Flame rating of nano clay/MCC/PLA composites with both reinforced strength and toughness

The mountmorinollite (MMT) nano clay, microcrystalline cellulose (MCC), and poly(Lactic acid) (PLA (MMT/MCC/PLA) composites with reinforced strength and toughness were prepared. This study aimed to develop MMT/MCC/PLA composite with improved thermal stability and flame rating based on reinforced strength and toughness. A simple and efficient method to hydrophobize MCC and intercalate the interlayer of MMT by mobilising cerium oxide nanoparticles (CeO 2 NP) bearing long-chain saturated fatty acid (Myristic acid; MA) to enhance compatibility with the PLA was adopted. The modified MCC (mMCC) and MMT (mMMT) were incorporated into PLA at different wt%. The flaming rating was studied by adding fire retardant (FR) into the composite. The mMCC, mMMT and their composites were characterised by Fourier Transformed Infrared spectroscopy(FTIR), Scanning Electron Microscopy(SEM), X-ray diffraction, Thermogravimetric analysis(TGA), UL-94 test, Limiting Oxygen Index(LOI), and mechanical analysis. FTIR and XRD confirmed the intercalation of MMT with the CeO 2 -MA and the mobilisation of CeO 2 -MA onto the surface of mMCC. SEM study showed the homogenous distribution of mMCC in the PLA matrix and revealed the layered clay structure with the deposition of nanoparticles into the clay interlayer space. The compatibility effect of the MA significantly improved the strength and toughness with more than 100% improvement in tensile strength of mMCC/PLA compared to neat PLA. The flame rating resulted in a 58.8% improvement in the LOI with the addition of the FR. The thermal stability was enhanced by the mMMT and mobility of CeO 2 NP into the interlayer space of the clay. The composite of mMCC/PLA, mMMT/PLA, and mMCC/mMMT/FR/PLA attained a V2, V1 and V0 rating in the UL-94 at a low FR addition. The improvement in fire retardancy did not significantly compromise the mechanical properties. The high mechanical performance of the mMCC/PLA presented MA as a potential fiber-matrix compatibiliser.