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. 2019 Jul 3;11(7):1129.
doi: 10.3390/polym11071129.

Flame Retardancy and Toughness of Poly(Lactic Acid)/GNR/SiAHP Composites

Ningjing Wu  1 , Jihang Yu  2 , Wenchao Lang  3 , Xiaobing Ma  2 , Yue Yang  2
Affiliations

Flame Retardancy and Toughness of Poly(Lactic Acid)/GNR/SiAHP Composites

Ningjing Wu et al. Polymers (Basel). .

Abstract

A novel flame-retardant and toughened bio-based poly(lactic acid) (PLA)/glycidyl methacrylate-grafted natural rubber (GNR) composite was fabricated by sequentially dynamical vulcanizing and reactive melt-blending. The surface modification of aluminum hypophosphite (AHP) enhanced the interfacial compatibility between the modified aluminum hypophosphite by silane (SiAHP) and PLA/GNR matrix and the charring ability of the PLA/GNR/SiAHP composites to a certain extent, and the toughness and flame retardancy of the PLA/GNR/SiAHP composites were slightly higher than those of PLA/GNR/AHP composites, respectively. The notched impact strength and elongation of the PLA composite with 20 wt. %GNR and 18 wt.% SiAHP were 13.1 kJ/m2 and 72%, approximately 385% and 17 fold higher than those of PLA, respectively, and its limiting oxygen index increased to 26.5% and a UL-94 V-0 rating was achieved. Notedly, the very serious melt-dripping characteristics of PLA during combustion was completely suppressed. The peak heat release rate and total heat release values of the PLA/GNR/SiAHP composites dramatically reduced, and the char yield obviously increased with an increasing SiAHP content in the cone calorimeter test. The good flame retardancy of the PLA/GNR/SiAHP composites was suggested to be the result of a synergistic effect involving gaseous and condensed phase flame-retardant mechanisms. The high-performance flame-retardant PLA/GNR/SiAHP composites have great potential application as replacements for petroleum-based polymers in the automotive interior and building fields.

Keywords: PLA composite; flame retardancy; melt-dripping resistance; surface modification; toughness.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Melt torque–time curves of the PLA/GNR/SiAHP composites.
Figure 2
Figure 2
Mechanical properties of PLA, PLA/GNR TPV, PLA/GNR/AHP, and PLA/GNR/SiAHP composites: (a) notched impact strength, (b) stress–strain curves.
Figure 3
Figure 3
SEM images of cryo-fractured surface for PLA/GNR/AHP and PLA/GNR/SiAHP composites. (a, a’) PLA/GNR/16wt%AHP; (b, b’) PLA/GNR/20wt%AHP; (c, c’) PLA/GNR/16wt% SiAHP; (d, d’) PLA/GNR/20wt%SiAHP.
Figure 4
Figure 4
SEM images of the impact-fractured surface for the PLA/GNR/AHP and PLA/GNR/SiAHP composites. (a, a’) PLA/GNR/16wt%AHP; (b, b’) PLA/GNR/20wt%AHP; (c, c’) PLA/GNR/16wt% SiAHP; and (d, d’) PLA/GNR /20wt%SiAHP.
Figure 5
Figure 5
TG and DTG curves of the PLA/GNR and FR PLA/GNR composites under N2 atmosphere.
Figure 6
Figure 6
Digital photographs of PLA/GNR and PLA/GNR/SiAHP composites after UL-94 vertical burning tests. (a) PLA/GNR/16wt%AHP; (b) PLA/GNR/16wt%SiAHP; (c) PLA/GNR/18wt%SiAHP; (d) PLA/GNR/20wt%AHP; (e) PLA/GNR/20wt%SiAHP.
Figure 7
Figure 7
Heat release rate (HRR) (a) and total release rate (THR) (b) curves of the PLA/GNR TPV and FR PLA/GNR composites.
Figure 8
Figure 8
Total smoke release (TSR) (a) and char residue mass (CR) (b) curves of PLA/GNR TPV and FR PLA/GNR composites.
Figure 9
Figure 9
HRR(t)/t versus time curves of PLA/GNR TPV and FR PLA/GNR composites (a) and FIGRA versus THR (b).
Figure 10
Figure 10
Digital photos of char residues for PLA/GNR TPV (a); PLA/GNR/16wt%SiAHP (b); PLA/GNR/18wt%SiAHP (c); PLA/GNR/20wt%SiAHP (d) after the cone calorimeter test.
Figure 11
Figure 11
SEM images of char residues for PLA/GNR/SiAHP composites. (a, a’) PLA/GNR/16wt% SiAHP; (b, b’) PLA/GNR/18wt%SiAHP; (c, c’) PLA/GNR/20wt%SiAHP.
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References

    1. Bourbigot S., Fontaine G. Flame retardancy of polylactide: An overview. Polym. Chem. 2010;1:1413–1422. doi: 10.1039/c0py00106f. - DOI
    1. Nampoothiri K.M., Nair N.R., John R.P. An overview of the recent developments in polylactide (PLA) research. Bioresour. Technol. 2010;101:8493–8501. doi: 10.1016/j.biortech.2010.05.092. - DOI - PubMed
    1. Tang G., Wang X., Xing W.Y., Zhang P., Wang B.B., Hong N.N., Yang W., Hu Y., Song L. Thermal degradation and flame retardance of biobased polylactide composites based on aluminum hypophosphite. Ind. Eng. Chem. Res. 2012;51:12009–12016. doi: 10.1021/ie3008133. - DOI
    1. Chen C., Gu X.Y., Jin X.D., Sun J., Zhang S. The effect of chitosan on the flammability and thermal stability of polylactic acid/ammonium polyphosphate biocomposites. Carbohydr. Polym. 2017;157:1586–1593. doi: 10.1016/j.carbpol.2016.11.035. - DOI - PubMed
    1. Ke C.H., Li J., Fang K.Y., Zhu Q.L., Zhu J., Yan Q., Wang Y.Z. Synergistic effect between a novel hyperbranched charring agent and ammonium polyphosphate on the flame retardant and anti-dripping properties of poly(lactide) Polym. Degrad. Stab. 2010;95:763–770. doi: 10.1016/j.polymdegradstab.2010.02.011. - DOI

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