Modified halloysite nanotubes (HNT) used as part of a flame retardant system for a LLDPE/EVA blend
Résumé
Cable industry is continuously improving the mechanical, electrical and fire properties of their sheaths
in order to keep competitive. For building applications, flexibility is a big issue while keeping good
fire properties. The objective of the present project, funded by the French National Research Agency
(ANR), aims at dispersing modified HNT into LLDPE/EVA blend to improve mechanical and ageing
properties with appropriate fire behavior. HNT, a tubular aluminosilicate clay, has gain much attention
thanks to its numerous interesting properties. Especially, its tubular shape allows to encapsulate
different molecules into the lumen (internal diameter of 10-20 nm) for several applications:
anticorrosion, antimicrobial, drugs, flame-retardant, microcrack self-healing. Especially, lumen can
contain encapsulated molecules to be used as a flame retardant system (in combination with other
additives) in polymer blends. Hence, the objectives of the project are: (1) to encapsulate molecules
into the lumen that can play the role of a flame retardant system for LLDPE/EVA, (2) to functionalize
the inner and/or outer surface of the HNT to selectively disperse it either in LLDPE or in EVA, in order
to see the influence of the selective dispersion in mechanical and fire properties. This presentation
will firstly explains how native HNT thermally degrade EVA copolymers during the melt mixing process.
The second objective of the presentation is to explain how 3-aminopropyltriethoxysilane modified
halloysite nanotubes are selectively dispersed into the LLDPE/EVA blend. Finally, the mechanical and
fire properties of different LLDPE/EVA/HNT blend nanocomposites are compared.