Green and Scalable Fabrication of Core–Shell Biobased Flame Retardants for Reducing Flammability of Polylactic Acid

Abstract

The design of flame-retardant biocomposites based on biobased flame retardants (FRs) represents a promising direction for creating a sustainable world. To date, it remains a major challenge to explore a green and scalable strategy for the design of highly effective, biobased FRs for bioplastics, such as polylactic acid (PLA). Herein, we have demonstrated a green, facile fabrication approach for a core–shell-structured biobased flame retardant (APP@CS@PA-Na) via layer-by-layer assembly using water as the assembly media. With electrostatic interactions, APP@CS@PA-Na was prepared by sequential assembly of ammonium polyphosphate (APP) with positively charged chitosan (CS) and then negatively charged phytic acid salt (PA-Na). The addition of APP@CS@PA-Na can enhance both the flame retardancy and the toughness of PLA. With the addition of 10 wt % APP@CS@PA-Na, the resultant PLA composite can pass an UL-94 V-0 rating and meanwhile shows an increased elongation at break by 28.4%, compared with that of neat PLA (8.1%). Through the analysis of the volatile gases and the residues, the flame retardant mechanism of APP@CS@PA-Na in PLA plays the key role in the condensed-phase. This work will broaden the practical application field of PLA, such as in electric and electronic and fibers fields.

Flame retardant and toughening behaviors of bio‐based DOPO‐containing curing agent in epoxy thermoset

“…In recent years, bio‐based materials chitosan, bamboo fiber, starch, cellulose, cyclodextrin, phytic acid, DNA, castor oil, and lignin have been reported to be used in reaction monomer to prepare flame retardants . Also, furfural as a bio‐based material can be extracted from natural wheat, corn cob, and sawdust .…”

Biomolecules as Flame Retardant Additives for Polymers: A Review

“…Despite variations in pH processing (hence P content and layer thickness) all systems evaluated reduced HR by 70% and increased char residue by (at least, if not greater) factor of 7. Chitosan has recently been examined more broadly as an FR additive, working in concert with a broad range of inorganic additives [71] and phosphorous sources [72]. Phytic acid has similarly been shown by multiple workers to be a useful FR agent, working synergistically with tannic acid [73], or as a phytate salt with ammonia [74], metal ions [75], piperidine [76] or 1,6-hexane diamine [77].…”

A Branched Polyelectrolyte Complex Enables Efficient Flame Retardant and Excellent Robustness for Wood/Polymer Composites

“…Figure 4c-e shows 3D images of the FTIR spectra of total gaseous products during the whole pyrolysis. For neat WPC, it is clear that almost no gas product is released below 280 • C. WPC starts to decompose at 298 • C, the peak at 2100~2200 cm −1 is attributed to CO [21]. As time continues, a large number of gaseous compounds, such as CO 2 , H 2 O, and some alkanes, ethers, phenols, ketones, aldehydes, and other organic substances begin to volatilize.…”