23][24] However, when APP is used alone, its compatibility with PLA and charring effect is poor.…”