Structure and thermal property of intumescent char produced by flame‐retardant high‐impact polystyrene/expandable graphite/microencapsulated red phosphorus composite

Abstract

Summary This paper is aimed to illustrate the structure and thermal property of intumescent char produced by flame‐retardant polymers containing expandable graphite (EG). For this purpose, high‐impact polystyrene (HIPS) flame retarded by EG individually or in combination with microencapsulated red phosphorus (MRP) was prepared. The results indicate that the intumescent char from HIPS/EG/MRP composite, which contains a small amount of phosphorus element and more oxygen element, is much more compact and continuous than that from HIPS/EG composite with identical loading of flame retardant due to binding effect of phosphoric acid and its derivatives. The intumescent char produced by HIPS/EG/MRP composite exhibits much enhanced thermal and thermo‐oxidative stability as well as thermal‐insulating effect, which can withstand destruction of heat and oxygen effectively and thus provide a good fire‐proof barrier. The temperature beneath this intumescent char is decreased significantly in case of action by flame. By comparison, the porous and loose intumescent char generated by HIPS/EG composite has poor thermo‐oxidative endurance, and most of it can be consumed in air at high temperature without effective protection for the polymer. This has resulted in remarkable increase in flame retardancy of the HIPS/EG/MRP composite.

Butyltriphenylphosphine‐based chelate borates influenced on flame retardancy of polystyrene composite containing self‐expanded intumescent flame retardants

“…The EG swells with exposure to heat due to promotion of gas derived from redox reaction in graphite sheets, and subsequently forms worm‐like char that entangle with each other to construct network. In addition, the phosphates decompose into polyphosphates and fill in gap of graphite sheet to improve thermal stability of network 16,17 . However, more than 20 wt% loading of IFRs is inevitable for PS to achieve self‐extinguishment and anti‐dripping performance.…”

Reactive and Additive Modifications of Styrenic Polymers with Phosphorus-Containing Compounds and Their Effects on Fire Retardance

“…Meanwhile, the solution mixing begins with the dispersion of the additives in a polymeric solution followed by a controlled solvent evaporation and a composite film casting [ 52 ]. The organic and inorganic compounds, multi-component formulations, and a range of nanomaterials are used as the additive FRs for different sub-classes of styrenic polymers [ 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 ...…”

“…The fire-retarding performance of the ABS copolymer with different aryl cyclic phosphorous FRs revealed that the phosphonate compounds were more thermally stable and generated higher char yields as opposed to phosphinates [ 99 ]. There is a range of publications dedicated to synergistic formulations, for HIPS and ABS, containing red phosphorous combined with other additives: EG [ 100 , 101 , 102 ], Mg(OH) 2 [ 103 , 104 , 105 ], and melamine polyphosphate [ 106 ].…”

Flame retardancy effects between expandable graphite and halloysite nanotubes in silicone rubber foam

“…When heated, EG expands and generates a voluminous isolative layer, providing ame retardance for the polymeric matrix. [25][26][27][28] In recent years, EG has been widely used in polyurethane, 29,30 PP, 31,32 PE, 33 polystyrene, 34 epoxy resin 35 and other polymer ame retardant materials and has achieved satisfactory results. However, when EG is used alone in polymer ame retardation, the carbon layer containing EG is loose and porous, thus hindering perfect ame retardation performance.…”