Organic–inorganic hybrid flame retardant: preparation, characterization and application in EVA

Abstract

A novel organic-inorganic hybrid flame retardant (DOPA-ATH), which was prepared via reacting dibenzo [c,e][1,2]oxaphosphinic acid (DOPA) with aluminum trihydroxide (ATH), was incorporated in ethylenevinyl acetate copolymer (EVA) to improve its flame retardance. The structure, morphology and thermal stability of the hybrid flame retardant were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results suggested that DOPA was grafted onto ATH successfully, therefore resulting in higher thermostability than ATH. The flame retardance and burning behaviour of EVA with DOPA-ATH were also studied using limiting oxygen index (LOI), Underwriter laboratory 94 vertical burning test (UL-94 V) and cone calorimeter test (CCT). Results of UL-94 tests and LOI tests showed that the flame retardance of EVA/DOPA-ATH was better than EVA/ATH binary and EVA/DOPA/ ATH ternary flame-retardant composites. The data obtained from the CCT showed that the peak heat release rate (PHRR) of EVA with the addition of 50 wt% DOPA-ATH was reduced by about 25% comparing with EVA with equivalent ATH. Total heat release (THR) and total smoke production (TSP) were reduced remarkably as well. The thermogravimetric analysis (TGA) data showed that the thermal stability of EVA/DOPA-ATH was improved with increased initial decomposition temperature and char residue. SEM observations of cryogenically fractured and tension fractured surfaces showed that EVA/ DOPA-ATH had better interfacial interaction comparing with those of EVA/ATH and EVA/DOPA/ATH, which resulted in better elongation at break and tensile strength.

Insight into Hyper-Branched Aluminum Phosphonate in Combination with Multiple Phosphorus Synergies for Fire-Safe Epoxy Resin Composites

“…In the gaseous phase, the notable phenomenon is the generation of a so-called "blowing-out effect", which is consistent with the above-mentioned combustion process and in accordance with previous reports [33,47]. It is noteworthy that the enormous improvement in fire safety for the EP/DOPO-AHPP composites, derived from LOI, UL-94, and cone calorimeter results, are probably connected with the continuous and compact residues, which can avoid oxygen from feeding the fire and inhibit the release of flammable gas, thus resulting in the relatively low THR and TSP of EP/DOPO-AHPP [48]. Therefore, the condensed mechanism and gaseous mechanism for flame retardance and smoke toxicity suppression between AHPP and DOPO are verified, and the former one is dominant in EP/DOPO-AHPP composites.…”

Improving the flame resistance and thermal conductivity of ethylene‐vinyl acetate composites by incorporating hexachlorocyclotriphosphazene‐modified graphite and carbon nanotubes

“…TGA curves of EVA, EVA80/G20, EVA80/M‐GO20, and EVA80/M‐GO18/M2 composites under air atmosphere are shown in Figure . For both neat EVA and EVA composites, similar two‐step degradation can be observed, which corresponding to the decomposition of branched chain and main chain in EVA molecules . Compared with neat EVA, the sample containing 20% graphite shows nearly superimposable degradation pathway before 450°C, but the residue amount after 600°C is increased sharply.…”

Morphology development of PP/POE blends with high loading of magnesium hydroxide

“…But even at the 50/50 PP/POE ratio, the tensile strength is still larger than 10 MPa. This indicates that acceptable mechanical properties can be achieved for halogen free flame retardant (HFFR) materials even at high loading of inorganic fillers, such as MDH and ATH (aluminium trihydroxide) [63] .…”