Fabrication and Characterization of Halogen-Free Flame Retardant Polyolefin Foams

Abstract

Mayor advances have been made in the field of halogen-free flame retardant composites in the last years, mainly due to increasing regulatory pressures. This paper focuses in aluminium trihydroxide (ATH) as the halogen-free flame retardant and low density polyethylene (LDPE) as the polymer matrix of the fire retardancy foam. The attempt of this article is to achieve a cellular structure by foaming these materials, when high loading levels (up to 60wt %) of ATH are introduced. This is a difficult task due to the high amount of filler in the formulation. The aim is to reduce density without losing thermal and mechanical properties. In order to characterize the cellular structure as well as the thermal, mechanical and combustion properties, a complete study of the foamed samples was made by means of scanning electronic microscopy (SEM), thermogravimetric analysis (TGA), melt flow index (MFI), air pycnometry, mechanical testing at low strain rates, limiting oxygen index (LOI) and calorimeter bomb tests.

Production of non‐crosslinked thermoplastic foams with a controlled density and a wide range of cellular structures

“…Any thermoplastic polymer or thermoplastic based composite or nanocomposite can be foamed by this process without the necessity of crosslinking the polymeric matrix. Up to now, pure polymers such as LDPE or EVA, composites such as LDPE/ATH, EVA/ATH, blends of EVA and starch, and nanocomposites based on LDPE and silica nanoparticles have been successfully foamed using the ICM process …”

Considerations on reaction to fire tests of polyethylene foam with a cone calorimeter apparatus

“…Kasiri et al 18 and Zandi et al 19 investigated non-crosslinked low-density polyethylene foams presenting results on the flammability, amount of dripping during burning test, and burning rate of the samples using Federal Aviation Regulations (FAR) 25.853 standard. Raszkowska-Kaczor et al 20 studied the flammability of crosslinked polyethylene foams by measurements of the oxygen index (OI), whereas a similar approach along with bomb calorimeter tests was used by Roma´n-Lorza et al 21 for characterization of the combustion properties of low-density polyethylene foam, fire retarded with aluminum trihydroxide (ATH). More pertinent to this work is the article of Carosio et al, 22 who investigated the layer-by-layer deposition of flame retardant thin coatings on closed-cell polyethylene terephthalate (PET) foams.…”

Fabrication and characterization of the physical properties of nanocellular polymers: The transition from the micro to the nanoscale

“…El Laboratorio CellMat se creó en 1999 en la Universidad de Valladolid tras la defensa de la primera tesis doctoral dentro de una línea de trabajo sobre propiedades térmicas y mecánicas de espumas de poliolefinas llevada a cabo por Miguel Ángel Rodríguez Pérez y dirigida por el profesor José Antonio de Saja Sáez [38]. A partir de entonces, bajo la dirección del profesor Miguel Ángel Rodríguez Pérez y del profesor José Antonio de Saja Sáez, se han desarrollado veintidós tesis doctorales [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] y se han publicado más de 150 artículos en revistas internacionales en el ámbito de los materiales celulares. En la actualidad CellMat mantiene cinco líneas de investigación principales: polímeros microcelulares y nanocelulares [56][57][58][59], nanocomposites celulares [60][61][62][63], polímeros celulares a partir de bioplásticos [64][65][66], espumas metálicas [67][68][69][70], y desarrollo de nuevas técnicas experimentales y dispositivos para el estudio de los mecanismos de espumado [71][72][73][74].…”