α-zirconium phosphate modified with intumescent flame retardant and its application in poly(lactic acid)

Abstract
 
A novel functionalized α-zirconium phosphate (F-ZrP) modified with intumescent flame retardant was synthesized by co-precipitation method and characterized.
 

Poly (lactic acid) (PLA)/F-ZrP nanocomposites were prepared by melt blending method.

 
The results showed that improve the flame retardancy of PLA composites.
 
In comparison with neat PLA, the LOI value of PLA/F-ZrP was increased from 19.0 to 26.5, and the UL-94 rating was enhanced to V-0 as the loading of F-ZrP at 10%.
 
Experimental

1.The synthesis route of compound a,b and F-ZrP.
 


2.The results of TGA measurement for all samples.
 

 
3.The LOI and UL-94 test results of PLA, PLA/F-ZrP and PLA/α-ZrP nanocomposites.
 

4.Combustion parameters obtained from cone calorimeter.


5.The digital photographs of the residue char after cone calorimeter test: (a) neat PLA, (b) PLA/F-ZrP 5%, (c) PLA/F-ZrP 10% and (d) PLA/F-ZrP 20%.



6.SEM images of the charred residue after CCT test: (a, b) out surface and inner surface of PLA/F-ZrP 5%, (c, d) out surface and inner surface of PLA/F-ZrP 10%.
 


Conclusion

The cone calorimeter results of PLA/F-ZrP nanocomposite showed low heat release rate(HRR),low total heat release(THR)and high amounts of char residues after combustion.
 
All these results indicated that F-ZrP significantly reduce the flammability of PLA
composites.
 
The SEM images showed that F-ZrP enhance the char quality after combustion, showing a compact and dense intumescent char.
 
This high quality char residues were proposed the main reason for the improvement of flame retardancy in PLA system.
 
(Contents lists available at SciVerse ScienceDirect, from Center for Degradable and Flame-Retardant Polymeric Materials, College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National)