Preparation and properties of nylon 11/ethylene‐vinyl alcohol/montmorillonite ternary composites

Abstract

It is known that polyamide 11 (PA11) is widely used in aviation, automobile, oil pipeline, gas engineering and other fields because of its excellent performance. However, pure PA11 as a carrier material of gas or liquid, its mechanical properties and barrier performance can not fully meet the application requirements in some circumstances, such as in narrow confined space or transporting flammable liquids. In this work, ternary blends were prepared by twin-screw extruder with PA11, ethylene-vinyl alcohol (EVOH) and modifier montmorillonite (MMT). The mechanical property, barrier functions, flame retardant performance and rheology of composites were studied. In comparison with those of the pure PA11, the impact properties, barrier properties and combustion intensity of ternary composites were significantly improved. Among them, the impact strength of the ternary composites (PA11/EVOH/ MMT = 67.5/22.5/10 wt%) was increased by 58% and the oil absorption value and peak heat release rate (PHRR) at this ratio were 0.190 and 164.124 w•g −1 , which were 23% and 43% of pure PA11, respectively. The addition of MMT had no obvious effect on ignition performance. All ternary composites were pseudo-plastic fluids and exhibited shear-thinning. SEM observation confirmed that composite materials changed from exfoliated composites to intercalated composites with an increase of the MMT content. The work offered the possibility of exploiting a high barrier performance low-cost polymer.