Diphenolic acid based biphosphate on the properties of polylactic acid: synthesis, fire behavior and flame retardant mechanism
writer：Jing J, Zhang Y, Fang, ZP*
keywords：Diphenolic acid based biphosphate, polylactic acid, synthesis, flame retardant
source：期刊
specific source：Polymer, 2017.1, 108: 29-37
Issue time：2016年
In an effort to impart fire protection properties to polylactic acid
(PLA) utilizing renewable
resources, diphenolic acid, a plant derived compound, was used to synthesize a
phosphate (hereinafter
shortened as FR) that contains two types of phosphorus. The chemical structure
of FR was confirmed by 1H NMR and 31P NMR, respectively. UL-94 V0 rating and LOI
value of 27.4 for
PLA were achieved at the FR loading content of 16 wt%. Besides, the heat
release rate and total heat release of the flame retardant PLA were decreased remarkably
in cone calorimetric tests. The significantly increased CO/CO2 ratio
in cone tests and the presence of phosphorous containing compound in gas phase in
TG-FIR tests confirmed that the gas phase mechanism is mainly responsible for the improved flame
retardant performance. Differential scanning calorimetric analysis showed the
glass transition temperature of PLA composites have no change indicating no
plasticizing effect of the FR. Finally, the tensile tests revealed that the
ductility of PLA was sustained and tensile strength was depressed in a minimal
content after the phosphate was incorporated. This
work suggests a novel green strategy for improving flame retardancy performance
of PLA and promoting the utilization of sustainable resource.