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Synthesis and characterization of isosorbide-based polyphosphonates as biobased flame-retardants.



Mauro Zammarano, Timothy C. Mauldin, Jeffrey W. Gilman, John R. Shields, Dylan B. Timothy


A new isosorbide-based polyphosphate was synthesized and applied as a flame-retardant for polylactic acid (PLA). The storage modulus and glass transition temperature of PLA is unaffected by the inclusion of polyphosphonate, but moderate depressions of PLA’s tensile strength (16 %, 28 %, and 45 % reduction from PLA at a polyphosphonate mass fraction of 5 %, 10 %, and 15 %, respectively) and strain-at-break (0 %, 17 %, and 30 % reduction from PLA at a polyphosphonate mass fraction of 5 %, 10 %, and 15 %, respectively) were observed. UL 94 flammability testing indicated that isosorbide- based polyphosphonates are effective flame retardants for PLA that are able to self-extinguish flames in less than 2 s and achieve V2 and V0 ratings at polyphosphonate mass fraction of 5 % and 15 %, respectively. Mechanisms for isosorbide-based polyphosphonate flame retardancy are discussed. Use of the biobased flame retardants described herein yields flame retardant PLA containing up to 97 % by mass of bio-derived content.
Polymer Chemistry


Polylactid acid, biobased, flame retardants
Created June 2, 2014, Updated November 10, 2018