Poly(lactic acid)-poly(methyl methacrylate) blends and nanocomposites with flame retardant properties
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Date
2016-06
Authors
Joyce Michael Retnasingam
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Abstract
Blends of poly(lactic acid) (PLA) and poly(methyl methacrylate) (PMMA) with triaryl phosphate flame retardant (Reofos 50; 10-20 part per hundred resin) were prepared by melt compounding technique. 5 phr of Halloysite Nanotube (HNT) and triphenyl phosphate (TPP) were added in PLA/PMMA/R50 blends as flame retardant agent and the combustion resistance effects were studied. Flammability and thermal stability were investigated through Underwriter Laboratory (UL-94) vertical burning test and by using thermogravimetric analyzer (TGA) and differential scanning calorimeter (DSC). Surface morphology of residual chars was also evaluated applying the scanning electron microscopy (SEM) technique. This study found that the inclusion of HNT and TPP in PLA/PMMA/R50 blends behaved as a very good flame retardant blend as V-0 rating in UL-94 test was achieved. The morphological structures observed by scanning electron microscopy (SEM) demonstrated that HNT and TPP promoted formation of the continuous and compact intumescent char layer. The TGA and DSC analyses showed that the onset decomposition temperature (To) and glass transition temperature (Tg) of PLA/PMMA blends were shifted to lower temperature by the addition of Reofos 50 and TPP. The incorporation of HNT in PLA/PMMA/R50 blend had reduced the thermal stability of PLA/PMMA/R50-10 blend but enhanced the char yield of the nanocomposites. The addition of TPP into PLA/PMMA/R50-10 blend had broaden the thermal decomposition temperature range as well as stabilized and delayed the thermal degradation process of PLA/PMMA/R50-10 blend at a higher temperature.