Mechanical, Thermal and Flammability Prosperties of Halloysite Nanotubes Filled Polyamide II

Abstract

Polyamide 11 (PA 11) is a semi-crystalline engineering polymer with excellent impact strength and the ability to accept high filler loading, making it a promising alternative in a variety of applications. However, using PA 11 alone results in lower stiffness and heat resistance, as well as more expensive materials; therefore, reinforcement with halloysite nanotube (HNTs) filler, magnesium hydroxide (MH) flame retardant additives and styrene-ethylene/butylene-styrene grafted maleic anhydride (SEBS-g-MA) elastomers has been considered. The goal of this research is to investigate the effects of HNTs as fillers, MH as flame retardants and SEBS-g-MA as an impact modifier contents on the thermal, mechanical and flammability properties of PA 11. This study used counter-rotating twin-screw extrusion and injection moulding to create nanocomposite samples, which were then characterized by using Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Dynamic Mechanical Analysis (DMA), tensile, flexural, impact, UL-94 standard flammability and limiting oxygen index (LOI). The addition of 4 phr HNTs improved the PA 11 matrix’s thermal, mechanical and flammability properties of the PA 11 matrix. The addition of 30 phr MH flame-retardant additives increased the young’s and flexural modulus by up to 34% and 31%, respectively, but decreased the elongation at break for all formulations. All the nanocomposite samples passed the UL 94 V-2 rating. The addition of 15 phr of SEBS-g-MA increased the elongation at break by 40% and impact strength up to 57%. However, the addition of elastomers reduced tensile and flexural strength. The study discovered that the adding nanofillers, flame retardant additives and elastomer to PA 11 can effectively improve these properties to a desired level, potentially opening new market opportunities for PA 11 manufacturers.