Preparation and properties of polyamide 6 nanocomposites covalently linked with amide functional graphene oxide

Abstract

Chemically engineered polyamide 6 (PA6)/graphene oxide (GO) nanocomposites were produced via the functionalization of GO with an amide (CONH2) functional group, in order to produce amide-GO with improved interfacial bonding and dispersion in the host polymer matrix. In situ polymerization of ε-caprolactam was carried out in the presence of amide-GO to create PA6/amide-GO nanocomposites. The nanomaterial (pre- and post-polymerization) and the composites were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and tensile testing. The single-layer nature of GO was attested by TEM. FTIR, XPS, XRD and thermal analysis techniques confirmed the successful amide modification of GO. The expected attachment of PA6 to the surface of GO is demonstrated, along with the reduction of GO during polymerization. Some reduction of GO during the chemical functionalization process was also observed. The thermal stability of the nanocomposites was confirmed, while promotion of α-phase crystallite formation and a molecular weight change of attached PA6 are observed. A linear improvement in stiffness and yield strength was observed as functionalized GO content increased from 0.1 wt% to 0.75 wt%. A levelling off of mechanical properties ensued once the GO content reached 1 wt%, and a decrease was seen at 2 wt%.

Improvement of electrical, thermal, and mechanical properties of poly(methyl methacrylate)/poly(ethylene oxide) blend using graphene nanosheets

“…Compared with the carbon black or carbon fiber as conductive fillers, graphene layers can form the effective conductive pathway in nanocomposites at low volume fraction because they have high aspect ratio. 1,5 Figure 5 shows the electrical conductivity versus filler concentration for the PMMA/PEO/GnP nanocomposites.…”

“…Graphene, as a monolayer of carbon atoms arranged in a honeycomb network, has recently attracted tremendous attention in the fields of fundamental and applied due to its outstanding physical, chemical, and mechanical properties. 1 –5 The discovery of new nanomaterial graphene by Andre Geim 6 in 2004 with its unique properties has created a new class of polymer nanocomposites and expanded the application of polymers. 7 Polymers have an important role in the industrial applications, but the increasing demand of materials for advanced applications cannot be provided by simple homopolymers.…”

Thermal properties and thermal stability of polypropylene composites filled with graphene nanoplatelets

“…2 Graphene is widely used in industries owing to its excellent physical and mechanical properties such as good conductivity and high specific strength. For example, a small amount of graphene can significantly improve the mechanical properties, 3 –8 electrical properties 9,10 and thermal properties 11,12 of polymer composite materials. O’Neill et al 8 measured the properties of polyamide 6 nanocomposites covalently linked with amide functional graphene oxide (GO) and observed a linear improvement in stiffness and yield strength as functionalized GO content increased from 0.1 to 0.75 wt%.…”

Low‐defect graphene–polyamide‐6 composites and modeling the filler–matrix interface

“…For example, a 20% increase in elastic modulus ( E ) was reported with a graphene concentration of 1%·w/w . Similarly, approximately 25% improvement in E was reported when 1%·w/w amide‐functionalised graphene oxide was compounded with PA6 . Melt‐mixing was also used to incorporate up to 5%·w/w graphene into PA6 prior to melt‐spinning for improved E but reported a reduction in yarn tenacity .…”