Search

In this work, we employed a two-step modification process to improve the properties of 2D bimetallic nanoplates M(OH)(OCH3) (M = Co, Ni), which were recently proven as a promising "nano-flame retardant". The nanoplates were in situ modified with metal-organic framework ZIF-67 first and then silanized with a coupling agent APTES. Epoxy resin (EP) nanocomposites were fabricated using the functionalized M(OH)(OCH3). We investigated the performance of the nanocomposites in flame retardance and thermal stability. The results showed that 3% of APTES@ZIF-67@M(OH)(OCH3) gave the EP nanocomposite the V-1 rating in UL-94 test and the highest limited oxygen index of 27.6%. Moreover, the pHRR value of EP/APTES@ZIF-67@M 3% was reduced by 20.0% and 9.6%, respectively, compared to neat EP and EP/ZIF-67@M 3%. Regarding the mechanical properties, the Tensile properties and energy storage modulus of EP nanocomposite were both improved with 3% of APTES@ZIF-67@M(OH)(OCH3). The GC-MS test results revealed that the functionalized M(OH)(OCH3) significantly increased the cross-linking propensity of the EP matrix upon combustion, leading to the formation of a dense char layer. This study demonstrates the great potential of M(OH)(OCH3) as a highly efficient "nano-flame retardant" with tunable functionality. [ABSTRACT FROM AUTHOR]

A novel bio-flame retardant (PA-B) was prepared based on green materials--banana peel powder (BPP) and phytic acid (PA), then PA-B was used to prepare flame retardant poly(lactic acid) (PLA) composites. The flame retardancy and thermal property of PLA composites were studied. It can be found that the limiting oxygen index (LOI) of PLA composite with 15.0 wt% BPP is 22.1%, showing the heavy dripping during the combustion and failing to reach the vertical burning tests (UL-94) V-0 rating. However, when 15.0 wt% PA-B is added, the LOI is significantly increased to 37.5%, and the composite can reach UL-94 V-0 rating with the dripping problem is obviously reduced. Furthermore, PA-B is helpful to ameliorate the thermal property of PLA composites under the high temperature. The char residue of PLA/PA-B15 is 10.9 wt% at 550.0 °C, showing much higher value than that of PLA/B15 (3.3 wt%) and pure PLA (almost nothing left). From flammability analysis, PA-B not only is a crucial part of promoting the formation of char layer with high quality in the solid phase, which can play a "barrier effect" role to protect the underlying matrix and retard combustion process, but also has the flame retardant effect in the gaseous phase on the basis of PO· free radical. This work provides an efficient way to prepare bio-based flame retardant PLA composites, and also offers a new method to reuse agricultural wastes like banana peel. [ABSTRACT FROM AUTHOR]