Curing behavior, mechanical, and flame‐retardant properties of epoxy‐based composites filled by expandable graphite and ammonium polyphosphate

Abstract

In this study, 4,4 0 -Diaminodiphenyl methane (DDM) was exploited as hardener for diglycidyl ether of daidzein (DGED) and epoxy resin mixture (E-D). The composites were produced by blending with different contents of ammonium polyphosphate (APP) and expandable graphite (EG) into E-D resin, named E-D/A-E composites. Firstly, E-D/A-E blends were analyzed by Fourier transform infrared spectroscopy and DSC to evaluate their curing behavior. The TGA was performed on the E-D/A-E composites to analyze their thermal stability, and the thermal properties of the composites were enhanced by adding APP-EG (A-E) flame retardants. The mechanical properties and the fractured surfaces of the E-D/A-E composites were studied by tensile, impact tests and scanning electron microscopy. Finally, through torch burning test, limiting oxygen index (LOI), vertical burning (UL-94) and micro-calorimetry tests, the influence of A-E flame retardants contents on flammability of composites were evaluated. The results showed that the UL-94 V-0 rating was obtained for the E-D/A-E composites and the composites exhibited a self-extinguishing phenomenon. When A-E flame retardants content reached 9.1 wt%, the LOI value reached 34.5%, and total heat release (Total HR

New Progress in the Application of Flame-Retardant Modified Epoxy Resins and Fire-Retardant Coatings

“…Improves Tg Promotes char formation [45][46][47][48][49][50][51] 3.1.1. POSS Silicon-based flame retardants, including siloxane [28], layered silicate [29], and SiO 2 [30][31][32], have been at the forefront of flame-retardant additives due to their high versatility, compatibility, low toxicity, and environmentally protective qualities [25].…”

“…The family of carbon-based nanomaterials, including carbon nanotubes (CNTs) [45,76], graphene [46,47,77], and expandable graphite (EG) [49][50][51], have been widely used in the preparation of polymer composites. The addition of carbon materials can not only enhance the mechanical properties of the substrate but also give the substrate excellent thermal stability, thermal or electrical conductivity, and fire resistance [78].…”

“…As another well-known carbon-based material, expandable graphite (EG) is a typical expansion flame retardant with an inherent self-expanding graphite flake [93]. When heated, it can expand and form a worm-like carbon layer that acts as a physical barrier to heat transfer, providing the polymer with fire-protection properties [50]. In addition, although EG contributes to the formation of carbon, the carbon structure is not tightly enough [49].…”

Transparent, Hydrolysable and Flame Retarded Bio-based Epoxy Resins via Catalyst-free Polymerization of Triglycidyl Isocyanurate and Aliphatic Diacids

“…However, there is some negative influence in this case, such as poor compatibility between ERs and flame retardant additives, migration of additives from ERs, etc. One of the solutions is to introduce flame retardant segments containing P [13][14][15], N [16][17][18][19], Si [4] or other flame retarded elements [5,20,21] into the backbones or side groups in bio-based ERs. Tailoring compounds with (poly)aromatic structure from biomass to the structure of epoxy building blocks can also improve the flame retardancy of ERs [11,16,22].…”

Enhanced Flame Retardancy of Styrene-Acrylic Emulsion Based Damping Composites Based on an APP/EG Flame-Retardant System

“…Intumescent flame retardants are considered environmentally friendly due to their low toxicity, low smoke, and halogen-free properties. The addition of intumescent flame retardant (IFR) to the polymer matrix has the advantages of being a simple process and providing a significant improvement in flame retardancy [8][9][10][11][12][13][14]. Ammonium polyphosphate (APP) is a type of phosphorus nitrogen flame retardant, which can act as both an acid source and a gas source to provide a synergistic effect to form an expanded protective burnt layer, which serves as a physical barrier to isolate the underlying polymer from heat and flame [15].…”