(193ae) Flammability and Structural Characterization of PE/EVA Blends Containing Keratin and DNA As a Flame Retardant Combinations

FLAMMABILITY
AND STRUCTURAL CHARACTERIZATION OF PE/EVA BLENDS CONTAINING KERATIN AND DNA AS
A FLAME RETARDANT COMBINATIONS

S. Sánchez-Valdes
¹, E. Ramírez-Vargas ¹, J. Albite-Ortega ¹, Y.
Nuñez-F ¹, R. Ramírez-Vargas ¹

CIQA,
Saltillo, Coahuila, México

(S. Sánchez,
tel: 8444389839 email: saul.sanchez@ciqa.edu.mx)

ABSTRACT

The
combination of keratin fibers obtained from feathers, with deoxyribose nucleic
acid (DNA) applied as a coating with a segregated structure on filler
dispersion and flame retardant properties of low-density polyethylene-ethylene
vinyl acetate (LDPE/EVA) blends was investigated. A maleic anhydride modified
polyethylene (PEgMA) was used as compatibilizer. The thermal stability and
flame retardant properties were evaluated by limiting oxygen index (LOI), cone
calorimeter determinations and flammability test (Underwriters Laboratory -
UL-94). The structural characterization was carried out by FTIR and scanning
electron microscopy in transmission mode (STEM). The mechanical properties were
also evaluated. The effect of coating procedure, direct melt compounding or
segregated structure deposition, on DNA dispersion and flame-retardant behavior
was discussed. The results indicated that the DNA deposition method of
segregated structure promoted the best flame retardant behavior and that the
incorporation of keratin fibers enhanced the mechanical performance of the
nanocomposites. It was demonstrated that DNA induced a char foamed layer that
was able to quite efficiently protect the blend polymer matrix against heat, reducing
the combustion kinetics. The thermal stability of PE/EVA blends increased to a
higher extent when using these filler combinations.