Synthesis and Characterization of Flame Retardant Polyamide 6/clay Nanocomposites for Textiles
H. Wu1, X. L. Yin1, M. Krifa1, M. Londa2, and J. H. Koo2,3
1 School of Human Ecology – Textiles and Apparel, The University of Texas at Austin, Austin, TX 78712, USA
2 Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
3 KAI, LLC, Austin, TX 78739, USA
Abstract
This study is focused on seeking an in-depth knowledge of the FR PA6 nanocomposites with two objectives: 1) optimize the concentration of FR intumescent additives and clay in PA6; 2.) recover the lost ductility of the material while maintaining its flame-retardant properties by using alternative synergistic nanofillers, such as polyhedral oligomeric silsesquioxane (POSS®). This study will be conducted in two phases. In phase 1, a screening design of experiment will be used to identify the optimal of intumescent FR additive and clay to achieve the best formulation from the viewpoint of flame retardancy based on microscale combustion calorimetry (MCC). In the second phase, small amount of POSS will be added into to the FR/clay system in order to recover the lost ductility of the material. A synergistic effect between clay and POSS will also be explored.
FR additives including montmorillonite (MMT) nanoclays and FR intumescent additives will be homogeneously dispersed into PA6 using high shear micro-extruder. The degree of dispersion of FR additives will be explored by transmission electron microscopy (TEM) and high resolution scanning electron microscopy (HRSEM) images demonstrating the fiber surface morphology will also be presented. Mechanical test will be performed using injection molded standard tensile bars (ASTM D638, Type I). Thermogravimetric analysis (TGA) will be used to assess the thermal stability of the processed PA6 nanocomposites. Flammability will be characterized by UL-94 and MCC. Moreover, the morphology and element composition of char residue of FR PA6 nanocomposites after burning will be evaluated by SEM and energy dispersive X-ray microanalysis (EDX) to understand the FR mechanisms.